Kenichi Hashimoto

Prediction of the efficacy of pulmonary vein isolation for the treatment of atrial fibrillation by the signal-averaged P-wave duration

Background: The noninvasive methods for predicting a successful pulmonary vein isolation (PVI) have not been well described. The aim of this study was to assess the usefulness of the P‐wave signal‐averaged electrocardiogram (P‐SAECG) in predicting the chance of a successful PVI in patients with atrial fibrillation (AF).

Anatomic and Electrophysiologic Differences between Chronic and Paroxysmal Atrial Flutter: Intracardiac Echocardiographic Analysis

Background : It remains unknown why atrial flutter (AFL) occurs as either a chronic or paroxysmal arrhythmia.

Wolff‐Parkinson‐White Syndrome Concomitant with Asymptomatic Brugada Syndrome

A 29‐year‐old man was referred for electrophysiological testing and radiofrequency ablation because of repeated episodes of palpitation over 2 years. A 12‐lead electrocardiogram during sinus rhythm showed manifest Wolff‐Parkinson‐White syndrome and during palpitation showed narrow QRS tachycardia at a rate of 213 beats/min. Following successful radiofrequency ablation of the left anterolateral accessory pathway, sustained atrial fibrillation was induced by atrial extrastimulation. Cibenzoline (2 mg/kg body weight) was injected to terminate atrial fibrillation. ST‐T segment elevation in the right precordial leads was observed following cibenzoline administration. Ventricular fibrillation was reproducibly induced by ventricular extrastimuli (S1: 600 ms, S2: 220 ms, S3: 210 ms). (PACE 2004; 27:109–111)

Usefulness of the polarity in high-density wide range-filtered bipolar mapping to detect isthmus block during radiofrequency ablation of typical atrial flutter.

Background: The atrial activation sequence around the tricuspid annulus (TA) cannot always be used to establish whether complete block has been achieved across the cavotricuspid isthmus (CTI) during radiofrequency ablation (RFCA) for typical counterclockwise atrial flutter (CCW-AFL).Aim: We examined whether a change in the polarity of the atrial high-density wide range-filtered bipolar electrograms recorded near the ablation line is an accurate indicator of complete CTI block.Methods: Nineteen patients with CCW-AFL underwent RFCA. Electrograms were recorded around the TA with duodecapolar conventional (2mm × 8mm × 2mm spacing) and high-density (2-mm spacing) Halo catheters. The bipolar electrograms on the high-density Halo catheter recorded from a series of adjacent electrode pairs positioned just lateral to the ablation line were filtered at a bandpass setting of 0.05–500 Hz. The activation sequence on the conventional Halo catheter during coronary sinus pacing (CSp) and inferolateral TA pacing, and the bipolar electrograms on the high-density Halo catheter during CSp were determined before and after RFCA. The final complete CTI block was verified by the presence of widely split double electrograms ≥100 msec along the ablation line.Results: The final complete CTI block was achieved in all the 19 patients. Before RFCA, the polarity of bipolar electrograms was predominantly negative during CCW-AFL and positive during CSp. In 18 of the 19 patients, the bipolar electrograms exhibited the CCW activation and a negative polarity during CSp only after complete CTI block. In one of those 18 patients, additional applications of RFCA changed the polarity of bipolar electrograms positive to negative although the conventional Halo electrogram activation sequence suggested complete CTI block during CSp. In seven patients, who had transverse conduction across the crista terminalis during CSp, the conventional Halo electrogram activation sequence suggested an incomplete CTI block. However, in six of those seven patients, the CCW activation had a predominantly negative polarity of the bipolar electrograms. In one of those seven patients, complete CTI block was unable to be detected even using the high-density Halo catheter.Conclusions: These data demonstrate that the high-density wide range-filtered mapping can identify the CTI block in undetectable cases of complete CTI block or incomplete CTI block by the conventional method. The polarity of the bipolar electrograms recorded just lateral to the ablation line during CSp after RFCA of AFL may be used as a simple and an accurate indicator of complete CTI block.

