Arrhythmias Flashcards
Sinus Bradycardia
Type, Etiology
- Bradyarrhythmias and conduction abnormalities
- Normal response to cardiovascular conditioning; also can result from sinus node dysfunction or beta-blocker or calcium channel blocker (CCB) excess
First degree AV block
Type, Etiology
- Bradyarrhythmias and conduction abnormalities
- Can occur in normal individuals; associated with increased vagal tone and with beta-blocker and CCB use
Second degree AV block (Mobitz I/Wenckebach)
Type, Etiology
- Bradyarrhythmias and conduction abnormalities
- Due to drug effects (digoxin, beta-blocker, CCBs) or increased vagal tone; right coronary ischemia or infarction
Second degree AV block (Mobitz II)
Type, Etiology
- Bradyarrhythmias and conduction abnormalities
- Results from fibrotic disease of the conduction system or from acute, subacute, or prior MI
Third degree AV block (Complete)
Type, Etiology
- Bradyarrhythmias and conduction abnormalities
- No electrical communication between the atria and ventricles
Sick Sinus syndrome/Tachycardia-bradycardia syndrome
Type, Etiology
- Bradyarrhythmias and conduction abnormalities
- A heterogeneous disorder that leads to intermittent supraventricular tachy- and bradyarrhythmias
Sinus Tachycardia
Type, Etiology
- Supraventricular tachyarrhythmias
- Normal physiologic response to fear, pain, and exercise. Can be secondary to hyperthyroidism, volume contraction, infection or pulmonary embolism
Atrial Fibrillation (AF) (Type, Etiology)
- Supraventricular tachyarrhythmias
- Acute AF: pulmonary disease, ischemia, rheumatic heart disease, anemia, atrial myxoma, thyrotoxicosis, ethanol and sepsis. Chronic AF: hypertension and congestive heart failure
Atrial Flutter
Type, Etiology
- Supraventricular tachyarrhythmias
- Circular movement of electrical activity around the atrium at a rate of about 300 times per minute
Multifocal Atrial Tachycardia
Type, Etiology
- Supraventricular tachyarrhythmias
- Multiple atrial pacemakers or reentrant pathways; COPD and hypoxemia
Atrioventricular Nodal Reentry Tachycardia (AVNRT)
Type, Etiology
- Supraventricular tachyarrhythymias
- A reentry circuit in the AV node depolarizes the atrium and ventricle nearly simultaneously
Atrioventricular Reciprocating Tachycardia (AVRT)
Type, Etiology
- Supraventricular tachyarrhythmias
- An ectopic connection between atrium and ventricle that causes a reentry circuit. Seen in Wolff-Parkinson-White syndrome (WPW) [Bundle of Kent (Atria to ventricles)] and Lown-Ganong-Levine syndrome (LGL) [Bundle of James (atria to bundle of His)]
Paroxysmal Atrial Tachycardia
Type, Etiology
- Supraventricular tachyarrhythmias
- Rapid ectopic pacemaker in the atrium (not sinus node)
Premature Ventricular Contraction (PVC)
Type, Etiology
- Ventricular tachyarrhythmias
- Ectopic beats arise from ventricular foci. Associated with hypoxia, electrolyte abnormalities, and hyperthyroidism
Ventricular Tachycardia (VT) (Type, Etiology)
- Ventricular tachyarrhythmias
- Can be associated with CAD, MI, and structural heart disease
Ventricular Fibrillation (VF) (Type, Etiology)
- Ventricular tachyarrhythmias
- Associated with CAD and structural heart disease. Also associated with cardiac arrest (together with asystole)
Torsades de Pointes
Type, Etiology
- Ventricular tachyarrhythmias
- Associated with long QT syndrome, proarrhythmic response to medications (AntiArrhythmics [Class IA, III], AntiBiotics [e.g., macrolides], Anti”C”ychotics [e.g., haloperidol], AntiDepressants [e.g., TCAs], AntiEmetics [e.g., ondanserton]), hypokalemia, hypomagnesemia, congenital deafness and alcoholism
Long QT Syndrome (LQTS)
Etiology
- Either congenital disorder of myocardial repolarization, typically due to ion channel defects; which increase the risk of sudden cardiac death due to torsade de pointes (either Romano-Ward syndrome [AD] which is pure cardiac phenotype or Jervell and Lange-Nielsen syndrome [AR] which is associated with sensorineural deafness) or acquired as in Anorexia nervosa
Brugada Syndrome
Etiology
- Autosomal dominant disease, most common in Asian males, due to myocytes sodium channel defects
- Associated with increased risk of ventricular tachyarrhythmias and sudden cardiac death
Right Bundle Branch Block (RBBB)
Etiology
- It can be due to ASD, Brugada syndrome, right ventricular hypertrophy, pulmonary embolism, IHD, rheumatic heart disease, cardiomyopathy, myocarditis and hypertension
Left Bundle Branch Block (LBBB)
Etiology
- It can be due to aortic stenosis, dilated cardiomyopathy, acute MI, hypertension with aortic root dilatation and Lyme disease
Sinus Bradycardia
Presentation, ECG findings
- May be asymptomatic, but may also present with lightheadedness, syncope, chest pain or hypotension
- ECG: Sinus rhythm and ventricular rate < 60 bpm
First degree AV block
Presentation, ECG findings
- Asymptomatic
- ECG: PR interval > 200 msec
Second degree AV block (Mobitz I/Wenckebach)
Presentation, ECG findings
- Usually asymptomatic
- ECG: progressive PR lengthening until a dropped beat occur; the PR interval then resets
Second degree AV block (Mobitz II)
Presentation, ECG findings
- Occasionally syncope; frequent progression to third degree AV block
- ECG: unexpected dropped beat(s) without a change in PR interval
Third degree AV block (Complete)
Presentation, ECG findings
- Syncope, dizziness, acute heart failure, hypotension and “cannon” a waves
- ECG: no relationship between p waves and QRS complexes
Sick Sinus syndrome/Tachycardia-bradycardia syndrome
Presentation, ECG findings
- Secondary to tachycardia or bradycardia; may include syncope, palpitations, dyspnea, chest pain, TIA, and stroke
- ECG: transient non-specific tachycardia or bradycardia