bohomolets pediatric lecture of cardiovascular

PECULIAR ANATOMIC AND PECULIAR ANATOMIC AND PHYSIOLOGICAL FEATURES OF PHYSIOLOGICAL FEATURES OF CARDIOVASCULAR SYSTEM IN CARDIOVASCULAR SYSTEM IN

CHILDRENCHILDREN

LECTURES FOR FOREIGN STUDENTS OF LECTURES FOR FOREIGN STUDENTS OF THE THIRD YEAR OF STUDYTHE THIRD YEAR OF STUDY

Prof. T.V. PochinokProf. T.V. Pochinok

National Ukrainian O.O. Bohomolets Medical National Ukrainian O.O. Bohomolets Medical University University

The main functions of the organs of The main functions of the organs of CARDIOVASCULAR SYSTEM IN CHILDRENCARDIOVASCULAR SYSTEM IN CHILDREN

consist in maintaining the consist in maintaining the homeostasis of the body, supplying homeostasis of the body, supplying the organs and the tissues with the the organs and the tissues with the

oxygen and the nutrients, and oxygen and the nutrients, and eliminating carbon dioxide and the eliminating carbon dioxide and the

products of the metabolism.products of the metabolism.

Embryogenesis of Embryogenesis of cardiovascular systemcardiovascular system

In the course of embryogenesis of In the course of embryogenesis of cardiovascular system, the vessels cardiovascular system, the vessels are formed the first. are formed the first.

Within the second week of the Within the second week of the embryonic development, the clusters embryonic development, the clusters of the cells known as blood islands, of the cells known as blood islands, which later give the origin to the blood which later give the origin to the blood vessels appear in mesoderm. vessels appear in mesoderm.

Continuation Continuation

The development of the heart from the part of the The development of the heart from the part of the mesoderm begins since the third week of the mesoderm begins since the third week of the embryonic development.embryonic development.

In the presumptive region of the neck, two In the presumptive region of the neck, two primary endocardial tubes are formed.primary endocardial tubes are formed.

The growing endocardial tubes approach one The growing endocardial tubes approach one another and finally fuse, the septum between them another and finally fuse, the septum between them resolves resulting in the tubular primitive heart resolves resulting in the tubular primitive heart structure.structure.

The internal layer of the tube is referred to as The internal layer of the tube is referred to as endocardium, the external layer – epimyocardium. endocardium, the external layer – epimyocardium.

ContinuationContinuation

The external layer develops later into the The external layer develops later into the muscular layer ormuscular layer or myocardium, and the external myocardium, and the external envelope, epicardium. envelope, epicardium.

The internal layer gives rise to endocardium. The internal layer gives rise to endocardium. The broadened caudal end of the heart tube forms The broadened caudal end of the heart tube forms

the venous sinus receiving the primary veins. the venous sinus receiving the primary veins. Cranial part of the heart tube is named as the Cranial part of the heart tube is named as the

cardiac bulb, from which later the arterial trunk cardiac bulb, from which later the arterial trunk originates. originates.

The middle part of the heart tube dilates The middle part of the heart tube dilates generating the ventricles and the atria.generating the ventricles and the atria.


The tube grows intensively within the third The tube grows intensively within the third week of the embryonic development bending into week of the embryonic development bending into S-shape. S-shape.

The heart turns around the axis approaching the The heart turns around the axis approaching the frontal one. frontal one.

The part of the heart between the atrium and the The part of the heart between the atrium and the ventricle narrows initiating the formation of the ventricle narrows initiating the formation of the atrioventricular orifice.atrioventricular orifice.

In the middle of Week 4, two primordial In the middle of Week 4, two primordial chambers of the heart are generated. chambers of the heart are generated.


Throughout Weeks 4-5, the partitioning of the Throughout Weeks 4-5, the partitioning of the atrium begins with the appearance of the atrium begins with the appearance of the interatrial septum with the oval foramen.interatrial septum with the oval foramen.

The oval foramen contains the valve on its left The oval foramen contains the valve on its left side.side.

Since the 4th week, the conducting system of the Since the 4th week, the conducting system of the heart begins to generate with its major heart begins to generate with its major structures, namely sinoatrial (Keith-Flack's) structures, namely sinoatrial (Keith-Flack's) node, atrioventricular (Aschaff-Tawara) node, node, atrioventricular (Aschaff-Tawara) node, atrioventricular (His) bundle, and Purkyne atrioventricular (His) bundle, and Purkyne fibers. fibers.


Meanwhile, in the embryonic heart, the Meanwhile, in the embryonic heart, the additional bundles of the conducting additional bundles of the conducting system are found out:system are found out:

1.1. left and right Kent's bundles between the left and right Kent's bundles between the atria and the ventricles; atria and the ventricles;

2.2. James bundle connecting the atria with James bundle connecting the atria with the atrioventricular node; the atrioventricular node;

3.3. Mihime's bundle connecting the Mihime's bundle connecting the atrioventricular node with the atrioventricular node with the myocardium of the ventricles.myocardium of the ventricles.


All these additional bundles degenerate before All these additional bundles degenerate before the birth. the birth.

