際際滷

際際滷Share a Scribd company logo

Disorders of Rhythm (Cardiology cycle Lectures 2024).pptx

Download as PPTX, PDF
ATU
ATU

Brief intro to rhythm disorders

1 of 43
Download to read offline
{ Disorders of Rhythm Azerbaijan Medical University MD PhD Tora Sadigova
DESCRIPTIVE PHYSIOLOGY
Normal ECG
A. Cellular atrial and ventricular action potentials. Phases 04 are the rapid upstroke, early repolarization, plateau, late repolarization, and diastole, respectively. The ionic currents and their respective genes are shown above and below the action potentials. The major currents that underlie the action potentials vary in atrial and ventricular myocytes. B. A ventricular action potential with a schematic of the ionic currents flowing during the phases of the action potential. Potassium current (IK1) is the principal current during phase 4 and determines the resting membrane potential of the myocyte.
phase 0 - Sodium current generates the upstroke of the action potential phase 1- activation of Ito with inactivation of the Na current inscribes early repolarization phase 2 - the plateau is generated by a balance of repolarizing potassium currents and depolarizing calcium current phase 3 repolarization - inactivation of the calcium current with persistent activation of potassium currents (predominantly I Kr and IKs) phase 4 - depolarization results from the concerted action of a number of ionic currents, including K+ currents, Ca2+ currents, electrogenic Na, K-ATPase, the Na-Ca exchanger, and the so-called funny, or pacemaker, current (If ); however, the relative importance of these currents remains controversial.
An irregular heartbeat is an arrhythmia (also called dysrhythmia). A normal heart rate is 50 to 100 beats per minute. Arrhythmias and abnormal heart rates don't necessarily occur together. Arrhythmias can occur with a normal heart rate, or with heart rates that are slow (called bradyarrhythmias -- less than 50 beats per minute). Arrhythmias can also occur with rapid heart rates (called tachyarrhythmias -- faster than 100 beats per minute). Introduction to Arrhythmia
Cardiac arrhythmias result from abnormalities of electrical impulse generation, conduction, or both. Bradyarrhythmias typically arise from disturbances in impulse formation at the level of the SA node or from disturbances in impulse propagation at any level, including exit block from the sinus node, conduction block in the AVN, and impaired conduction in the His-Purkinje system. Tachyarrhythmias can be classified according to mechanism, including enhanced automaticity (spontaneous depolarization of atrial, junctional, or ventricular pacemakers), triggered arrhythmias (initiated by afterdepolarizations occurring during or immediately after cardiac repolarization, during phase 3 or 4 of the action potential), or reentry (circus propagation of a depolarizing wavefront). A variety of mapping and pacing maneuvers typically performed during invasive electrophysiologic testing can often determine the underlying mechanism of a tachyarrhythmia MECHANISMS OF CARDIAC ARRHYTHMIAS
MECHANISMS OF CARDIAC ARRHYTHMIAS
The evaluation of patients with suspected cardiac arrhythmias is highly individualized; however, two key featuresthe history and ECGare pivotal in directing the diagnostic workup and therapy. Patients with cardiac arrhythmias exhibit a wide spectrum of clinical presentations that range from asymptomatic ECG abnormalities to survival from cardiac arrest. Evaluation
Arrhythmias may be caused by many different factors, including: Coronary artery disease. Electrolyte imbalances in your blood (such as sodium or potassium). Changes in your heart muscle. Injury from a heart attack. Healing process after heart surgery. Irregular heart rhythms can also occur in "normal, healthy" hearts. What causes an arrhythmia?
Classic Symptoms Palpitations Lightheadednes s Syncope Cardiac arrest
Other symptoms Fatigue Dyspnea (shortness of breath) Poor exercise tolerance Generalized weakness Confusion Chest pain In addition to these classic symptoms, cardiac arrhythmias may also produce several less specific symptoms that may not necessarily point a healthcare provider toward considering an arrhythmia as the cause. Most of these other symptoms are related to an arrhythmia causing a relative reduction in the ability of the heart to pump blood to the bodys organs.
