Electrical Cardioversion Failure Research Articles

Optimal timing of electrical cardioversion for acute decompensated heart failure caused by atrial arrhythmias: The earlier, the better?

The optimal timing for electrical cardioversion (ECV) in acute decompensated heart failure (ADHF) with atrial arrhythmias (AAs) is unknown. Here, we retrospectively evaluated the impact of ECV timing on SR maintenance, hospitalization duration, and cardiac function in patients with ADHF and AAs. Between October 2017 and December 2022, ECV was attempted in 73 patients (62 with atrial fibrillation and 11 with atrial flutter). Patients were classified into two groups based on the median number of days from hospitalization to ECV, as follows: early ECV (within 8days, n = 38) and delayed ECV (9days or more, n = 35). The primary endpoint was very short-term and short-term ECV failure (unsuccessful cardioversion and AA recurrence during hospitalization and within one month after ECV). Secondary endpoints included (1) acute ECV success, (2) ECVs attempted, (3) periprocedural complications, (4) transthoracic echocardiographic parameter changes within two months following successful ECV, and (5) hospitalization duration. ECV successfully restored SR in 62 of 73 patients (85%), with 10 (14%) requiring multiple ECV attempts (≥ 3), and periprocedural complications occurring in six (8%). Very short-term and short-term ECV failure occurred without between-group differences (51% vs. 63%, P = 0.87 and 61% vs. 72%, P = 0.43, respectively). Among 37 patients who underwent echocardiography before and after ECV success, the left ventricular ejection fraction (LVEF) significantly increased (38% [31-52] to 51% [39-63], P = 0.008) between admission and follow-up. Additionally, hospital stay length was shorter in the early ECV group than in the delayed ECV group (14days [12-21] vs. 17days [15-26], P < 0.001). Hospital stay duration was also correlated with days from admission to ECV (Spearman's ρ = 0.47, P < 0.001). In clinical practice, early ECV was associated with a shortened hospitalization duration and significantly increased LVEF in patients with ADHF and AAs.

Maintenance of sinus rhythm after electrical cardioversion to identify patients with persistent atrial fibrillation who respond favorably to pulmonary vein isolation: the pre-pacific study.

Pulmonary vein isolation (PVI) is successful in approximately 50% of patients with persistent atrial fibrillation (PsAF) at one year. Identifying pre-procedurally the patients who respond favorably to a PVI alone strategy could improve their management. The present study aims to assess the predictive value of clinical response to pre-ablation electrical cardioversion (ECV) to identify the responders to PVI. Consecutive patients undergoing catheter ablation for PsAF were retrospectively classified, as "ECV successful" vs. "ECV failure", according to the rhythm of presentation after an ECV performed ≥4 weeks. Clinical and procedural data were analyzed in both groups according to the ablation strategy applied (PVI vs. PVI + substrate modification). In total, 58 patients (39.4%) had successful ECVs and 89 (60.6%) had failed ECV. Preprocedural characteristics were similar in both groups. Compared to the ECV failure group, patients with successful ECV presented less frequently (34% vs. 60%; P = 0.004) and less extended (21.3 ± 22.2% vs. 38.9 ± 27.4% of LA surface, P = 0.008) low-voltage areas. Over 55 ± 19 weeks of follow-up, AF-free survival was similar in both groups (72.7% vs. 67.8%, p = 0.39). PVI alone resulted in 83% AF-free survival among patients in the ECV successful group at 13 months. In approximately 40% of patients with PsAF, sinus rhythm can be restored by ECV and maintained for at least 1 month prior to catheter ablation. This clinical response is associated with less abnormal substrate as identified by left atrial voltage mapping and a procedural success rate of >80% with PVI alone.

