Jin Kyung Hwang

Electrical PR Interval Variation Predicts New Occurrence of Atrial Fibrillation in Patients With Frequent Premature Atrial Contractions

AbstractAtrial fibrillation (AF) is associated with the autonomic nervous system (ANS), and fluctuation of autonomic tone is more prominent in patients with AF. As autonomic tone affects the heart rate (HR), and there is an inverse relationship between HR and PR interval, PR interval variation could be greater in patients with AF than in those without AF. The purpose of this study was to investigate the correlation between PR interval variation and new-onset AF in patients with frequent PACs.We retrospectively enrolled 207 patients with frequent PACs who underwent electrocardiographs at least 4 times during the follow-up period. The PR variation was calculated by subtracting the minimum PR interval from the maximum PR interval. The outcomes were new occurrence of AF and all-cause mortality during the follow-up period.During a median follow-up of 8.3 years, 24 patients (11.6%) developed new-onset AF. Univariate analysis showed that prolonged PR interval (PR interval > 200 ms, P = 0.021), long PR variation (PR variation > 36.5 ms, P = 0.018), and PR variation (P = 0.004) as a continuous variable were associated with an increased risk of AF. Cox regression analysis showed that prolonged PR interval (hazard ratio = 3.321, 95% CI 1.064–10.362, P = 0.039) and PR variation (hazard ratio = 1.013, 95% CI 1.002–1.024, P = 0.022) were independent predictors for new-onset AF. However, PR variation and prolonged PR interval were not associated with all-cause mortality (P = 0.465 and 0.774, respectively).PR interval variation and prolonged PR interval are independent risk factors for new-onset AF in patients with frequent PACs. However we were unable to determine a cut-off value of PR interval variation for new-onset AF.

Clinical Characteristics and Features of Frequent Idiopathic Ventricular Premature Complexes in the Korean Population

Background and Objectives Frequent ventricular premature complexes (VPCs) increase the risk of cardiomyopathy (CMP). However, most data regarding VPCs have been obtained from Western population and in-hospital patient-based studies. The objective of this study was to define the clinical characteristics and features of idiopathic VPCs in the Korean population. Subjects and Methods We investigated subjects undergoing transthoracic echocardiography and documented VPC burdens >1% by Holter monitoring in an outpatient clinic at Samsung Medical Center, Korea. We analyzed demographic and clinical features and the nature of the VPCs by electrocardiography (ECG). Results A total of 666 patients were registered. Mean age was 54.7±16.8 years, and 365 (54.8%) patients were female. Typical VPC-related symptoms, such as palpitation and a dropped beat, were observed in 394 (59.2%) patients. Some patients received beta-blockers (n=95; 14.3%) and anti-arrhythmic agents (n=14; 2.1%). The ECG analysis was performed in 405 patients; 322 (79.5%) exhibited left bundle branch block (LBBB) and 347 (85.8%) exhibited an inferior axis. The precordial R-wave transition was predominantly distributed over V3 in 230 patients (56.6%). Thirty-one patients (4.5%) were diagnosed with VPC-induced CMP. Conclusion The incidence of frequent VPCs was slightly higher in females, and palpitation was the most frequent complaint. The most common ECG features were LBBB, inferior axis, and late precordial R-wave transition.

Impact of moderate to severe renal impairment on long-term clinical outcomes in patients with atrial fibrillation

BACKGROUND The deleterious effect of renal impairment in non-valvular atrial fibrillation (AF) patients has recently been reported. We investigated the impact of moderate to severe renal impairment on long-term clinical outcomes in AF patients. METHODS A total of 2126 AF patients were enrolled and divided into two groups according to ≥ or <60mL/min estimated glomerular filtration rate (eGFR). Clinical outcomes including all-cause death, cardiac death, ischemic stroke (IS), bleeding, and admission for heart failure (HF) were analyzed. RESULTS Compared to the ≥60mL/min eGFR group, <60mL/min eGFR patients were older; had a higher proportion of females; were more likely to have diabetes, hypertension, and history of stroke; and had higher CHADS2, CHA2DS2-VASc, and HAS-BLED scores. During the follow-up period (median 6.23 years), all-cause death, bleeding, admission for HF, and progression to persistent or permanent AF were significantly increased in the <60mL/min eGFR group compared to the ≥60mL/min eGFR group. After multivariate Cox regression analyses, <60mL/min eGFR increased the risk of all-cause death [hazard ratio (HR): 1.84; 95% confidence interval (CI): 1.03-3.28, p=0.04] and bleeding (HR: 1.28; 95% CI: 1.04-1.57, p=0.02). IS was only significantly increased in the <60mL/min eGFR group not receiving antithrombotic treatment. CONCLUSION Moderate to severe renal impairment is a poor prognostic factor of long-term clinical outcomes in AF patients.

