kuliah disritmia
TRANSCRIPT
DISRITMIA
DR. dr. Taufik Indrajaya, SpPD,KKV, FINASIM
Division of Cardiology
Departement of Internal Medicine
General Hospital Muh Husin Palembang
Electrophysiology of The HeartThe different waveforms for each of the specialized cells.
ECG as done by Willem Einthoven
Electromechanical technology.
Holter Recorders ~ Record (log) data to a tape or memory for 24 hours to monitor paroxysmal (intermittent short
duration) arrhythmias
What does cardiovascular system do?
Lecture
A. Normal Rhytm ?B. Disrhytmias ? (Arrhytmias ?)
and Conduction Disturbances
Principles of Rhythm Analysis
• The standard 12-lead ECG and Rhythm strips are the most easily accessible tools for the diagnosis of a cardiac rhythm disturbance.
• Recognition of the P-wave and QRS morphology and their relative timing may be the only information needed to diagnose the arrhytmia correctly.
12-lead EKG
• 12 leads commonly used clinically
• Standard leads (I, II, III)
• Augmented leads (aVR, aVL, aVF) in which the signal is compared to the average of two others
– Chest leads (V1-6)
The chest leads look at the transverse plane:
A systematic and complete approach
• Check the patient details - is the ECG correctly labelled? • What is the rate? • Is this sinus rhythm? If not, what is going on? • What is the mean frontal plane QRS axis • Are the P waves normal (Good places to look are II and V1) • What is the PR interval? • Are the QRS complexes normal? Specifically, are there:
– significant Q waves? – voltage criteria for LV hypertrophy? – predominant R waves in V1? – widened QRS complexes?
• Are the ST segments normal, depressed or elevated? Quantify abnormalities.
• Are the T waves normal? What is the QT interval? • Are there abnormal U waves?
Diagnosis of Cardiac Rhythm
1. What is the atrial rhythm ? (P waves)
2. What is the ventricular rhythm ? (QRS)
3. Is AV conduction normal ? (P – QRS)
4. Are there any unusual complexes ?
5. Is the rhythm dangerous ?
Normal EKG
Normal Sinus Rhythm
Is defined as
a rate of 60 to 100 bpm, originating in the sinus node,
the rhythm is regular
A. Normal Rhytm ?
B. Disrhytmias ? (Arrhytmias ?) and Conduction Disturbances
Dis- /Arrhythmias :
• disorders of the regular rhythmic beating of the heart.
• Common — 2.2 million Americans are living with AF(one type of rhythm problem).
• Can occur in a healthy heart and be of minimal consequence.
• Also may indicate a serious problem and lead to heart disease, stroke or sudden cardiac death.
• The goal : ultimately reduce disability and death from heart disease and stroke.
Signs or Symptoms
May not cause any signs or symptoms.
A fluttering in your chest
A racing heartbeat
A slow heartbeat
Chest pain
Shortness of breath
Lightheadedness
Dizziness
Fainting (syncope) or near fainting
Causes• Common~ heart disease, high BP, DM, smoking,
excessive alcohol or caffeine, drug abuse, stress • Scarring — most commonly, from a previous
heart attack — disrupt the initiation or conduction of electrical impulses.
• In a healthy person with a normal, healthy heart, a sustained arrhythmia to develop caused by outside trigger: an electrical shock or the use of illicit drugs.
• However, in a heart with some evidence of disease or deformity, the initiation or conduction of the heart's electrical impulses may be destabilized, making arrhythmias more likely to develop.
Any pre-existing structural heart condition
can lead to arrhythmia development due to:
• Inadequate blood supply.
It can alter the ability of heart tissue — including the cells that conduct electrical impulses — to function properly.
• Damage or death of heart tissue.
This can affect the way electrical impulses spread in the heart.
These pre-existing heart conditions may
include:
• Coronary artery disease (CAD).
• Cardiomyopathy.
• Valvular heart diseases.
Complication
• Stroke. When your atrial chambers fibrillate, they're unable to pump blood effectively. Stagnant blood in the atria can form blood clots. If a clot breaks loose, it can travel to and obstruct a brain artery, causing an ischemic stroke. This may damage or kill a portion of your brain or lead to death.
• Congestive heart failure. This can result if your heart is pumping ineffectively for a prolonged period due to a bradycardia or tachycardia, such as atrial fibrillation. Sometimes, controlling the rate of an arrhythmia that's causing congestive heart failure can lead to improved heart function.
