Comparison between two defibrillation waveforms

Rate versus rhythm control for atrial fibrillation: from AFFIRM to EAST-AFNET 4 - a paradigm shift

The clinical choice between rate or rhythm control therapies has been debated over the years. In 2002, the AFFIRM trial demonstrated that the rhythm-control strategy had no survival advantage over the rate-control strategy. Eighteen years later, EAST-AFNET 4 showed that the rhythm-control approach is better than rate control in reducing adverse cardiovascular outcomes in patients with a recent diagnosis of atrial fibrillation (AF). During the time between AFFIRM and EAST-AFNET 4, rhythm control understanding, specifically ablation, improved, while rate-control strategies remained the same possibly leading to the change in results seen in EAST-AFNET 4. This review seeks to evaluate the rate- and rhythm-control strategies, focusing on the important clinical trials in the past two decades. These trials have shown great advancement in AF management; however, the search for the best approach to controlling AF and minimizing the burden of symptoms is still a work in progress and needs further research.

Cardioversion Efficacy Using Pulsed Biphasic or Biphasic Truncated Exponential Waveforms: A Randomized Clinical Trial

Background

Several different defibrillators are currently used for cardioversion and defibrillation of cardiac arrhythmias. The efficacy of a novel pulsed biphasic (PB) waveform has not been compared to other biphasic waveforms. Accordingly, this study aims to compare the efficacy and safety of PB shocks with biphasic truncated exponential (BTE) shocks in patients undergoing cardioversion of atrial fibrillation or ‐flutter.

Methods and Results

This prospective, randomized study included patients admitted for elective direct current cardioversion. Patients were randomized to receive cardioversion using either PB or BTE shocks. We used escalating shocks until sinus rhythm was obtained or to a maximum of 4 shocks. Patients randomized to PB shocks received 90, 120, 150, and 200 J and patients randomized to BTE shocks received 100, 150, 200, and 250 J, as recommended by the manufacturers. In total, 69 patients (51%) received PB shocks and 65 patients (49%) BTE shocks. Successful cardioversion, defined as sinus rhythm 4 hours after cardioversion, was achieved in 43 patients (62%) using PB shocks and in 56 patients (86%) using BTE shocks; ratio 1.4 (95% CI 1.1–1.7) (P=0.002). There was no difference in safety (ie, myocardial injury judged by changes in high‐sensitive troponin I levels; ratio 1.1) (95% CI 1.0–1.3), P=0.15. The study was terminated prematurely because of an adverse event.

Conclusions

Cardioversion using a BTE waveform was more effective when compared with a PB waveform. There was no difference in safety between the 2 waveforms, as judged by changes in troponin I levels.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02317029.