cardiac physiology

CARDIAC PHYSIOLOGY & ANAESTHETIC CONSIDERATIONSMODERATOR : DR.ANIL VERMA SPEAKER : BY RAJEEV PUBLISHED

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Heart Hollow Located within the mediastinum of the thorax Distal end extends downward to the left forming apex at the fifth intercostal space.


HEART STRUCTURE ANATOMICALLY ONE ORGAN FUNCTIONALLY DIVIDE INTO RT. & LT PUMPS FOUR VALVES WITH UNIDIRECTIONAL FLOW



Pulmonary and Systemic Bloodflow


The heart consists of three different layerswww.medicalppt.blogspot.com


Coronary supplyInferior Anteroseptal Anteroapical Anterolateral Posterior Rt coronary Lt ant descening Lt ant desceding( distal) Circumflex Rt coronary arterywww.medicalppt.blogspot.com

l

CARDIAC ACTION POTENTIAL


MEMBRANE POTENTIAL (mV)

0

PHASE 0 = Rapid Depolarization Mechanical Response (inward Na+ current) 1 1 = Overshoot 2 2 = Plateau (inward Ca++ current) 3 = Repolarization (outward K+ current) 0 3 4 = Resting Potential

-90 TIME

4


PACEMAKERS (in order of their inherent rhythm) Sino-atrial (SA) node Atrio-ventricular (AV) node Bundle of His Bundle branches Purkinje fibers


Sinoatrial Node

AtrioVentricular Node

Atrioventricular Bundle

Purkinje Fibers Heart Conduction Systemwww.medicalppt.blogspot.com

INITIATION & CONDUCTION OF THE CARDIAC IMPULSE


Heart Actions Atrial systole is when the atria contract while the ventricles relax which is called ventricular diastole. Thus systolic and diastolic blood pressure. This series of contraction and relaxation is called a cardiac www.medicalppt.blogspot.com cycle.

EVENTS IN CARDIAC CYCLE DIASTOLE

LATE DIASTOLE

ISOMETRIC VENTRICULAR RELAXATION

ATRIAL SYSTOLE

VENTRICULAR ISOMETRIC VENTRICULAR EJECTION www.medicalppt.blogspot.com CONTRACTION

CAR DI AC CYC LEAortic opensAtrial Systole Isovolumic contract. Rapid Ejection

Mitral Closes

S1 S2Aortic closes Mitral opens

Reduced Ejection Isovolumic Relax.Rapid Ventricular Filling


Reduced Ventricular Filling

Atrial Systole

CARDIAC OUTPUT DEFIND AS VOLUME OF BLOOD PUMPED BY HEART/MIN CO = SV X HR SV IS VOLUME PUMPED PER CONTRACTION average cardiac output would be 5L.min-1 for a human male and 4.5L.min-1 for a female.www.medicalppt.blogspot.com

CARDIAC OUTPUT AND THE FICK PRINCIPLEBODY O2 CONSUMPTION Lungs PULMONARY ARTERY PaO2 190mlO2/l bloodPulmonary capillaries

250mlO2/min

PULMONARY VEIN PvO2 140mlO2/l blood

CARDIAC OUTPUT=

O2 CONSUMPTION (ml/min) PaO

www.medicalppt.blogspot.com 2

-

PvO2

Pulse

Pressure wave move along the artery wall which are pliable usually measured in beats per minute normal range from 60 to 100 beats per minutewww.medicalppt.blogspot.com

Factors Influencing the Pulse Stroke volume Rate of ejection Distensibility of peripheral arteries Peripheral resistance Pulse rate Pulse pressure Size of the vessel Distance from the heartwww.medicalppt.blogspot.com

Pulsus Parvus

The pressure is diminished, and the pulse feels weak and small, seen in - restrictive pericardial disease, hypovolemia, mitral stenosis Pulsus Parvus et Tardus (weak and delayed): Aortic Stenosis www.medicalppt.blogspot.com

Bisferiens Pulse

Increased arterial pulse with a double systolic peak. Causes : AR HCM


Bigeminal Pulse

characterized by groups of two heartbeats close together followed by a longer pause. The second pulse is weaker than the first Causes: severe HF, hypovolemic shock, www.medicalppt.blogspot.com cardiac tamponade)

Pulsus Alternans

arterial pulse waveform showing alternating strong and weak beats Causes: Left ventricular failure severe AR www.medicalppt.blogspot.com

Pulsus Paradoxus

Pressure drop > 20 mmHg during inspiration. Normally, systolic arterial pressure falls 8-12 mmHg during inspiration. Causes: Cardiac Tamponade COPD, hypovolemic shockwww.medicalppt.blogspot.com

BLOOD PRESSURE DEFINE AS PRESSURE OF BLOOD AGAINST THE WALL OF MAIN ARTRIES HIGHEST DURING SYSTOLE N LOWEST DURING DIASTOLE MEASURED BY SPHYGMOMANOMETER @ BRACHIAL ARTERY OF ARMwww.medicalppt.blogspot.com

Blood Pressure (BP): Measurements

Figure 15-7: Measurement of arterial blood pressure


CLASSIFICATIONCategory normal Systolic 90 119 Diastolic 100 hypotension 160


Pulse and Mean Arterial Pressures Pulse pressure = Systolic Diastolic Mean arterial pressure (MAP) = Diastolic + 1/3 pulse pressure





EJECTION FRACTION Ejection fraction (Ef) is the fraction of the end-diastolic volume that is ejected with each beat it is stroke volume (SV) divided by end-diastolic volume (EDV):


EJECTION FRACTION In a healthy man, the SV is approximately 70 ml and the left ventricular EDV is 120 ml, giving an ejection fraction of 70/120, or 0.58 (58%). Healthy individuals typically have ejection fractions between 50% and 65%www.medicalppt.blogspot.com

METHODS OF EF MEASUREMENT CARDIAC CATHETRISATION RADIONUCLEOTIDE STUDIES ANGIOCARDIOGRAPHY


CARDIAC INDEX Cardi ac index (CI ) i s a vasodynami c parameter that rel ates the cardi ac output to body surf ac e area uni t of measurement is (l/mi n/m2 ) normal range of cardiac index is 2.6 - 4.2 L/min per square meter.www.medicalppt.blogspot.com

ANAESTHETIC

Halothaane isoflurane CONSIDERATION and

enflurane depress SA node automaticity. IV induction agent have limited effect on usual clinical doses. Opioids can depress cardiac conduction. LA associated with systemic toxicity. www.medicalppt.blogspot.com

GOALS OF ANAESTHESIA IN CVS DISEASES PREMEDICATE BY BZPS BLUNT RESPONSE BY LARYGOSCOPY N INTUBATION AVOID TACHYCARDIA AVOID HYPOCAPNIA


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cardiac physiology

Documents

ventricular diastole

cardiac impulse

cardiac action potential

rapid ventricular filling

heart actions atrial

ejection isovolumic

volume of blood

pvo2 pulse pressure