Shock & Pace: quiz on ECG, pacemakers, ICDs and electrophysiology

At a glance

Shock & Pace is a training app for cardiac rhythm management: ECG interpretation, programming and follow-up of pacemakers and implantable cardioverter-defibrillators (ICDs), cardiac resynchronisation therapy (CRT) and conduction system pacing, remote monitoring and electrophysiology (EP studies, pacing manoeuvres, ablation). Every question comes with a detailed answer, a comment on each option and clickable references.

• 1,170 questions with detailed answers
• 61 real 12-lead ECGs
• 17 EP simulator scenarios
• 17 reference guidelines

Question bank updated on 26 September 2026 (version 2026.09.26).

Who is it for?

Cardiologists and cardiology trainees, cardiac physiologists, device and EP nurses and technicians, remote monitoring teams, industry specialists and students: anyone who interprets ECGs or follows patients with a pacemaker or ICD. Questions range from beginner (1/10) to expert (10/10).

Learning modes

• Training by domain or customised (topic, subtopic, manufacturer, question type, level, tracings only), with instant feedback.
• Competitive: an endless, adaptive stream of questions with an ELO rating (starting at 600); the better you do, the harder the questions.
• Timed exam mode with answers at the end, and spaced-repetition review of your mistakes.
• Electrophysiology simulator: a real-time EP recording system and scored mystery cases.
• Progress: day-by-day ELO curve, badges and weak spots.

Question types: single answer, multiple answers (select all that apply), true/false and open questions. The app works offline and can be installed like a native app (PWA). The interface and content are available in English and French.

Topics covered

ECG (314 questions)

Tracing interpretation, real 12-lead ECGs, paced ECGs.

• Real 12-lead ECGs (61)
• Paced ECG: modes and normal function (45)
• Ventricular tachycardia and wide-QRS tachycardia (33)
• Supraventricular tachycardias and ectopic beats (26)
• Paced ECG: CRT and conduction system pacing (21)
• Paced ECG: malfunction (19)
• Channelopathies, repolarisation and electrolytes (18)
• Sinus node dysfunction and escape rhythms (17)
• Atrioventricular block (17)
• Bundle branch and fascicular blocks (15)
• Pacing indications and syncope (15)
• ECG basics (12)
• ICD ECGs (8)
• Pre-excitation and WPW (7)

Pacemaker and ICD programming (526 questions)

Pacing modes, manufacturer algorithms, ICD, CRT.

• ICD: SVT–VT discrimination and inappropriate shocks (66)
• CRT, conduction system pacing and heart failure (63)
• ICD: indications, zones and therapies (54)
• Thresholds, sensing and leads (45)
• Minimising ventricular pacing (45)
• Timing intervals, upper rate and mode switching (39)
• Leadless pacing, implantable monitors and remote monitoring (26)
• ICD: after a shock, S-ICD and end of life (24)
• Rate response and rate algorithms (23)
• Pacemaker EGMs: malfunction and troubleshooting (23)
• Follow-up, longevity, MRI and interference (22)
• Device clinic: practical pitfalls (22)
• Pacing modes and mode selection (21)
• ICD: practical pitfalls (20)
• ICD EGMs: appropriate therapies (13)
• ICD EGMs: inappropriate therapies and oversensing (13)
• Pacemaker EGMs: reading marker channels (7)

Remote monitoring alerts (148 questions)

Remote monitoring, alert triage, management.

• Technical alerts: leads, battery, transmission (19)
• AF and AHRE alerts (18)
• Alert triage: practical pitfalls (17)
• CRT and heart failure alerts (15)
• Organisation, regulatory framework and platforms (15)
• VT/VF and shock alerts (12)
• Remote monitoring EGMs: ventricular episodes (12)
• Remote monitoring EGMs: atrial episodes (10)
• Implantable loop recorders (9)
• Remote monitoring EGMs: technical alerts (8)
• Evidence and trials (7)
• Implantable loop recorder EGMs (6)

Electrophysiology (182 questions)

Mechanisms, EP studies, ablation, antiarrhythmic drugs.

• AVNRT, accessory pathways and pacing manoeuvres (48)
• EP study: conduction, syncope and sinus node function (23)
• Ablation of AF, flutter and the AV junction (20)
• Reading EP study tracings (simulator) (17)
• Complications, anticoagulation and the left atrial appendage (15)
• Cellular electrophysiology and mechanisms (14)
• Anatomy and intracardiac intervals (14)
• PVC/VT ablation and mapping (12)
• Antiarrhythmic drugs (11)
• Clinical trials (8)

Device manufacturers covered: Medtronic, Abbott, Boston Scientific, Biotronik, MicroPort.

