Ventricular arrhythmias originating from the cardiac crux and the basal inferior segment of the interventricular septum in the patients with structural heart diseases: characteristics, mapping, and electrophysiological properties.

PURPOSE: There are few reports describing ventricular arrhythmias (VAs) from the crux and the corresponding endocardial site, i.e., the basal inferior segment of the interventricular septum (IVS). We aimed to investigate a distinct clinical group of VAs arising from the endocardium at this area in patients with structural heart diseases (SHD). METHODS: We included 17 patients with SHD and clinically documented VAs. Thirteen patients underwent endocardial mapping only. Three patients underwent both epicardial and endocardial approaches and one had only epicardial mapping. Eighteen VAs were identified, 14 focal and 4 reentrant VAs, confirmed by entrainment. RESULTS: There were 2 VAs from the crux, 5 VAs from the corresponding endocardial site in the right ventricle (RV), and 11 from the site in the left ventricle (LV). Compared with the VAs from RV endocardium, VAs from LV endocardium had a higher R wave in V3 than V2 (V2R/V3R ratio, 1.83 ± 0.84 vs. 0.86 ± 0.38, P = 0.008) and a higher V3 transition ratio percentage (2.16 ± 2.07 vs. 0.58 ± 0.62, P = 0.008). Combining all 16 patients with endocardial mapping, there were also lower bipolar voltages (1.21 ± 1.05 vs. 3.10 ± 2.65 mv, P < 0.0001), lower unipolar voltages (4.05 ± 1.92 vs. 5.75 ± 2.90 mv, P < 0.0001), and longer local electrocardiogram (EGM) lateness (157.6 ± 47.9 vs.140.3 ± 52.5 ms, P = 0.0001) in the dominant chambers. CONCLUSIONS: In VAs from the crux and the corresponding endocardial site, the complete ECG V2R/V3R ratio and V3 transition ratio percentage could differentiate the VAs from the RV or LV endocardium. The lower unipolar, bipolar voltage mapping, and longer EGM lateness are helpful to identify the abnormal substrate in the endocardium in these patients.

Characteristics and long-term catheter ablation outcome in long-standing persistent atrial fibrillation patients with non-pulmonary vein triggers.

BACKGROUND: There are limited literatures regarding the non-pulmonary vein (NPV) triggers in long-standing persistent atrial fibrillation (LSPAF). The goal of the present study was to investigate the characteristics and long-term outcome of catheter ablation among these patients. METHODS: The study included 776 patients (age 53.59±11.38years-old, 556 males) who received catheter ablation for drug-refractory atrial fibrillation (AF). We divided these patients into 3 groups. Group 1 consisted of 579 patients with paroxysmal AF (PAF), group 2 consisted of 103 patients with persistent AF (PerAF) and group 3 consisted of 94 patients with long-standing persistent AF (LSPAF). The average follow-up duration was 28.53±23.21months. RESULTS: The clinical endpoint was the recurrence of atrial tachyarrhythmia. Among these 3 groups, higher percentages of male (93.6%, P<0.001), NPV triggers (44.7%, P<0.001), longer AF duration (6.65±6.72years, P=0.029), larger left atrium diameter (44.44±6.79mm, P<0.001), and longer procedure time (181.94±70.02min, P<0.001) were noted in LSPAF. After the first catheter ablation, the recurrence rate of AF was highest in LSPAF (Log Rank, P<0.001). Larger left atrium diameters (LAD) (P=0.006; HR: 1.063; CI: 1.018-1.111) and NPV triggers (P=0.035; HR: 1.707; 1.037-2.809) independently predicted AF recurrence in LSPAF. CONCLUSIONS: Compared with PAF and PerAF, LSPAF had a higher incidence of NPV triggers and worse long-term outcome after catheter ablation. NPV triggers and LAD independently predicted AF recurrence after catheter ablation in LSPAF.

Left Atrial Size and Left Ventricular End-Systolic Dimension Predict the Progression of Paroxysmal Atrial Fibrillation After Catheter Ablation.

INTRODUCTION: Although rare, some paroxysmal atrial fibrillations (AF) still progress despite radiofrequency (RF) ablation. In the study, we evaluated the long-term efficacy of RF ablation and the predictors of AF progression. METHODS: A total of 589 paroxysmal AF patients (404 men and 185 women; aged 54 ± 12 years) who received 3-dimensional mapping and ablation were enrolled. Their clinical parameters and electrophysiological characteristics were collected. They were divided into Group 1 (N = 13, with AF progression) and Group 2 (N = 576, no AF progression). AF progression was defined as recurrence of persistent AF. RESULTS: Group 1 patients had larger left atrial (LA) diameter, larger left ventricle (LV) end-systolic and end-diastolic diameters, poorer LV systolic function, and more amiodarone use at baseline. After 1.2 ± 0.5 procedures, 123 (21%) patients experienced recurrence during 56 ± 29 months' follow-up. In the multivariate analysis, LA diameter (P = 0.018, HR = 1.12, 95% CI = 1.02-1.24) and LV end-systolic diameter (P = 0.005, HR = 1.10, 95% CI = 1.03-1.17) independently predicted AF progression. LA diameter >43 mm and LV end-systolic diameter >31 mm were the best cut-off values for predicting AF progression by ROC analysis. AF progression rate achieved 19% if they had both larger LA diameter (>43 mm) and LV end-systolic diameter (>31 mm). CONCLUSION: RF ablation prevents the progression of paroxysmal AF effectively, except in patients with increased LA diameter and LV end-systolic diameter on echocardiogram, suggesting more aggressive rhythm control therapies should be considered in these patients.

