Effects of nicorandil, a potassium channel opener, on idiopathic ventricular tachycardia

AbstractObjectives. We assessed the effects of the adenosine triphosphate (ATP)–sensitive potassium channel opener, nicorandil, on ATP- and verapamil-responsive ventricular tachycardias (VTs).Background. Adenosine- or ATP-sensitive VTs are thought to be due to a nonreentrant mechanism, presumably delayed afterdepolarization. We suggest that this potassium channel opener may suppress ATP- and verapamil-sensitive VTs.Methods. The subjects included 13 patients with idiopathic VTs, 7 of whom had sustained VT and 6 of whom had nonsustained VT. We evaluated the effects of ATP, nicorandil and verapamil on VTs.Results. Sustained VT: Verapamil had preventive effects on seven VTs. Four VTs were terminated by ATP, and of these, nicorandil terminated two and prevented exercise-induced VT in the two others. Three ATP-insensitive VTs, which were determined to be due to a reentry by an electrophysiologic study, were not terminated by nicorandil. Nonsustained VT: All six VTs were inhibited by ATP, and five of these were suppressed by nicorandil. Verapamil inhibited four of the five VTs. QT intervals and the corrected QT intervals were significantly shortened by nicorandil.Conclusions. Nicorandil suppresses ATP- and verapamil-responsive VTs. One of the mechanisms of suppression by nicorandil might be related to a reduction of calcium in the myocardium, because it reduces the action potential duration

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

カンゴシ ガ ヒテイテキナ カンジョウ オ ヒキオコス タイジン カンケイ ニカンスル ブンケン レビュー

目的：看護師が否定的な感情を引き起こす対人関係について、先行研究の概略を整理し、今後の研究の方向性について示唆を得ることを目的とした。方法：医中誌WEB（Ver6）にて、「看護師」「対人関係」「ハラスメント」「ストレス」をキーワードに、否定的な感情を引き起こす対人関係の実態を明らかにした23文献を対象とした。結果：職業性ストレスの研究と、ハラスメント・いじめの研究、対人関係上の困難の研究の３つに分類された。ハラスメントを行ったのは多くが上司や先輩・同僚の看護師で、被害率は１割以上であり、主観的な被害認識を調査した研究もあった。考察：看護師の職業性ストレスの原因や、ハラスメント・いじめと感じる原因は、職務遂行上避けて通れない他者との関わりの中で生じるものであると考えられた。さらにストレスやハラスメントという概念では説明できない様々な要因が否定的な感情を引き起こし、他者が受けた行為も含めハラスメント被害と認識している人が多いことが示された。看護師の間には仕事における何らかの力関係の差が生じ、ハラスメント・いじめが発生しやすい環境にあると考えられた。今後は、看護師間の対人関係に焦点をあてた研究の必要性が示唆された

Right Atrial Volume Calculated by Multi-detector Computed Tomography: Useful Predictor of Atrial Fibrillation Recurrence after Pulmonary Vein Catheter Ablation

We investigated whether right atrial (RA) volume could be used to predict the recurrence of atrial fibrillation (AF) after pulmonary vein catheter ablation (CA). We evaluated 65 patients with paroxysmal AF (mean age, 60+10 years, 81.5% male) and normal volunteers (57 ± 14 years, 41.7% male). Sixty-four-slice multi-detector computed tomography was performed for left atrial (LA) and RA volume estimations before CA. The recurrence of AF was assessed for 6 months after the ablation. Both left and right atrial volumes were larger in the AF patients than the normal volunteers (LA: 99.7+33.2ml vs. 59.7+17.4ml; RA: 82.9+35.7ml vs. 43.9+12ml; P100ml) for predicting the recurrence of AF was 81.3% in 13 of 16 patients with AF recurrence, and the specificity was 69.4% in 34 of 49 patients without recurrence. The sensitivity with large RA volumes (>87ml) was 81.3% in 13 of 16 patients with AF recurrence, and the specificity was 75.5% in 37 of 49 patients without recurrence. RA volume is a useful predictor of the recurrence of AF, similar to LA volume

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

Use of implantable and external loop recorders in syncope with unknown causes

The gold standard for diagnosing syncope is to elucidate the symptom-electrocardiogram (ECG) correlation. The ECG recordings during syncope allow physicians to either confirm or exclude an arrhythmia as the mechanism of syncope. Many studies have investigated the use of internal loop recorder (ILR), while few studies have used external loop recorder (ELR) for patients with unexplained syncope. The aim of this review is to clarify the clinical usefulness of ILR and ELR in the diagnosis and management of patients with unexplained syncope. Many observational and four randomized control studies have shown that ILR for patients with unknown syncope is a useful tool for early diagnosis and improving diagnosis rate. ILR also provides important information on the mechanism of syncope and treatment strategy. However, there is no evidence of total mortality or quality of life improvements with ILR. The diagnostic yield of ELR in patients with syncope was similar to that with ILR within the same timeframe. Therefore, ELR could be considered for long-term ECG monitoring before a patient switches to using ILR. A systematic approach and selection of ECG monitoring tools reduces health care costs and improves the selection of patients for optimal treatment possibilities. Keywords: Internal loop recorder, External loop recorder, Unknown Syncop

New Parameter to Predict Recurrence of Paroxysmal Atrial Fibrillation after Pulmonary Vein Isolation by the P-Wave Signal-Averaged Electrocardiogram

Noninvasive methods for predicting the recurrence of atrial fibrillation (AF) after initial pulmonary vein isolation (PVI) have not been well described. The aim of the present study was to evaluate the usefulness of the P-wave signal-averaged electrocardiogram (P-SAECG) in predicting the recurrence of AF after initial PVI. The P-SAECG was recorded before and after (within 1 week) the initial PVI session. The filtered P-wave duration (FPD) and root mean square voltage of the last 20ms of the filtered P-wave (LP20) were measured in 87 consecutive idiopathic AF patients (ejection fraction ≥50%, B-type natriuretic peptide ≤200pg/ml). During the follow-up period (12±7 months), 22 of 87 (25%) patients had recurrence of AF (11 with paroxysmal AF and 11 with persistent AF). In the group with recurrence of paroxysmal AF, the post-PVI FPD was significantly shorter and the post-PVI LP20 was significantly larger than in the non-recurrence group. Furthermore, the post-PVI LP20/FPD ratio was significantly higher in the group with paroxysmal AF recurrence than in the non-recurrence group (0.024±0.009 vs 0.015±0.007µV/ms, respectively; P0.015µV/ms than in those with a post-PVI LP20/FPD ≤0.015µV/ms. The optimal post-PVI LP20/FPD cut-off value of 0.015µV/ms had a sensitivity of 90% and a specificity of 60%. The data also suggest that the post-PVI LP20/FPD may be a new parameter for predicting successful PVI in patients with idiopathic paroxysmal AF after PVI