Electrophysiology simulator

The simulator recreates an EP recording system: surface leads (I, II, aVF, V1, V6), intracardiac electrograms (high right atrium, proximal and distal His, coronary sinus, right ventricle, ablation catheter), sweep speeds from 12.5 to 400 mm/s, programmed stimulation (drive trains, extrastimuli, ramp pacing), adenosine, isoprenaline, atropine and ablation. Decremental conduction (Wenckebach), refractory periods, re-entry and responses to pacing manoeuvres all emerge from a model of about thirty cardiac sites.

Scenarios: Normal conduction; Dual AV nodal physiology without tachycardia; Typical AVNRT (slow–fast); Atypical AVNRT (fast–slow); Orthodromic AVRT (concealed left lateral accessory pathway); Wolff-Parkinson-White syndrome (left lateral pathway); Typical atrial flutter (counterclockwise, CTI-dependent); Focal atrial tachycardia; Orthodromic AVRT (concealed posteroseptal accessory pathway); Permanent junctional reciprocating tachycardia (Coumel); Mahaim fibres (atriofascicular pathway); Typical AVNRT with 2:1 infra-Hisian block; Left lateral AVRT with functional left bundle branch block; Perimitral flutter (left atrial macro-re-entrant tachycardia); Focal junctional tachycardia; Scar-related ventricular tachycardia; Atrial fibrillation.

Method and reliability

• Questions based only on scientifically validated sources: ESC, EHRA, HRS and ACC/AHA guidelines, consensus documents, indexed articles with DOI and official technical manuals.
• Every question reviewed by an electrophysiologist, with its review date shown; the English version is a translation of the French original, checked against a medical glossary for consistent terminology.
• Automated checks of the question bank at every update (format, sources, answer-length bias, completeness of the translation).
• The real 12-lead ECGs come from the public PTB-XL database (PhysioNet, CC BY 4.0 licence).
• Errors can be reported from every answer.

Reference guidelines

• ESC 2021 pacing and CRT (184 questions)
• ESC 2022 ventricular arrhythmias (111 questions)
• HRS 2023 remote device clinic (89 questions)
• 2015 ICD programming consensus (88 questions)
• ESC 2024 AF (84 questions)
• ESC 2019 SVT (65 questions)
• 2019 ICD programming consensus (46 questions)
• ACC/AHA/HRS 2018 bradycardia (41 questions)
• ESC 2018 syncope (32 questions)
• ESC 2026 heart failure (28 questions)
• EHRA 2023 conduction system pacing (23 questions)
• EHRA/HRS 2024 AF ablation (18 questions)
• HRS 2023 physiologic pacing (15 questions)
• ESC/EHRA 2025 conduction system pacing (8 questions)
• HRS 2017 MRI (8 questions)
• 2019 ventricular arrhythmia ablation consensus (3 questions)
• ESC 2026 CVD and kidney disease (1 questions)

