Late Potential as a Predictor of re-Hospitalization after Percutaneous Coronary Intervention for Acute Coronary Syndrome.

OBJECTIVE: The aim of this study was to investigate the significance of late potential (LP) after percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS). METHOD: We enrolled 135 consecutive patients with ACS admitted to Tokai University Hospital from February to December 2012. Twenty-four hour high-resolution ambulatory electrocardiogram was performed between post-PCI procedure and hospital discharge. The patients were divided into the LP-positive (33 patients) and LP-negative (102 patients) groups, and the relationship between LP and re-hospitalization was prospectively investigated. RESULTS: The body mass index, serum creatinine, and creatine phosphokinase-MB were higher in the LP-positive group than in the LP-negative group (p < 0.05). The re-hospitalization rate was higher in the LP-positive group. (9 patients, 27.3% vs. 10 patients, 9.8%; p = 0.03). There were no significant differences in the occurrence of ventricular tachycardia or cardiac death between the groups. According to Kaplan-Maier analysis, proportion of re-hospitalization was significantly lower in the LP-positive group than in the LP-negative group (p = 0.01; average follow-up, 451.4 ± 25.9 days). The odds ratio of LP presence was 3.45 (highest among all variables; 95% confidence interval, 1.3-9.4; p < 0.01). CONCLUSION: Positive LP in patients with ACS after PCI may predict re-hospitalization.

Investigation of a Correlation between Thoracic Vertebra Hyperplasia and Relapse in Paroxysmal Atrial FIbrillation Patients Following Extended Pulmonary Vein Isolation.

Pulmonary vein isolation (PVI) with radio-frequency catheter ablation (RFCA) is effective therapy for the patients with paroxysmal atrial fibrillation (pAF). However, it is not easy to predict relapse of pAF. Approximately 70% pAF patients were maintained sinus rhythm for 1 year after PVI in Japan. In this study, all of the cases were underwent chest computed tomography (CT) to check for the morphology and positional relationship of the left atrium. We detected relapse cases that exhibited spur formation in the thoracic vertebrae. Therefore, we conducted an investigation based on the hypothesis that, "Because hyperostosis involves proliferative changes in the synovium or pia mater cells with an inflammatory basis, it is related to the onset of atrial fibrillation." The study sample consisted of 24 sequential cases (males: 20, mean age: 66.2 ± 6.9 years) of drug-resistant pAF that underwent PVI at our hospital between January and May, 2015. When subjects were divided into a relapse group and a non-relapse group and 21 background factors were compared, it was found that the relapse group subjects were older than the non-relapse group subjects (70.3 ± 7.2 vs 64.1 ± 5.7, p = 0.04). The proportion of cases with thoracic vertebra hyperplasia was markedly high in the relapse group (6 cases [75%] vs. 3 cases [18%], p = 0.007). No statistically significant differences were observed between the two groups for any other background factors. Our results suggested that thoracic vertebra hyperplasia could be a marker for predicting relapse after PVI in pAF patients.

Usefulness of Continuous 24-hour Ventricular Late Potential to Predict Prognosis in Patients with Heart Failure.

OBJECTIVES: An estimated 50,000 patients have heart failure (HF) in Japan, and the left ventricular ejection fraction (LVEF) is the typical predictor of prognosis. The identification of a noninvasive marker to predict most high-risk patients is urgently needed. This study aimed to log the continuous ventricular late potential (LP) by using high-resolution ambulatory monitoring in patients with HF with non-sustained ventricular tachycardia, and determine the association between the LP variation and prognosis. METHODS: The 90 hospitalized patients were classified into cardiogenic death (n = 10) and non-death (n = 80) groups. The LVEF, LP, and coefficient of variation (CV) of the filtered QRS (fQRS), and low-amplitude signal < 40 µV for the terminal QRS portion of (LAS40) of both groups were evaluated. The maximum fQRS over 24 h was defined as the maximum fQRS (Max-fQRS). RESULTS: The results were as follows: (1) cardiogenic death occurred in 32% (10/31 patients) with an LVEF ≤ 45% and a Max-fQRS ≤ 114 ms; (2) cardiogenic death occurred in 38% (10/26 patients) with a LAS40-CV ≥ 0.09; and (3) using LVEF, Max-fQRS, and LAS40-CV as the three predictors, the specificity and accuracy were 83% and 82%, respectively, with an odds ratio of 12.3. CONCLUSIONS: LAS40 variations and increases might be new risk indicators of prognosis.

Comparative study of nifekalant versus amiodarone for shock-resistant ventricular fibrillation in out-of-hospital cardiopulmonary arrest patients.

BACKGROUND: In Japan, intravenous nifekalant (NIF) was often used for direct current cardioversion-resistant ventricular fibrillation (VF), until the use of intravenous amiodarone (AMD) was approved in 2007. The defibrillatory efficacy of NIF and AMD has thus far not been compared for resuscitation. METHODS AND RESULTS: Between August 2007 and April 2009, 403 consecutive out-of-hospital patients with cardiopulmonary arrest were transferred to the Emergency Medical Service of Tokai University. Of these, 30 patients with first defibrillation failure or VF recurrence were enrolled for this NIF/AMD study. The final defibrillation success (and hospital survival rate) was 67% (10/15) in the AMD and 47% (7/15) in the NIF group. The discharge survival rate was 53% (8/15) in the AMD and 21% (4/15) in the NIF group (P = 0.06). Notably, all 4 survivors in the NIF group could take up normal daily life again, whereas this was restricted to only 2 patients from the 11 survivors in the AMD group. The difference is probably partly attributable to longer time from AMD administration to defibrillation success compared with NIF. In the cases of defibrillation failure, VF continued in 4/8 by NIF, however, asystole or pulseless electrical activity occurred in 4/5 patients by AMD. CONCLUSIONS: AMD may be borderline superior over NIF to facilitate defibrillation in out-of-hospital patients with cardiopulmonary arrest. However, from the view point of preservation of brain function, NIF is not inferior to AMD for CPR.

