100+ Free ABIM Clinical EP Practice Questions

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Question 1

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Which ion current is primarily responsible for phase 0 depolarization of a ventricular myocyte action potential?

Slow inward calcium current (ICaL)

Fast inward sodium current (INa)

Rapidly activating delayed rectifier potassium current (IKr)

Funny pacemaker current (If)

to track

2026 Statistics

Key Facts: ABIM Clinical EP Exam

~$2,990

Exam Fee

ABIM 2026

2 years

EP Fellowship

ACGME-accredited

~90%

First-Time Pass Rate

ABIM historical

~90%

PV Triggers in Paroxysmal AF

Haissaguerre 1998

$650K-$850K+

EP Compensation

MGMA 2024

300-500 hrs

Avg Study Time

Board candidates

Clinical Cardiac Electrophysiology sits at the apex of cardiology subspecialty training: ~100 ACGME-accredited EP fellowship positions annually feed demand from >1,500 US EP labs performing AF ablation, device implantation, and complex ventricular tachycardia ablation. Electrophysiologists command among the highest salaries in internal medicine (median $650K-$850K+, MGMA 2024). The CCEP exam tests cellular EP, Vaughan Williams pharmacology, AF/flutter/SVT/VT ablation (PVI, PFA, substrate mapping, entrainment), CIEDs (pacemakers, ICDs, CRT, LBBAP, leadless), and inherited channelopathies (LQTS, Brugada, CPVT) at subspecialty depth. Maintenance of certification uses LKA (~30 questions/quarter open-book) or a 10-year exam.

Sample ABIM Clinical EP Practice Questions

Try these sample questions to test your ABIM Clinical EP exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which ion current is primarily responsible for phase 0 depolarization of a ventricular myocyte action potential?

A.Slow inward calcium current (ICaL)

B.Fast inward sodium current (INa)

C.Rapidly activating delayed rectifier potassium current (IKr)

D.Funny pacemaker current (If)

Explanation: Phase 0 of the ventricular (fast-response) action potential is caused by rapid opening of voltage-gated sodium channels producing the fast inward sodium current (INa). Class I antiarrhythmics block this current. ICaL dominates phase 2 plateau; IKr contributes to phase 3 repolarization; If drives pacemaker automaticity in nodal tissue.

2The transient outward potassium current (Ito) is primarily responsible for which phase of the ventricular action potential?

A.Phase 0 depolarization

B.Phase 1 early repolarization (the notch)

C.Phase 2 plateau

D.Phase 4 diastolic depolarization

Explanation: Ito produces the brief phase 1 repolarization notch immediately following phase 0. Ito is more prominent in epicardium than endocardium, creating a transmural voltage gradient important in Brugada syndrome. Exaggerated Ito unmasked by loss-of-function SCN5A mutations contributes to the coved ST elevation and phase 2 reentry arrhythmias.

3Which currents jointly maintain the phase 2 plateau of the ventricular action potential?

A.INa inward and IK1 outward

B.ICaL inward and delayed rectifier potassium currents (IKs/IKr) outward

C.If inward and Ito outward

D.INa/K ATPase and Na/Ca exchanger only

Explanation: During phase 2, sustained inward L-type calcium current (ICaL) is electrically balanced by outward delayed rectifier potassium currents (IKs and IKr), producing the characteristic plateau. This phase triggers calcium-induced calcium release for excitation-contraction coupling. Loss of IKs (LQT1) or IKr (LQT2) prolongs the plateau and QT interval.

4In a sinoatrial node cell, which current is the 'funny current' (If) responsible for pacemaker automaticity?

A.Voltage-gated sodium current (INa)

B.HCN channel-mediated mixed Na+/K+ inward current activated by hyperpolarization

C.L-type calcium current (ICaL)

D.Na+/K+ ATPase pump current

Explanation: If is carried through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and is a mixed inward Na+/K+ current activated at hyperpolarized potentials (~-60 mV). It drives the slow diastolic (phase 4) depolarization of SA node cells. Ivabradine blocks If and slows heart rate without negative inotropy.