Premature atrial contractions. Premature ventricular contractions(PVCs). Atrial fibrillation. Atrial flutter. Paroxysmal supraventricular tachycardia (PSVT) Accessory pathway tachycardias AV nodal reentrant tachycardia Ventricular tachycardia (V-tach) Ventricular fibrillation Long QT syndrome Bradyarrhythmias Sinus node dysfunction Heart block The types of arrhythmias include:
{ Premature atrial contractions (PACs) are extra heartbeats that start in the upper chambers of your heart. When the premature, or early, signal tells the heart to contract, there may not be much blood in the heart at that moment. That means there's not much blood to pump out Premature atrial contractions
{ Premature ventricular contractions (PVCs) are extra heartbeats that begin in one of the heart's two lower pumping chambers (ventricles). These extra beats disrupt the regular heart rhythm, sometimes causing a sensation of a fluttering or a skipped beat in the chest Premature ventricular contractions(PVCs)
{ Atrial fibrillation happens when abnormal electrical impulses suddenly start firing in the atria. These impulses override the heart's natural pacemaker, which can no longer control the rhythm of the heart. This causes you to have a highly irregular pulse rate. Atrial fibrillation
{ Atrial flutter is a type of abnormal heart rhythm, or arrhythmia. It occurs when a short circuit in the heart causes the upper chambers (atria) to pump very rapidly. Atrial flutter is important not only because of its symptoms but because it can cause a stroke that may result in permanent disability or death. Atrial flutter
Atrial fibrillation. Atrial flutter.
Paroxysmal supraventricular tachycardia PSVT A normal heartbeat begins with an electrical impulse from the sinus node, a small area in the heart's right atrium (upper chamber). PSVT occurs because of a short circuit an abnormal electrical pathway made of heart cells that allows electricity to speed around in a circle and repeat the signal over and over. As a result, the chambers contract rapidly, which may impair heart function and cause symptoms such as lightheadedness or shortness of breath. There are two main types: accessory path tachycardias and AV nodal reentrant tachycardias.
{ Example of PSVT with arrows showing the location of P- waves in the ST segment. Note that the P-waves are negative in lead I. Also, seen is alternation in the amplitude of QRS amplitude best seen in C3. PSVT
Accessory pathways-related tachycardias: WolffParkinsonWhite syndrome Atrioventricular reentrant tachycardias
{ Risks possibly associated with an accessory pathway. A. During sinus rhythm there is conduction via the atrioven AV node and accessory pathway. The delta wave in the ECG represents the ventricular pre-excitation caused by the conduction via the accessory pathway. The size of the delta wave and the PR interval depend on the location of the accessory pathway and the conduction properties of the AV node and accessory pathway. B. A retrograde conduction of the accessory pathway bears the risk of an orthodromic AV re-entrant tachycardia with antegrade conduction via the AV node and retrograde conduction via the accessory pathway. C. During atrial fibrillation there is a risk of a fast conduction via the accessory pathway to the ventricles depending on the conduction properties of the accessory pathway. As most accessory pathways have no decremental conduction in contrast to the AV node, the conduction via the accessory pathway can be much faster than via the AV node. This can lead to ventricular fibrillation and sudden cardiac death
{ Wolff-Parkinson-White (WPW) syndrome is a relatively common heart condition that causes the heart to beat abnormally fast for periods of time. The cause is an extra electrical connection in the heart. This problem with the heart is present at birth (congenital), although symptoms may not develop until later in life. WolffParkinsonWhite syndrome
WPW syndrome
Atrioventricular reentrant tachycardias Atrioventricular nodal reentry tachycardia (AVNRT) is the most common type of supraventricular tachycardia. People with AVNRT have episodes of an irregularly fast heartbeat (more than 100 beats per minute) that often start and end suddenly.