Arrhythmias can be placed into 3
Broad categories:
Abnormalities of
Impulse Formation
Impulse Conduction
Combination of Both
Abns of Impulse Formation Supraventricular :• Atrial
– Sinus arrest– Atrial premature complexes (APCs)– Atrial bigeminy, trigeminy– Atrial tachycardia
– Atrial Flutter – Atrial Fibrillation
• Atrioventricular Junction– AV junctional premature complexes– AV junctional tachycardia
• AV junctional escape rhytm (secondary)
Abns of Impulse Formation, Cont
Ventricular :– Ventricular premature complexes (VPCs or
PVCs)– Ventricular bigeminy, trigeminy– Ventricular tachycardia – Ventricular flutter – Ventricular fibrillation – Ventricular asystole – Ventricular escape rhytm (secondary).
Abns of Impulse Conduction
• Sinoatrial block
• Persistent atrial standstill ("Silent Atrium", Hyperkalemia)
• A-V Block :– First-Degree – Second-Degree – Third-Degree (complete heart block)
• A-V dissociation
Abns of Both (Combination)
• Pre-excitation – Wolf-Parkinson-White syndrome
• Parasystole
• Other complex rhythms– Electrical alternans
1. Abnormalities of Impulse Formation
2. Abnormalities of Impulse Conduction
3. A Combination of Both
Abnormalities of Impulse Formation
Supraventricular
Atrial Flutter
• Is an atrial tacharrhythmia, characterized by very rapid (atrial rate is typically greater than 300 bpm in the dog and horse), but regular heart rate, and an ECG with a typically "saw-toothed" appearance.
• May occur secondary to atrial enlargement.
Atrial flutter
Atrial flutter is similar to atrial fibrillation but characterized by more-organized and more-rhythmic electrical impulses.
Atrial Fibrillation
• Is characterized by an irregularly irregular rhythm, an absence of P waves, and the presence of f (for fibrillation) waves.
• Is not an uncommon arrhythmia in veterinary patients.
ECG of atrial fibrillation (top) and
sinus rhythm (bottom)
Atrial fibrillation
• Electrical signals fire from multiple locations in the atria, causing abnormal quivering of the atria. (1).
• The atrioventricular node — your heart's natural pacemaker — is unable to prevent all of these chaotic signals from entering the ventricles (2).
• Your ventricles respond to these extra, chaotic signals by beating faster than normal (3).
Abnormalities of Impulse Formation
Ventricular
Ventricular Premature Complexes
• VPCs - impulse originating from an area distal to the AV junctional tissue.
• These early beats do not have a preceding, corresponding P wave and the QRS complex may be abnormally wide and unusual in shape.
• Can occur singly, in pairs(couplets), in sequence; (four or more together = ventricular tachycardia), or alternate regularly with sinus beats (v. bigeminy or trigeminy).
• It is normal to see occasional VPCs; however, frequent VPCs in any form may necessitate treatment.
Ventricular Bigeminy
• This VPCs alternating with normal sinus complexes in an "every-other-one" pattern.
• Necessity of treatment would depend on the presence of any other cardiac pathology and the frequency of the arrhythmia.
• Ventricular trigeminy can also occur. In this case, two VPCs follow each normal sinus complex.
Ventricular Tachycardia • Is characterized by an elevated ventricular rate with
a typically regular rhythm. • QRS complexes are usually aberrant in shape and P
waves are not usually present. • A P wave may be present if retrograde conduction
occurs and may cause a capture beat (if the ventricles are not refractory). The capture beat may then merge with an ectopic focus beat and result in a fusion beat.
• VT is usually the result of reentrant activity distal to the A-V junction area that leads to an ectopic rhytm. There may be more than one ectopic focus present, which can be determined by examining the morphology of the complexes.
Ventricular Tachycardia, Cont
• Unifocal (or uniform) VT arises from a single ectopic focus and produces aberrant, although similar-looking QRS complexes. Multifocal (or multiform) VT is the result of two or more ectopic foci and produces QRS complexes attributable to each foci. Four or more rapid QRS complexes (with or without an accompanying P wave) constitute a VT. Paroxysmal VT is a short burst of ventricular tachycardia that ends spontaneously, while sustained VT is prolonged indefinitely.
• ?? (Obviously, the primary concern with VT is inadequate cardiac output due to decreased ventricular filling. The extent of the VT determines the course and necessity of treatment.)
• ?? (Other inciting stimuli for VT under anesthesia?)
Ventricular tachycardia
• Ventricular tachycardia — caused by abnormal electrical impulses originating in the ventricles — is a fast, regular beating of the heart.
12 lead ECG showing a run of
monomorphic ventricular tachycardia (VT)
Ventricular Flutter
• Is characterized by a high ventricular rate with a regular rhythm.
• An ECG shows large sine wave-like complexes that oscillate in a regular pattern. P waves are not present, and the QRS complex is indistinguishable from the T wave.
• Ventricular flutter, if untreated, may precede ventricular fibrillation.
• In severe cardiac or systemic disease states, ventricular tachycardia can progress to ventricular flutter, then to ventricular fibrillation. These final two arrhythmias are severe and require immediate attention.
