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A tale of two QRS: Misleading irregular tachycardia in an ICD carrier

Year: 2026

Type: article

Abstract: We report a 52-year-old man with coronary artery disease, reduced left ventricular ejection fraction, and a cardiac resynchronization therapy-defibrillator (CRT-D), admitted to the emergency department for palpitations. Surface ECG showed a wide-complex tachycardia with a 2:1 ventricular-to-atrial (V:A) relationship. Device interrogation revealed episodes detected in the ventricular tachycardia monitor zone, according to the atrioventricular discrimination algorithms. Detailed analysis of surface ECG and device intracardiac electrograms was performed, followed by an electrophysiological study and catheter ablation of the responsible circuit of the tachycardia. This case illustrates the diagnostic complexity and differential diagnosis of tachycardias presenting with a 2:1 V:A relationship and highlights the importance of integrating surface ECG, device tracings, and electrophysiological findings to correctly identify the underlying mechanism, to avoid misclassification by device algorithms, and to treat the arrhythmia effectively.

Source: Journal of Electrocardiology

DOI: 10.1016/j.jelectrocard.2026.154247

Authors: Antonino Micari, Giuseppe Certo, Giuseppe Andò, Antonio Taormina

Institutions: University of Messina, Azienda Ospedaliera Ospedali Riuniti Papardo Piemonte

Language: English

Topic: Cardiac Arrhythmias and Treatments

Subfield: Cardiology and Cardiovascular Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $2,890