Long-term effectiveness of right septal pacing vs. right apical pacing in patients with atrioventricular block

AbstractBackgroundLong-term right ventricular apical (RVA) pacing increases the risk of heart failure (HF) by inducing ventricular dyssynchronization. Although recent studies suggest that right ventricular septal (RVS) pacing results in improved short-term outcomes, its long-term effectiveness remains unclear.Methods and resultsThis study investigated 149 consecutive patients who underwent implantation of a dual chamber pacemaker for atrioventricular block with either RVS-pacing between July 2007 and June 2010 or RVA-pacing between January 2003 and June 2007. The endpoint was defined as death and hospitalization due to heart failure (HF). The rates of mortality and hospitalization due to HF were significantly lower in the RVS-pacing group than that in the RVA-pacing group (event free RVS: 1 year, 98% and 2 years, 98%; RVA: 1 year, 85% and 2 years, 81%; p<0.05). None of the patients died from HF in the RVS-pacing group, while 4 patients died from HF in the RVA-pacing group within 2 years after pacemaker implantation. The paced QRS interval was significantly shorter with RVS pacing than with RVA pacing at different times after pacemaker implantation (RVS: immediately 157.8±24.0ms, after 3 months 157.3±17.5ms, after 6 months 153.6±21.7ms, after 12 months 153.6±19.4ms, after 24 months 149.3±24.0ms vs. RVA: immediately 168.3±23.7ms, after 3 months 168.7±26.0ms, after 6 months 168.0±22.8ms, after 12 months 171.2±22.3ms, after 24 months 176.1±25.5ms; p<0.05).ConclusionsRVS pacing is feasible and safe with more favorable clinical benefits than RVA pacing

Large Right Pulmonary Vein Is a Predictor of Atrial Fibrillation Recurrence after Pulmonary Vein Isolation in Patients with Persistent Atrial Fibrillation

Pulmonary vein isolation（PVI）is an effective treatment for atrial fibrillation（AF）. However, outcomes differ between paroxysmal AF and persistent AF. We analyzed the predictors of recurrence by examining the recurrence group after ablation. Of 372 consecutive patients with AF who underwent PVI between June 2016 and December 2018, we evaluated 250 patients（age, 67±12y, 65％ men）whose left atrium（LA）was constructed using the PENTARAY catheter（BioSense Webster, Los Angeles, CA）, a multipolar electrode catheter with a novel shape and excellent mapping capability. We measured the LA total volume（LATV）, right pulmonary vein＋antrum volume（RPAV）, left PV＋antrum volume（LPAV）, LA central volume（LACV）, and LA bipolar voltage. Of the 250 patients, 78 had persistent AF（recurrence, 20）and 172 had paroxysmal AF（recurrence, 16）. In all patients, LATV, LACV, RPAV, and LPAV were significantly larger in patients with persistent AF than those with paroxysmal AF. The mean LA bipolar voltage in patients with persistent AF was significantly lower than those with paroxysmal AF. In cases of persistent AF, RPAV was significantly larger in the recurrence group than that in the non-recurrence group（15.9±4.8 vs 13.4±5.4ml; P＜0.05）. In cases of paroxysmal AF, there were no differences in any volume between the recurrence and non-recurrence groups. In conclusion, larger right PV is a predictor of AF recurrence after PVI in patients with persistent AF. The right PV is close to the atrial septum and the septopulmonary bundle, and the expansion of RPAV reflects the disruption of these structures, which may be involved in this result

Recurrence of Atrial Fibrillation within Three Months after Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation : Analysis Using an External Loop Recorder with Auto-trigger Function

Pulmonary vein isolation (PVI) via catheter ablation has been shown to be a highly effective option for patients with symptomatic paroxysmal atrial brillation (AF). The recurrence of AF within 3 months after PVI is not considered a failure of the ablation procedure because early recurrence of AF is not always associated with late recurrence. We examined the usefulness of an external loop recorder with auto-trigger function (ELR-AUTO) to detect AF following PVI to characterize early recurrence and determine the implication of AF within 3 months after PVI. The study included 53 consecutive patients with symptomatic paroxysmal AF (age, 61.6 ± 12.6 years ; 77％ male) who underwent PVI, and were fitted with an ELR-AUTO for 7 ± 2 days within 3 months after PVI. Of the 33 patients(62.2％) who did not have AF within the 3-month period, only 1 patient had AF recurrence at 12 months. Seven of 20 patients (35％) who experienced AF within 3 months had symptomatic AF recurrence at 12 months. The sensitivity, specificity, positive predictive value, and negative predictive value of early AF recurrence for late recurrence was 87.5％, 71.1％, 35.0％, and 96.9％, respectively. Thus, AF recurrence detected by ELR-AUTO within 3 months after PVI can predict late AF recurrence. Freedom from AF in the firrst 3 months following ablation significantly predicts long-term freedom from AF. An ELR-AUTO is useful for detecting symptomatic and asymptomatic AF