Ventricular Fibrillation
• This ventricular tacharrhythmia is characterized an irregular pattern of high or low-amplitude waves that cannot be differentiated into QRS complexes or T waves. In cardiac arrest, it may be preceded by ventricular flutter. This is a serious arrhythmia which requires immediate treatment. Often, electrical defibrillation is indicated.
Ventricular fibrillation
• During ventricular fibrillation, your ventricles quiver uselessly instead of pumping blood.
1. Abnormalities of Impulse Formation
2. Abnormalities of Impulse Conduction
3. A Combination of Both
First-Degree AV Block
• Characterized by a delay of the impulse in the AV node region.
• Heart rate is usually normal and rhythm may be regular or irregular.
• There is a P for every QRS complex and the most notable finding is a prolonged but constant P-R interval.
Second-Degree AV Block • Is more than just a delayed impulse at the AV node.
The impulse is delayed and blocked resulting in both conducted and non-conducted P waves on the ECG.
• This translates into some P waves that are followed by a QRS complex and some P waves that occur without a subsequent QRS complex.
• Can result from high vagal tone, electrolyte imbalances (hyperkalemia), pharmacologic effects (opiates in dogs), or A-V nodal disease.
• Second-degree A-V block with only occasional non-conducted complexes does not require treatment. If pauses in ventricular activity are frequent or of long enough duration to result in significant decreases in blood pressure or cardiac output, treatment is necessary.
Second-Degree AV Block, Cont
• There are two types of second-degree AV block that are differentiated by the character of the P-R interval:– Mobitz type I (or Wenkebach): The P-R interval
gradually lengthens until a QRS-T is dropped, thus the P-R interval is variable. This type is a common finding in the normal horse (and can also occur as a result of digitalis treatment or electrolyte imbalance). It is abnormal in cattle.
– Mobitz type II: The P-R interval is constant before and after the dropped beat.
Third-Degree AV Block (Complete Heart Block)
• Impulse is completely blocked at the AV node region.
• The P wave and QRS complex are dissociated. In awake patients, this rhythm usually indicates disease of the A-V node.
• If a ventricular escape rhytm is present, the patient may have adequate cardiac output to maintain consciousness.
• This arrhythmia often necessitates treatment. A pacemaker can be placed.
1. Abnormalities of Impulse Formation
2. Abnormalities of Impulse Conduction
3. A Combination of Both
Wolf-Parkinson-White Syndrome
• This arrhythmia is denoted by ventricular pre-excitation with episodes of paroxysmal supraventricular tachycardia.
• The P-R interval is shortened (the impulse reaches the ventricles without going through the AV node) due to the activation of an alternate, shorter pathway through the myocardium.
• Again, this often due to re-entry of the impulse back into the atria (reciprocal re-entry). The "detour" of the impulse may cause an aberrant QRS configuration.
• This syndrome may occur in patients with valvular abnormalities, cardiomyopathy, or otherwise normal heart function.
Wolff-Parkinson-White syndrome
• Wolff-Parkinson-White syndrome is caused by an extra electrical pathway between the atria and the ventricles.
• The electrical activity goes down the normal pathway from the atria to the ventricles but returns to the atria by coming up the extra pathway.
WPW is a syndrome of pre-excitation of the
ventricles, shaded in dark blue at the bottom.
Wolff-Parkinson-White syndrome 12 lead EKG
Treatment
• If you've received a diagnosis of arrhythmia, treatment may or may not be necessary.
• Usually, it's required only if the arrhythmia is causing significant symptoms or if it's putting you at risk of a more serious arrhythmia or arrhythmia complication.
Treating Bradycardias• If symptom-producing bradycardias don't have a
cause that can be corrected — such as hypothyroidism or a drug side effect — doctors often treat them with a pacemaker.
• A pacemaker is a small, battery-powered device that's usually implanted near your collarbone. One or more electrode-tipped wires run from the pacemaker through your blood vessels to your inner heart. If your heart rate is too slow or if it stops, the pacemaker sends out electrical impulses that stimulate your heart to beat at a steady, proper rate.
Treating Bradycardias, Cont
• The newest pacemakers can monitor and pace your atria or ventricles — or both — in proper sequence to maximize the output of blood from your heart.
• In addition, your doctor can program your pacemaker to meet your pacing needs.
Treating tachycardias
• For tachycardias originating in the atria or ventricles, treatments may include one or more of the following:
• Vagal maneuvers. You may be able to stop a supraventricular tachycardia (SVT) by using particular maneuvers, which include holding your breath and straining, dunking your face in ice water, or coughing. Your doctor may be able to recommend other maneuvers to halt a fast heartbeat. These maneuvers affect the nervous system that controls your heartbeat (vagal nerves), often causing your heart rate to slow.