Meanwhile, in 0.2% of the adults these Meanwhile, in 0.2% of the adults these embryonic conducting paths partially embryonic conducting paths partially preserve. preserve.

The preservation of the embryonic elements of The preservation of the embryonic elements of heart conducting system may be the cause of heart conducting system may be the cause of the paroxysmal tachycardia and arrhythmia the paroxysmal tachycardia and arrhythmia in the children.in the children.


Within the 5th week of the embryonic Within the 5th week of the embryonic development, the interventricular development, the interventricular septum is formed growing from the septum is formed growing from the apex towards the atrium. apex towards the atrium.

For some time, the foramen between For some time, the foramen between the ventricles exists. the ventricles exists.

Later on, the interventricular foramen Later on, the interventricular foramen overgrows with the connective tissue. overgrows with the connective tissue.


Within the 7Within the 7thth week, the partition week, the partition of the ventricles comes to an end. of the ventricles comes to an end.

At the same time, the common At the same time, the common arterial trunk separates to aorta arterial trunk separates to aorta and the pulmonary trunk. and the pulmonary trunk.


The formation of the valves of the The formation of the valves of the heart follows the formation of the heart follows the formation of the septa. septa.

The valves grow as the The valves grow as the duplicators of the endocardial duplicators of the endocardial layer. layer.


At the end of Weeks 7-8, the heart At the end of Weeks 7-8, the heart has the four-chamber structure.has the four-chamber structure.

Since the 8th week, the heart Since the 8th week, the heart descends from the germinal descends from the germinal position in the presumptive neck position in the presumptive neck region into the thoracic cavity. region into the thoracic cavity.

The peculiarities of the fetal blood The peculiarities of the fetal blood circulationcirculation

Throughout the fetal stage of Throughout the fetal stage of development, the maternal blood development, the maternal blood supplies the fetus with oxygen and supplies the fetus with oxygen and nutrients and carries away carbon nutrients and carries away carbon dioxide through the placental blood dioxide through the placental blood circulation. circulation.

The fetal tissues are supplied with the The fetal tissues are supplied with the mixture of arterial and venous blood.mixture of arterial and venous blood.


Several specific paths of blood circulation exist in Several specific paths of blood circulation exist in the fetus, in particular ductus arteriosus the fetus, in particular ductus arteriosus (Botallo's duct), ductus venosus (Arantius' duct), (Botallo's duct), ductus venosus (Arantius' duct), and the oval foramen. and the oval foramen.

The pulmonary circuit is absent in fetus.The pulmonary circuit is absent in fetus. The period of the placental blood circulation The period of the placental blood circulation

begins at the end of the second – at the beginning begins at the end of the second – at the beginning of the third months of the fetal stage of of the third months of the fetal stage of development.development.

Placental blood Placental blood circulation of fetuscirculation of fetus

The arterial blood collecting from The arterial blood collecting from the villi of placenta enters the body the villi of placenta enters the body of the fetus via the umbilical veinof the fetus via the umbilical vein

The length of the umbilical cord at The length of the umbilical cord at the end of the fetal stage of the end of the fetal stage of development amounts to 50 cm.development amounts to 50 cm.


The umbilical vein runs to the hilus of liver and The umbilical vein runs to the hilus of liver and divides into two branches. divides into two branches.

One of them, Arantius' duct joins the inferior One of them, Arantius' duct joins the inferior vena cava. There, the oxygenated blood from the vena cava. There, the oxygenated blood from the placenta is mixed with the deoxygenated venous placenta is mixed with the deoxygenated venous blood from the lower parts of the body. blood from the lower parts of the body.

Another branch that joins the portal vein carries Another branch that joins the portal vein carries the oxygen-saturated blood diluted partially by the oxygen-saturated blood diluted partially by the venous blood to the liver. the venous blood to the liver.

Then the blood flows to inferior vena cava via Then the blood flows to inferior vena cava via the hepatic vein.the hepatic vein.


The blood from inferior vena The blood from inferior vena cava enters the right atrium. cava enters the right atrium. The blood from the head and The blood from the head and the upper limbs also enters the the upper limbs also enters the right atrium via superior vena right atrium via superior vena cava. cava.


The blood from the right atrium The blood from the right atrium enters the aorta by two paths:enters the aorta by two paths:

a) through the oval foramen from the a) through the oval foramen from the right atrium to the left one, and then right atrium to the left one, and then to the left ventricle and the ascending to the left ventricle and the ascending aorta;aorta;


b) a portion of blood (about 10%) runs b) a portion of blood (about 10%) runs from the right atrium to the right ventricle from the right atrium to the right ventricle and then to the pulmonary trunk. Since and then to the pulmonary trunk. Since the pulmonary circuit in fetus does not the pulmonary circuit in fetus does not operate and the pulmonary blood vessels operate and the pulmonary blood vessels have a high resistance to flow, this portion have a high resistance to flow, this portion of the blood is directed from the of the blood is directed from the pulmonary trunk to the arterial arch via pulmonary trunk to the arterial arch via ductus arteriosus (Botallo's duct).ductus arteriosus (Botallo's duct).