A 1 bit binary-decision-diagram adder circuit using single-electron transistors made by selective-area metalorganic vapor-phase epitaxy

We demonstrate single-electron operation of a 1 bit adder circuit using GaAs single-electron tunneling transistors (SETs). GaAs dot and wire coupled structures for the fabrication of SETs were grown by a selective-area metalorganic vapor-phase epitaxy technique. The logic circuit was realized based on a binary decision diagram architecture using Coulomb blockade (CB) in GaAs dots and switching operations were achieved in a single-electron mode because of the CB effects. Through this architecture, a 1 bit adder circuit was realized with three SETs, two of which were for AND logic and one with two input gates for exclusive OR (XOR). Both AND and XOR operations were demonstrated at 1.9 K, which indicated successful fabrication of the 1 bit adder

Ordinary Autonomic Unbalance Can Reflect Diagnosis of Neurally Mediated Reflex Syncope

Background: In the present study we investigated autonomic dysfunction using hemodynamics and analysis of heart rate variability (HRV) following ambulatory blood pressure monitoring (APBM) in patients with neurally mediated reflex syncope (NMRS). In addition, we evaluated the usefulness of ABPM for diagnosing NMRS. Methods: In all, 88 consecutive patients with syncope and 12 controls (Group C) were subjected to a head-up tilt (HUT) test (80°, 30 min). If no syncope or presyncope occurred, the HUT test was repeated in the patient group following drug loading (ATP, isoproterenol, and/or isosorbide dinitrate). Results: Forty patients had a positive HUT test, with or without drug loading (Group P) ; the HUT test was negative in 48 patients, even after drug loading. Average daytime systolic and diastolic blood pressure (SBP and DBP, respectively) was significantly lower in Group P than in Group C (P = 0.042 and P = 0.047, respectively). The average standard deviation of SBP at night (SD-SBPNight) was significantly higher in Group P than in Group C (P = 0.004). HRV analysis revealed a significantly higher daytime high-frequency component in Group P than in Group C (P = 0.041). Conclusion: The results of the present study suggest that lower daytime blood pressure and a larger SD-SBPNight, as determined by ABPM, are associated with vagal nerve hyperactivity and sympathetic hypoactivity in patients with NMRS. Thus, an inadequate circadian rhythm in blood pressure variation, as identified by ABPM, may be useful for the diagnosis of NMRS

The Effects of Nicorandil and Nifekalant, Which Were Injected into the Pericardial Space, for Transmural Dispersion of Repolarization in the Pig

Introduction: Some studies have reported that transmural dispersion of repolarization (TDR) is involved in the onset of ventricular arrhythmia. We investigated the effects of nicorandil (NIC) and nifekalant (NIF) injected into the pericardial space, on TDR and T waves in the pig. Methods and Results: We injected NIC 4 or 8 mg and NIF 50 or 100 mg at intervals into the pericardial space for eleven pigs. The effects of these drugs were investigated on the effective refractory period (ERP) between the endocardial and epicardial myocardial cells, as well as on QT time, QT peak-end (QTcpe) as an index of TDR, and T waveforms, respectively. QTcpe increased from 91 ± 21 to 116 ± 19 msec, 2.8 min after injection of NIC (p < 0.01), although corrected QT (QTc) interval did not changed. But 5.5 min after injection, QTc decreased while QTcpe recovered. T wave amplitude significantly increased, and epicardium ERP decreased. When NIF was injected, TDR decreased from 55 ± 10 msec to 44 ± 8 msec (p < 0.01) although QTc did not change. In a later phase, QTc increased (p < 0.01) and QTcpe recovered. T wave amplitude rapidly decreased and became negative. Conclusion: Injected into the pericardial space, NIC and NIF brought about certain changes in ERP, QT and T waveform. Furthermore, NIC increased TDR while NIF decreased TDR

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

Background: 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. Methods: Fifty-three consecutive symptomatic patients with paroxysmal AF (age 61.6±12.6 years, 77% male) who underwent PVI and were fitted with ELR-AUTO for 7±2.0 days within 3 months after PVI were enrolled in this study. Results: Of the 33 (62.2%) patients who did not have AF recurrence within 3 months after PVI, only 1 patient experienced AF recurrence at 12 months. Seven (35%) of the 20 patients who experienced AF within 3 months of PVI experienced symptomatic AF recurrence at 12 months. The sensitivity, specificity, positive predictive value, and negative predictive value of early AF recurrence for late recurrence were 87.5%, 71.1%, 35.0%, and 96.9%, respectively. Conclusions: AF recurrence measured by ELR-AUTO within 3 months after PVI can predict the late recurrence of AF. Freedom from AF in the first 3 months following ablation significantly predicts long-term AF freedom. ELR-AUTO is useful for the detection of symptomatic and asymptomatic AF