Norikazu Watanabe

Microvolt T-Wave Alternans as a Predictor of Ventricular Tachyarrhythmias A Prospective Study Using Atrial Pacing

Background—Microvolt T-wave alternans (TWA) is reported to be closely associated with sudden cardiac death (SCD) and ventricular tachycardia (VT). Animal experiments revealed that microvolt TWA is highly dependent on heart rate. The purpose of this study was to determine whether patients with TWA at relatively low heart rates have increased vulnerability to ventricular tachyarrhythmias. Methods and Results—Subjects were 248 consecutive patients (158 men, 90 women; mean age, 59±17 years) who underwent electrophysiological study from 1997 to 2000. TWA recording was made in sinus rhythm and at atrial pacing rates of 90, 100, 110, and 120 bpm with the Cambridge Heart CH2000 system. Alternans voltage (Valt) was measured when the alternans ratio was >3 for a period of >1 minute in VM, X, Y, Z, or 2 adjacent precordial leads. Study end point was the first appearance of VT, ventricular fibrillation (VF), appropriate implantable cardioverter-defibrillator therapy with pacing or shocks, or SCD. During the 37±12-month follow-up period, 22 patients had sustained VT, and 5 patients died of SCD. In patients with >1.9-μV Valt at rates of 90, 100, and 110 bpm, the incidence of VT/VF/SCD was 56%, 28%, and 18%, respectively. Valt of >2.9 μV at a heart rate of 90 bpm had a 70% positive predictive value for VT/VF/SCD. However, when Valt was <0.9 μV at a rate of 120 bpm, negative predictive value was 100%. Conclusions—Patients with TWA at relatively low heart rates are susceptible to ventricular tachyarrhythmias.

Prolonged Paced QRS Duration as a Predictor for Congestive Heart Failure in Patients with Right Ventricular Apical Pacing

Background: The recent studies showed that right ventricular (RV) pacing was associated with worsening of heart failure. The aim of this study is to clarify the clinical significance of paced QRS duration during RV pacing to predict congestive heart failure (CHF) patients.

Candesartan decreases type III procollagen-N-peptide levels and inflammatory marker levels and maintains sinus rhythm in patients with atrial fibrillation.

This study has evaluated whether candesartans prevent the recurrence of atrial fibrillation (AF) and decrease type III procollagen-N-peptide (PIIINP) levels. A total of 153 patients with AF were enrolled in this study. Three groups of patients were compared; candesartan group was treated with candesartan plus bepridil (n = 52); and carvedilol group with carvedilol plus bepridil (n = 51); and bepridil group with bepridil alone (n = 50). The primary end point was length of time to the recurrence of AF and all patients were ultimately followed-up for 730 days. Serum levels of the biomarkers were measured at baseline and after 24 months. Maintenance of sinus rhythm was achieved in 25 (50%) patients in bepridil group, 37 (73%) in candesartan group, and 34 (67%) in carvedilol group, giving a bepridil group/candesartan group hazard ratio of 0.36 (95% confidence interval 0.21-0.63; P = 0.03). Candesartan significantly decreased PIIINP levels at 24 months than at baseline in sinus rhythm group (0.57 ± 0.02 vs. 0.64 ± 0.05 U/mL, P = 0.04) and did not decrease PIIINP levels in the recurrence group. In conclusions, PIIINP might be related to the possibility of the atrial fibrosis for AF. However, further studies are needed to clarify the relationship between PIIINP and AF.

Impact of depression on masked hypertension and variability in home blood pressure in treated hypertensive patients.

This study was conducted to determine the effects of depression and/or insomnia on masked hypertension (MHT) compared with other types of HT and on variability in home-measured blood pressure (HBP) and clinic BP (CBP). Three hundred and twenty-eight hypertensives (132 women) aged 68±10 years were classified into four BP types: controlled HT (CHT), white-coat HT, MHT and sustained HT (SHT), based on CBP (140/90 mm Hg) and morning HBP (135/85 mm Hg) measurements. A score of ⩾16 on the Center for Epidemiologic Studies Depression Scale (CES-D) was defined as depression. The mean values and s.d. of BP were calculated from measurements taken during the 14 consecutive days just before the CES-D evaluation. Compared with the CHT group, the risk of depression was 2.77-fold higher in the SHT group and even higher in the MHT group (7.02-fold). The association between depression and MHT was augmented in the presence of insomnia and was somewhat stronger in women. A HBP variability index defined as s.d./mean BPs in both morning and night time was significantly higher in MHT than in the other BP types, whereas that of CBP was not. Both morning and night-time HBP variability were significantly higher in depressive patients than in non-depressives. These suggest that depression is associated with MHT and that increases both morning and night-time HBP variability but not CBP variability. Physicians should be mindful of mental stresses such as depression in their hypertensive patients when forming strategies to control BP over the diurnal cycle.