The blood directing to the lower part of the The blood directing to the lower part of the body and the lower limbs runs through the body and the lower limbs runs through the celiac arteries; celiac arteries;

The blood outflows from the body of the fetus The blood outflows from the body of the fetus via the arterial arteries comprising the via the arterial arteries comprising the umbilical cord, and returns to the placenta. umbilical cord, and returns to the placenta.

About 65% of blood returns to the placenta.About 65% of blood returns to the placenta.


The first contraction of the fetal heart takes place The first contraction of the fetal heart takes place in the 4-th week of the intrauterine development.in the 4-th week of the intrauterine development.

First, the fetal heart rate is rather low – 15-35 First, the fetal heart rate is rather low – 15-35 beats per minute. beats per minute.

As soon as the placental circulation is formed, the As soon as the placental circulation is formed, the heart rate increases up to 125-130 beats per heart rate increases up to 125-130 beats per minute. minute.

Such a rhythm is rather stable in normal Such a rhythm is rather stable in normal gestation while in pathological conditions the gestation while in pathological conditions the deceleration or the acceleration of the fetal heart deceleration or the acceleration of the fetal heart rate is possible.rate is possible.


The liver, the head, and the upper The liver, the head, and the upper part of fetal body obtain the blood, part of fetal body obtain the blood, which is more saturated with oxygen which is more saturated with oxygen and the nutrients providing for more and the nutrients providing for more intensive development of these parts intensive development of these parts of the body as compared with the of the body as compared with the pelvic organs and the lower limbs.pelvic organs and the lower limbs.

Peculiar features of newborn Peculiar features of newborn bloodblood circulation circulation

The placental blood circulation finishes.The placental blood circulation finishes. The fetal blood communications are The fetal blood communications are

closed.closed. The pulmonary circuit becomes operative The pulmonary circuit becomes operative

in full extent.in full extent. The vascular resistance of the pulmonary The vascular resistance of the pulmonary

blood vessels decreases 5-10 fold.blood vessels decreases 5-10 fold. The systemic vascular pressure increases.The systemic vascular pressure increases.

Newborn blood Newborn blood circulationcirculation

Soon after the birth, the blood Soon after the birth, the blood circulation system rearranges.circulation system rearranges.

The vascular resistance of the The vascular resistance of the pulmonary blood vessels pulmonary blood vessels decreases 5-fold by the first and decreases 5-fold by the first and 10-fold by the second month of 10-fold by the second month of the postnatal life. the postnatal life.


An increased amount of blood flows An increased amount of blood flows from the right atrium to the right from the right atrium to the right ventricle and into the pulmonary ventricle and into the pulmonary arteries. arteries.

The increased left atrial pressure and The increased left atrial pressure and decreased right atrial pressure causes decreased right atrial pressure causes the closure of the foramen ovale by the closure of the foramen ovale by the valve. the valve.


The flow of the blood from the The flow of the blood from the right atrium to the left one right atrium to the left one terminates. terminates.

Within two weeks after the birth, Within two weeks after the birth, the foramen ovale is joined with the foramen ovale is joined with the valve resulting in the the valve resulting in the anatomical closure of the foramen anatomical closure of the foramen within 5-7 months after the birth. within 5-7 months after the birth.


Sometimes, the foramen ovale is Sometimes, the foramen ovale is present anatomically for a long present anatomically for a long period: in 50% of the children up to period: in 50% of the children up to the end of the first year of life; the end of the first year of life; in 15 - 30% of persons, the foramen in 15 - 30% of persons, the foramen ovale is present throughout the life. ovale is present throughout the life.

The open foramen ovale may be the The open foramen ovale may be the cause of the congenital heart defects. cause of the congenital heart defects.


Within the first minutes after Within the first minutes after birth, Arantius' duct is closed.birth, Arantius' duct is closed.

Nevertheless, the complete Nevertheless, the complete obliteration of ductus venosus obliteration of ductus venosus occurs within 8 weeks.occurs within 8 weeks.

With the first breath of the With the first breath of the newborn child, the spasm of newborn child, the spasm of ductus arteriosus occurs.ductus arteriosus occurs.


Meanwhile, ductus arteriosus operates Meanwhile, ductus arteriosus operates throughout first eight hours of the postnatal life throughout first eight hours of the postnatal life providing for two-side outflow of the blood from providing for two-side outflow of the blood from aorta to the pulmonary artery.aorta to the pulmonary artery.

The anatomical obliteration of ductus arteriosus The anatomical obliteration of ductus arteriosus completes within 6-8 weeks of the postnatal life. completes within 6-8 weeks of the postnatal life.

Sometimes, ductus arteriosus as well as other Sometimes, ductus arteriosus as well as other fetal blood communication do not completely fetal blood communication do not completely close resulting in formation of the congenital close resulting in formation of the congenital heart defects.heart defects.

Anatomical features of Anatomical features of heart in childrenheart in children

The heart of the newborn makes up to The heart of the newborn makes up to 0.8% of body mass (in adults only 0.4%). 0.8% of body mass (in adults only 0.4%).

The atria and the cardinal vessels in the The atria and the cardinal vessels in the newborns are somehow larger than the newborns are somehow larger than the ventricles. ventricles.

