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[Initial clinical experiences with low energy internal cardioversion of chronic atrial fibrillation after
Insights
External electrical cardioversion successfully treated chronic atrial fibrillation in most patients. However, internal cardioversion was needed for those resistant to external methods, but relapses were frequent despite its effectiveness.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Context:
- Chronic atrial fibrillation (AF) poses significant clinical challenges.
- External electrical cardioversion is a standard treatment for AF.
- Patient characteristics like higher body weight may predict resistance to external cardioversion.
Purpose:
- To evaluate the efficacy and safety of internal cardioversion for chronic atrial fibrillation refractory to external cardioversion.
- To compare relapse rates between external and internal cardioversion strategies.
- To assess the long-term clinical value of internal cardioversion in this patient subset.
Summary:
- 54 patients with chronic AF underwent external electrical cardioversion; 91% achieved sinus rhythm.
- Five patients resistant to external cardioversion (higher body weight) underwent successful low-energy internal cardioversion.
- Despite initial success, internal cardioversion showed a high early relapse rate (100% within 2 weeks) compared to external cardioversion (33%).
Impact:
- Internal low-energy cardioversion is effective and safe for AF patients resistant to external methods.
- The clinical utility of internal cardioversion is limited by high early relapse rates in this population.
- Further studies with larger cohorts are needed to clarify the role of internal cardioversion in chronic AF management.
Abstract:
Between January and September 1995, 54 consecutive patients (male: 34, age: 66 +/- 10 years) with symptomatic chronic atrial fibrillation (median duration: 4.5 months) were referred for external electrical cardioversion to our hospital. Mean left atrial diameter was 49 +/- 9 mm, heart disease was apparent in 81%. All patients were under antiarrhythmic drugs (class III: 85%). In 49 patients (91%) sinus rhythm was achieved. In five patients atrial fibrillation persisted after delivery of 360 Joules. These five patients were characterized by a significantly higher body weight in comparison to patients with successful external cardioversion. All five patients underwent low energy internal cardioversion the following day: biphasic R-wave synchronous shocks were delivered through catheters positioned in the right atrium and the coronary sinus using stepwise increased energy levels. Internal cardioversion was successful in all patients resistant to external cardioversion: stable sinus rhythm was established at a mean energy level of 13 +/- 6.7 Joules. No complications were observed. During the follow-up, each patient revealed a relapse of symptomatic atrial fibrillation within 2 weeks after internal cardioversion despite antiarrhythmic therapy, whereas only 16 patients (33%) lost sinus rhythm during the same period of time after external cardioversion (p < 0.01). During a mean follow-up of 283 +/- 72 days 21 patients (43%) preserved stable sinus rhythm after external cardioversion. Internal low energy cardioversion seems to be effective and safe in conversion of chronic atrial fibrillation resistant to external cardioversion. The clinical value of this invasive, time- and material-consuming therapy seems to be limited in this setting because of the high early relapse-rate in the investigated patient population. Further clinical studies in a larger cohort of patients are necessary.