Full-motion two- and three-dimensional pulmonary vein imaging by intracardiac echocardiography after pulmonary vein isolation.

Background: The pulmonary veins (PVs) are topographically complex and motile, so angiographic visualization of the PVs anatomy is limited. An imaging technique that accurately portrays the pulmonary vein (PV) anatomy would be valuable during and after catheter ablation procedures.

Reproducible induction of atrioventricular nodal reentrant tachycardia with adenosine triphosphate.

A 29‐year‐old woman was referred for electrophysiological testing and radiofrequency ablation because of repeated episodes of palpitation of a 8‐year duration. The 12‐lead ECG during palpitations showed narrow QRS tachycardia at a rate of 160 beats/min. Dual AVN physiology according to electrophysiological criteria was not shown by single atrial extrastimulation and the tachycardia could not be induced. Slow/fast atrioventricular nodal reentrant tachycardia (AVNRT) was induced once by double atrial extrastimuli, but it was not reproducible. However, intravenous bolus injection of adenosine triphosphate (12.5 mg) during sinus rhythm led to reproducible initiation of slow/fast AVNRT. (PACE 2003; 26:2321–2323)

A novel signal-averaged electrocardiogram and an ambulatory-based signal-averaged electrocardiogram show strong correlations with conventional signal-averaged electrocardiogram in healthy subjects: A validation study

BACKGROUND A novel signal-averaged electrocardiogram (SAECG) device and a novel ambulatory SAECG device are clinically available, but reference values have not been established. This study aimed to validate the novel SAECG and the novel ambulatory-based SAECG devices by comparison with the conventional SAECG device. METHODS AND RESULTS High-resolution SAECGs were recorded consecutively in 83 healthy volunteers using the 3 devices. A novel ambulatory SAECG device was used as real-time recording within 15 min for validation study (15 min ambulatory-based SAECG). We examined the concordance of positive results (at least 2/3 abnormal SAECG parameters) and negative results (0 or 1/3 abnormal parameters), as well as the correlations between SAECG parameters (filtered QRS duration [fQRS]); duration of low-amplitude signals < 40 μV in the terminal filtered QRS complex [LAS40]; root mean square voltage of the terminal 40 ms of the filtered QRS complex [RMS40]). Qualitative analysis showed excellent concordance among the novel SAECG, the 15 min ambulatory-based SAECG, and the conventional SAECG methods (novel SAECG vs. conventional SAECG = 94%; 15 min ambulatory-based SAECG vs. conventional SAECG = 91.6%; p = 0.755), while quantitative analysis indicated strong correlations between the novel SAECG and the conventional SAECG values for fQRS, LAS40, and LnRMS40 (r = 0.838-0.805, p < 0.0001, respectively). Strong correlations were also seen between 15 min ambulatory-based SAECG and conventional SAECG values for fQRS, LAS40, and RMS40 (r = 0.943-0.888, p < 0.0001, respectively). However, Bland-Altman quantitative analysis showed better agreement in fQRS and LnRMS40 measured by the 15 min ambulatory-based SAECG and the conventional SAECG than those by the novel SAECG and the conventional SAECG (fQRS, Lins rho_c = 0.923 vs. 0757; RMS40, Lins rho_c = 0.932 vs. 0.818, respectively). CONCLUSION In healthy subjects, the parameters of either the novel SAECG or the 15 min ambulatory-based SAECG and those of the conventional SAECG were strongly correlated. Relatively good agreements were observed among 3 SAECGs, especially better between the 15 min ambulatory-based SAECG and the conventional SAECG probably due to similar measurement system of 2 methods.

