Electrical cardioversion of patients with implanted pacemaker or cardioverter-defibrillator: results of a survey of german centers and systematic review of the literature

Long-term risk of cardiovascular implantable electronic device reinterventions following external cardioversion of atrial fibrillation and flutter: A nationwide cohort study

BACKGROUND

External cardioversion (ECV) is an essential part of rhythm control of atrial fibrillation and flutter in patients with and without cardiovascular implantable electronic devices (CIEDs). Long-term follow-up data on ECV-related CIED dysfunctions are limited.

OBJECTIVE

The purpose of this study was to investigate the risk of CIED reintervention following ECV in a nationwide cohort.

METHODS

We identified CIED implants and surgical reinterventions from 2005 to 2021 in the Danish Pacemaker and ICD Register. We included CIED patients undergoing ECV from 2010 to 2019 from the Danish National Patient Registry. For each ECV-exposed generator, 5 matched generators without ECV were identified, and for each ECV-exposed lead, 3 matched leads were identified. The primary endpoints were generator replacement and lead reintervention.

RESULTS

We compared 2582 ECV-exposed patients with 12,910 matched patients with a pacemaker (47%), implantable cardioverter-defibrillator (ICD) (29%), cardiac resynchronization therapy-pacemaker (6%), or cardiac resynchronization therapy-defibrillator (18%). During 2 years of follow-up, 210 ECV-exposed generators (8.1%) vs 670 matched generators (5.2%) underwent replacements, and 247 ECV-exposed leads (5.6%) vs 306 matched leads (2.3%) underwent reintervention. Unadjusted hazard ratios were 1.61 (95% confidence interval [CI] 1.37-1.91; P <.001) for generator replacement and 2.39 (95% CI 2.01-2.85; P <.001) for lead reintervention. One-year relative risks were 1.73 (95% CI 1.41-2.12; P <.001) for generator replacement and 2.85 (95% CI 2.32-3.51; P <.001) for lead reintervention, and 2-year relative risks were 1.39 (95% CI 1.19-1.63; P <.001) and 2.18 (95% CI 1.84-2.57; P <.001), respectively.

CONCLUSION

ECV in patients with a CIED is associated with a higher risk of generator replacement and lead reintervention. The risks of reinterventions were more pronounced within the first year after cardioversion.

External cardioversion of atrial fibrillation and flutter in patients with cardiac implantable electrical devices

BACKGROUND

Atrial fibrillation and flutter are often treated with external electrical cardioversion (ECV) in patients with potentially electrically sensitive cardiovascular implantable electronic devices (CIED). Long-term follow-up data on contemporary CIED undergoing ECV is sparse. The aim is to investigate shock-related complications and impact on CIEDs.

METHODS

All ECV procedures from 2010 to 2020 in patients with CIED performed at a tertiary university hospital were identified in the Danish National Patient Registry. Changes in device measurements after ECV were retrospectively studied and procedure-related complications were identified by review of medical records.

RESULTS

We analyzed 763 ECV procedures in 372 patients, median device implant time 1.9 years. The mean age of patients was 69.9 ± 9.9 years of which 73.4% were men. We identified two cases of device programming changes and four cases of premature battery depletion (≤3 years after device implant). Minor changes in device measurements were found for impedances, sensing, and pacing thresholds. No patients died due to ECV-related device dysfunctions within the first 12 months after cardioversions.

CONCLUSION

External cardioversion in patients with contemporary pacemakers and implantable cardioverter-defibrillators seems safe in the majority of patients. Clinically important changes in device function following cardioversion were rarely observed but may be critical for device function. In an observational study, causality between cardioversion and device dysfunction cannot be established. For patient safety, we suggest that routine device interrogation after cardioversion still should be part of standard care.

External versus internal cardioversion for atrial fibrillation: a meta-analysis of randomized controlled trials

BACKGROUND

Patients with atrial fibrillation (AF) often require rhythm control strategy for amelioration of symptoms. It is unclear if there is any difference between external cardioversion (ECV) and internal cardioversion (ICV) for successful conversion of AF to normal sinus rhythm.

METHODS

We performed a meta-analysis of published randomized controlled trials (RCTs) evaluating success of cardioversion using ECV versus ICV.

RESULTS

In the pooled analysis of 5 RCTS, there was no difference in success of cardioversion using ECV versus ICV (OR 1.69, 95% CI 0.24-11.83, p = 0.6). In the subgroup analysis, there was no difference between ECV and direct electrode ICV (OR 0.41, 95% CI 0.09-1.83, p = 0.24). However, ECV was significantly better compared with ICV using ICD (OR 11.97, 95% CI 1.87-76.73, p = 0.009).

CONCLUSIONS

There was no difference between ECV versus ICV in effectiveness for termination of AF. Larger well-designed randomized controlled trials are needed to confirm our findings.

Randomized trial comparing the effectiveness of internal (through implantable cardioverter defibrillator) versus external cardioversion of atrial fibrillation

PURPOSE

When patients with implantable cardioverter defibrillators (ICD) develop symptomatic atrial fibrillation (AF), external direct current cardioversion (EDCCV), as well as internal cardioversion using their ICD, are the options available. It is currently unknown which of these two methods are more effective. We compared the effectiveness of EDCCV versus internal cardioversion to terminate AF in patients with a single-coil ICD.

