Oral Class I and III antiarrhythmic drugs for maintaining sinus rhythm after catheter ablation of atrial fibrillation

BACKGROUND

Recurrence of atrial tachyarrhythmias (ATa) following catheter ablation for atrial fibrillation (AF) is a common problem. Antiarrhythmic drugs have been used shortly after ablation in an attempt to maintain sinus rhythm, particularly Class I and III agents. However, it still needs to be established if the use of Class I or III antiarrhythmic medications, or both, reduce the risk of recurrence of ATa.

OBJECTIVES

To assess the effects of oral Class I and III antiarrhythmic drugs versus control (standard medical therapy without Class I or III antiarrhythmics, or placebo) for maintaining sinus rhythm in people undergoing catheter ablation for AF.

SEARCH METHODS

We systematically searched CENTRAL, MEDLINE, Embase, Web of Science Core Collection, and two clinical trial registers without restrictions on language or date to 5 August 2022.

SELECTION CRITERIA

We sought published, unpublished, and ongoing parallel-design, randomised controlled trials (RCTs) involving adult participants undergoing ablation for AF, with subsequent comparison of Class I and/or III antiarrhythmic use versus control (standard medical therapy or non-Class I and/or III antiarrhythmic use).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and performed meta-analyses with risk ratios (RR) and Peto odds ratios (Peto OR). Our primary outcomes were recurrence of atrial tachyarrhythmias; adverse events: thromboembolic events; adverse events: myocardial infarction; adverse events: new diagnosis of heart failure; and adverse events: requirement for one or more hospitalisations for atrial tachyarrhythmia. Our secondary outcomes were: all-cause mortality; and requirement for one or more repeat ablations. Where possible, we performed comparison analysis by Class I and/or III antiarrhythmic and divided follow-up periods for our primary outcome. We performed comprehensive assessments of risk of bias and certainty of evidence applying the GRADE methodology.

MAIN RESULTS

We included nine RCTs involving a total of 3269 participants. Participants were on average 59.3 years old; 71.0% were male; and 72.9% and 27.4% had paroxysmal and persistent AF, respectively. Class I and/or III antiarrhythmics may reduce recurrence of ATa at 0 to 3 months postablation (risk ratio (RR) 0.74, 95% confidence interval (CI) 0.59 to 0.94, 8 trials, 3046 participants, low-certainty evidence) and likely reduce recurrence at > 3 to 6 months, our a priori primary time point (RR 0.85, 95% CI 0.78 to 0.93, 5 trials, 2591 participants, moderate-certainty evidence). Beyond six months the evidence is very uncertain, and the benefit of antiarrhythmics may not persist (RR 1.14, 95% CI 0.84 to 1.55, 4 trials, 2244 participants, very low-certainty evidence). The evidence suggests that Class I and/or III antiarrhythmics may not increase the risk of thromboembolic events, myocardial infarction, all-cause mortality, or requirement for repeat ablation, at 0 to 3, > 3 to 6, and > 6 months (where data were available; low- to very low-certainty evidence). The use of Class I and/or III antiarrhythmics postablation likely reduces hospitalisations for ATa by approximately 57% at 0 to 3 months (RR 0.43, 95% CI 0.28 to 0.64, moderate-certainty evidence). No data were available beyond three months. No data were available on new diagnoses of heart failure. Fewer data were available for Class I and III antiarrhythmics individually. Based on only one and two trials (n = 125 to 309), Class I antiarrhythmics may have little effect on recurrence of ATa at 0 to 3, > 3 to 6, and > 6 months (RR 0.88, 95% CI 0.64 to 1.20, 2 trials, 309 participants; RR 0.54, 95% CI 0.25 to 1.19, 1 trial, 125 participants; RR 0.87, 95% CI 0.57 to 1.32, 1 trial, 125 participants; low-certainty evidence throughout); requirement for hospitalisation for ATa at 0 to 3 months (low-certainty evidence); or requirement for repeat ablation at 0 to 3 months (low-certainty evidence). No data were available for thromboembolic events, myocardial infarction, new diagnosis of heart failure, or all-cause mortality at any time points, or hospitalisation or repeat ablation beyond three months. Class III antiarrhythmics may have little effect on recurrence of ATa at up to 3 months and at > 3 to 6 months (RR 0.76, 95% CI 0.50 to 1.16, 4 trials, 599 participants, low-certainty evidence; RR 0.82, 95% CI 0.62 to 1.09, 2 trials, 318 participants, low-certainty evidence), and beyond 6 months one trial reported a possible increase in recurrence of ATa (RR 1.95, 95% CI 1.29 to 2.94, 1 trial, 112 participants, low-certainty evidence). Class III antiarrhythmics likely reduce hospitalisations for ATa at 0 to 3 months (RR 0.40, 95% CI 0.26 to 0.63, moderate-certainty evidence), and may have little effect on all-cause mortality (low- to very low-certainty evidence). The effect of Class III antiarrhythmics on thromboembolic events and requirement for repeat ablation was uncertain (very low-certainty evidence for both outcomes). No data were available for myocardial infarction or new diagnosis of heart failure at any time point, outcomes other than recurrence beyond 6 months, or for hospitalisation and repeat ablation > 3 to 6 months. We assessed the majority of included trials as at low or unclear risk of bias. One trial reported an error in the randomisation process, raising the potential risk of selection bias; most of the included trials were non-blinded; and two trials were at high risk of attrition bias.

