Atsuhiko Yagishita

Electrophysiological Characteristics of Localized Reentrant Atrial Tachycardia Occurring After Catheter Ablation of Long‐Lasting Persistent Atrial Fibrillation

Background: Mapping of recurrent atrial tachycardia (AT) after extensive ablation for long‐lasting persistent atrial fibrillation (AF) is complex. We sought to describe the electrophysiological characteristics of localized reentry occurring after ablation of long‐lasting persistent AF.

Clinical Characteristics of Patients With Persistent Atrial Fibrillation Successfully Treated by Left Atrial Ablation

Background—We sought to characterize patients with persistent atrial fibrillation (AF) who were successfully treated by ablation targeting the left atrium (LA). Methods and Results—Ninety-three patients (58±10 years, 79 male) undergoing ablation of persistent AF were studied. During the first procedure, ablation was performed in the LA and coronary sinus, consisting of pulmonary vein isolation, linear ablation, and electrogram-based ablation. During follow-up after the first procedure, 35 patients (38%) remained free from tachyarrhythmias, 27 patients (29%) had atrial tachycardia, and 31 patients (33%) had AF. Duration of persistent AF according to medical history and whether AF was terminated by ablation were associated with the outcome (P=0.005, P=0.004, respectively). In multivariate analysis, the duration of persistent AF was the only predictor of freedom from AF (sinus rhythm or atrial tachycardia) (odds ratio, 0.80 for a 1-year increase; 95% confidence interval, 0.67 to 0.95; P=0.01). Of 31 patients in whom AF recurred during follow-up, electrogram-based ablation was performed in the right atrium in 26 patients. Sixteen of those patients (62%) remained free from AF during follow-up. Overall, 82% of patients were free from any tachyarrhythmias at 2-year follow-up after a median of 2 procedures. Conclusions—Patients with shorter duration of persistent AF were more likely to be free from AF by LA ablation. Right atrial ablation may provide incremental efficacy in patients who are refractory to LA ablation.

Clinical characteristics of massive air embolism complicating left atrial ablation of atrial fibrillation: lessons from five cases.

AIMS This study aimed to elucidate the clinical characteristics of massive air embolism occurring during atrial fibrillation (AF) ablation. METHODS AND RESULTS Of 2976 patients undergoing AF ablation, 5 patients complicated by serious air embolism were examined. Atrial fibrillation ablation was performed with the use of three long sheaths for circular mapping and ablation catheters under conscious sedation. Two patients had air spontaneously introduced through a haemostasis valve of the long sheaths, at the end of long apnoea caused by the sedation, even though the catheters were placed within the long sheaths. The remaining three patients, all of whom also exhibited long apnoea, had air entry at the circular mapping catheter exchanges. Air accumulated in the right and left ventricles, left atrial appendage, right coronary artery, and ascending aorta. Haemodynamic collapse and hypoxaemia occurred in all and two patients, respectively, and supportive treatment and the accumulated air were aspirated. ST elevation, haemodynamic collapse, and hypoxaemia persisted for 10-35 min; however, all patients recovered completely. After we changed the sedative to one with less respiratory depressive effects and the timing of the saline flush at the circular mapping catheter exchanges, we never experienced such serious complications any further. CONCLUSION Serious air embolism can occur in patients with long apnoea under sedation during AF ablation with the use of long sheaths. Supportive therapy and air aspiration were effective in resolving the complication. A sedative that causes less respiratory depression and the timing of the saline flush were important for preventing air embolism.

Discrete Prepotential as an Indicator of Successful Ablation in Patients With Coronary Cusp Ventricular Arrhythmia

Background— Although coronary cusp (CC) ventricular arrhythmia (VA) can be treated by catheter ablation, reliable indicators of successful ablation sites have not been fully identified. Methods and Results— This study comprised 392 patients undergoing radiofrequency catheter ablation for outflow tract-VA at 3 institutions from January 2007 to August 2012. The successful ablation site was on the left CC or right CC in 35 (8.9%) of the 392 patients. In 9 (26%) of these 35 patients, a discrete prepotential was recognized, 5 of whom had left CC-VAs and 4 of whom had right CC-VAs. Radiofrequency catheter ablation was successful at the site of the prepotential in all 9 of these patients. The duration of the isoelectric line between the end of the discrete prepotential and the onset of the ventricular electrogram was 27±13 ms. The time from onset of the discrete prepotential at the successful ablation site on the CC to the QRS onset (activation time) was 69±20 ms (range, 50–98 ms). Pace mapping was graded as excellent at the successful ablation site in only 1 patient. No discrete prepotential was recorded in any successful right outflow tract-VA ablation case in this study. Conclusions— A discrete prepotential was seen in 9 (26%) of 35 patients with CC-VA. In left and right CC-VA, the site of a discrete prepotential with ≥50 ms activation time may indicate a successful ablation site.