Predictors and long-term clinical outcomes of newly developed atrial fibrillation in patients with cardiac implantable electronic devices

Objective: To evaluate predictors and long-term prognosis of atrial fibrillation (AF) following cardiac implantable electronic device (CIED) implantation in patients without history of AF. Methods: From May 1994 to April 2014, 1825 patients with CIED were enrolled in a retrospective, single-center registry. A total of 880 patients from the registry without prior documented AF history were included in the final analysis and were placed into either non-detected AF (NDAF) group or CIED-detected AF group according to development of AF over a follow-up period of 7 years. AF development was defined as any paroxysmal atrial tachyarrhythmia (atrial rate ≥ 180 beats/min) lasting at least 5 minutes according to CIED records. Results: Overall, 122 (13.8%) of the 880 patients experienced new development of AF during follow-up period. According to multivariate analysis, the independent predictors for development of AF were prior heart failure (hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.50–3.85; P < 0.001), prior sinus node dysfunction (HR, 2.33; 95% CI, 1.62–3.55; P < 0.001), and left atrium volume index of 38.5 mL/m2 or more (HR, 2.01; 95% CI, 1.23–3.30; P = 0.005). In CDAF group, the risk of heart failure readmission (adjusted HR, 3.79; 95% CI, 1.99–7.22; P < 0.001) and stroke readmission (adjusted HR, 5.33; 95% CI, 1.58–17.97; P = 0.007) was higher than in nondetected AF group. Conclusion: In patients with CIED, prior history of heart failure, sinus node dysfunction, and LA volume index ≥38.5 mL/m2 were independent predictors of new AF cases. Newly developed AF was significantly associated with increased risk of HF and stroke readmission, according to long-term follow up.

Prediction of early-onset atrial tachyarrhythmia after successful trans-catheter device closure of atrial septal defect.

AbstractAtrial tachyarrhythmia is a well-known long-term complication of atrial septal defect (ASD) in adults, even after successful trans-catheter closure. However, the risk factors for early-onset atrial tachyarrhythmia after trans-catheter closure remain unclear. This retrospective study enrolled adults with secundum ASD undergoing trans-catheter closure from January 2000 to March 2014. We analyzed the clinical characteristics of patients and assessed risk factors for new-onset atrial tachyarrhythmia defined as a composite of atrial fibrillation or flutter (AF/AFL) after ASD closure. We enrolled a total of 427 patients; 123 were male (28.8%) and the median age was 37.0 (interquartile range [IQR]: 18.3–49.0). Nineteen (4.4%) patients had documented atrial tachyarrhythmia during the follow-up period (median: 11.4 months [IQR: 5.4–24]). Patients with transient AF/AFL during closure showed a greater incidence of new-onset atrial tachyarrhythmia during the follow-up period than patients with consistent sinus rhythm during closure (27.3% vs 3.8%; P = 0.01). Most new-onset atrial tachyarrhythmias were documented within 6 months (median: 2.6 [IQR: 1.2–4.1] months) of closure. In the multivariate analysis, the risk for new-onset atrial tachyarrhythmia was significant in patients with AF/AFL during closure (hazard ratio [HR]: 9.90, 95% confidence interval [CI]: 2.86–34.20; P < 0.001), deficient posteroinferior rim (HR: 5.48, 95% CI: 1.15–25.72; P = 0.04), and age of closure over 48 years (HR: 3.30, 95% CI: 1.30–8.38; P = 0.01). In conclusion, transient AF/AFL during trans-catheter closure of ASD as well as deficient posteroinferior rim and age of closure over 48 years may be useful for predicting early new-onset atrial tachyarrhythmia after device closure.