Electrical cardioversion for early recurrences post pulmonary vein isolation

BackgroundTo study the association between timing and success of electrical cardioversion (ECV) for the treatment of early recurrences (ERs) of atrial fibrillation post pulmonary vein isolation (PVI) on long-term rhythm outcome.MethodsData of 133 patients ablated for paroxysmal or persistent atrial fibrillation receiving ECV for ERs, i.e., atrial tachyarrhythmia recurrences within 90 days post ablation were analyzed. During 1-year follow-up, patients were screened for late recurrences (LRs), i.e., recurrences after the blanking period.ResultsIn 114 patients (85.7%), ECV was successful compared to 19 patients (14.3%) with failed ECV. A higher body mass index (odds ratio (OR) 1.19 (95% CI 1.02–1.39), p = 0.029), a lower left ventricular ejection fraction (OR 1.07 (95% CI 0.99–1.15), p = 0.079), and performance of ECV > 7 days from ER onset (OR 2.99 (95% CI 1.01–8.87), p = 0.048) remained independently associated with ECV failure. During 1-year follow-up, the rate of LR was significantly higher among patients with failed ECV as compared to patients with successful ECV (hazard ratio (HR) 3.00 (95% CI, 1.79–5.03), p < 0.001). Patients with ECV performed > 7 days from ER onset had a significantly higher risk of developing LR as compared to patients with ECV performed within ≤ 7 days from ER onset (HR 1.73 (95% CI 1.15–2.62), p = 0.009). Performance of ECV > 7 days from ER onset (HR 1.76 (95% CI 1.16–2.67), p = 0.008) and failed ECV (HR 3.32 (95% CI 1.96–5.64), p < 0.001) remained independently associated with LR.ConclusionsA failed ECV and performance of ECV > 7 days from ER onset were independently associated with LR.

Multi-scale Entropy Evaluates the Proarrhythmic Condition of Persistent Atrial Fibrillation Patients Predicting Early Failure of Electrical Cardioversion.

Atrial fibrillation (AF) is nowadays the most common cardiac arrhythmia, being associated with an increase in cardiovascular mortality and morbidity. When AF lasts for more than seven days, it is classified as persistent AF and external interventions are required for its termination. A well-established alternative for that purpose is electrical cardioversion (ECV). While ECV is able to initially restore sinus rhythm (SR) in more than 90% of patients, rates of AF recurrence as high as 20–30% have been found after only a few weeks of follow-up. Hence, new methods for evaluating the proarrhythmic condition of a patient before the intervention can serve as efficient predictors about the high risk of early failure of ECV, thus facilitating optimal management of AF patients. Among the wide variety of predictors that have been proposed to date, those based on estimating organization of the fibrillatory (f-) waves from the surface electrocardiogram (ECG) have reported very promising results. However, the existing methods are based on traditional entropy measures, which only assess a single time scale and often are unable to fully characterize the dynamics generated by highly complex systems, such as the heart during AF. The present work then explores whether a multi-scale entropy (MSE) analysis of the f-waves may provide early prediction of AF recurrence after ECV. In addition to the common MSE, two improved versions have also been analyzed, composite MSE (CMSE) and refined MSE (RMSE). When analyzing 70 patients under ECV, of which 31 maintained SR and 39 relapsed to AF after a four week follow-up, the three methods provided similar performance. However, RMSE reported a slightly better discriminant ability of 86%, thus improving the other multi-scale-based outcomes by 3–9% and other previously proposed predictors of ECV by 15–30%. This outcome suggests that investigation of dynamics at large time scales yields novel insights about the underlying complex processes generating f-waves, which could provide individual proarrhythmic condition estimation, thus improving preoperative predictions of ECV early failure.

Predictors of Failure Cardioversion for Recurrent Atrial Fibrillation Following Mitral Valve Surgery With Ablation.

Electrical cardioversion (ECV) often is required for terminating recurrent atrial fibrillation (AF) after surgical radiofrequency ablation in patients undergoing mitral valve surgery. However, ECV is unsuccessful in some cases. In this study, we aimed to identify possible predictors of failed ECV for recurrent atrial fibrillation following mitral valve surgery with concomitant radiofrequency ablation. We enrolled 1,136 persistent AF patients with history of mitral valve surgery and concomitant radiofrequency ablation. Three-hundred-nineteen patients experienced recurrence of persistent AF and received ECV therapy. Comparison was made between patients with failed ECV (Failure group, N = 68) and successful ECV (Success group, N = 251). In multivariate regression analysis, age, pre-ECV loading-dose amiodarone, left atrial diameter, atrial flutter and time from surgery to ECV were independent predictors for outcomes of ECV. According to receiver operating characteristic curve analysis, the best threshold values of age, left atrial diameter and time from surgery to ECV for predicting failed ECV were 55.5 years, 64.5 mm, and 90.5 days, respectively. Older age, larger left atrium and longer time from surgery to ECV are independent predictors for failed ECV in this group. Compared with AF, atrial flutter is easier to be successfully terminated by ECV. Pre-ECV loading-dose amiodarone is helpful for successful ECV. These findings have important implications for identifying the kinds of patients to receive effective ECV.

