Chuen-Wang Chiou

Reappraisal of radiofrequency ablation of multiple accessory pathways

Complete electrophysiologic study and radiofrequency ablation were performed in 145 consecutive patients with Wolff-Parkinson-White syndrome. Presence of multiple accessory atrioventricular pathways was documented in 20 patients (13.8%); 17 had two, two had three, and one had four accessory pathways. Location of accessory pathways was posteroseptal in 18, left free wall in 15, right free wall in nine, and right midseptal in two. Of the 44 pathways, 36 were found during baseline electrophysiologic study and eight were found after successful ablation of the initially attempted pathways. After delivery 20 +/- 23 pulses (per patient) of radiofrequency energy (37 +/- 6 W, 70 +/- 30 seconds), 43 accessory pathways were ablated successfully without complications. Duration of the procedure (4.5 +/- 1.7 vs 3.7 +/- 1.6 hours, p < 0.05) and radiation exposure time (53 +/- 30 vs 38 +/- 18 minutes, p < 0.05) were longer in patients with multiple pathways, whereas the success rate (95% vs 95%, p > 0.05) and incidence of recurrent conduction (11% vs 11%, p > 0.05) were similar in patients with single or multiple accessory pathways. These findings confirmed that multiple accessory pathways were common in patients with Wolff-Parkinson-White syndrome, and these pathways could be ablated successfully by radiofrequency energy with a success rate comparable to that of a single accessory pathway.

Sudden changes in heart rate variability during the 1999 Taiwan earthquake

Sympathovagal imbalance resulting from reactions to an earthquake was not prominent in patients who were taking beta-blockers.

Recurrent conduction in accessory pathway and possible new arrhythmias after radiofrequency catheter ablation

Radiofrequency catheter ablation was performed in 142 patients with 166 accessory pathways. One hundred thirty-six patients with 160 accessory pathways underwent successful ablation in the first ablation session. Serial follow-up electrophysiologic studies were performed immediately (30 minutes), early (5 to 7 days), and late (3 to 6 months) after successful ablation to determine the recurrent accessory pathway conduction and possible new arrhythmias. After a minimum follow-up period of 6 months (mean, 14 +/- 3 months), accessory pathway conduction recurred in 13 patients (9.6%), with recurrent tachycardia in three patients (2.2%). Five of the recurrent accessory pathways had decremental conduction properties. Incidence of recurrent accessory pathway conduction was similar in different accessory pathway locations (6.4% to 9.0%). Patients with concealed accessory pathways (12.2 vs 2.9%; p < 0.05), and patients without accessory pathway potentials in the ablation site (15.5% vs 2.2%; p < 0.05) had a higher recurrence rate. Patients without tachycardia in the late electrophysiologic study did not have recurrent tachycardia during follow-up. New arrhythmias, including atrial and ventricular arrhythmias, which were detected by 24-hour Holter monitoring, were apparent only on the first day after ablation. The findings indicate that the overall incidence of recurrent accessory pathway conduction was low and that possible new arrhythmias were rare in the late follow-up period.

Radiofrequency Catheter Ablation of Ventricular Arrhythmias Originating from the Continuum between the Aortic Sinus of Valsalva and the Left Ventricular Summit: Electrocardiographic Characteristics and Correlative Anatomy.

BACKGROUNDnRadiofrequency ablation of ventricular arrhythmias (VAs) originating from the continuum between the aortic sinus of Valsalva (ASV) and the left ventricular (LV) summit is a challenge.nnnOBJECTIVESnThe objectives of this study were to investigate the electrocardiographic, electrophysiological, and anatomical characteristics of VAs and to develop an algorithm for predicting the successful ablation site.nnnMETHODSnWe recruited 66 patients (mean age, 47 ± 15 years; 42 male patients) with symptomatic VAs originating from the continuum between the ASV and the LV summit who underwent radiofrequency ablation. Patients were classified into 4 groups (group 1: ASV, n = 20; group 2: subvalvular region, n = 15; group 3: great cardiac vein/anterior interventricular vein [GCV/AIV], n = 16; group 4: epicardium requiring pericardial access, n = 15). The QRS morphological characteristics of VAs were compared between the 4 groups.nnnRESULTSnElectrocardiographic analysis revealed that the aVL/aVR Q-wave ratio is useful in the prediction of successful ablation sites in the ASV, subvalvular area, GCV/AIV, and epicardium requiring pericardial access at cutoff values of ≤1.415, 1.416-1.535, 1.536-1.740, and >1.740, respectively. The aVL/aVR Q-wave ratio was well correlated with the distance between the successful ablation site and the tip of the LV summit. A distance of >18.9 mm and an LV myocardial thickness of >9.1 mm predicted the need for the epicardial or GCV/AIV approaches. There were no major procedural complications. Eight patients (12.1%) developed VA recurrence during a mean follow-up of 15.9 months (interquartile range 9.2-24.2 months).nnnCONCLUSIONnThe aVL/aVR Q-wave ratio is a useful parameter for predicting the successful ablation sites of VAs originating from the continuum between the ASV and the LV summit.