Staged hybrid procedure versus radiofrequency catheter ablation in the treatment of atrial fibrillation

The treatment effect of the hybrid procedure, consisting of a thoracoscopic ablation followed by an endocardial radiofrequency catheter ablation (RFCA), is unclear. A total of 117 ablation-naïve patients who underwent either the staged hybrid procedure (n = 72) or RFCA alone (n = 105) for drug-refractory, non-valvular persistent or long-standing persistent atrial fibrillation (AF) were enrolled. The primary outcome is occurrence of total atrial arrhythmia, defined as a composite of AF, sustained atrial tachycardia (AT), and atypical atrial flutter (AFL) after index procedure. The mean age was 52.7 years. Eighty-four percentage of the patients were male. Patients with prior history of stroke and long-standing persistent AF were more prevalent in the hybrid group than RFCA group. The left atrial volume index was larger in the hybrid group (P<0.001). During 2.1 years of median follow-up, the incidence of total atrial arrhythmia was not different between the two groups (32.5% vs. 35.7%; adjusted hazard ratio: 0.64; 95% confidence interval: 0.36–1.14; P = 0.13). The AF recurrence was significantly lower in the hybrid group than in the RFCA group (29.6% vs. 34.9%; adjusted HR: 0.53; 95% CI: 0.29–0.99; P = 0.046). The hospital stay was longer in the hybrid group than in the RFCA group (11 days vs. 4 days; P<0.001). A staged hybrid procedure may be an alternative choice for drug-refractory persistent AF, but it is no more effective than RFCA alone to eliminate atrial arrhythmias. Considering the long-length of stay and the morbidity, careful consideration should be given in selection of treatment strategy.

Which antiarrhythmic drug to choose after electrical cardioversion: A study on non-valvular atrial fibrillation patients

The relative efficacy of antiarrhythmic drugs (AADs) after electrical cardioversion are not well established. This study aimed to investigate the efficacies of different AADs for maintaining sinus rhythm (SR) after electrical cardioversion for atrial fibrillation (AF). We selected patients from a retrospective registry including patients admitted for cardioversion between January 2012 and June 2016. The primary outcome was time to AF recurrence during the first year after cardioversion. The secondary outcomes included AF recurrence within 1 month, and first readmission due to heart failure, stroke, or additional non-pharmacological rhythm control. A total of 265 patients were divided into the 4 groups according to AAD type: flecainide (n = 33), propafenone (n = 64), amiodarone (n = 128), and dronedarone (n = 40). During the first year after cardioversion, the AF recurrence-free survival was similar between all AAD groups (69.7% vs. 67.2% vs. 71.9% vs. 80.0%, p = 0.439). About half of all recurrences occurred during the first month. There was no difference in any of the secondary outcomes, although the amiodarone group showed a trend toward more non-pharmacological rhythm control. AAD type was not associated with recurrence in multivariate analysis. In this study, half of all patients received amiodarone after electrical cardioversion. Flecainide, propafenone, amiodarone, and dronedarone showed similar efficacies for maintaining SR after electrical cardioversion. Thus, it might be reasonable to reconsider amiodarone use after cardioversion, since it did not show superior efficacy to the other drugs considered and is associated with potential side effects.

Clinical significance of fragmented QRS complexes or J waves in patients with idiopathic ventricular arrhythmias