Discrete Pre-Potential as an Indicator of Successful Ablation in Patients with Coronary Cusp Ventricular Arrhythmia

Background— Although coronary cusp (CC) ventricular arrhythmia (VA) can be treated by catheter ablation, reliable indicators of successful ablation sites have not been fully identified. Methods and Results— This study comprised 392 patients undergoing radiofrequency catheter ablation for outflow tract-VA at 3 institutions from January 2007 to August 2012. The successful ablation site was on the left CC or right CC in 35 (8.9%) of the 392 patients. In 9 (26%) of these 35 patients, a discrete prepotential was recognized, 5 of whom had left CC-VAs and 4 of whom had right CC-VAs. Radiofrequency catheter ablation was successful at the site of the prepotential in all 9 of these patients. The duration of the isoelectric line between the end of the discrete prepotential and the onset of the ventricular electrogram was 27±13 ms. The time from onset of the discrete prepotential at the successful ablation site on the CC to the QRS onset (activation time) was 69±20 ms (range, 50–98 ms). Pace mapping was graded as excellent at the successful ablation site in only 1 patient. No discrete prepotential was recorded in any successful right outflow tract-VA ablation case in this study. Conclusions— A discrete prepotential was seen in 9 (26%) of 35 patients with CC-VA. In left and right CC-VA, the site of a discrete prepotential with ≥50 ms activation time may indicate a successful ablation site.

Bleeding events and activated partial thromboplastin time with dabigatran in clinical practice

BACKGROUND Dabigatran has demonstrated promising results for the prevention of strokes in patients with non-valvular atrial fibrillation (NVAF). However, there have been episodes of major bleeding, especially in elderly patients or those with renal dysfunction. The purpose of this study was to retrospectively examine the relationship between the bleeding events and activated partial thromboplastin time (APTT) values under dabigatran usage in the everyday clinical practice. Moreover, we investigated which factors would contribute to the APTT values. METHODS AND RESULTS A total of 139 NVAF patients (112 men, 65 ± 11 years) were included. We evaluated the influence of the putative etiological variables and the bleeding score, HAS-BLED score, on APTT values: age greater than 70 years, renal function, gender, dose of dabigatran, and the concomitant prescription of a P-glycoprotein inhibitor. There were 50 patients with an age of ≥ 70 years (36.0%). A P-glycoprotein inhibitor was administered in 18 patients. During the observation period (median 120 days) there was 1 episode of asymptomatic cerebral infarction. There were no intrinsic major bleeding events, however, 11 patients had minor hemorrhagic events. The results of the APTT measurements exhibited a variety of values both among inter- and intra-individuals. On multivariable analysis, significant associations were found between the following risk factors and the APTT values: creatinine clearance, dose of dabigatran, and concomitant use of a P-glycoprotein inhibitor. The minor bleeding events did not correlate with the APTT values, nor HAS-BLED score. CONCLUSIONS The APTT values became prolonged under dabigatran usage and exhibited a remarkable diversity. Although major bleeding did not occur unless APTT was prolonged excessively, minor bleeding arose irrespective of the APTT values even within the range of the APTT values not exceeding 80s.

