QTc Interval Prolongation Predicts Arrhythmia Recurrence After Catheter Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Prevalence and Risk Factors of QTc Prolongation During Pregnancy

Background

Prolonged QT intervals have been observed in pregnant women, which predispose them to a higher risk of potentially lethal ventricular arrhythmias. This study was designed to evaluate the prevalence of QTc prolongation in Chinese hospitalized parturient women with single and twin pregnancies, and to explore potential risk factors associated with QTc prolongation.

Methods

This retrospective study included 1,218 patients from a large Chinese population between January 2014 and October 2020. Data from parturient women with single and twin pregnancies without pre-pregnancy cardiac diseases were collected. QTc was corrected by the Fridericia formula [QTc = QT/RR(1/3)], and QTc ≥ 460 ms for females was defined as prolonged QTc, QTc ≥ 500 ms was defined as severely prolonged QTc. The prevalence and common risk factors of QTc prolongation during pregnancy were analyzed in this cohort. Uni- and multivariable logistic regression analysis were performed to identify clinical parameters associated with QTc prolongation in this population.

Results

The prevalence of QTc prolongation was 48.19% among this population, 10.56% in single pregnancy, 89.44% in twin pregnancies. The prevalence of severely prolonged QTc was 23.48% among the total cohort, 0.49% in single pregnancy, and 46.47% in twin pregnancies. The mean QTc interval was significantly longer in twin pregnancies than in single pregnancy (498.65 ± 38.24 vs. 424.96 ± 27.67 ms, P < 0.001). Systolic blood pressure, diastolic blood pressure, total cholesterol, serum uric acid, gestational hypertension and twin pregnancies were associated with QTc prolongation in parturient women.

Conclusion

This is the first study to assess the prevalence and risk factors of QTc prolongation between single and twin pregnancies. QTc prolongation is more prevalent, and QTc intervals are significantly longer in twin pregnancies as compared to single pregnancy.

Evaluation of acute alterations in electrocardiographic parameters after cryoballoon ablation of atrial fibrillation and possible association with recurrence

OBJECTIVE

This study aimed to evaluate the acute effect of cryoballoon ablation (CB-A) on electrocardiographic parameters that have been suggested to reflect heterogeneity in atrial conduction and ventricular repolarization.

METHODS

A total of 67 patients (52.6±13.2 years, 43 men) without any exclusion criteria who had undergone CB-A for atrial fibrillation (AF) between January 01, 2015, and December 31, 2018, constituted our study population. Electrographic recordings obtained before and after the ablation procedure on the same day were retrospectively evaluated for the P-wave dispersion, QTc dispersion, Tp-Te interval, and Tp-Te/QT ratio. The pre- and post-ablation values were tested for significant differences. The association of the possible CB-A-related changes in these parameters with AF recurrence during follow-up was evaluated.

RESULTS

P dispersion (30.1±6.8 vs. 35.9±9.4 ms, p<0.001), QT dispersion (20.7±7.5 vs. 24.0±8.8 ms, p<0.001), Tp-Te duration (on V5 83.6±8.1 vs. 110.2±9.5 ms, p<0.001), and Tp-Te/QT ratio (on V5 0.22±0.03 vs. 0.28±0.02, p<0.001) were observed to increase significantly after CB-A. There was no association between the magnitudes of change in any parameter and AF recurrence.

CONCLUSION

CB-A had significant effects on electrocardiographic parameters related to atrial conduction and ventricular repolarization in the acute phase after CB-A. Further prospective studies are required to examine the time-related course of these alterations and their impact on clinical outcomes.

Five-Year Outcomes and Cardiac Remodeling Following Left Atrial Appendage Occlusion

Purpose

LAAO has been an alternative therapy to oral anticoagulants (OACs) for stroke prophylaxis in patients with nonvalvular atrial fibrillation (NVAF) with elevated CHA₂DS₂-Vasc score, but the long-term outcomes of LAAO and its impacts on cardiac electrical and mechanical remodeling remain to be learned. We aimed to describe the impact of left atrial appendage occlusion (LAAO) on atrial remodeling and cardiovascular outcomes within 5-year follow-up.

Patients and Methods

A total of 107 patients with nonvalvular atrial fibrillation (NVAF) undergoing LAAO in the Shanghai Tenth People’s Hospital between January 2014 and July 2017 were included. All participants were followed for ECG, transthoracic echocardiography (TTE), and clinical outcomes (including cardiovascular death, heart failure, ischemic stroke/systemic embolism, and pericardial effusion) at 6 and 12 months, and thereafter every 12 months after LAAO discharge until 5 years.

Results

After LAAO, the left atrial diameter significantly increased at 6 months (48.6 ± 6.7 vs 46.5 ± 7.0 mm); heart rate decreased immediately after the procedure (78.5 ± 14.7 vs 85.3 ± 21.7 bpm) when compared with the pre-procedure level. The QTc interval prolongated to the highest value of 460.7 ± 46.8 ms at 6 months (pre-procedure level of 433.7±49.0 ms). All these changes return to the pre-procedure level within the follow-up. For clinical outcomes, 51 patients suffered the composite of cardiovascular death (n=4, 3.7%), heart failure (n=25, 23.4%), ischemic stroke/systemic embolism (n=22, 20.6%), and pericardial effusion (n=26, 26.2%).