5According to the Vaughan Williams classification, which class consists of sodium channel blockers subclassified A, B, and C based on kinetics and effect on action potential duration?

A.Class I

B.Class II

C.Class III

D.Class IV

Explanation: Class I drugs block fast sodium channels (INa). IA (quinidine, procainamide, disopyramide) have intermediate kinetics and prolong APD; IB (lidocaine, mexiletine) bind fast and shorten APD; IC (flecainide, propafenone) have slow unbinding and minimal APD change but markedly slow conduction. Class II are beta-blockers, III are K+ blockers, IV are non-DHP calcium channel blockers.

6Which antiarrhythmic drug is a Class IC agent most commonly used for pill-in-pocket cardioversion of paroxysmal atrial fibrillation in patients without structural heart disease?

A.Amiodarone

B.Lidocaine

C.Flecainide

D.Sotalol

Explanation: Flecainide (IC) is used for pill-in-pocket cardioversion in lone AF. The CAST trial showed increased mortality with IC agents in patients with prior MI or structural heart disease, so flecainide and propafenone are contraindicated in ischemic or significantly structurally diseased hearts. An AV nodal blocker should be co-administered to prevent 1:1 atrial flutter.

7Which Class III antiarrhythmic is a pure IKr blocker requiring mandatory in-hospital initiation with QTc monitoring and renal dosing?

A.Amiodarone

B.Dronedarone

C.Dofetilide

D.Sotalol

Explanation: Dofetilide is a pure IKr blocker indicated for maintenance of sinus rhythm in AF. FDA labeling requires 3-day in-hospital initiation with ECG monitoring, serial QTc measurements, and renal dose adjustment (based on CrCl) because of risk of torsades de pointes. Contraindicated if CrCl <20 mL/min or baseline QTc >440 ms (500 ms with conduction abnormalities).

8A 62-year-old with persistent AF is started on dronedarone. Which trial finding limits dronedarone use in this population?

A.ATHENA showed benefit in paroxysmal/persistent AF

B.PALLAS showed increased mortality in permanent AF

C.RACE II showed benefit in rate control

D.CASTLE-AF showed reduced mortality

Explanation: The PALLAS trial demonstrated excess cardiovascular death, stroke, and heart failure with dronedarone in patients with permanent AF, leading to a contraindication in permanent AF and NYHA III-IV or recently decompensated HF. ATHENA previously showed benefit in paroxysmal/persistent AF. Dronedarone also lacks iodine, avoiding amiodarone's thyroid/pulmonary toxicity.

9Amiodarone toxicity monitoring should include which baseline studies because of its long half-life and multi-organ toxicity profile?

A.LFTs, TSH, PFTs with DLCO, and chest X-ray

B.Only ECG and CBC

C.Only renal function and lipid panel

D.Abdominal ultrasound and HbA1c

Explanation: Amiodarone's half-life is ~50-100 days. Baseline and periodic monitoring should include LFTs (hepatotoxicity), TSH (hypo- or hyperthyroidism), pulmonary function tests with DLCO and chest X-ray (pulmonary fibrosis), ophthalmologic evaluation (corneal microdeposits, optic neuropathy), and skin/neurologic assessment. ECG monitors for QT prolongation and bradyarrhythmia.

10Which proportion of paroxysmal AF triggers originate from the pulmonary vein ostia?

A.~30%

B.~50%

C.~70%

D.~90%

Explanation: Approximately 90% of paroxysmal AF triggers arise from ectopic foci within the pulmonary vein sleeves, particularly the superior pulmonary veins. This observation by Haissaguerre in 1998 established pulmonary vein isolation (PVI) as the cornerstone of AF ablation. Non-PV triggers (superior vena cava, crista terminalis, ligament of Marshall, left atrial posterior wall) account for the remainder and may become dominant in persistent AF.