Disorders of Rhythm (Cardiology cycle Lectures 2024).pptx
Associated with Fast AV nodal pathway for anterograde conduction and Slow AV nodal pathway for retrograde conduction. The retrograde P wave appears after the corresponding QRS ECG QRS -P-T complexes P waves are visible between the QRS and T wave
Ventricular tachycardia
Ventricular tachycardia (VT) is three or more consecutive beats at a rate faster than 100 beats/min. Three or more consecutive beats at slower rates are designated an idioventricular rhythm . VT that terminates spontaneously within 30 s is designated non- sustained whereas sustained VT persists >30 s or is terminated by an active intervention, such as administration of an intravenous medication, external cardioversion, or pacing or a shock from an implanted cardioverter defibrillator.
Ventricular fibrillation Ventricular Fibrillation is a very fast, irregular heartbeat that is caused by abnormal firing of electrical signals in the ventricles of the heart. In ventricular fibrillation, disorganized electrical impulses in the hearts lower chambers cause the heart to stop beating (cardiac arrest). The ventricles quiver uselessly, instead of pumping blood.
Ventricular fibrillation
Long QT syndrome is a heart rhythm disorder caused by changes in the heart's electrical recharging system. It doesn't affect the heart's structure. In long QT syndrome, the heart's electrical system takes longer than usual to recharge between beats. This delay is called a prolonged QT interval. Long QT syndrome
Congenital long QT syndrome. Some forms of long QT syndrome result from altered DNA that is passed down through families (inherited). Acquired long QT syndrome - this type of long QT syndrome is usually reversible when the underlying cause is identified and treated. Long QT syndrome is often grouped into two main categories, depending on the cause.
There are two forms of congenital long QT syndrome: Romano-Ward syndrome (autosomal dominant form). This more common form occurs in people who inherit only a single gene variant from one parent. Jervell and Lange-Nielsen syndrome (autosomal recessive form). Episodes of this rare form of LQTS usually occur very early in life and are more severe. In this syndrome, children receive the altered gene variants from both parents. The children are born with long QT syndrome and deafness. Causes of congenital long QT syndrome
Causes of acquired long QT syndrome Drug-induced long QT syndrome. Medications that can cause LQTS include: Certain antibiotics, such as erythromycin (Eryc, Erythrocin, others), azithromycin (Zithromax) and others Antifungal drugs Diuretics that cause an electrolyte imbalance (low potassium, most commonly) Anti-arrhythmics that lengthen the QT interval Some antidepressant and antipsychotic medications Some anti-nausea medications Health conditions that can lead to acquired long QT syndrome include: Hypothermia Hypocalcemia Hypomagnesemia Hypokalemia Pheochromocytoma Stroke or intracranial bleeding Hypothyroidism
Bradyarrhythmia is a type of heart arrhythmia. It is characterized by an abnormally slow and irregular heart beat. It may be a warning sign of an underlying heart health issue or another serious health problem. Bradyarrhythmias
Whats the difference between bradyarrhythmia and bradycardia?
{ { Sinus node dysfunction Sinus node dysfunction, previously known as sick sinus syndrome, describes disorders related to abnormal conduction and propagation of electrical impulses at the sinoatrial node. An abnormal atrial rate may result in the inability to meet physiologic demands, especially during periods of stress or physical activity. Heart block A heart block is when the electrical impulses that control the beating of the heart muscle are disrupted. The most serious type of heart block known as a complete, or third degree, heart block will have symptoms, but often those with less serious heart block can have symptoms too. Types of bradyarrhythmias
Sinus node dysfunction
Heart block
Heart blocks Constant P-R interval I degree block II degree block type II Variable P-R interval II degree block type I III degree block
Disorders of Rhythm (Cardiology cycle Lectures 2024).pptx
Disorders of Rhythm (Cardiology cycle Lectures 2024).pptx

More Related Content

Disorders of Rhythm (Cardiology cycle Lectures 2024).pptx

  • 1. { Disorders of Rhythm Azerbaijan Medical University MD PhD Tora Sadigova
  • 4. A. Cellular atrial and ventricular action potentials. Phases 04 are the rapid upstroke, early repolarization, plateau, late repolarization, and diastole, respectively. The ionic currents and their respective genes are shown above and below the action potentials. The major currents that underlie the action potentials vary in atrial and ventricular myocytes. B. A ventricular action potential with a schematic of the ionic currents flowing during the phases of the action potential. Potassium current (IK1) is the principal current during phase 4 and determines the resting membrane potential of the myocyte.