Conclusion

LAAO did not change ECG or TTE characteristics and nonprocedure-related pericardial effusion is common during long-term follow-up. Further studies are warranted to investigate the optimal time frame of anticoagulation in patients undergoing LAAO.

Atrial fibrillation in patients with inherited cardiomyopathies

Atrial fibrillation (AF) often complicates the course of inherited cardiomyopathies and, in some cases, may be the presenting feature. Each inherited cardiomyopathy has its own peculiar pathogenetic characteristics that can contribute to the development and maintenance of AF. Atrial fibrillation may occur as a consequence of disease-specific defects, non-specific cardiac chamber changes secondary to the primary illness, or a combination thereof. The presence of AF can denote a turning point in the progression of the disease, promoting clinical deterioration and increasing morbidity and mortality. Furthermore, the management of AF can be particularly challenging in patients with inherited cardiomyopathies. In this article, we review the current information on the prevalence, pathophysiology, risk factors, and treatment of AF in three different inherited cardiomyopathies: hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia/cardiomyopathy, familial dilated cardiomyopathy, and left ventricular non-compaction cardiomyopathy.

Left atrial structure and function predictors of recurrent fibrillation after catheter ablation: a systematic review and meta-analysis

BACKGROUND

Catheter ablation (CA) has become a conventional treatment for atrial fibrillation (AF), but remains with high recurrence rate. The aim of this meta-analysis was to determine left atrial (LA) structure and function indices that predict recurrence of AF.

METHODS

We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry, up to September 2017 in order to select clinical trials and observational studies which reported echocardiographic predictors of AF recurrence after CA. Eighty-five articles with a total of 16 126 patients were finally included.

RESULTS

The pooled analysis showed that after a follow-up period of 21 ± 12 months, patients with AF recurrence had larger LA diameter with weighted mean difference (WMD: 2·99 ([95% CI 2·50-3·47], P<0·001), larger LA volume index (LAVI) maximal and LAVI minimal (P<0·0001 for both), larger LA area (P<0·0001), lower LA strain (P<0·0001) and lower LA total emptying fraction (LA EF) (P<0·0001) compared with those without AF recurrence. The most powerful LA predictors (in accuracy order) of AF recurrence were as follows: LA strain <19% (OR: 3·1[95% CI, -1.3-10·4], P<0·0001), followed by LA diameter ≥50 mm (OR: 2·75, [95% CI 1·66-4·56,] P<0·0001), and LAVmax >150 ml (OR: 2·25, [95% CI, 1.1-5·6], P = 0·0002).

CONCLUSIONS

Based on this meta-analysis results, a dilated left atrium with diameter more than 50 mm and volume above 150 ml or myocardial strain below 19% reflect an unstable LA that is unlikely to hold sinus rhythm after catheter ablation for atrial fibrillation.

Depolarization and repolarization parameters on ECG predict recurrence after atrial fibrillation ablation in patients with hypertrophic cardiomyopathy

INTRODUCTION

The outcomes of atrial fibrillation (AF) ablation remain suboptimal. It is important to identify which AF patients will most likely benefit from ablation and who are more likely to show treatment failure, especially in those with structural heart disease such as hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

We enrolled 120 HCM patients who underwent primary AF ablation (48 with persistent AF). Preprocedural QTc was measured and corrected using the Bazett's formula, and the distribution of fragmentation of the QRS complex (fQRS) was recorded. Arrhythmia recurrence was defined as any kind of documented atrial tachyarrhythmia of more than 30 seconds. Overall, arrhythmia recurrence occurred in 69 patients after 13.4 months' follow-up. fQRS was present in 71 (59.17%) patients and was most commonly (81.69%) observed in the inferior leads. QTc more than 448 ms could predict arrhythmia recurrence with a sensitivity of 68.1% and specificity of 68.6%. Patients with QTc more than 448 ms (hazard ratio [HR]: 1.982; 95% confidence interval [CI]: 1.155-3.402; P = .013) or those with fQRS+ (HR: 1.922; 95% CI: 1.151-3.210; P = .012) were at an increased risk of recurrence. A combination of fQRS+ and QTc more than 448 ms was superior to fQRS or QTc alone in predicting arrhythmia recurrence.

CONCLUSION

In patients with HCM undergoing AF ablation, QTc prolongation, specifically >448 ms, and presence of fQRS are independent risk factors for arrhythmia recurrence at follow-up. The combination of these two parameters has greater predictive value and would help to identify patients who are at the highest risk of procedural failure.

