Arrhythmias & Devices Flashcards¶
SVT Basics¶
Q: What is the most common tachyarrhythmia in children? A: Supraventricular tachycardia (SVT) Tags: arrhythmia, svt, high-yield
Q: What is the most common mechanism of SVT in children? A: Atrioventricular reentrant tachycardia (AVRT) via accessory pathway Tags: arrhythmia, svt, mechanism
Q: What ECG finding suggests WPW syndrome? A: Delta wave (slurred upstroke of QRS), short PR interval, wide QRS Tags: arrhythmia, wpw, ecg, high-yield
Q: What is first-line acute treatment for stable SVT? A: Vagal maneuvers (ice to face in infants, Valsalva in older children) Tags: arrhythmia, svt, treatment, high-yield
Q: What medication is first-line for SVT not responding to vagal maneuvers? A: Adenosine 0.1 mg/kg IV (max 6mg first dose, 12mg second) Tags: arrhythmia, svt, adenosine, high-yield
Q: What medication is contraindicated for wide-complex SVT with possible WPW? A: AV nodal blocking agents (adenosine, verapamil, digoxin) - can accelerate conduction Tags: arrhythmia, wpw, high-yield
Q: What is the initial energy for synchronized cardioversion in SVT? A: 0.5-1 J/kg, can increase to 2 J/kg Tags: arrhythmia, svt, cardioversion
Atrial Arrhythmias¶
Q: What defines atrial flutter on ECG? A: Sawtooth flutter waves at 250-350 bpm, often with 2:1 or 4:1 block Tags: arrhythmia, flutter, ecg
Q: What is the most common atrial arrhythmia in post-operative CHD? A: Intra-atrial reentrant tachycardia (IART/atrial flutter) Tags: arrhythmia, flutter, chd, high-yield
Q: What structural heart disease is associated with atrial fibrillation? A: Dilated atria (mitral valve disease, cardiomyopathy, post-Fontan) Tags: arrhythmia, afib
Ventricular Arrhythmias¶
Q: What defines non-sustained VT (NSVT)? A: ≥3 consecutive ventricular beats at >120 bpm lasting <30 seconds Tags: arrhythmia, vt, definition
Q: What is the first-line medication for recurrent sustained VT? A: Amiodarone or lidocaine Tags: arrhythmia, vt, treatment
Q: What electrolyte abnormalities can cause ventricular arrhythmias? A: Hypokalemia, hypomagnesemia, hypocalcemia Tags: arrhythmia, vt, electrolytes
Q: What medication can cause QT prolongation and torsades? A: Many including: macrolides, antipsychotics, antiemetics, antiarrhythmics Tags: arrhythmia, qt-prolongation, medications
Q: What is the first-line treatment for Torsades de Pointes? A: IV Magnesium sulfate 25-50 mg/kg (even with normal Mg levels) Tags: arrhythmia, torsades, treatment, high-yield
Q: What causes Torsades de Pointes? A: Acquired or congenital QT prolongation; triggered by bradycardia or PVCs (R-on-T) Tags: arrhythmia, torsades, mechanism
Q: What is the initial defibrillation dose for VFib in pediatrics (2025 PALS)? A: 2 J/kg, increase to 4 J/kg for subsequent shocks Tags: arrhythmia, vfib, pals, 2025-update, high-yield
Q: When should epinephrine be given in shockable rhythms (VF/pVT) per 2025 PALS? A: After the SECOND shock (not immediately) Tags: arrhythmia, vfib, pals, 2025-update, high-yield
Q: When should epinephrine be given in non-shockable rhythms per 2025 PALS? A: As soon as possible (ASAP) - associated with improved outcomes Tags: arrhythmia, pals, 2025-update, high-yield
Q: What are the target DBP values during CPR with arterial monitoring (2025 PALS)? A: ≥25 mmHg (infants) or ≥30 mmHg (children) - physiology-directed resuscitation Tags: arrhythmia, pals, resuscitation, 2025-update
Bradycardia & Conduction¶
Q: What defines first-degree AV block? A: PR interval prolonged >upper limit of normal for age, all P waves conducted Tags: arrhythmia, heart-block, ecg