  • 5. phase 0 - Sodium current generates the upstroke of the action potential phase 1- activation of Ito with inactivation of the Na current inscribes early repolarization phase 2 - the plateau is generated by a balance of repolarizing potassium currents and depolarizing calcium current phase 3 repolarization - inactivation of the calcium current with persistent activation of potassium currents (predominantly I Kr and IKs) phase 4 - depolarization results from the concerted action of a number of ionic currents, including K+ currents, Ca2+ currents, electrogenic Na, K-ATPase, the Na-Ca exchanger, and the so-called funny, or pacemaker, current (If ); however, the relative importance of these currents remains controversial.
  • 6. An irregular heartbeat is an arrhythmia (also called dysrhythmia). A normal heart rate is 50 to 100 beats per minute. Arrhythmias and abnormal heart rates don't necessarily occur together. Arrhythmias can occur with a normal heart rate, or with heart rates that are slow (called bradyarrhythmias -- less than 50 beats per minute). Arrhythmias can also occur with rapid heart rates (called tachyarrhythmias -- faster than 100 beats per minute). Introduction to Arrhythmia
  • 7. Cardiac arrhythmias result from abnormalities of electrical impulse generation, conduction, or both. Bradyarrhythmias typically arise from disturbances in impulse formation at the level of the SA node or from disturbances in impulse propagation at any level, including exit block from the sinus node, conduction block in the AVN, and impaired conduction in the His-Purkinje system. Tachyarrhythmias can be classified according to mechanism, including enhanced automaticity (spontaneous depolarization of atrial, junctional, or ventricular pacemakers), triggered arrhythmias (initiated by afterdepolarizations occurring during or immediately after cardiac repolarization, during phase 3 or 4 of the action potential), or reentry (circus propagation of a depolarizing wavefront). A variety of mapping and pacing maneuvers typically performed during invasive electrophysiologic testing can often determine the underlying mechanism of a tachyarrhythmia MECHANISMS OF CARDIAC ARRHYTHMIAS
  • 8. MECHANISMS OF CARDIAC ARRHYTHMIAS
  • 9. The evaluation of patients with suspected cardiac arrhythmias is highly individualized; however, two key featuresthe history and ECGare pivotal in directing the diagnostic workup and therapy. Patients with cardiac arrhythmias exhibit a wide spectrum of clinical presentations that range from asymptomatic ECG abnormalities to survival from cardiac arrest. Evaluation
  • 10. Arrhythmias may be caused by many different factors, including: Coronary artery disease. Electrolyte imbalances in your blood (such as sodium or potassium). Changes in your heart muscle. Injury from a heart attack. Healing process after heart surgery. Irregular heart rhythms can also occur in "normal, healthy" hearts. What causes an arrhythmia?
  • 12. Other symptoms Fatigue Dyspnea (shortness of breath) Poor exercise tolerance Generalized weakness Confusion Chest pain In addition to these classic symptoms, cardiac arrhythmias may also produce several less specific symptoms that may not necessarily point a healthcare provider toward considering an arrhythmia as the cause. Most of these other symptoms are related to an arrhythmia causing a relative reduction in the ability of the heart to pump blood to the bodys organs.