In the newborns, the right ventricle is the In the newborns, the right ventricle is the same by its size as the left one, with the same by its size as the left one, with the thickness of the walls being of 5 mm. thickness of the walls being of 5 mm.


When the child growth, the left ventricle When the child growth, the left ventricle becomes the predominated one with the ratio of becomes the predominated one with the ratio of right to left ventricle shifting in the following right to left ventricle shifting in the following way: 1:1.5 at the age of one year; 1:2 – at the age way: 1:1.5 at the age of one year; 1:2 – at the age of five years; 1:2.76 at the age of 14. of five years; 1:2.76 at the age of 14.

The thickness of the wall in the left ventricle The thickness of the wall in the left ventricle increases 3-fold with the age while the thickness increases 3-fold with the age while the thickness of the wall in the right ventricle increases only by of the wall in the right ventricle increases only by a third. a third.


At the age of 8 months the two-fold increase of At the age of 8 months the two-fold increase of heart mass is recorded; at the age of three years heart mass is recorded; at the age of three years the heart increases 3-fold, and at the age of 15, the heart increases 3-fold, and at the age of 15, the heart increases ten-fold. the heart increases ten-fold.

The minimal ratio of heart mass to body mass is The minimal ratio of heart mass to body mass is evident at the age of 5-6 months, in boys at the evident at the age of 5-6 months, in boys at the age of 8 years and in girls at the age of 12 years. age of 8 years and in girls at the age of 12 years. Therefore, at the periods indicated, the heart is Therefore, at the periods indicated, the heart is maximally vulnerable to the physical and maximally vulnerable to the physical and psychoemotional loads.psychoemotional loads.


The growth of different divisions of the heart The growth of different divisions of the heart is not uniform.is not uniform.

Up to the age of two years, the atria grow Up to the age of two years, the atria grow more intensively.more intensively.

After 10 years the ventricles grow After 10 years the ventricles grow predominantly. predominantly.

The size of the heart in boys is superior to that in girls The size of the heart in boys is superior to that in girls except for the age of 13-15 when the girls overrun the except for the age of 13-15 when the girls overrun the

boys in their growthboys in their growth. .


Up to the age of six years, the heart is round Up to the age of six years, the heart is round in the shape. in the shape.

Later on, the shape of the heart becomes oval.Later on, the shape of the heart becomes oval. Up to the age of 2-3 years, the position of the Up to the age of 2-3 years, the position of the

heart on the diaphragm is horizontal. heart on the diaphragm is horizontal. The right ventricle is adjacent to the thoracic The right ventricle is adjacent to the thoracic

wall generating for the most part the apical wall generating for the most part the apical impulse of the heart. impulse of the heart.


At the age of 3-4 years, the thoracic cavity At the age of 3-4 years, the thoracic cavity increases, the diaphragm descends, and the increases, the diaphragm descends, and the thymus reduces in size. thymus reduces in size.

As a result, the heart occupies the oblique As a result, the heart occupies the oblique position turning around its long axis, the left position turning around its long axis, the left ventricle forward. ventricle forward.

At this time, the heart impulse is generated At this time, the heart impulse is generated mainly by the left ventricle. mainly by the left ventricle.

Later on, the heart occupies the vertical position Later on, the heart occupies the vertical position in the thoracic cavity. in the thoracic cavity.


Due to the change in the shape and the Due to the change in the shape and the position of the heart, the apical impulse position of the heart, the apical impulse shifts with the age. shifts with the age.

In the newborn, the apical impulse is In the newborn, the apical impulse is assessed in the fourth intercostals space, assessed in the fourth intercostals space, 2 cm outwards from the left middle 2 cm outwards from the left middle clavicular line. clavicular line.


At the age of 3-7 years, the position of the At the age of 3-7 years, the position of the apical impulse shifts to the fifth apical impulse shifts to the fifth intercostals space, 1 cm outwards from the intercostals space, 1 cm outwards from the left middle clavicular line. left middle clavicular line.

At the age of 7-12 years, the apical impulse At the age of 7-12 years, the apical impulse is assessed in the fifth intercostals space, is assessed in the fifth intercostals space, 0.5 cm inwards from the left middle 0.5 cm inwards from the left middle clavicular line. The same position is in clavicular line. The same position is in adults.adults.

Main features of the Main features of the internal structure of heart internal structure of heart

in the childrenin the children Myocardium in the newborns follows the Myocardium in the newborns follows the

embryonic patterns of the structure representing embryonic patterns of the structure representing undifferentiated symplast rich in vacuoles.undifferentiated symplast rich in vacuoles.

The muscular fibers of the myocardium are thinThe muscular fibers of the myocardium are thin The longitudinal fibrillarity and the transverse The longitudinal fibrillarity and the transverse

striation are not pronounced, striation are not pronounced, The number of nuclei is high, while the nuclei are The number of nuclei is high, while the nuclei are

small and low differentiated, therefore the small and low differentiated, therefore the myocardium does not look as a compact myocardium does not look as a compact structure.structure.