Treating Tachycardias, Cont
• Medications. Many types of tachycardias respond well to anti-arrhythmic medications. Though they don't cure the problem, they can reduce episodes of tachycardia or slow down the heart when an episode occurs. Some medications can slow down your heart so much that you may need a pacemaker. It's very important to take any anti-arrhythmic medication exactly as directed by your doctor in order to avoid complications.
Treating Tachycardias, Cont• Cardioversion. If you have an atrial tachycardia,
including atrial fibrillation, your doctor may use cardioversion, which is an electrical shock used to reset your heart to its regular rhythm. Usually this is done externally in a monitored setting, and you're given medication to sedate you during the procedure, so there's no pain involved.
• Cardiac ablation. In this procedure, one or more catheters are threaded through your blood vessels to your inner heart. They're positioned on areas of your heart identified by your doctor as causing your arrhythmia. Electrodes at the catheter tips are heated with radiofrequency energy. Another method involves cooling the tips of the catheters, which freezes the problem tissue. Either method destroys (ablates) a small spot of heart tissue and creates an electrical block along the pathway that's causing your arrhythmia. Usually, this stops your arrhythmia.
Treating Tachycardias, Cont• Implantable devices
Treatment for heart arrhythmias also may involve use of an implantable device:
• Pacemaker. A pacemaker is an implantable device that helps regulate slow heartbeats (bradycardia). A small battery-driven device is placed under the skin near the collarbone in a minor surgical procedure. An insulated wire extends from the device to the right side of the heart, where it's permanently anchored. If a pacemaker detects a heart rate that's too slow or no heartbeat at all, it emits electrical impulses that stimulate your heart to speed up or begin beating again. Most pacemakers have a sensing device that turns them off when your heartbeat is above a certain level. It turns back on when your heartbeat is too slow. Most people can be discharged from the hospital one to two days after a pacemaker is implanted.
Treating Tachycardias, Cont
• Implantable cardioverter-defibrillator (ICD). Your doctor may recommend this device if you're at high risk of developing a dangerous ventricular tachycardia (VT) or ventricle fibrillation (VF). Implantable defibrillator units designed to treat atrial fibrillation also are available. An ICD is a battery-powered unit that's implanted near the left collarbone. One or more electrode-tipped wires from the ICD run through veins to the heart. The ICD continuously monitors your heart rhythm. If it detects a rhythm that's too slow, it paces the heart as a pacemaker would. If it detects VT or VF, it sends out low- or high-energy shocks to reset the heart to a normal rhythm. An ICD may lessen your chance of having a fatal arrhythmia, compared with preventive drug treatment.
Radiofrequency catheter ablation
• In radiofrequency catheter ablation, catheters are threaded through the blood vessels to the inner heart, and electrodes at the catheter tips are heated to destroy a small spot of heart tissue.
Pacemakers, defibrillator
• A dual chamber pacemaker paces the atrium and ventricle. A biventricular pacemaker paces both ventricles. An implantable cardioverter-defibrillator can function as a pacemaker would. In addition, if it detects ventricular tachycardia or fibrillation, it sends out a shock to reset the heart to a normal rhythm.
• Surgical treatmentsIn some cases, surgery may be the recommended treatment for heart arrhythmias:
• Maze procedure. This involves making a series of surgical incisions in the atria. These heal into carefully placed scars in the atria that form boundaries that force electrical activation to proceed in an orderly manner from top to bottom. The procedure has a high success rate, but because it requires open-heart surgery, it's usually reserved for people who don't respond to other treatments. The surgeon may use a cryoprobe — an instrument for applying extreme cold to tissue — or a hand-held radiofrequency probe, rather than a scalpel, to create the scars.
• Ventricular aneurysm surgery. In some cases, an aneurysm in the heart is the cause of an arrhythmia. If catheter ablation and implanted ICD don't work, you may need this surgery. It involves removing the bulge (aneurysm) that's causing your arrhythmia. By removing the source of the abnormal impulses, the arrhythmia often can be eliminated.
• Coronary bypass surgery. If you have severe coronary artery disease in addition to frequent ventricular tachycardia, your doctor may recommend coronary bypass surgery. This may improve the blood supply to your heart and reduce the frequency of your ventricular tachycardia.
Self-care
Many arrhythmias can be blamed on underlying heartdisease, so your doctor may advise that, in addition toother treatments, you make lifestyle changes that will keep your heartas healthy as possible.
For instance, he or she may advise that you:• Eat heart-healthy foods • Increase your physical activity • Quit smoking • Cut back on caffeine and alcohol • Find ways to reduce the amount of stress in your life • Avoid stimulant medications, such as medications found in over-the-
counter treatments for colds and nasal congestion
tHankS fOr AtTentiOn