  • 13. Premature atrial contractions. Premature ventricular contractions(PVCs). Atrial fibrillation. Atrial flutter. Paroxysmal supraventricular tachycardia (PSVT) Accessory pathway tachycardias AV nodal reentrant tachycardia Ventricular tachycardia (V-tach) Ventricular fibrillation Long QT syndrome Bradyarrhythmias Sinus node dysfunction Heart block The types of arrhythmias include:
  • 14. { Premature atrial contractions (PACs) are extra heartbeats that start in the upper chambers of your heart. When the premature, or early, signal tells the heart to contract, there may not be much blood in the heart at that moment. That means there's not much blood to pump out Premature atrial contractions
  • 15. { Premature ventricular contractions (PVCs) are extra heartbeats that begin in one of the heart's two lower pumping chambers (ventricles). These extra beats disrupt the regular heart rhythm, sometimes causing a sensation of a fluttering or a skipped beat in the chest Premature ventricular contractions(PVCs)
  • 16. { Atrial fibrillation happens when abnormal electrical impulses suddenly start firing in the atria. These impulses override the heart's natural pacemaker, which can no longer control the rhythm of the heart. This causes you to have a highly irregular pulse rate. Atrial fibrillation
  • 17. { Atrial flutter is a type of abnormal heart rhythm, or arrhythmia. It occurs when a short circuit in the heart causes the upper chambers (atria) to pump very rapidly. Atrial flutter is important not only because of its symptoms but because it can cause a stroke that may result in permanent disability or death. Atrial flutter
  • 18. Atrial fibrillation. Atrial flutter.
  • 19. Paroxysmal supraventricular tachycardia PSVT A normal heartbeat begins with an electrical impulse from the sinus node, a small area in the heart's right atrium (upper chamber). PSVT occurs because of a short circuit an abnormal electrical pathway made of heart cells that allows electricity to speed around in a circle and repeat the signal over and over. As a result, the chambers contract rapidly, which may impair heart function and cause symptoms such as lightheadedness or shortness of breath. There are two main types: accessory path tachycardias and AV nodal reentrant tachycardias.
  • 20. { Example of PSVT with arrows showing the location of P- waves in the ST segment. Note that the P-waves are negative in lead I. Also, seen is alternation in the amplitude of QRS amplitude best seen in C3. PSVT
  • 21. Accessory pathways-related tachycardias: WolffParkinsonWhite syndrome Atrioventricular reentrant tachycardias
  • 22. { Risks possibly associated with an accessory pathway. A. During sinus rhythm there is conduction via the atrioven AV node and accessory pathway. The delta wave in the ECG represents the ventricular pre-excitation caused by the conduction via the accessory pathway. The size of the delta wave and the PR interval depend on the location of the accessory pathway and the conduction properties of the AV node and accessory pathway. B. A retrograde conduction of the accessory pathway bears the risk of an orthodromic AV re-entrant tachycardia with antegrade conduction via the AV node and retrograde conduction via the accessory pathway. C. During atrial fibrillation there is a risk of a fast conduction via the accessory pathway to the ventricles depending on the conduction properties of the accessory pathway. As most accessory pathways have no decremental conduction in contrast to the AV node, the conduction via the accessory pathway can be much faster than via the AV node. This can lead to ventricular fibrillation and sudden cardiac death
  • 23. { Wolff-Parkinson-White (WPW) syndrome is a relatively common heart condition that causes the heart to beat abnormally fast for periods of time. The cause is an extra electrical connection in the heart. This problem with the heart is present at birth (congenital), although symptoms may not develop until later in life. WolffParkinsonWhite syndrome
  • 25. Atrioventricular reentrant tachycardias Atrioventricular nodal reentry tachycardia (AVNRT) is the most common type of supraventricular tachycardia. People with AVNRT have episodes of an irregularly fast heartbeat (more than 100 beats per minute) that often start and end suddenly.
  • 27. Associated with Fast AV nodal pathway for anterograde conduction and Slow AV nodal pathway for retrograde conduction. The retrograde P wave appears after the corresponding QRS ECG QRS -P-T complexes P waves are visible between the QRS and T wave
  • 29. Ventricular tachycardia (VT) is three or more consecutive beats at a rate faster than 100 beats/min. Three or more consecutive beats at slower rates are designated an idioventricular rhythm . VT that terminates spontaneously within 30 s is designated non- sustained whereas sustained VT persists >30 s or is terminated by an active intervention, such as administration of an intravenous medication, external cardioversion, or pacing or a shock from an implanted cardioverter defibrillator.
  • 30. Ventricular fibrillation Ventricular Fibrillation is a very fast, irregular heartbeat that is caused by abnormal firing of electrical signals in the ventricles of the heart. In ventricular fibrillation, disorganized electrical impulses in the hearts lower chambers cause the heart to stop beating (cardiac arrest). The ventricles quiver uselessly, instead of pumping blood.