Functions of heartFunctions of heart

The heart pumps the blood to the aorta, the The heart pumps the blood to the aorta, the pulmonary artery, the systemic and the pulmonary artery, the systemic and the pulmonary circuits of circulation. pulmonary circuits of circulation.

The indices of the pumping function of the heart The indices of the pumping function of the heart are the systolic (stroke) volume and the cardiac are the systolic (stroke) volume and the cardiac output. output.

The stroke volume increases with the age due to The stroke volume increases with the age due to increasing capacity of the myocardium of the left increasing capacity of the myocardium of the left ventricle. The increase in the cardiac output is ventricle. The increase in the cardiac output is less intensive because the heart rate decreases less intensive because the heart rate decreases with the age with the age


The connective tissue in the myocardium is The connective tissue in the myocardium is poorly developedpoorly developed

The elastic fibers are practically absent The elastic fibers are practically absent (they appear at the age of 7 years).(they appear at the age of 7 years).

The vascularity of the myocardium is well The vascularity of the myocardium is well developed, later on the vasculature of the developed, later on the vasculature of the myocardium decreases. myocardium decreases.


The myocardium of the atria consists of The myocardium of the atria consists of two layers of the muscular fibers: circular two layers of the muscular fibers: circular and elongated.and elongated.

The myocardium of the ventricles consists The myocardium of the ventricles consists of three layers of the muscular fibers: two of three layers of the muscular fibers: two spiral, shared for two ventricles and one spiral, shared for two ventricles and one circular, separate for each ventricle.circular, separate for each ventricle.


The conducting system is not yet perfect.The conducting system is not yet perfect. The myocardium differentiate The myocardium differentiate

substantially with the age, the connective substantially with the age, the connective tissue develops intensively, the muscular tissue develops intensively, the muscular fibers thicken. fibers thicken.

The development of the myocardium The development of the myocardium finishes at the beginning of the pubertant finishes at the beginning of the pubertant period. period.


The heart pumps the blood to the The heart pumps the blood to the aorta, the pulmonary artery, the aorta, the pulmonary artery, the systemic and the pulmonary circuits systemic and the pulmonary circuits of circulation. of circulation.

The indices of the pumping function The indices of the pumping function of the heart are the systolic (stroke) of the heart are the systolic (stroke) volume and the cardiac output.volume and the cardiac output.


The stroke volume increases with the The stroke volume increases with the age due to increasing capacity of the age due to increasing capacity of the myocardium of the left ventricle. myocardium of the left ventricle.

The increase in the cardiac output is The increase in the cardiac output is less intensive because the heart rate less intensive because the heart rate decreases with the age decreases with the age

Table 1. The systolic (stroke)Table 1. The systolic (stroke) volume volume and the cardiac output of the heart in and the cardiac output of the heart in the children (after A.V. Mazurin, I.V. the children (after A.V. Mazurin, I.V.

Vorontsov, 1999)Vorontsov, 1999)

AgeAge Systolic volumeSystolic volume Cardiak outputCardiak output

mlml ml/kgml/kg mlml ml/kgml/kg

newbornnewborn 3,03,0 0,90,9 420420 120120

11 10,210,2 1,01,0 11731173 117117

77 23,023,0 1,01,0 19551955 8585

1212 41,041,0 1,151,15 30753075 8585

13 - 1613 - 16 59,059,0 1,21,2 44254425 9292


The second function of the heart, contractile one, The second function of the heart, contractile one, is characterized by the heart rate. is characterized by the heart rate.

The heart rate decreases with the age: The heart rate decreases with the age: = in the newborns the heart rate is 140-160 = in the newborns the heart rate is 140-160 per min; per min;

= at the age of 6 months – 130-135 per min; = at the age of 6 months – 130-135 per min; = at the age of one year – 120-125; = at the age of one year – 120-125; = at the age of 5 years – 100; = at the age of 5 years – 100;

= at the age of 10 years – 80-85; = at the age of 10 years – 80-85; = at the age over 12 years – 70-75; = at the age over 12 years – 70-75; = in the adults – 65-75 per min. = in the adults – 65-75 per min.


The high values of heart rate in the The high values of heart rate in the children result from domination of the children result from domination of the sympathetic heart innervation. sympathetic heart innervation.

For young children, the sinus arrhythmia For young children, the sinus arrhythmia is typical expressing as the deceleration of is typical expressing as the deceleration of heartbeats at the moment of breathing-out heartbeats at the moment of breathing-out and its acceleration at the moment of and its acceleration at the moment of breathing-in. breathing-in.


Such a phenomenon is the result of the Such a phenomenon is the result of the increasing vagal tonus in the course of the increasing vagal tonus in the course of the inspiration and vice versa. inspiration and vice versa.

The high values of heart rate in the The high values of heart rate in the newborns and infants result in diminishing newborns and infants result in diminishing length of the heart cycle.length of the heart cycle.

Heart cycleHeart cycle

The heart cycle is defined as the set of The heart cycle is defined as the set of the electrophysiological, biochemical the electrophysiological, biochemical and biophysical processes in the heart and biophysical processes in the heart occurring within one heart occurring within one heart contraction. contraction.

The start of the heart cycle is marked The start of the heart cycle is marked by P wave in electrocardiogram. by P wave in electrocardiogram.