Impact of aortic encroachment to left atrium on non-pulmonary vein triggers of atrial fibrillation.

BACKGROUND: Aortic dilatation was frequently observed in patients with atrial fibrillation (AF) and non-pulmonary vein (PV) triggers are important for mapping and ablation of AF. We hypothesized that the aortic encroachment area over left atrium (LA) could contribute to the local substrate characteristics. METHODS: We studied 32 consecutive patients of AF (age=57.34±8.07, male=30), including 26 paroxysmal and 6 persistent AFs. Anatomic relationship between LA and aorta, and electrophysiological characteristics of the encroachment areas were investigated. IRB approval was taken. RESULTS: The LA bipolar voltage (mean 0.49±0.26mV) was lower at aortic encroached area compared to global LA (mean 1.52±0.48mV) and it was statistically significant (p<0.001). There was a linear correlation between the voltages of LA and distance from the aorta to the aortic encroachment area of LA (p<0.001, R=0.616). Non-PV triggers were observed in 34.37% (n=11) of total patients. The initiation of AF in aortic encroached area was seen in 45.45% (n=5) of non-PV trigger and 15.62% of total patients. All the patients were followed up for 6months and 4 (14.81%) out of 27 patients without trigger at aortic encroached site of LA and 1 (20%) out of 5 patients with trigger at aortic encroached site of LA had recurrence of AF. CONCLUSION: The aorta contributed to low voltages on its encroachment area over the anterior wall of LA. Non-pulmonary vein triggers originating from the aortic encroachment area were found in 15.62% of total patients. Careful evaluation of the anatomical relationship between LA and aorta is important during AF ablation for a better long term outcome.

Long-Term Outcome of Non-Sustained Ventricular Tachycardia in Structurally Normal Hearts.

BACKGROUND: The impact of non-sustained ventricular tachycardia (NSVT) on the risk of thromboembolic event and clinical outcomes in patients without structural heart disease remains undetermined. This study aimed to evaluate the association between NSVT and clinical outcomes. METHODS: The study population of 5903 patients was culled from the "Registry of 24-hour ECG monitoring at Taipei Veterans General Hospital" (REMOTE database) between January 1, 2002 and December 31, 2004. Of that total, we enrolled 3767 patients without sustained ventricular tachycardia, structural heart disease, and permanent pacemaker. For purposes of this study, NSVT was defined as 3 or more consecutive beats arising below the atrioventricular node with an RR interval of <600 ms (>100 beats/min) and lasting < 30 seconds. RESULT: There were 776 deaths, 2042 hospitalizations for any reason, 638 cardiovascular (CV)-related hospitalizations, 350 ischemic strokes, 409 transient ischemic accident (TIA), 368 new-onset heart failure (HF), and 260 new-onset atrial fibrillation (AF) with a mean follow-up duration of 10 ± 1 years. In multivariate analysis, the presence of NSVT was independently associated with death (hazard ratio [HR]: 1.362, 95% confidence interval [CI]: 1.071-1.731), CV hospitalization (HR: 1.527, 95% CI: 1.171-1.992), ischemic stroke (HR: 1.436, 95% CI: 1.014-2.032), TIA (HR 1.483, 95% CI: 1.069-2.057), and new-onset HF (HR: 1.716, 95% CI: 1.243-2.368). There was no significant association between the presence of NSVT and all-cause hospitalization or new-onset AF. CONCLUSION: In patients without structural heart disease, presence of NSVT on 24-hour monitoring was independently associated with death, CV hospitalization, ischemic stroke, TIA, and new onset heart failure.

Novel electrophysiological characteristics of atrioventricular nodal continuous conduction curves in atrioventricular nodal re-entrant tachycardia with concomitant cavotricuspid isthmus-dependent atrial flutter.

AIMS: The detailed electrophysiological characteristics of patients with both atrioventricular nodal re-entrant tachycardia (AVNRT) and atrial flutter (AFL) have not been clarified. This study investigated the related electrophysiological differences in a large series of patients undergoing radiofrequency catheter ablation of AVNRT. METHODS AND RESULTS: A total of 1063 clinically documented AVNRT patients underwent catheter ablation were enrolled. Before the slow pathway (SP) ablation, 61 patients (5.7%) had inducible sustained cavotricuspid isthmus (CTI)-dependent AFL (Group 1), and the others (94.3%) without inducible sustained CTI-dependent AFL were defined as Group 2. The electrophysiological characteristics of these two groups and effect of the SP ablation on the inducibility of AFL were assessed. In Group 1, 36 patients (59%) had inducible/sustained AFL after the ablation of AVNRT and required a CTI ablation. The Group 1 patients had more AVNRT with continuous atrioventricular (AV) node function curves (P < 0.001, odds ratio = 7.55 [3.70-16.7], multivariate regression), and a younger age (P = 0.02, odds ratio = 1.02 [1.003-1.03], multivariate regression) than Group 2. The other characteristics were comparable between the two groups. The long-term follow-up (64.9 ± 34.9 months) revealed that the recurrence of AFL/atrial fibrillation was similar between the two groups (P > 0.05). CONCLUSION: Atrioventricular nodal re-entrant tachycardia patients with concomitant CTI-dependent AFL had more continuous AV node function curves. Forty-one per cent of these patients had non-inducible AFL after the SP ablation, indicating a slow conduction isthmus in the triangle of Koch area.