About the ABIM Clinical EP Exam

The ABIM Clinical Cardiac Electrophysiology (CCEP) subspecialty certification validates expertise in diagnosis and management of cardiac arrhythmias, including catheter ablation, cardiac implantable electronic devices (CIEDs), channelopathies, and sudden cardiac death prevention. Candidates must hold ABIM Cardiovascular Disease certification and complete a 2-year ACGME-accredited EP fellowship.

Questions

220 scored questions

Time Limit

~9 hours (four 60-minute modules + breaks)

Passing Score

Criterion-referenced ABIM scaled score (cut set per administration)

Exam Fee

~$2,990 ABIM certification fee (American Board of Internal Medicine (ABIM))

ABIM Clinical EP Exam Content Outline

15%

Cellular Electrophysiology & Antiarrhythmic Drugs

Cardiac action potential phases (0 INa, 1 Ito, 2 ICaL + IKs/IKr, 3 IKr/IKs, 4 If/IK1), Vaughan Williams classes I-IV, amiodarone/sotalol/dofetilide/dronedarone monitoring.

25%

Atrial Fibrillation & Atrial Flutter

AF classification (paroxysmal/persistent/longstanding/permanent), PV triggers (~90% paroxysmal), PVI (RF, cryo, PFA), CASTLE-AF, CHA2DS2-VASc, LAA occlusion, CTI-dependent typical flutter, perimitral/roof atypical flutter.

15%

SVT & Pre-Excitation

Typical/atypical AVNRT, orthodromic/antidromic AVRT, WPW localization (Arruda), Mahaim fibers, EP maneuvers (entrainment, para-Hisian pacing, V-A-V vs V-A-A-V), IST, POTS, vasovagal syncope.

20%

VT, PVC & Channelopathies

Idiopathic RVOT/LVOT VT, fascicular (verapamil-sensitive) VT, scar-related VT, ARVC, sarcoidosis, Chagas, HCM, LQT1-3, Brugada, CPVT (RYR2), short QT, commotio cordis, SADS.

20%

CIEDs, Pacing & ICDs

PPM indications, NBG code, CRT (LBBB >=150 ms, COMPANION/CARE-HF), LBBAP/His bundle pacing, leadless (Micra, Aveir), ICD primary (SCD-HeFT, MADIT-II, DANISH) and secondary prevention, S-ICD, MADIT-RIT programming.

Mapping, Ablation & Special Populations

Entrainment with concealed fusion (PPI-TCL <30 ms), substrate voltage mapping, ICE-guided transseptal, contact force catheters, pregnancy arrhythmia, adult CHD (Fontan, TOF), athlete ECG, CIED extraction.

How to Pass the ABIM Clinical EP Exam

What You Need to Know

Passing score: Criterion-referenced ABIM scaled score (cut set per administration)
Exam length: 220 questions
Time limit: ~9 hours (four 60-minute modules + breaks)
Exam fee: ~$2,990 ABIM certification fee

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

ABIM Clinical EP Study Tips from Top Performers

1Memorize the cardiac action potential by phase and link each to the dominant ion current (phase 0 INa, phase 1 Ito, phase 2 ICaL + IKs/IKr, phase 3 IKr + IKs, phase 4 If in nodes, IK1 in working myocardium) — this is the backbone of antiarrhythmic pharmacology and channelopathy questions.

2Drill EP maneuvers for SVT discrimination: para-Hisian pacing (node vs accessory pathway), V-A-V (AVNRT/AVRT) vs V-A-A-V (AT) after ventricular entrainment, HA interval comparisons, and delta HA during PVCs during tachycardia.

3Know the landmark trials cold: CASTLE-AF (AF ablation in HFrEF), MADIT-II/SCD-HeFT (primary-prevention ICD), MADIT-RIT (high-rate/delayed ICD programming), DANISH (NICM ICD), COMPANION/CARE-HF (CRT), PALLAS (dronedarone in permanent AF), PROTECT-AF/PREVAIL (Watchman), PRAETORIAN (S-ICD).