AUTHORS' CONCLUSIONS

We found evidence to suggest that the use of Class I and/or III antiarrhythmics up to 3 months after ablation is associated with a reduced recurrence of ATa 0 to 6 months after ablation, which may not persist beyond 6 months, and an immediate reduction in hospitalisation for ATa 0 to 3 months after ablation. The evidence suggests there is no difference in rates of all-cause mortality, thromboembolic events, or myocardial infarction between Class I and/or III antiarrhythmics versus control.

Microvascular permeability changes might explain cardiac tamponade after alcohol septal ablation for hypertrophic cardiomyopathy

Various sequelae of alcohol septal ablation for hypertrophic obstructive cardiomyopathy have been reported. Of note, some cases of cardiac tamponade after alcohol septal ablation cannot be well explained. We describe the case of a 78-year-old woman with hypertrophic obstructive cardiomyopathy in whom cardiac tamponade developed one hour after alcohol septal ablation, probably unrelated to mechanical trauma. At that time, we noted a substantial difference in the red blood cell-to-white blood cell ratio between the pericardial effusion (1,957.4) and the peripheral blood (728.3). In addition to presenting the patient's case, we speculate that a possible mechanism for acute tamponade--alcohol-induced changes in microvascular permeability--is a reasonable explanation for cases of alcohol septal ablation that are complicated by otherwise-unexplainable massive pericardial effusions.

Rapid growth of left atrial myxoma after radiofrequency ablation

Atrial myxoma is the most common benign tumor of the heart, but its appearance after radiofrequency ablation is very rare. We report a case in which an asymptomatic, rapidly growing cardiac myxoma arose in the left atrium after radiofrequency ablation. Two months after the procedure, cardiovascular magnetic resonance, performed to evaluate the right ventricular anatomy, revealed a 10 × 10-mm mass (assumed to be a thrombus) attached to the patient's left atrial septum. Three months later, transthoracic echocardiography revealed a larger mass, and the patient was diagnosed with myxoma. Two days later, a 20 × 20-mm myxoma weighing 37 g was excised. To our knowledge, the appearance of an atrial myxoma after radiofrequency ablation has been reported only once before. Whether tumor development is related to such ablation or is merely a coincidence is uncertain, but myxomas have developed after other instances of cardiac trauma.

Sinus arrest during radiofrequency ablation of the atrioventricular-node slow pathway: implications and possible mechanisms

Radiofrequency ablation has been associated with changes in autonomic function. In this case, a 52-year-old woman was referred for electrophysiologic study of recurrent supraventricular tachycardia. Typical slow/fast atrioventricular node re-entry tachycardia was induced and confirmed during the study. Radiofrequency ablation of the slow pathway of the atrioventricular node led to sinus arrest, which resolved once ablation was stopped. Given the distance of the ablation site from the sinus node, we inferred that mechanisms other than direct injury to the sinus node were involved. To our knowledge, this is only the 2nd reported finding of sinus arrest during slow-pathway ablation of the atrioventricular node. This case highlights the complex interaction between the autonomic nervous system and the cardiac conduction system. Possible mechanisms include a Bezold-Jarisch reflex and modification of the intrinsic autonomic nervous system.