Single center experience in Japanese patients with syncope

BACKGROUND AND PURPOSE The present diagnostic method and features of syncope in Japan are unclear. Implantable loop recorder (ILR) and head-up tilt tests have recently become available for diagnosing syncope. The examination method and rates of diagnosing syncope may vary. This study aimed to clarify the present diagnostic method and features of syncope in a single Japanese medical center. METHODS AND RESULTS We retrospectively reviewed the medical records of consecutive patients who were seen at our hospital from January 1, 2009, to December 31, 2012. A total of 547 patients (328 men, 60.4±21.5 years) with syncope were seen at our hospital. Reflex syncope was diagnosed in 29.1% of the cases, orthostatic hypotension in 11.7%, cardiac syncope in 34.0%, and unexplained syncope in 23.9% by initial and early evaluations. The number of patients with situational syncope and orthostatic hypotension that could be diagnosed in the initial evaluation of the first examination was significantly greater than that in subsequent evaluations. Forty-three percent of the unexplained syncope patients received an ILR. The consent rate for ILR implantations in the unexplained syncope patients with a suspected arrhythmia nature was 53.1%. The cumulative ILR diagnostic rates were 47% and 65% at 1 and 2 years after the ILR implantation, respectively. The estimated ILR diagnostic rates were significantly greater than that for conventional test without using an ILR. When patients with unexplained syncope could be diagnosed, the recurrent symptoms were greatly reduced. CONCLUSIONS Syncope is induced by various causes in Japan. It is important that we understand the characteristics of each syncope cause. The consent rate for implanting an ILR in appropriate unexplained syncope patients is low. We need to educate these patients about the importance of making a diagnosis of syncope.

Recurrence of atrial fibrillation within three months after pulmonary vein isolation for patients with paroxysmal atrial fibrillation: Analysis using external loop recorder with auto-trigger function

Pulmonary vein isolation (PVI) via catheter ablation has been shown to be a highly effective treatment option for patients with symptomatic paroxysmal atrial fibrillation (AF). The recurrence of AF within 3 months after PVI is not considered to be the result of ablation procedure failure, because early recurrence of AF is not always associated with late recurrence. We examined the usefulness of an external loop recorder with an auto‐trigger function (ELR‐AUTO) for the detection of atrial fibrillation following PVI to characterize early recurrence and to determine the implications of AF occurrence within 3 months after PVI.

J-Wave in Patients With Syncope

BACKGROUND Syncope is a common occurrence. The presence of J-wave, also known as early repolarization, on electrocardiogram is often seen in the general population, but the relationship between syncope and J-wave is unclear. METHODSANDRESULTS After excluding 67 patients with structural heart disease from 326 with syncope, we classified 259 patients according to the presence or absence of J-wave (≥1 mm) in at least 2 inferior or lateral leads. Head-up tilt test (HUT) was performed for 30 min. If no syncope or presyncope occurred, HUT was repeated after drug loading. Before tilt, 97/259 (37%) had J-wave (57 male, 47.6±22.5 years) and 162 patients had no remarkable change (89 male, 51.1±21.2 years). HUT-positive rate was higher in patients with J-wave, compared with patients without (P<0.0001). The combination of J-wave and descending/horizontal ST segment in the inferior leads was more strongly associated with positive HUT than J-wave with ascending ST segment (odds ratio, 3.23). CONCLUSIONS Prevalence of J-wave in the inferior or lateral leads was high in patients with syncope and was associated with HUT-induced neurally mediated reflex syncope (NMRS). Furthermore, the combination of J-wave and descending/horizontal ST segment in the inferior leads could be associated with a much higher risk of NMRS.

Increase in Tpeak-Tend interval induced by cardiac resynchronization therapy is a predictor of ventricular tachyarrhythmia

The impact of cardiac resynchronization therapy (CRT) on dispersion of repolarization is controversial. This study aimed to determine whether CRT alters the QT interval and Tpeak–Tend interval (Tpeak–end) and whether such changes relate to the risk of developing a major arrhythmic event (MAE).

Hemodynamics Changes after Tilting and the Efficacy of Preventive Drugs

Background: We investigated whether hemodynamics changes during head‐up tilt test (HUT) predict the efficacy of preventive drugs in neurally mediated syncope (NMS) patients, in order to clarify the differences between drug responders and nonresponders.

Immediate discontinuation of ablation during pulmonary vein isolation remarkably decreases the incidence of esophageal thermal lesions even when using steerable sheaths

Left atrial–esophageal fistulas (LAEFs) are serious complications with high mortality after atrial fibrillation radiofrequency ablation (AFRA). Decreasing the incidence of esophageal thermal lesions (EsoTLs) that may lead to LAEFs is important. The aim of this study was to suppress EsoTL development and determine the appropriate alarm setting for a temperature‐monitoring probe by using steerable sheath (STS) methods.