Most cited sources

1. Glikson M, et al. 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Eur Heart J 2021;42:3427-3520 (187)
2. Zeppenfeld K, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J 2022;43:3997-4126 (114)
3. Ferrick AM et al. 2023 HRS/EHRA/APHRS/LAHRS expert consensus statement on practical management of the remote device clinic. Heart Rhythm 2023;20:e92-e144 (89)
4. Mulpuru SK et al. Cardiac pacemakers: function, troubleshooting, and management: part 1 of a 2-part series. J Am Coll Cardiol 2017;69:189-210 (89)
5. Van Gelder IC, et al. 2024 ESC Guidelines for the management of atrial fibrillation. Eur Heart J 2024;45:3314-3414 (84)
6. Barold SS, Stroobandt RX, Sinnaeve AF. Cardiac Pacemakers and Resynchronization Step by Step: An Illustrated Guide. 2nd ed. Wiley-Blackwell; 2010 (79)
7. Brugada J, et al. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. Eur Heart J 2020;41:655-720 (75)
8. Wilkoff BL et al. 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing. Heart Rhythm 2016;13:e50-e86 (71)
9. PTB-XL, a large publicly available electrocardiography dataset, version 1.0.3 (PhysioNet, licence CC BY 4.0) (61)
10. Wagner P, Strodthoff N, Bousseljot RD, et al. PTB-XL, a large publicly available electrocardiography dataset. Sci Data 2020;7:154 (61)
11. Stiles MK, et al. 2019 HRS/EHRA/APHRS/LAHRS focused update to 2015 expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing. Heart Rhythm 2020;17:e220-e228 (48)
12. Josephson ME. Josephson's Clinical Cardiac Electrophysiology: Techniques and Interpretations. 5th ed. Philadelphia: Wolters Kluwer; 2016 (ouvrage de référence) (47)
13. Swerdlow CD et al. Troubleshooting implanted cardioverter defibrillator sensing problems I. Circ Arrhythm Electrophysiol 2014;7:1237-1261 (45)
14. Kusumoto FM, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay. J Am Coll Cardiol 2019;74:e51-e156 (40)
15. Brignole M, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018;39:1883-1948 (32)
16. Køber L, Adamo M, et al. 2026 ESC Guidelines for the management of heart failure. Eur Heart J 2026 (publication en ligne le 28 août 2026) (28)
17. Ellenbogen KA, Wilkoff BL, Kay GN, Lau CP, Auricchio A (eds). Clinical Cardiac Pacing, Defibrillation and Resynchronization Therapy, 5th ed. Elsevier, 2017 (26)
18. Surawicz B, et al. AHA/ACCF/HRS Recommendations for the standardization and interpretation of the electrocardiogram. Part III: intraventricular conduction disturbances. J Am Coll Cardiol 2009;53:976-981 (26)
19. Burri H et al. EHRA clinical consensus statement on conduction system pacing implantation. Europace 2023;25:1208-1236 (23)
20. Ellenbogen KA, Wilkoff BL, Kay GN, Lau CP, Auricchio A (eds). Clinical Cardiac Pacing, Defibrillation and Resynchronization Therapy. 5th ed. Elsevier; 2017 (21)
21. Swerdlow CD et al. Troubleshooting implantable cardioverter-defibrillator sensing problems II. Circ Arrhythm Electrophysiol 2015;8:212-220 (21)
22. Bordachar P, Eschalier R, Ploux S, Strik M. Encyclopédie Boston Scientific : des fondamentaux à l'expertise (stimulateur, DAI endocavitaire, S-ICD, resynchronisation) — cas cliniques sur tracés. Stimuprat Éditions, 2018 (18)
23. Tzeis S et al. 2024 EHRA/HRS/APHRS/LAHRS expert consensus statement on catheter and surgical ablation of atrial fibrillation. Europace 2024;26:euae043 (18)
24. Wilkoff BL et al. 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing. J Arrhythm 2016;32:1-28 (18)
25. Bordachar P, Ellenbogen K, Koneru J, Ploux S. Encyclopédie Medtronic — des fondamentaux à l'expertise : stimulateur cardiaque, défibrillateur, resynchronisation, Holter implantable. Stimuprat Éditions, 2017 (16)
26. Abbott. Gallant™ Dual Chamber ICD (CDDRA500T) — Product Highlights & Product Specifications (MAT-2400586 v4.0) (15)
27. Chung MK et al. 2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure. Heart Rhythm 2023;20:e17-e91 (15)
28. Veenhuyzen GD, et al. Diagnostic pacing maneuvers for supraventricular tachycardias: part 2. Pacing Clin Electrophysiol 2012;35:757-769 (15)
29. Veenhuyzen GD, et al. Diagnostic pacing maneuvers for supraventricular tachycardia: part 1. Pacing Clin Electrophysiol 2011;34:767-782 (14)
30. Bordachar P, Chinitz LA, Park D, Ploux S. Encyclopédie Biotronik — des fondamentaux à l'expertise : BioMonitor, stimulateur cardiaque, défibrillateur automatique implantable. Stimuprat Éditions, 2017 (13)
31. Hayes DL et al. Cardiac resynchronization therapy and the relationship of percent biventricular pacing to symptoms and survival. Heart Rhythm 2011;8:1469-1475 (13)
32. Josephson ME. Josephson's Clinical Cardiac Electrophysiology: Techniques and Interpretations, 6e éd. Wolters Kluwer, 2021 (13)
33. Alasti M et al. Pacemaker-mediated arrhythmias. J Arrhythm 2018;34:485-492 (12)
34. Moss AJ et al. Reduction in inappropriate therapy and mortality through ICD programming (MADIT-RIT). N Engl J Med 2012;367:2275-2283 (12)
35. Stühlinger M et al. EHRA consensus on prevention and management of interference due to medical procedures in patients with cardiac implantable electronic devices. Europace 2022;24:1512-1537 (12)
36. Kligfield P, et al. Recommendations for the standardization and interpretation of the electrocardiogram. Part I: the electrocardiogram and its technology (AHA/ACC/HRS). J Am Coll Cardiol 2007;49:1109-1127 (10)
37. Mahfouz K, Bordachar P, Grosmaire D, Ritter P. Stimulateur cardiaque implantable – Cas cliniques basés sur des tracés MicroPort. Stimuprat Éditions, 2019 (10)
38. MicroPort CRM. Périodes réfractaires et marqueurs – gammes brady et tachy (support de formation) (10)
39. Swerdlow CD et al. Downloadable software algorithm reduces inappropriate shocks caused by implantable cardioverter-defibrillator lead fractures: a prospective study. Circulation 2010;122:1449-1455 (10)
40. Bordachar P, Ploux S, Ritter P, et al. Stimulateur cardiaque implantable : interrogation et programmation. Stimuprat Éditions, 2015 (chapitre « Modes de stimulation ») (9)

Frequently asked questions

Disclaimer

Educational tool: the questions are designed for learning and maintaining knowledge. They do not replace official guidelines, manufacturers' manuals or clinical judgement.