QT as a predictor of recurrence after atrial fibrillation ablation and the impact of amiodarone: results from the placebo-controlled AMIO-CAT trial

Aims

Prolonged corrected QT interval (QTc) might be associated with arrhythmia recurrence after atrial fibrillation (AF) ablation. The effect of short-term amiodarone in this setting remains unknown. This study seeks to quantify short-term amiodarone’s impact on QTc, and to investigate QTc and amiodarone treatment as predictors of recurrence of arrhythmia after ablation.

Methods and results

The Short-term AMIOdarone treatment after CATheter ablation for atrial fibrillation (AMIO-CAT) trial randomized patients to 8 weeks of oral amiodarone or placebo following AF ablation. Scheduled and symptom-driven 12-lead electrocardiography and 3-day Holter-monitorings were performed. The endpoint was atrial fibrillation, atrial flutter or atrial tachycardia (AF/AT) lasting >30 s. The cut-off for prolonged QTc was 450 ms for men and 460 ms for women. A total of 212 patients were included, of which 108 were randomized to amiodarone and 104 to placebo. From baseline to 1 month QTc in the amiodarone group increased by 27 (±30) ms, while at 6 months QTc had normalized. After 3-months of blanking, new AF/AT recurrence was detected in 63% of patients with prolonged QTc vs. 41% of patients with normal QTc at baseline, and in multivariate Cox regression, prolonged QTc was associated with AF/AT recurrence [hazard ratio (HR) 2.19, P = 0.023]. Among patients with baseline QTc below median, amiodarone treatment decreased the rate of AF/AT recurrences (HR 0.43, P = 0.008).

Conclusions

Amiodarone increased QTc with 27 ms compared to placebo, and this effect decreased rapidly after drug discontinuation. Prolonged QTc at baseline independently predicted AF/AT recurrence, and baseline QTc identified patients who would possibly benefit from short-term amiodarone following ablation.

Prolonged corrected QT interval in predicting atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Corrected QT interval (QTc) on the electrocardiogram is a marker of ventricular repolarization. Recent studies have examined its value in predicting the occurrence of atrial fibrillation (AF).

METHODS AND RESULTS

We conducted a meta-analysis to determine whether alterations in QTc interval are associated with an increased risk of incident AF. The PUBMED and EMBASE databases were searched for all studies that evaluated the incident AF associated with prolonged QTc interval published before December 2016. Sensitivity and subgroup analysis were subsequently performed. A total of six studies including eight data sets for prolonged QTc interval were eligible. Subjects with prolonged QTc interval as a categorical variable had a significantly higher risk of AF during follow-up (hazard ratio [HR]: 1.16; 95% confidence interval [CI], 1.09-1.24, I2  = 90%) based on Bazett formula. In continuous variable analysis, we found a statistically significant risk for AF (HR, 1.17; 95% CI, 1.09-1.25; I2  = 0) every 10-ms prolongation in QTc. AF type, QTc cut-off value, geographical location, follow-up duration, and study population may be the possible reasons for the significant heterogeneity among the studies.

CONCLUSIONS

Prolonged QTc interval is associated with an increased risk of AF. And the potential mechanisms underlying this cause-and-effect relationship need further investigation.

QTc interval predicts outcome of catheter ablation in paroxysmal atrial fibrillation patients with type 2 diabetes mellitus

Catheter ablation has been recommended as a treatment option for paroxysmal atrial fibrillation (PAF) patients complicated with type 2 diabetes mellitus (T2DM). PAF patients with T2DM have a higher recurrence rate after catheter ablation. Prolongation of corrected QT (QTc) interval has been linked to poor outcomes in T2DM patients. Whether the abnormal QTc interval is associated with the ablation outcome in the PAF patients with T2DM remains unknown. In this study, 134 PAF patients with T2DM undergoing primary catheter ablation were retrospectively enrolled. Pre-procedural QTc interval was corrected by using the Bazett's formula. Cox proportional hazards models were constructed to assess the relationship between QTc interval and the recurrence of AF. After a 29.1-month follow-up period, 61 patients experienced atrial tachyarrhythmia recurrence. Recurrent patients had a longer QTc interval than non-recurrent patients (425.2±21.5 ms vs. 414.1±13.4 ms, P=0.002). Multivariate Cox regression analysis revealed that QTc interval [hazard ratio (HR)=1.026, 95% confidence interval (CI) 1.012-1.040, P=0.005] and left atrial diameter (LAD) (HR=1.125, 95% CI 1.062-1.192, P=0.003) were independent predictors of recurrent atrial tachyarrhythmia. Receiver operating characteristic analysis demonstrated that the cut-off value of QTc (418 ms) predicted arrhythmia recurrence with a sensitivity of 55.7% and a specificity of 69.9%. A combination of LAD and QTc was more effective than LAD alone (P<0.001) in predicting arrhythmia recurrence after the procedure. QTc interval could be used as an independent predictor of arrhythmia recurrence in T2DM patients undergoing AF ablation, thus providing a simple method to identify those patients who likely have a better outcome following the procedure.