Background Idiopathic ventricular fibrillation (IVF) can cause sudden cardiac death. Previous studies have reported that J waves and fragmented QRS complexes (f-QRS) are arrhythmogenic markers and predictors of cardiac events. We evaluated the prevalence and clinical significance of J waves and f-QRS in patients with IVF. Methods We studied 81 patients who received an implantable cardioverter defibrillator (ICD) due to IVF between October 1999 and June 2015. We assessed the prevalence of J waves and f-QRS using electrocardiograms (ECGs). Patients were classified into three groups: J wave group (n = 35), f-QRS group (n = 20), or normal ECG group (n = 26). The control group included 81 subjects without heart disease who were matched for age, sex, and race. We compared syncope, sudden cardiac arrest, and appropriate ICD shock between the three groups. Results The follow-up duration was 4.1 years. J waves and f-QRS were more frequent in patients with IVF than in control subjects (43.2%, 21% vs. 24.7%, 19.7%, P < 0.001). Out of the three groups, clinical cardiac events were most frequent in the f-QRS group (50% vs. 45.7% vs. 11.5%, P = 0.028). A comparison of the combined group of J wave and f-QRS versus the normal ECG group revealed that the combined group had a higher frequency of clinical cardiac events than the normal ECG group (47.3% vs. 11.5%, respectively, P = 0.009). Conclusions Patients with IVF had higher prevalence of f-QRS or J waves. And patients with f-QRS or J waves were at higher risk of recurrent ventricular fibrillation.

Additional cavotricuspid isthmus ablation may reduce recurrent atrial tachyarrhythmia after total thoracoscopic ablation for persistent atrial fibrillation

OBJECTIVES Unlike catheter ablation, little is known about the benefits of cavotricuspid isthmus (CTI) ablation in total thoracoscopic ablation (TTA) of atrial fibrillation (AF). This study aimed to investigate the incidence of recurrent atrial tachyarrhythmia (ATa) according to additional CTI ablation after TTA in patients with persistent AF. METHODS Among 208 consecutive patients who underwent TTA for persistent AF at the Samsung Medical Center from February 2012 to January 2016, a total of 63 patients with CTI ablation and 91 patients without CTI ablation were included in the final analysis. CTI ablation was performed in patients who had long-standing AF or atrial flutter episodes during the admission period. RESULTS There was no difference in baseline characteristics between the CTI ablation and non-CTI ablation groups, except for a higher number of male patients in the CTI ablation group. The CTI ablation group showed a significantly higher survival rate free from recurrent ATa than that of the non-CTI ablation group at 5 years (52.5% vs 41.4%, P = 0.046). In the multivariable analysis, CTI ablation (hazard ratio 0.46, 95% confidence interval 0.217-0.971; P = 0.042) and left atrial volume index (hazard ratio 1.05, 95% confidence interval 1.029-1.070; P < 0.001) were significantly correlated with recurrent ATa. CONCLUSIONS Patients with CTI ablation showed a better survival rate free from recurrent ATa compared with the non-CTI ablation group. The additional CTI ablation may reduce recurrent ATa after TTA in patients with documented atrial flutter or long-standing AF.

Is the stroke volume during post-ectopic beat associated with ventricular premature complex-related symptoms?

Aims This study aimed to investigate if increased stroke volume (SV) after a ventricular premature complex (VPC) was related to VPC-related symptoms. Methods and results We selected patients having an isolated VPC during echocardiography from a prospective registry that included patients with a structurally normal heart and 24-h VPC >1%. Patients were divided into two groups according to the presence or absence of VPC-related symptoms (skipped beat or palpitation) when VPC occurred. Left ventricular (LV) volumes and time-velocity integral (TVI) at the LV outflow tract were measured during the preceding sinus beat, VPC, and post-ectopic sinus beat. Percent LV SV of the VPC and post-ectopic sinus beat were calculated by dividing each SV by the SV of the preceding sinus beat. A total of 47 patients were eligible. Most patients had VPC with left bundle branch block morphology and inferior axis. Patients in the symptom (+) group had a significantly lower SV, %LV SV, and TVI during post-ectopic sinus beat than those in the symptom (-) group. The sum of SVs during VPC and post-ectopic beat was significantly lower in symptomatic patients than non-symptomatic patients (103.4 mL vs. 125.1 mL, P = 0.02), while the sum of %LV SVs during VPC and post-ectopic beat tended to be lower in patients with symptoms than those without symptoms (P = 0.08). The sum of %LV SVs during VPC and post-VPC was positively correlated with coupling interval (CI) and CI ratio. Conclusion Ventricular premature complex-related symptoms may not be associated with the amount of post-VPC SV.