Usefulness of Failed Electrical Cardioversion for Early Recurrence After Catheter Ablation for Atrial Fibrillation as a Predictor of Future Recurrence

Early recurrence of atrial arrhythmia (ERAA) during a blanking period after catheter ablation (CA) for atrial fibrillation (AF) does not always result in subsequent AF recurrence. We investigated whether failed electrical cardioversion (ECV) during the blanking period was associated with recurrence. A total of 1,240 consecutive patients who underwent first-time CA for AF at our institution between March 2012 and March 2016 were investigated. Among the 517 patients (42%) who experienced ERAA, 262 underwent ECV. Failure or success of ECV was defined according to the current expert consensus statement. Failed ECV was defined as failure to terminate AF and/or relapse into AF within 30 seconds after transient sinus rhythm conversion by ECV with a shock energy of 270 J in this study. Of the patients, 254 (97%) with restored sinus rhythm were included, and 8 who experienced sustained AF afterward and discontinued the rhythm-control strategy were excluded. We divided the 254 patients into the following 2 groups on the basis of failed or successful ECV: failed-ECV (n = 105; at least 1 failed ECV but experienced successful ECV at a later date nevertheless) and successful-ECV (n = 149, no failed ECV) groups. At the median follow-up period of 610 days after CA, the recurrence rate was higher in the failed-ECV group than in the successful-ECV group (76.2% vs 45.6%, log-rank p < 0.001). After adjustment for baseline differences, failed ECV was found to be a significant predictor of recurrence in the multivariate model (p < 0.001). In conclusion, failed ECV for ERAA was an independent predictor of future recurrence.

Association between transthoracic impedance and electrical cardioversion success with biphasic defibrillators: An analysis of 1055 shocks for atrial fibrillation and flutter.

The relevance of transthoracic impedance (TTI) to electrical cardioversion (ECV) success for atrial tachyarrhythmias when using biphasic waveform defibrillators is unknown. TTI is predictive of ECV success with contemporary defibrillators. De-identified data stored in biphasic defibrillator memory cards from ECV attempts for atrial fibrillation (AF) or atrial flutter (AFL) over a 2-year period at our center were evaluated. ECV success, defined as arrhythmia termination and ≥ 1 sinus beat, was adjudicated by 2 blinded cardiac electrophysiologists. The association between TTI and ECV success was assessed via Cochrane-Armitage trend and Spearman rank correlation tests, as well as simple and multivariable logistic regression. The influence of TTI on the number of shocks and on cumulative energy delivered per patient was also examined. 703 patients (593 with AF, 110 with AFL) receiving 1055 shocks were included. Last shock success was achieved in 88.0% and 98.2% of patients with AF and AFL, respectively. In patients with AF, TTI was positively associated with last shock failure (Ptrend =0.019), the need for multiple shocks (Ptrend <0.001), and cumulative energy delivered (ρ = 0.348; P < 0.001). After adjusting for first shock energy, 10-Ω increments in TTI were associated with odds ratios of 1.36 (95% CI: 1.24-1.49) and 1.22 (95% CI: 1.09-1.37) for first and last shock failure, respectively (P < 0.001 for both). Although contemporary defibrillators are designed to compensate for TTI, this variable continues to be associated with ECV failure in patients with AF. Strategies to lower TTI during ECV for AF may improve procedural success.

Predictors, management, and outcome of cardioversion failure early after atrial fibrillation ablation.

Electrical cardioversion (ECV) is frequently required for early atrial fibrillation (AF) recurrence after catheter ablation. However, in some cases, ECV is unsuccessful, and factors associated with long-term rhythm outcomes after failed ECV are unknown. This study aimed to identify possible predictors of ECV failure early after AF ablation and to analyse management and long-term rhythm outcome of these patients. Between 2010 and 2012, 180 consecutive patients (mean age 63.7 ± 9.4 years, male 53.3%, persistent AF 60%) underwent successful radiofrequency AF ablation but required post-procedural ECV due to early AF recurrence (≤ 7 days). Of these, 120 patients were successful (Group A, n = 120, 66.7%) and 60 failed (Group B, n = 60, 33.3%). ECV failure was associated with diabetes [odds ratio (OR) 2.34, 95% confidence interval (CI) 1.154-4.763; P = 0.01] and lack of beta-blocker medication (OR 2.38, 95% CI 1.005-5.635; P = 0.04). In contrast, there were no significant differences in echocardiographic or procedure-related parameters. Atrial fibrillation recurrence was monitored with sequential 7 days of Holter electrocardiogram for 24 months (on average 10.8 ± 8.8 months) and was documented in 56%, n = 102 in total (Group A: 57%, n = 69 vs. Group B: 55%, n = 33; P = 0.75). Compared with successful ECV, ECV failure shortly after AF ablation had no predictive value on rhythm outcome in the long term (P = 0.98). The necessity of additional linear lesions during catheter ablation [hazard ratio (HR) 2.72, 95% CI 1.47-5.05; P = 0.001], AF duration (HR 1.08, 95% CI 1.04-1.12; P < 0.001), and a prolonged ablation time (HR 3.27, 95% CI 1.53-6.97; P = 0.002) were associated with long-term AF recurrence. Patients with diabetes and absence of beta-blocker medication are at higher risk for ECV failure. Early post-ablation ECV failure is not associated with long-term rhythm outcome.

