Clinical Impact of Arrhythmias Detected by an Implantable Cardiac Monitoring Device With Real-Time Transmission Among Patients With Early Reduced Left Ventricular Ejection Fraction After ST-Segment Elevation Acute Myocardial Infarction: The TeVeO Study.

Background

Modern therapeutic strategies have reduced mortality after a ST-segment elevation acute myocardial infarction (STEMI). However, up-to-date information on the incidence and prognostic impact of arrhythmias following this event is lacking.

Objectives

This study sought to evaluate the incidence and clinical impact of ambulatory arrhythmias detected by an implantable cardiac monitor (ICM) using Bluetooth connectivity and remote monitoring after STEMI.

Methods

The TeVeO study was a multicenter, prospective study of patients who survived STEMI with reduced left ventricular ejection fraction (LVEF). Patients underwent continuous electrocardiographic monitoring using an ICM after discharge. Indication for implantable cardioverter-defibrillator (ICD) placement for primary prevention was evaluated at 6 months.

Results

A total of 3,565 patients were hospitalized for STEMI and subsequently discharged from our institutions. Of these, 636 had an LVEF ≤40% on day 4 or later. After application of the inclusion and exclusion criteria, 224 patients (35%) were enrolled (median LVEF: 35%). After a median follow-up time of 3.1 years, the mortality rate was 3.7 per 100 patient-years. No cases of sudden arrhythmic death were observed. At 6 months, an ICD was implanted in 25 (11%) patients (23 for primary prevention, 2 for secondary prevention). During follow-up, 119 patients (53%) experienced at least 1 ambulatory arrhythmia: 39 (17%) atrial fibrillation (AF), 35 (16%) nonsustained ventricular tachycardia, 33 (15%) sinus pauses >3 seconds, 14 (6%) second-or third-degree atrioventricular block, and 5 (2.2%) sustained monomorphic ventricular tachycardia/appropriate ICD therapy. The incidence rate of nonsustained ventricular tachycardia was 5.4 and for sustained monomorphic ventricular tachycardia/appropriate ICD therapy 0.9 per 100 patient-years. Only AF was independently associated with increased mortality (adjusted HR = 2.5; P = 0.04).

Conclusions

The incidence and burden of ventricular arrhythmias were lower than expected. AF was associated with an increased mortality.