Radiofrequency catheter ablation for treatment of Wolff-Parkinson-White syndrome--short- and long-term follow-up.

One hundred and twenty-five patients with accessory pathways mediated tachyarrhythmias underwent radiofrequency ablation. Right-sided accessory pathways were ablated from the atrial aspect of the tricuspid anulus (all from the femoral vein approach) and the left-sided accessory pathways were ablated from the atrial or ventricular aspect of the mitral anulus. Immediately after the procedures, 3 of 8 accessory pathways (38%) and 131 of 137 accessory pathways (95%) were ablated successfully with radiofrequency through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Seven of the 11 accessory pathways that failed radiofrequency ablation had a later successful direct current ablation. During follow-up (3 to 22 months), serial electrophysiological study showed that 11 of the 114 patients (10%) with successful ablation had return of accessory pathway conduction (2 had recurrence of tachycardia, 2%). Complications included accidental AV block (1 patient), cardiac tamponade (1 patient) and possible aortic dissection (1 patient). Transient proarrhythmic effects (more atrial and ventricular premature beats) were seen during the first week and sustained ventricular tachyarrhythmias were not inducible. In a successful session, procedure and radiation exposure times (including the time for diagnostic procedures) were 3.8 +/- 0.2 h and 45 +/- 4 min, respectively. This study confirms that radiofrequency ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of Wolff-Parkinson-White syndrome, with a low complication and recurrence rate.

Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long‐Term Outcome

Background The prognostic significance of premature atrial complex (PAC) burden is not fully elucidated. We aimed to investigate the relationship between the burden of PACs and long-term outcome. Methods and Results We investigated the clinical characteristics of 5371 consecutive patients without atrial fibrillation (AF) or a permanent pacemaker (PPM) at baseline who underwent 24-hour electrocardiography monitoring between January 1, 2002, and December 31, 2004. Clinical event data were retrieved from the Bureau of National Health Insurance of Taiwan. During a mean follow-up duration of 10±1 years, there were 1209 deaths, 1166 cardiovascular-related hospitalizations, 3104 hospitalizations for any reason, 418 cases of new-onset AF, and 132 PPM implantations. The optimal cut-off of PAC burden for predicting mortality was 76 beats per day, with a sensitivity of 63.1% and a specificity of 63.5%. In multivariate analysis, a PAC burden >76 beats per day was an independent predictor of mortality (hazard ratio: 1.384, 95% CI: 1.230 to 1.558), cardiovascular hospitalization (hazard ratio: 1.284, 95% CI: 1.137 to 1.451), new-onset AF (hazard ratio: 1.757, 95% CI: 1.427 to 2.163), and PPM implantation (hazard ratio: 2.821, 95% CI: 1.898 to 4.192). Patients with frequent PAC had increased risk of mortality attributable to myocardial infarction, heart failure, and sudden cardiac death. Frequent PACs increased risk of PPM implantation owing to sick sinus syndrome, high-degree atrioventricular block, and/or AF. Conclusions The burden of PACs is independently associated with mortality, cardiovascular hospitalization, new-onset AF, and PPM implantation in the long term.

Long-term outcome of multiform premature ventricular complexes in structurally normal heart.

