Chizuru Sato

Olmesartan Improves Coronary Flow Reserve of Hypertensive Patients Using Coronary Magnetic Resonance Imaging Compared with Amlodipine

Objectives: Hypertension impairs coronary endothelial cell function, coronary microvascular function and the coronary flow (CF) reserve (CFR). Angiotensin II receptor blockers (ARBs) have been reported to possibly improve coronary endothelial function and coronary microvascular function. The purpose of this study was to determine whether treatment with the ARB olmesartan was more effective for improving CFR than the calcium channel blocker amlodipine. Methods: Twenty patients with untreated essential hypertension (M/F = 13/7, aged 55.6 ± 11.6 years) were randomly assigned to treatment with either olmesartan (n = 10) or amlodipine (n = 10) for 6 months. CF was measured in the proximal left anterior descending artery by magnetic resonance imaging before and during intravenous infusion of adenosine. CFR was calculated as the ratio of the hyperemic to baseline diastolic peak flow before and after 6 months of treatment. Results: The extent of systolic blood pressure reduction was similar in both groups (–40.0 ± 19.1 vs. –48.8 ± 14.7 mm Hg, p = 0.26). The olmesartan group showed significant improvement of CFR (from 1.9 ± 1.0 to 3.1 ± 1.1, p = 0.005), but this did not occur in the amlodipine group. Conclusion: Olmesartan, but not amlodipine, improves CFR in hypertensive patients.

Utility and Validation of Corrected Left Ventricular Filling Time for Determining the Optimal AV Delay in Patients Receiving Cardiac Resynchronization Therapy

Background: Optimizing the atrio‐ventricular delay (AVD) is important for increasing the left ventricular (LV) preload in patients receiving cardiac resynchronization therapy (CRT). The optimal AVD may be considered an AVD in which the maximum LV filling time (LVFT) is obtained. However, it is unclear whether or not the optimal AVD determined by Ritters method (AVD‐Ritter) is identical to the AVD in which the maximum LVFT is obtained. The aim of this study was to clarify this point.

A potential pitfall of the modified 12 lead electrocardiogram (Mason–Likar modification) in catheter ablation of idiopathic ventricular arrhythmias originating from the outflow tract

AIMS The Mason-Likar modified electrocardiogram (ML-ECG) can be interchanged with standard 12 lead ECG electrode positions (standard ECG) without affecting the diagnostic interpretation during sinus rhythm, but the morphological differences during ventricular arrhythmias have not been sufficiently evaluated. This study aimed to elucidate the morphological changes in the ML-ECG precordial leads. METHODS AND RESULTS In 53 consecutive patients with premature ventricular contractions predicted to originate from the outflow tract (OT-PVCs), the arrhythmias were analysed by those two ECG methods. The OT-PVC origin sites, which were predicted by currently published criteria with the respective ECG methods prior to catheter ablation, were compared with the successful ablation sites. Compared with the standard-ECG, S-waves in the ML-ECG became shallower in leads V1-4 (P < 0.05 in lead V1; P < 0.001 in leads V2-4), and pseudo-R-waves in lead V1 appeared in seven patients. The precordial leads transition zone shifted counter-clockwise in 18 patients in the ML-ECG. In leads I and aVL, the negative deflection amplitudes of the ML-ECG were greater than those of the standard ECG (P < 0.001), and polarity reversals in lead I appeared in 18 patients. The R-wave amplitudes in all ML-ECG inferior leads were greater than those in the standard-ECG leads (all for P < 0.001). Those changes had an effect on the diagnostic indexes for the localization, and the specificity of the criteria for the ML-ECG was poorer than that for the standard-ECG. CONCLUSION Great differences were found between those two ECG methods. Predicting OT-PVC origins by diagnostic criteria with the ML-ECG might result in a misdiagnosis and inefficient ablation.

Usefulness of SafeR Mode for Reduction of Ventricular Pacing in Patients with Sick Sinus Syndrome

Background: It was reported that unnecessary right ventricular pacing increased the risk of atrial fibrillation (Af) or congestive heart failure (CHF). We evaluated the usefulness of SafeR mode, a new pacing algorithm designed to minimize ventricular pacing. Methods: 18 patients (75±8 years old, 7 men) who had pacemaker implantation were randomized to SafeR mode or DDD mode for 3 months and then crossed over to the alternate pacing modality for 3 months. Atrioventricular (AV) conduction interval during atrial pacing set at 90 beats/min was measured and the paced/sensed AV delays were programmed at 30 msec longer than the measured AV interval in device implantation. On completion of the 3-month crossover phase, we evaluated the percentage of ventricular pacing, the number of premature atrial conduction (PAC), premature ventricular conduction (PVC), plasma BNP level and the prevalence of Af. Results: The percentage of ventricular pacing was significantly lower in SafeR mode than that in DDD mode (3.3% vs 31.1%, P<0.001). The number of PAC, PVC, BNP and Af episodes tend to be reduced by SafeR mode compared with DDD mode, however, there were no statistically difference in both modes. Adverse events potentially related with SafeR mode were not observed. Conclusion: SafeR mode significantly reduced unnecessary right ventricular pacing. This mode may reduce the risk of Af or CHF in patient with SSS.