METHODS

This randomized controlled trial (clinicaltrial.gov NCT03164395) enrolled consecutive patients with a single-coil ICD that presented with symptomatic AF of less than 1-year duration. They received either the maximum energy internal shock through the ICD or an EDCCV using transcutaneous pads of 200 J. The primary endpoint was a successful conversion to sinus rhythm after one shock. Crossover was permitted if the first shock was unsuccessful.

RESULTS

Thirty-one patients were enrolled in the study, including 16 in the internal ICD cardioversion group. The study included patients with a mean age of 59.5 ± 16.0 years, 41.9% females, median AF duration 1 month (interquartile range 1-3), 45.2% non-ischemic cardiomyopathies, mean EF 28.6 ± 16.0%, and 45.2% biventricular ICD. There were no significant differences in baseline clinical characteristics between the two groups. In the internal cardioversion group, 5/16 patients (31.3%) met the primary endpoint versus 14/15 (93.3%) in the EDCCV group, p < 0.001. All patients that failed the first shock were subsequently cardioverted externally.

CONCLUSION

Among patients with a single-coil ICD and symptomatic AF of less than 1 year, external direct current cardioversion is much more effective than internal shock through the ICD.

Internal Versus External Electrical Cardioversion of Atrial Arrhythmia in Patients With Implantable Cardioverter-Defibrillator: A Randomized Clinical Trial

BACKGROUND

Atrial arrhythmias are common in patients with implantable cardioverter-defibrillator (ICD). External shocks and internal cardioversion through commanded ICD shock for electrical cardioversion are used for rhythm-control. However, there is a paucity of data on efficacy of external versus internal cardioversion and on the risk of lead and device malfunction. We hypothesized that external cardioversion is noninferior to internal cardioversion for safety, and superior for successful restoration of sinus rhythm.

METHODS

Consecutive patients with ICD undergoing elective cardioversion for atrial arrhythmias at 13 centers were randomized in 1:1 fashion to either internal or external cardioversion. The primary safety end point was a composite of surrogate events of lead or device malfunction. Conversion of atrial arrhythmia to sinus rhythm was the primary efficacy end point. Myocardial damage was studied by measuring troponin release in both groups.

RESULTS

N=230 patients were randomized. Shock efficacy was 93% in the external cardioversion group and 65% in the internal cardioversion group (P<0.001). Clinically relevant adverse events caused by external or internal cardioversion were not observed. Three cases of pre-existing silent lead malfunction were unmasked by internal shock, resulting in lead failure. Troponin release did not differ between groups.

CONCLUSIONS

This is the first randomized trial on external vs internal cardioversion in patients with ICDs. External cardioversion was superior for the restoration of sinus rhythm. The unmasking of silent lead malfunction in the internal cardioversion group suggests that an internal shock attempt may be reasonable in selected ICD patients presenting for electrical cardioversion.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT03247738.

Prognostic impact of recurrences of ventricular tachyarrhythmias and appropriate ICD therapies in a high-risk ICD population

PURPOSE

The study sought to evaluate the prognostic impact of recurrences of ventricular tachyarrhythmias in consecutive ICD recipients with ventricular tachyarrhythmias on admission.

METHODS

All consecutive patients surviving at least one episode of ventricular tachyarrhythmias from 2002 to 2016 and discharged with an ICD (pre-existing ICD or ICD implantation at index hospitalization) were included. The primary endpoint was all-cause mortality according to the presence or absence of recurrences of ventricular tachyarrhythmias at 5 years. Secondary endpoints comprised the impact of different types of recurrences, appropriate ICD therapies, as well as predictors of recurrences and appropriate ICD therapies. Kaplan-Meier, multivariable Cox regression and propensity score matching analyses were applied.

RESULTS

A total of 592 consecutive ICD recipients was included (44% with recurrences of ventricular tachyarrhythmias and 56% without). Recurrences of ventricular tachyarrhythmias were associated with increased all-cause mortality at 5 years (HR = 1.498; 95% CI = 1.052-2.132; p = 0.025). Worst survival was observed in patients with sustained VT or VF as first recurrences compared to non-sustained VT, as well as in patients with cumulative recurrences of non-sustained or sustained VT plus VF, whereas mortality was not affected by the number of recurrences of ventricular tachyarrhythmias (> 4 vs. ≤ 4). Moreover, appropriate ICD therapies were associated with increased all-cause mortality (HR = 1.874; 95% CI = 1.318-2.666; p = 0.001), mainly attributed to secondary preventive ICDs. Finally, atrial fibrillation, LVEF < 35% and non-ischemic cardiomyopathy were identified as predictors of recurrences of ventricular tachyarrhythmias and appropriate ICD therapies.

CONCLUSIONS

Recurrences of ventricular tachyarrhythmias and recurrent appropriate ICD therapies are associated with increased long-term all-cause mortality in consecutive ICD recipients. Non-ischemic cardiomyopathy, AF and LVEF < 35% revealed to be significant predictors of both endpoints.