Diagnostic evaluation of unexplained ventricular tachyarrhythmias in younger adults

• Published in: Journal of cardiovascular electrophysiology Vol. 34; no. 4; pp. 959 - 966
• Main Authors: William, Jeremy, Xiao, Xiaoman, Shirwaiker, Anita, Patel, Hitesh, Prabhu, Sandeep, Ling, Liang‐Han, Sugamar, Hariharan, Mariani, Justin, Kistler, Peter, Voskoboinik, Aleksandr
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.04.2023
• Subjects: Adult; Anti-Arrhythmia Agents; Arrhythmias, Cardiac - complications; automatic implantable cardiac defibrillator; Cardiac arrest; Cardiac arrhythmia; Drug therapy; Echocardiography; EKG; Electrophysiology; Etiology; Female; Flecainide; Genetic screening; Genetic testing; Heart Arrest; Heart diseases; Humans; Magnetic resonance imaging; Retrospective Studies; Tachycardia, Ventricular; Ventricle; ventricular fibrillation; ventricular tachycardia; ventricular fibrillation; ventricular tachycardia; cardiac arrest; automatic implantable cardiac defibrillator
• ISSN: 1045-3873; 1540-8167
• DOI: 10.1111/jce.15868

Background The diagnostic work‐up for cardiac arrest from ventricular tachyarrhythmias occurring in younger adults and structurally normal hearts is variable and often incomplete. Methods We reviewed records for all recipients of a secondary prevention implantable cardiac defibrillator (ICD) younger than 60 years at a single quaternary referral hospital from 2010 to 2021. Patients with unexplained ventricular arrhythmias (UVA) were identified as those with no structural heart disease on echocardiogram, no obstructive coronary disease, and no clear diagnostic features on ECG. We specifically evaluated the adoption rate of five modalities of “second‐line” cardiac investigations: cardiac magnetic resonance imaging (CMR), exercise ECG, flecainide challenge, electrophysiology study (EPS), and genetic testing. We also evaluated patterns of antiarrhythmic drug therapy and device‐detected arrhythmias and compared them with secondary prevention ICD recipients with a clear etiology found on initial assessment. Results One hundred and two recipients of a secondary prevention ICD under the age of 60 were analyzed. Thirty‐nine patients (38.2%) were identified with UVA and were compared with the remaining 63 patients with VA of clear etiology (61.8%). UVA patients were younger (35.6 ± 13.0 vs. 46.0 ± 8.6 years, p < .001) and were more often female (48.7% vs. 28.6%, p = .04). CMR was performed in 32 patients with UVA (82.1%), whereas flecainide challenge, stress ECG, genetic testing, and EPS were only performed in a minority of patients. Overall, the use of a second‐line investigation suggested an etiology in 17 patients with UVA (43.5%). Compared to patients with VA of clear etiology, UVA patients had lower rates of antiarrhythmic drug prescription (64.1% vs. 88.9%, p = .003) and had a higher rate of device‐delivered tachy‐therapies (30.8% vs. 14.3%, p = .045). Conclusion In this real‐world analysis of patients with UVA, the diagnostic work‐up is often incomplete. While CMR was increasingly utilized at our institution, investigations for channelopathies and genetic causes appear to be underutilized. Implementation of a systematic protocol for work‐up of these patients requires further study. Diagnotic yield of second‐line investigations in the workup of unexplained ventricular tachyarrhythmia. Of 102 recipients of secondary prevention implantable cardiac defibrillators aged under the age of 60 years, 39 patients met criteria for unexplained ventricular arrhythmia. Seventeen of these 39 patients had an underlying diagnosis suggested by a second‐line investigation. Cardiac MRI was the most frequently utilized test, while the remaining investigations were utilized less commonly.