The length of the heart cycle is the The length of the heart cycle is the newborn is 0.4-0.5 s. newborn is 0.4-0.5 s.

Later on, the length of the heart cycle Later on, the length of the heart cycle decreases. At the age of 10 years, the decreases. At the age of 10 years, the length of the heart cycle is 0.7 s. In adults, length of the heart cycle is 0.7 s. In adults, the length of the heart cycle is 0.77-0.8 sthe length of the heart cycle is 0.77-0.8 s

Anatomical and Anatomical and physiological features of physiological features of

blood vessels in the blood vessels in the childrenchildren

The arteries in the children are The arteries in the children are wider than in the adults.wider than in the adults.

The diameter of the arteries in the The diameter of the arteries in the newborns and the young children newborns and the young children is superior to that of the veins.is superior to that of the veins.

Anatomical and Anatomical and physiological features of physiological features of

blood vessels in the blood vessels in the childrenchildren With the age, the veins grow faster than With the age, the veins grow faster than

the arteries. As a result, at the age of 16, the arteries. As a result, at the age of 16, the diameter of the veins is twice as wide the diameter of the veins is twice as wide as that of the arteries. as that of the arteries.

The growth of the arteries and the veins The growth of the arteries and the veins does not correspond to that of the heart: does not correspond to that of the heart: the circumference of the aorta at the age of the circumference of the aorta at the age of 15 increases three-fold, while the volume 15 increases three-fold, while the volume of the heart – seven-fold.of the heart – seven-fold.


In the newborns, the walls of the blood In the newborns, the walls of the blood vessels are thin.vessels are thin.

The muscular and elastic fibers of the The muscular and elastic fibers of the blood vessels are not developed blood vessels are not developed sufficiently. sufficiently.

With the age, the vascular walls are With the age, the vascular walls are differentiated and the percentage of the differentiated and the percentage of the muscular and elastic fibers increases. muscular and elastic fibers increases.


Up to the age of 5 years, the muscular layer of Up to the age of 5 years, the muscular layer of the vascular walls grows faster;the vascular walls grows faster;

at the age of 5-8, the growth rate of all the layers at the age of 5-8, the growth rate of all the layers is uniform; is uniform;

at the age of 8-12, the connective tissue is at the age of 8-12, the connective tissue is differentiated and the intima of the vascular differentiated and the intima of the vascular walls grow predominantly; walls grow predominantly;

at the age of 12 years, the structure of the at the age of 12 years, the structure of the vascular walls is the same as in the adults.vascular walls is the same as in the adults.


The capillaries in the children are well The capillaries in the children are well developed. developed.

The capillaries in the guts, the kidneys, the skin, The capillaries in the guts, the kidneys, the skin, and the lungs are wider than that in the adults, and the lungs are wider than that in the adults, both in absolute and in relative values. both in absolute and in relative values.

The shape of the capillaries is not regular; they The shape of the capillaries is not regular; they are short and twisted. The capillary permeability are short and twisted. The capillary permeability in the children is higher than in the adults. in the children is higher than in the adults.

– – At the age of 12-13, the formation of the At the age of 12-13, the formation of the vasculature of the body is completed. vasculature of the body is completed.


The shape of the capillaries is not The shape of the capillaries is not regular: they are short and twisted. regular: they are short and twisted.

The capillary permeability in the The capillary permeability in the children is higher than in the adults. children is higher than in the adults.

At the age of 12-13, the formation of At the age of 12-13, the formation of the vasculature of the body is the vasculature of the body is completed. completed.

The functional indices of the The functional indices of the blood circulation in the blood circulation in the

childrenchildren are the circulation rate, the are the circulation rate, the spread of the pulse wave, and spread of the pulse wave, and the arterial blood pressure.the arterial blood pressure.

The circulation rate in The circulation rate in the childrenthe children

The circulation rate in the children is faster than The circulation rate in the children is faster than in adults due to increased heart rate, the in adults due to increased heart rate, the relatively high volume of the circulating blood, relatively high volume of the circulating blood, the relatively short length of the vasculature, and the relatively short length of the vasculature, and the high intensity of the metabolism. the high intensity of the metabolism.

The time of full blood circulation in the newborn The time of full blood circulation in the newborn is 12 s, in the adult – 22 s. is 12 s, in the adult – 22 s.

As a result, the blood supply in the children is As a result, the blood supply in the children is higher than in the adults. higher than in the adults.

The spread of the pulse The spread of the pulse wavewave

The spread of the pulse wave in The spread of the pulse wave in the children is slower than in the the children is slower than in the

adults due to the decreased adults due to the decreased percentage of the elastic fibers in percentage of the elastic fibers in

the arterial walls.the arterial walls.

The arterial blood The arterial blood pressure in the childrenpressure in the children The arterial blood pressure in the The arterial blood pressure in the

children is lower than in the adults due children is lower than in the adults due to decreased pumping and contractile to decreased pumping and contractile capacities of the heart, the relatively capacities of the heart, the relatively higher diameter of the arteries, and the higher diameter of the arteries, and the insufficient development of the elastic insufficient development of the elastic fibers in the arterial walls. fibers in the arterial walls.

