Letter to the Editor Regarding “Active Compression During External Cardioversion of Atrial Fibrillation: A Meta-Analysis of Randomized Controlled Trials”

We read with interest the recent meta-analysis by Taha et al. (2025) on active chest compression during direct current cardioversion (DCCV) for atrial fibrillation (AF), which offers a valuable synthesis of randomized trials. While commendable, certain methodological and clinical aspects deserve closer scrutiny.

The study by Voskoboinik et al. (2019) markedly differs from others as it compared handheld paddles versus patches in obese patients, demonstrating superior success with paddles. Manual pressure was only evaluated in a substudy. Squara et al. (2021) and Kirchhof et al. (2005) highlighted the benefits of compression, while Ferreira et al. (2024) reported no added advantage.

Secondly, defibrillator models and waveforms, known to influence success, were not stratified in the meta-analysis. Schmidt et al. (2017) showed biphasic truncated exponential waveforms outperformed pulsed biphasic forms. Kirchhof et al. (2005) similarly found biphasic shocks and paddle electrodes to improve outcomes. These technical nuances are critical for clinical translation but were not considered.

Antiarrhythmic drug use, a key modifier of cardioversion outcomes, was also not addressed. Squara et al. (2021) and Ferreira et al. (2024) documented baseline drug use but did not adjust for it. Moreover, AF duration is a well-established determinant of success; Gallagher et al. (2001) reported success rates declining from 84% (< 30 days) to 66% (> 180 days), while Carpenter et al. (2019) confirmed that shorter AF history correlates with better long-term outcomes.

Compression methodology also varied. Only Squara et al. (2021) specified a compression force (~80 N), while other studies lacked standardized parameters. This inconsistency limits reproducibility and comparability.

Lastly, some included studies, such as Kirchhof et al. (2005), used older-generation defibrillators (e.g., Lifepak 9/12), whereas newer trials like Ferreira et al. (2024) employed advanced biphasic platforms with impedance compensation. This technological evolution is significant and may impact the generalizability of pooled results.

In conclusion, while Taha et al. (2025) provide valuable insight into active compression during DCCV, future research should rigorously account for procedural variables such as compression parameters, waveform types, antiarrhythmic drug use, AF duration, and defibrillator technology to enhance clinical relevance.

Yusuf Hosoglu: conceptualization, writing – original draft, investigation. Mehmet Göl: writing – review and editing.

The authors declare no conflicts of interest.