BACKGROUNDnMultiform premature ventricular complexes (PVCs) are common electrocardiographic abnormalities in patients with structurally normal hearts. However, the prognostic value of these complexes remains unclear. This study aimed to clarify the role of PVC polymorphism in predicting adverse outcomes.nnnMETHODS AND RESULTnWe examined the database for 24-hour electrocardiography monitoring between January 1, 2002 and December 31, 2004. We analyzed 3351 individuals with apparently normal hearts. Kaplan-Meier curves and multivariate Cox proportional hazards models were employed to estimate the effect of multiform PVC and uniform PVC on the number of incident adverse events. Average follow-up time was 10±1years. Patients with multiform PVC were older and had a higher prevalence of comorbidities. In multivariate analysis, patients with multiform PVC had an increased incidence of mortality (hazard ratio [HR]: 1.642, 95% confidence interval [CI]: 1.327-2.031), hospitalization (HR: 1.196, 95% CI: 1.059-1.350), cardiovascular hospitalization (HR: 1.289, 95% CI: 1.030-1.613), new-onset heart failure (HF; HR: 1.456, 95% CI: 1.062-1.997), transient ischemic accident (HR: 1.411, 95% CI 1.063-1.873), and new-onset atrial fibrillation (AF; HR: 1.546, 95% CI: 1.058-2.258) compared to the group without PVC. Patients with multiform PVC had a higher rate of mortality (HR: 1.231, 95% CI: 1.033-1.468) and all cause-hospitalization (HR: 1.147, 95% CI: 1.025-1.283) compared with patients with uniform PVC.nnnCONCLUSIONnThe presence of multiform PVC was associated with a higher incidence of mortality, hospitalization, transient ischemic attack, new-onset AF, and new-onset HF independent of other clinical risk factors.

Neural mechanism of atrial fibrillation: insight from global high density frequency mapping.

Frequency Mapping During Neurally Mediated AF. Background: It has been demonstrated that intrinsic cardiac autonomic activation of ganglionated plexi (GPs) exhibits a frequency gradient from the center to the periphery with limited mapping.

Radiofrequency ablation of bilateral quadruple accessory pathways in a patient with Wolff-Parkinson-White syndrome.

A patient with drug refractory supraventricular tachycardia showed electrophysiological evidence of bilateral quadruple accessory pathways. The conduction was bidirectional in the left posteroseptal and left posterolateral accessory pathways, antegrade in the right lateral accessory pathway, and retrograde in the right anterior accessory pathway. The four pathways participated in seven types of reciprocating tachycardias. Radiofrequency ablation eliminated the four pathways successfully. The patient was asymptomatic and free of any drug during a 10‐month follow‐up.

Long-Term Follow-Up of Catheter Ablation of Ventricular Arrhythmias: Experiences from a Tertiary Referral Center in Taiwan

BACKGROUNDnRadiofrequency catheter ablation (RFCA) is an alternative therapeutic management for drug-refractory ventricular arrhythmias (VA). However, long-term follow-up of clinical outcome after RFCA for VAs in Taiwan remains unknown.nnnMETHODSnFrom 1999 to 2013, patients undergoing RFCA for VAs from a single referral center were consecutively enrolled. The annual distribution of cases, clinical characteristics, etiology, disease entity and electrophysiological studies were investigated. The clinical outcomes and recurrences between distinct entities were compared.nnnRESULTSnA total of 502 patients receiving RFCA of VAs were eligible, including 388 patients for idiopathic VAs and 114 for substrate VAs. The annual distribution displayed a tendency towards a gradual increase in ablation cases within 2009-2013 compared with the prior decade (p < 0.001). Acute success was achieved in 453 patients (90.2%), partial success in 3 (0.6%), and failed ablation in 46 (9.2%). During a mean follow-up of 39.77 ± 48.75 months, 126 (25.1%) patients developed recurrences. Kaplan-Meier analysis demonstrated better prognosis after RFCA in patients with idiopathic fascicular VT and RVOT VAs (p < 0.001) and attenuation of the occurrences of sustained VT/VF, ICD therapies, and mortality in patients with BrS and ARVD/C (p = 0.036), as well as overall ICD interventions in substrate VAs (p < 0.001).nnnCONCLUSIONSnRFCA could be an effective and alternative strategy in the elimination of idiopathic VAs and prevention of malignant events in substrate VAs at an experienced referral center in Taiwan. Distinct location of arrhythmogenic trigger and disease entities may result in non-uniform recurrences and prognosis.nnnKEY WORDSnIdiopathic; Radiofrequency catheter ablation; Recurrence; Substrate; Ventricular arrhythmias.