The arterial blood The arterial blood pressure in the childrenpressure in the children In the newborn systolic arterial In the newborn systolic arterial

pressure in 76 mm Hg; its monthly pressure in 76 mm Hg; its monthly increment is 2 mm Hg. increment is 2 mm Hg.

At the age below one year, the following At the age below one year, the following formula of the systolic arterial pressure formula of the systolic arterial pressure is valid: 76+2n, where n – the age of the is valid: 76+2n, where n – the age of the child in months.child in months.

The arterial blood The arterial blood pressure in the childrenpressure in the children At the age of one year, the systolic At the age of one year, the systolic

arterial pressure is around 90 mm Hg arterial pressure is around 90 mm Hg with its further annual increment of 2 with its further annual increment of 2 mm Hg. Therefore, the following formula mm Hg. Therefore, the following formula of the systolic arterial pressure may be of the systolic arterial pressure may be used: 90+2n, where n – the age of the used: 90+2n, where n – the age of the child in years. child in years.

The diastolic blood pressure equals 1/2–The diastolic blood pressure equals 1/2–1/3 of the systolic one.1/3 of the systolic one.

Clinical Examination of Clinical Examination of cardiovascular systemcardiovascular system

The clinical examination of The clinical examination of cardiovascular system comprises cardiovascular system comprises the complaints, the anamnesis, the the complaints, the anamnesis, the visual examination, the palpation, visual examination, the palpation, the percussion, the auscultation.the percussion, the auscultation.

ComplaintsComplaints

1. The fatigue upon the physical exercises 1. The fatigue upon the physical exercises (walking, games, ascending the staircase etc.)(walking, games, ascending the staircase etc.)

2. The dyspnea at the rest or in the movements.2. The dyspnea at the rest or in the movements. 3. The difficulties in breast-feeding 3. The difficulties in breast-feeding 4. The cyanosis of the lips, the nails, the mucosa; 4. The cyanosis of the lips, the nails, the mucosa;

the cyanotic skin at rest or in the movements.the cyanotic skin at rest or in the movements. 5. The paleness of the skin.5. The paleness of the skin.


6. The edema in the lower limbs, the waist, 6. The edema in the lower limbs, the waist, the face.the face.

7. The palpitations (the subjective feelings 7. The palpitations (the subjective feelings of the heartbeats).of the heartbeats).

8. The pains in the heart. 8. The pains in the heart. 9. The headaches 9. The headaches 10. The sudden fainting for several 10. The sudden fainting for several

seconds.seconds.


11. The delay in the physical development, 11. The delay in the physical development, especially in the young children without the especially in the young children without the overt constitutional and alimentary factors.overt constitutional and alimentary factors.

12. The frequent bronchitis and pneumonia, 12. The frequent bronchitis and pneumonia, especially with the congestive symptoms.especially with the congestive symptoms.

13. The frequent anginas.13. The frequent anginas. 14. The noises in the heart.14. The noises in the heart. 15. The disturbed heart rhythm15. The disturbed heart rhythm

Visual examinationVisual examination

The severity of the conditions The severity of the conditions The delay in the physical developmentThe delay in the physical development The position of the patientThe position of the patient in bedin bed The stigmas of dysembriogenesisThe stigmas of dysembriogenesis The deformities of thorax in the area of The deformities of thorax in the area of

the heart (gibbus cardiacus) the heart (gibbus cardiacus)


Tachipnea (the frequent superficial respiration: Tachipnea (the frequent superficial respiration: more than 60 breathings per minute in the more than 60 breathings per minute in the children below 2 months; more than 50 – in the children below 2 months; more than 50 – in the children aged 2-12 months; more than 40 – in the children aged 2-12 months; more than 40 – in the children aged 1-3 years; more than 30 – in the children aged 1-3 years; more than 30 – in the children aged 3-7 years; more than 25 – in the children aged 3-7 years; more than 25 – in the children at the age above 7) or dyspnea children at the age above 7) or dyspnea (deep respiration with normal or slightly (deep respiration with normal or slightly increased rate)increased rate)


The paleness or cyanosis of the skin The paleness or cyanosis of the skin The subcutaneous blood vessels in the The subcutaneous blood vessels in the

thorax thorax The edema and the pastosityThe edema and the pastosity The phalanges of the fingers in the patients The phalanges of the fingers in the patients

with heart diseases have sometimes the with heart diseases have sometimes the appearance of the "drumsticks", the nails appearance of the "drumsticks", the nails may look as the "watch glasses". may look as the "watch glasses".


The pulsation of the carotid The pulsation of the carotid arteries arteries

Gibbus cardiacus Gibbus cardiacus The apical heart impulse or the The apical heart impulse or the

impulse of the base of heartimpulse of the base of heart

PalpationPalpation

The heart impulseThe heart impulse The arterial pulse.The arterial pulse. The phenomen of The phenomen of

"cat murmurs" "cat murmurs"

Heart percussionHeart percussion

The percussion of the heart allows one to The percussion of the heart allows one to assess the size of the heart, its assess the size of the heart, its configuration and position as well as the configuration and position as well as the width of the vascular bundle. width of the vascular bundle.