Predicting Unsuccessful Electrical Cardioversion for Acute Atrial Fibrillation (from the AF-CVS Score)

Electrical cardioversion (ECV) is the standard treatment for acute atrial fibrillation (AF), but identification of patients with increased risk of ECV failure or early AF recurrence is of importance for rational clinical decision-making. The objective of this study was to derive and validate a clinical risk stratification tool for identifying patients at high risk for unsuccessful outcome after ECV for acute AF. Data on 2,868 patients undergoing 5,713 ECVs of acute AF in 3 Finnish hospitals from 2003 through 2010 (the FinCV study data) were included in the analysis. Patients from western (n= 3,716 cardioversions) and eastern (n= 1,997 cardioversions) hospital regions were used as derivation and validation datasets. The composite of cardioversion failure and recurrence of AF within 30days after ECV was recorded. A clinical scoring system was created using logistic regression analyses with a repeated-measures model in the derivation data set. A multivariate analysis for prediction of the composite end point resulted in identification of 5 clinical variables for increased risk: Age (odds ratio [OR] 1.31, confidence interval [CI] 1.13 to 1.52), not the First AF (OR 1.55, CI 1.19 to 2.02), Cardiac failure (OR 1.52, CI 1.08 to 2.13), Vascular disease (OR 1.38, CI 1.11 to 1.71), and Short interval from previous AF episode (within 1 month before ECV, OR 2.31, CI 1.83 to 2.91) [hence, the acronym, AF-CVS]. The c-index for the AF-CVS score was 0.67 (95% CI 0.65 to 0.69) with Hosmer-Lemeshow p value 0.84. With high (>5) scores (i.e., 12% to 16% of the patients), the rate of composite end point was ∼40% in both cohorts, and among low-risk patients (score <3), the composite end point rate was ∼10%. In conclusion, the risk of ECV failure and early recurrence of AF can be predicted with simple patient and disease characteristics.

Constitutively Active Acetylcholine-Dependent Potassium Current Increases Atrial Defibrillation Threshold by Favoring Post-Shock Re-Initiation.

Electrical cardioversion (ECV), a mainstay in atrial fibrillation (AF) treatment, is unsuccessful in up to 10–20% of patients. An important aspect of the remodeling process caused by AF is the constitutive activition of the atrium-specific acetylcholine-dependent potassium current (IK,ACh → IK,ACh-c), which is associated with ECV failure. This study investigated the role of IK,ACh-c in ECV failure and setting the atrial defibrillation threshold (aDFT) in optically mapped neonatal rat cardiomyocyte monolayers. AF was induced by burst pacing followed by application of biphasic shocks of 25–100 V to determine aDFT. Blocking IK,ACh-c by tertiapin significantly decreased DFT, which correlated with a significant increase in wavelength during reentry. Genetic knockdown experiments, using lentiviral vectors encoding a Kcnj5-specific shRNA to modulate IK,ACh-c, yielded similar results. Mechanistically, failed ECV was attributed to incomplete phase singularity (PS) removal or reemergence of PSs (i.e. re-initiation) through unidirectional propagation of shock-induced action potentials. Re-initiation occurred at significantly higher voltages than incomplete PS-removal and was inhibited by IK,ACh-c blockade. Whole-heart mapping confirmed our findings showing a 60% increase in ECV success rate after IK,ACh-c blockade. This study provides new mechanistic insight into failing ECV of AF and identifies IK,ACh-c as possible atrium-specific target to increase ECV effectiveness, while decreasing its harmfulness.

The mechanical fibrillation pattern of the atrial myocardium is associated with acute and long-term success of electrical cardioversion in patients with persistent atrial fibrillation.