Q: What defines second-degree AV block Mobitz Type I (Wenckebach)? A: Progressive PR prolongation until dropped QRS, then cycle repeats Tags: arrhythmia, heart-block, ecg
Q: What defines second-degree AV block Mobitz Type II? A: Fixed PR interval with intermittent non-conducted P waves (more serious) Tags: arrhythmia, heart-block, ecg
Q: What defines complete (third-degree) heart block? A: Complete AV dissociation - P waves and QRS complexes at independent rates Tags: arrhythmia, heart-block, ecg, high-yield
Q: What is the most common cause of congenital complete heart block? A: Maternal anti-Ro/SSA antibodies (neonatal lupus) Tags: arrhythmia, heart-block, congenital, high-yield
Q: What is the indication for pacing in congenital complete heart block? A: Ventricular rate <55 bpm, wide QRS escape, symptoms, ventricular dysfunction Tags: arrhythmia, heart-block, pacemaker
Q: Why is Mobitz Type II more dangerous than Mobitz Type I (Wenckebach)? A: Mobitz II can progress suddenly to complete heart block without warning; often indicates infranodal disease Tags: arrhythmia, heart-block, high-yield
Q: What is the typical escape rhythm in complete heart block with narrow QRS? A: Junctional escape (40-60 bpm); more stable than ventricular escape Tags: arrhythmia, heart-block, mechanism
Q: What is the typical escape rhythm in complete heart block with wide QRS? A: Ventricular escape (20-40 bpm); less reliable, higher pacing urgency Tags: arrhythmia, heart-block, mechanism
Premature Beats¶
Q: What are PACs and how do they appear on ECG? A: Premature Atrial Contractions - early P wave with different morphology, usually followed by normal QRS Tags: arrhythmia, pacs, ecg
Q: When are PACs clinically significant in children? A: Usually benign; concerning if very frequent, multifocal, or associated with structural heart disease Tags: arrhythmia, pacs, clinical
Q: What defines benign PVCs in pediatrics? A: Unifocal, suppressed with exercise, no structural heart disease, no family history of SCD Tags: arrhythmia, pvcs, high-yield
Q: When are PVCs concerning and require further workup? A: Multifocal, couplets/triplets, increased with exercise, symptoms, >10-15% burden, structural disease Tags: arrhythmia, pvcs, high-yield
Pacemakers & ICDs¶
Q: What does the first letter in pacemaker code represent? A: Chamber paced (A=atrium, V=ventricle, D=dual) Tags: devices, pacemaker, coding
Q: What does the second letter in pacemaker code represent? A: Chamber sensed (A=atrium, V=ventricle, D=dual) Tags: devices, pacemaker, coding
Q: What does the third letter in pacemaker code represent? A: Response to sensing (I=inhibited, T=triggered, D=dual) Tags: devices, pacemaker, coding
Q: What pacing mode is used for complete heart block with normal atrial function? A: DDD (dual chamber paced, dual sensed, dual response) Tags: devices, pacemaker, high-yield
Q: What are primary prevention ICD indications in pediatrics? A: LVEF <35% with symptoms, LMNA mutation with conduction disease, high-risk channelopathy Tags: devices, icd, indications, high-yield
Q: What are secondary prevention ICD indications? A: Survivors of cardiac arrest, sustained VT with structural heart disease Tags: devices, icd, indications
Ablation¶
Q: What is the success rate for SVT ablation in children? A: >90% for most pathways Tags: arrhythmia, ablation, outcomes
Q: What accessory pathway location has highest risk with ablation? A: Septal pathways (risk of AV block) and left-sided near coronary arteries Tags: arrhythmia, ablation, risk
Q: At what age is ablation typically recommended for asymptomatic WPW? A: Consider after age 5; shared decision-making based on risk features Tags: arrhythmia, ablation, wpw