  • 32. Long QT syndrome is a heart rhythm disorder caused by changes in the heart's electrical recharging system. It doesn't affect the heart's structure. In long QT syndrome, the heart's electrical system takes longer than usual to recharge between beats. This delay is called a prolonged QT interval. Long QT syndrome
  • 33. Congenital long QT syndrome. Some forms of long QT syndrome result from altered DNA that is passed down through families (inherited). Acquired long QT syndrome - this type of long QT syndrome is usually reversible when the underlying cause is identified and treated. Long QT syndrome is often grouped into two main categories, depending on the cause.
  • 34. There are two forms of congenital long QT syndrome: Romano-Ward syndrome (autosomal dominant form). This more common form occurs in people who inherit only a single gene variant from one parent. Jervell and Lange-Nielsen syndrome (autosomal recessive form). Episodes of this rare form of LQTS usually occur very early in life and are more severe. In this syndrome, children receive the altered gene variants from both parents. The children are born with long QT syndrome and deafness. Causes of congenital long QT syndrome
  • 35. Causes of acquired long QT syndrome Drug-induced long QT syndrome. Medications that can cause LQTS include: Certain antibiotics, such as erythromycin (Eryc, Erythrocin, others), azithromycin (Zithromax) and others Antifungal drugs Diuretics that cause an electrolyte imbalance (low potassium, most commonly) Anti-arrhythmics that lengthen the QT interval Some antidepressant and antipsychotic medications Some anti-nausea medications Health conditions that can lead to acquired long QT syndrome include: Hypothermia Hypocalcemia Hypomagnesemia Hypokalemia Pheochromocytoma Stroke or intracranial bleeding Hypothyroidism
  • 36. Bradyarrhythmia is a type of heart arrhythmia. It is characterized by an abnormally slow and irregular heart beat. It may be a warning sign of an underlying heart health issue or another serious health problem. Bradyarrhythmias
  • 37. Whats the difference between bradyarrhythmia and bradycardia?
  • 38. { { Sinus node dysfunction Sinus node dysfunction, previously known as sick sinus syndrome, describes disorders related to abnormal conduction and propagation of electrical impulses at the sinoatrial node. An abnormal atrial rate may result in the inability to meet physiologic demands, especially during periods of stress or physical activity. Heart block A heart block is when the electrical impulses that control the beating of the heart muscle are disrupted. The most serious type of heart block known as a complete, or third degree, heart block will have symptoms, but often those with less serious heart block can have symptoms too. Types of bradyarrhythmias
  • 41. Heart blocks Constant P-R interval I degree block II degree block type II Variable P-R interval II degree block type I III degree block

Editor's Notes

  • #3: The ECG waveforms are labeled alphabetically, beginning with the P wave, which represents atrial depolarization. The QRS complex represents ventricular depolarization, and the ST-T-U complex (ST segment, T wave, and U wave) represents ventricular repolarization. The J point is the junction between the end of the QRS complex and the beginning of the ST segment. Atrial repolarization waveforms (ST-Ta) are usually of too low in amplitude to be detected, it may become apparent in acute pericarditis, atrial infarction, and AV heart block.
  • #8: Cardiac arrhythmias result from abnormalities of electrical impulse generation, conduction, or both. Bradyarrhythmias typically arise from disturbances in impulse formation at the level of the SA node or from disturbances in impulse propagation at any level, including exit block from the sinus node, conduction block in the AVN, and impaired conduction in the His-Purkinje system. Tachyarrhythmias can be classified according to mechanism, including enhanced automaticity (spontaneous depolarization of atrial, junctional, or ventricular pacemakers), triggered arrhythmias (initiated by afterdepolarizations occurring during or immediately after cardiac repolarization, during phase 3 or 4 of the action potential), or reentry (circus propagation of a depolarizing wavefront). A variety of mapping and pacing maneuvers typically performed during invasive electrophysiologic testing can often determine the underlying mechanism of a tachyarrhythmia