Role of oral amiodarone in patients with atrial fibrillation and congestive heart failure

BACKGROUND Amiodarone is recognized as the most effective therapy for maintaining sinus rhythm (SR) post cardioversion in patients with atrial fibrillation (AF). It is also recommended for controlling AF in patients with congestive heart failure (CHF). We retrospectively examined the efficacy and safety of oral amiodarone in patients with AF and CHF. METHODS Forty-eight consecutive AF patients whose left ventricular ejection fraction (LVEF) was less than 50% and B-type natriuretic peptide (BNP) was higher than 100 pg/ml were investigated retrospectively, and divided into 3 groups: paroxysmal AF, 16 patients; persistent AF, 9 patients; and permanent AF, 23 patients. RESULTS The permanent AF group had a longer history of AF, larger left ventricular end-diastolic diameter (LVDd) and left atrial diameter (LAD) than paroxysmal and persistent AF groups (p<0.05). After median follow-up of 265 days, amiodarone suppressed paroxysms in 88% of paroxysmal AF patients, while SR was maintained in all persistent AF patients, and 35% of permanent AF patients. Of the 32 persistent and permanent AF patients, 12 (71%) out of 17 maintained SR after successful electrical cardioversion, and conversion to SR occurred spontaneously in 5 (33%) out of 15. The effective group had significantly smaller LVDd and LAD than the ineffective group. In the effective group, BNP decreased significantly from 723±566 pg/ml to 248±252 pg/ml, (p<0.0005) and LVEF increased significantly from 33±7% to 50±13% (p<0.0005) during follow up, while no changes were observed in the ineffective group. The patients with low LVEF (≤30%) benefited comparably from amiodarone to the patients with LVEF >30%. Complications occurred in 24 (50%) patients leading to discontinuation of amiodarone in 11 (23%). CONCLUSIONS Oral amiodarone helped restore SR in paroxysmal and persistent AF patients with CHF. The successful rhythm control by amiodarone resulted in the improvement of LV function and the decrease of BNP levels.

Idiopathic ventricular fibrillation associated with early repolarization which was unmasked by a sodium channel blocker after catheter ablation of atrial fibrillation

A 57-year-old woman with paroxysmal atrial fibrillation (AF) underwent catheter ablation. After pulmonary vein isolation, an intravenous injection of pilsicainide, a pure sodium channel blocker, was administered for the sustained AF. Premature ventricular beats began to appear and culminated in ventricular fibrillation (VF) storm. The notches at the end of the terminal portion of the QRS complexes on the ECG became more manifest in the V2, V3, and V4 leads and were accompanied by a pause-dependent augmentation Fig. 1. The VF storm was suppressed and the notches disappeared by the administration of isoproterenol. No VF recurred after a tapering of the isoproterenol and the initiation of quinidine. A pause-dependent augmentation of the J wave was a specific finding for a VF storm in patients with idiopathic VF associated with early repolarization [1], and isoproterenol was effective in controlling VF [2]. It was suggested that the VF storm was due to idiopathic VF, which was unmasked by pilsicainide. Additionally, autonomic modification brought about by the catheter ablation procedure may have played an important role in the induction of VF [3].

Superior vena cava isolation by right pulmonary vein ablation

A 77-year-old female patient with paroxysmal atrial fibrillation was referred for catheter ablation. Before the right superior pulmonary vein isolation (RSPV), two components of potentials were recorded at a circular mapping catheter placed in the antrum of RSPV …

Difference of culprit plaque composition between patients with and without pre-infarction angina: an intravascular ultrasound radiofrequency analysis.

AIMS This study was performed to assess the differences in culprit plaque composition between patients with and without pre-infarction angina (PA) by using spectral analysis of intravascular ultrasound (IVUS) radiofrequency (RF) data. METHODS AND RESULTS Of 57 patients consecutively admitted to our institution with acute myocardial infarction, pre-intervention IVUS RF data of culprit plaques were obtained and analysed in 35 patients after percutaneous aspiration thrombectomy. Among the 35 patients, 21 patients had PA. Culprit plaques of patients without PA consisted of a higher percentage of the necrotic core component than those with PA (minimum lumen area [MLA]) site, 21.2+/-8.9% versus 9.9+/-9.8%, p=0.0015; entire culprit lesion, 18.9+/-6.3% versus 12.0+/-9.6%, p=0.023). In contrast, culprit plaques of patients with PA contained a higher percentage of the fibrofatty component than those without PA (MLA site, 21.0+/-12.0% versus 11.5+/-7.6%, p=0.013; entire culprit lesion, 16.8+/-7.9% versus 12.1+/-5.5%, p=0.062). There was no significant difference in quantitative parameters between the patients with and without PA. CONCLUSIONS Culprit plaques of patients with PA were different from those without PA. Plaque composition may play an important role in the occurrence of PA.