Electrophysiological studies demonstrate that a short atrial fibrillation cycle length (AFCL) is related with poor outcome of electrical cardioversion (ECV) of atrial fibrillation (AF). We found previously that the mechanical AFCL (AFCL-tvi) and atrial fibrillatory velocity (AFV-tvi) may be determined noninvasively using color tissue velocity imaging (TVI) and closely relates to the electrophysiological AFCL. To evaluate the relation between AFCL-tvi, AFV-tvi, and success of ECV in patients with AF. We prospectively studied 133 patients with persistent AF by performing echocardiography before ECV and measured the AFCL-tvi and AFV-tvi in the right atrium and left atrium. Recurrent AF was monitored. Nineteen (14%) patients had failure of ECV, 42 (32%) remained in sinus rhythm after 1-year follow-up, and 72 (54%) had a recurrence of persistent AF. Patients with immediate ECV failure had a lower median AFV-tvi measured in the right atrium than did patients with a successful ECV: 0.7 cm/s (0.2-1.0 cm/s) vs. 1.7 cm/s (0.9-2.8 cm/s) (P = .008). Patients with maintenance of sinus rhythm after 1 year had a longer AFCL-tvi measured in the left atrium than did patients with recurrence of AF (150 ms vs 137 ms; P = .017) and had a higher AFV-tvi in both atria (1.4 vs. 0.9 cm/s in the left atrium; P = .013 and 2.2 vs 1.4 cm/s in the right atrium; P = .011). Multivariate analyses showed that all atrial TVI parameters were independently associated with the maintenance of sinus rhythm after 1 year. Higher atrial fibrillatory wall velocities and longer AFCLs determined by echocardiography are associated with acute and long-term success of ECV.

Electrical Cardioversion of Persistent Atrial Fibrillation: Acute and Long‐Term Results Stratified According to Arrhythmia Duration

Current definition of persistent atrial fibrillation (PAF) enrolls a heterogeneous population with different atrial fibrillation (AF) exposure and degree of atrial substrate. Study aims were to evaluate acute and long-term results of electrical cardioversion (ECV) and to identify temporal cutoff of previous AF exposure to reclassify PAF in subgroups with different chance of sinus rhythm (SR) maintenance. Five hundred twenty-one patients (66% men; age 69 ± 10 years) with PAF undergoing ECV, were divided in four groups according to AF duration at the time of ECV: group A with AF ≤2 months (141 patients); group B with AF >2 and ≤4 months (176 patients); group C with AF >4 and ≤6 months (89 patients); and group D with AF >6 months and <1 year (115 patients). There was no difference in term of acute success among groups (98.5% vs 97.1% vs 98.9% vs 96.5%, respectively, P = 0.95). At 5-year follow-up, 198 (41%) patients were in SR: 50% in group A, 44% in group B, 42% in group C, and 25% in group D (P < 0.001). At the multivariate analysis, previous ECV (hazard ratio [HR] 1.55, P < 0.001), left atrium enlargement (HR 1.39, P = 0.013), and AF duration >6 months at time of procedure (HR 1.59, P = 0.001) independently predict ECV failure. ECV is associated with high acute success rate and low complications rate. Long-term results are strongly related with AF duration at time of ECV: a cutoff of >6 months helps in selecting patients that can take greater advantage of the procedure.

Electrical cardioversion of emergency department patients with atrial fibrillation

Study objectiveElectrical cardioversion of emergency department (ED) patients with atrial fibrillation has not been well investigated. The objective of this study is to identify the outcomes and complications associated with ED electrical cardioversion of patients with atrial fibrillation. MethodsThis retrospective health records survey investigated a consecutive cohort of ED patients with atrial fibrillation who underwent electrical cardioversion in 4 EDs during a 42-month period. Trained personnel reviewed medical records for demographic characteristics, clinical descriptors, medical interventions, complications, and ED return visits within 7 days. Data were analyzed using descriptive statistics. ResultsThe study population consisted of 388 patients (mean age 61 years; range 20 to 93 years). Duration of atrial fibrillation was less than 48 hours in 99% of the cohort. Electrical cardioversion was successful in 332 (86%) patients. Twenty-eight complications were noted in 25 electrical cardioversion encounters: 22 attributed to procedural sedation and analgesia and 6 attributed to electrical cardioversion. Three hundred thirty-three (86%) patients were discharged to home from the ED: 301 after electrical cardioversion success and 32 with electrical cardioversion failure. Thirty-nine patients (10%) returned to the ED within 7 days, 25 of these patients (6% of successful electrical cardioversion patients) returned because of relapse of atrial fibrillation. ConclusionIn this multicenter cohort, selected ED patients with atrial fibrillation had high rates of electrical cardioversion success, infrequent hospital admission, and few immediate and short-term complications.