The percussion is performed in the supine The percussion is performed in the supine position of the patient. position of the patient.

The techniques of The techniques of percussionpercussion::

Direct percussionDirect percussion is is performed only with one performed only with one flexed finger. This technique is flexed finger. This technique is the most adequate one for the most adequate one for examining the children examining the children whatever age.whatever age.


Indirect percussionIndirect percussion is performed is performed with two hands, namely the finger of with two hands, namely the finger of one hand striking the back surface one hand striking the back surface of distal or middle phalange of the of distal or middle phalange of the finger-pleximeter, the latter placed finger-pleximeter, the latter placed on the skin. This technique is on the skin. This technique is possible to use for examining the possible to use for examining the children of relatively elder age.children of relatively elder age.


OrthopercussionOrthopercussion is is performed for assessing performed for assessing the left boundary of the the left boundary of the heart. heart.

Major guidelines of Major guidelines of percussionpercussion

11. For assessing the relative borders . For assessing the relative borders of the heart, the subtle percussion of the heart, the subtle percussion should be used. For assessing the should be used. For assessing the absolute borders of the heart, the absolute borders of the heart, the percussion should be the most subtle. percussion should be the most subtle.

2. The heart percussion should be 2. The heart percussion should be performed along the intercostals performed along the intercostals spaces in the direction from the lungs spaces in the direction from the lungs to the heartto the heart

Major guidelines of Major guidelines of percussionpercussion

3. The relative border of the heart is 3. The relative border of the heart is assessed by the external edge of the finger, assessed by the external edge of the finger, the absolute one – by the internal edge of the absolute one – by the internal edge of the finger.the finger.

4. The heart percussion is performed in 4. The heart percussion is performed in specified sequence: First, the right border specified sequence: First, the right border is assessed, then, the left border, and is assessed, then, the left border, and finally, the upper border.finally, the upper border.

5. Prior to the assessment of the right 5. Prior to the assessment of the right border of the heart, the height of the border of the heart, the height of the diaphragm is assesseddiaphragm is assessed

AuscultationAuscultation For auscultation in the children, the special For auscultation in the children, the special

pediatric stethoscope is used with the pediatric stethoscope is used with the diameter of the diaphragm no more than 20 diameter of the diaphragm no more than 20 mm.mm.

Auscultation is performed in the different Auscultation is performed in the different positions of the patient: supine, lateral, positions of the patient: supine, lateral, sitting, standing, prior to and after the sitting, standing, prior to and after the physical exercises, at the maximum of physical exercises, at the maximum of breathing-in, upon the arrest of the breathing-in, upon the arrest of the breathings, upon the complete breathing-breathings, upon the complete breathing-out. out.

AuscultationAuscultation

The following order of heart auscultation is The following order of heart auscultation is operative:operative:

Point 1. Apex of the heart (sounds of mitral Point 1. Apex of the heart (sounds of mitral valve).valve).

Point 2. The second intercostal space near Point 2. The second intercostal space near the right edge of sternum (sounds of the the right edge of sternum (sounds of the aortal valves).aortal valves).

Point 3. The second intercostal space near Point 3. The second intercostal space near the left edge of sternum (sounds of the the left edge of sternum (sounds of the valves of the pulmonary artery).valves of the pulmonary artery).

AuscultationAuscultation

Point 4. The lower third of sternum at the Point 4. The lower third of sternum at the base of the xiphoid process attachment, base of the xiphoid process attachment, slightly to the right from the middle sternal slightly to the right from the middle sternal line (sounds of the tricuspid valve).line (sounds of the tricuspid valve).

Point 5 (Botkin-Naunin-Erb point). This is Point 5 (Botkin-Naunin-Erb point). This is the point of the intersection of the left edge the point of the intersection of the left edge of sternum with the line drawn from the of sternum with the line drawn from the second intercostal space on the right from second intercostal space on the right from the edge of sternum to the apex of the heart the edge of sternum to the apex of the heart (sounds originating from all the valves of (sounds originating from all the valves of the heart).the heart).

Laboratory examinationLaboratory examination

General blood analysis General blood analysis Biochemistry of blood serumBiochemistry of blood serum Immunologic statusImmunologic status Bacterial analysis of the blood Bacterial analysis of the blood

Instrumental methods of Instrumental methods of examinationexamination

X-ray examination of the chestX-ray examination of the chest Electrocardiography (ECG), Electrocardiography (ECG), phonocardiography (PCG), phonocardiography (PCG), echocardiography (Echo-CG), echocardiography (Echo-CG),

Dopplerography of the peripheral blood Dopplerography of the peripheral blood vessels, vessels,

magnetic resonance tomography (MRT).magnetic resonance tomography (MRT).

To sum up, the complex of examination To sum up, the complex of examination techniques, namely visual examination, techniques, namely visual examination, palpation, percussion, auscultation and palpation, percussion, auscultation and the techniques of laboratory and the techniques of laboratory and instrumental examination provides for instrumental examination provides for diagnosing various diseases of diagnosing various diseases of cardiovascular system in the children. cardiovascular system in the children.