Catheter Ablation for Three Focal Atrial Tachycardias in a Patient with Prior Fontan Surgery for Tricuspid Atresia

A 28‐year‐old woman who had undergone Fontan surgery for tricuspid atresia at 6 years of age was admitted to Nihon University Hospital due to syncope. Supraventricular tachycardia at 141 beats/min was induced with isoproterenol infusion during a tilt table test. The patient showed atresia of the right atrial orifice of the coronary sinus with persistent drainage into the left superior vena cava. Electrophysiological study was performed. Atrial tachycardia (AT) was induced by rapid atrial pacing. The AT originated in the lower lateral right atrium and electroanatomical mapping showed a focal origin. After successful ablation of the AT, two additional ATs were induced. These ATs were also shown to be of focal origin and were successfully ablated without recurrence during follow‐up.

T-wave alternans during cardiac resynchronization therapy

Biventricular (BV) pacing has been shown to be effective in selected patients with left ventricular (LV) dysfunction. However, BV pacing does not necessarily decrease sudden cardiac death. Recent studies have shown that epicardial LV pacing may lead to the prolongation of the QT interval and the development of torsade de pointes. On the other hand, microvoltage T-wave alternans (TWA) has been shown to be associated with increased susceptibility to ventricular tachyarrhythmias. The purpose of this study was to examine the effectiveness of right ventricular (RV), LV, and BV pacings on the TWA. Methods: T-wave alternans was measured during each pacing mode incrementally from 70 to 120 bpm in 6 patients with a mean ejection fraction of 33% F 9%. T-wave alternans was considered positive if the alternans voltage was higher than 1.9 lVand the alternans ratio was higher than 3.0 lV for at least 1 minute. Results: The mean alternans voltage values during BV, RV, and LV pacings were 2.2 F 0.5, 0.96 F 0.2, and 1.45 F 0.6 lV, respectively ( P b .01 vs RV). The mean alternans ratios during BV, RV, and LV pacings were 14.5 F 6.5, 6.3 F 2.7, and 6.5 F 1.1 lV, respectively. Positive TWA was observed in 83%, 50%, and 60% during BV, RV, and LV pacings, respectively. Conclusion: Biventricular pacing may increase the inhomogeneity of ventricular repolarization, which may lead to the development of ventricular tachyarrhythmias.

Identifying the Origin of Right and Left Ectopic Atrial Beats Triggering Atrial Fibrillation before Atrial Transseptal Procedure

Atrial premature depolarizations (APDs) triggering atrial fibrillation (AF) originate from mainly the pulmonary veins (PVs), but, in some cases, atrial ectopic beats (AEBs) triggering AF originate from the right atrium (RA) or the superior vena cava. Accurate identification of the origin of APDs in the PVs by means of RA and coronary sinus mapping is difficult. Purpose: The aim of this study was to identify the origin of AEBs triggering AF before transseptal catheterization. Electrode catheters were placed in the posteroseptal RA (PSRA), right pulmonary artery (RPA), left pulmonary artery (LPA), and esophagus in 10 patients with paroxysmal AF. We analyzed endocardial electrograms from the PSRA, RPA and LPA, and epicardial electrograms from the esophagus. The origin of the AEBs in the PVs was determined before PV ablation by mapping 4 PVs simultaneously. Four AEBs originated from the left superior PV (LSPV), 2 from the left inferior PV (LIPV), 4 from the right superior PV (RSPV), 2 from the RA or superior vena cava. In AEBs originating from the RA, the PSRA activation was the earliest and it proceeded in a cranial to caudal direction. In AEBs originating from the RUPV, RPA was the earliest. The esophageal activation sequence was in a cranial to caudal direction. In AEBs from the LSPV, LPA was the earliest and the esophageal activation sequence proceeded in a cranial to caudal direction. In AEDs from LIPV, LPA was the earliest, and the esophageal activation sequence was nearly simultaneous. Atrial activation sequences from the PSRA, RPA, LPA, and esophageal catheters can accurately identify the location of the initiating foci of AF before a transseptal procedure.