4Build ECG localization algorithms: WPW (Arruda), VT origin (LBBB inferior axis = RVOT, RBBB left superior = left posterior fascicle), typical vs atypical flutter (inferior-lead sawtooth F-wave polarity), LQT type identification from T-wave morphology.

5Drill CIED indications as tables with class of recommendation: primary-prevention ICD (LVEF <=35%, NYHA II-III, GDMT >=3 mo NICM or >=40 d post-MI), CRT (LBBB >=150 ms, LVEF <=35%), PPM (symptomatic SND, complete AV block, HV >=70 ms with syncope). Memorize NBG code and DDDR logic.

Frequently Asked Questions

Who is eligible to sit for the ABIM Clinical Cardiac Electrophysiology exam?

Candidates must hold ABIM certification in Cardiovascular Disease and complete an ACGME-accredited 2-year (24-month) Clinical Cardiac Electrophysiology fellowship. A program director attestation and documentation of required procedural volumes (ablations, device implants) is required. Unrestricted state medical license is mandatory.

How is the ABIM Clinical EP exam structured?

The exam is a computer-based multiple-choice test administered at Pearson VUE, consisting of approximately 220 single-best-answer questions delivered across four 60-minute modules over a full testing day (~9 hours with tutorial and breaks). Content covers the ABIM CCEP blueprint with emphasis on AF management, CIEDs, SVT/VT, and channelopathies.

What is the ABIM Clinical EP exam fee in 2026?

The ABIM certification fee for Clinical Cardiac Electrophysiology is approximately $2,990 for initial certification. Late fees apply for applications submitted after the priority deadline. Maintenance of certification (LKA) is a separate enrollment fee (~$220 per year). Fees are subject to change on the ABIM fee schedule.

What topics carry the most weight on the exam?

Atrial fibrillation/flutter (roughly a quarter of content) and ventricular arrhythmias/channelopathies and CIEDs (each ~20%) dominate. Mastery of the 2023 ACC/AHA/ACCP/HRS AF guideline, 2017 AHA/ACC/HRS VT/SCD guideline, and 2018 ACC/AHA/HRS bradycardia/CRT guidelines is essential, along with landmark trials (CASTLE-AF, MADIT-II/RIT, SCD-HeFT, DANISH, COMPANION, PROTECT-AF).

How do electrophysiologists maintain certification after passing the exam?

Most choose the ABIM Longitudinal Knowledge Assessment (LKA): ~30 questions per quarter, open-book, 4 minutes per question. Alternatively, diplomates may take the traditional 10-year recertification exam. Both require ongoing CME and self-evaluation. Missed LKA questions can be repeated in the next cycle.

Is the ABIM Clinical EP certification worth the time and cost?

Yes for practicing electrophysiologists. Board-certified EPs command among the highest cardiology salaries (median $650K-$850K+, MGMA 2024), with strong demand driven by AF ablation volume growth, CRT/ICD indications, and aging populations. Certification is also required for most hospital EP lab credentialing, academic faculty positions, and industry consulting.

What resources are recommended for ABIM Clinical EP prep?

Core texts: Zipes/Jalife Cardiac Electrophysiology: From Cell to Bedside, Issa/Miller/Zipes Clinical Arrhythmology and Electrophysiology, and Josephson's Clinical Cardiac Electrophysiology. Popular review courses: HRS Heart Rhythm Board Review, Mayo Clinic EP Board Review, and online question banks. Focused review of ACC/AHA/HRS guidelines and landmark trials is high-yield.

How difficult is the ABIM Clinical EP exam?

The CCEP exam is considered very challenging, with EP-specific questions requiring integration of cellular mechanisms, catheter ablation techniques, complex device programming, pharmacology, and genetic channelopathies. Fellowship graduates with 300-500 hours of focused study generally pass on first attempt (~90% first-time pass rate), but the breadth of material (drugs to devices to ablation to genetics) makes it unforgiving without structured preparation.