Year-long upregulation of connexin43 in rabbit hearts by heavy ion irradiation.

A previous study from our laboratory has shown that a single targeted heavy ion irradiation (THIR; 15 Gy) to rabbit hearts increases connexin43 (Cx43) expression for 2 wk in association with an improvement of conduction, a decrease of the spatial inhomogeneity of repolarization, and a reduction of vulnerability to ventricular arrhythmias after myocardial infarction. This study investigated the time- and dose-dependent effects of THIR (5-15 Gy) on Cx43 expression in normal rabbit hearts (n = 45). Five rabbits without THIR were used as controls. A significant upregulation of Cx43 protein and mRNA in the ventricular myocardium was recognized by immunohistochemistry, Western blotting, and real-time PCR from 2 wk up to 1 yr after a single THIR at 15 Gy. THIR > or =10 Gy caused a significant dose-dependent increase of Cx43 protein and mRNA 2 wk after THIR. Anterior, lateral, and posterior free wall of the left ventricle, interventricular septum, and right ventricular free wall were affected similarly by THIR in terms of Cx43 upregulation. The radiation-induced increase of immunolabeled Cx43 was observed not only at the intercalated disk region but also at the lateral surface of ventricular myocytes. The increase of immunoreactive Cx43 protein was predominant in the membrane fraction insoluble in Triton X-100, that is the Cx43 in the sarcolemma. In vivo examinations of the rabbits 1 yr after THIR (15 Gy) revealed no significant changes in ECGs and echocardiograms (left ventricular dimensions, contractility, and diastolic function), indicating no apparent late radiation injury. A single application of THIR causes upregulation and altered cellular distribution of Cx43 in the ventricles lasting for at least 1 yr. This long-lasting remodeling effect on gap junctions may open the pathway to novel therapy against life threatening ventricular arrhythmias in structural heart disease.

Impact of vascular remodeling on the coronary plaque compositions: an investigation with in vivo tissue characterization using integrated backscatter-intravascular ultrasound.

Recent studies have indicated that positive remodeling is strongly associated with development of acute coronary syndrome (ACS). The aim of this study was to compare plaque composition of vascular remodeling patterns by an established in vivo tissue characterization method using integrated backscatter (IB)-intravascular ultrasound (IVUS). The study population consisted of 41 consecutive patients who received IVUS prior to percutaneous coronary intervention. Remodeling index (RI) was calculated as the external elastic membrane (EEM) area at the minimal lumen area (MLA) site divided by average EEM area at the proximal and distal reference sites. The patients were divided into two groups based on RI: positive remodeling (PR) defined as RI>1 and non-PR as RI

A case of acute myocardial infarction due to coronary spasm in the myocardial bridge.

A 68-year-old Japanese man with acute inferior myocardial infarction underwent emergent coronary angiography which showed a myocardial bridge, but no coronary stenosis, at the infarctrelated artery. A spasm provocation test using intracoronary acetylcholine revealed a total occlusion due to severe spasm at the site of the myocardial bridge. Thus, the myocardial ischemia in this case was caused by the coronary spasm, but not by the limited flow due to the myocardial bridge. Although a beta-blocker is usually the appropriate drug, it should be avoided for coronary spasm. The spasm provocation test is useful to determine the type of medication needed for treatment.

[Frequency and characteristics of incomplete stent apposition during and after sirolimus-eluting stent implantation].

OBJECTIVES: Incomplete stent apposition (ISA) is frequently observed after sirolimus-eluting stent (SES) implantation. This study investigated the incidence, morphological features, and possible mechanisms of this phenomenon. METHODS: Fifty-two lesions in 47 eligible patients were treated with SES and serial intravascular ultrasound (IVUS) assessment at the time of post-intervention and 8-month follow-up. ISA was carefully identified from the IVUS images of these lesions. Specifically, quantitative two dimensional IVUS analysis was performed if the lesions demonstrated ISA, including routine IVUS parameters as well as other measurements related to ISA. RESULTS: Overall, ISA was observed in 13 lesions (25.0%) at follow-up. Persistent ISA (n = 6, 11.5%), defined as ISA consistently observed both at post-intervention and follow-up, and late-acquired ISA (n = 7, 13.5%)were systematically compared. Eighty-three percent of cases of persistent ISA were located around the stent edges, whereas all cases of late-acquired ISA were in the stent body. In the persistent ISA group, no serial changes were observed in the lumen area or external elastic membrane area (EEMA) from post-intervention to follow-up. However, in the late-acquired ISA group, EEMA and lumen area significantly increased from post-intervention to follow-up (EEMA: 13.4 +/- 3.2 vs 17.6 +/- 3.3 mm2, respectively, p < 0.0001 ; lumen area: 6.7 +/- 1.4 vs 9.2 +/- 1.8 mm2, respectively, p = 0.004). No adverse clinical events were observed in either group. CONCLUSIONS: ISA was frequently observed during and after SES implantation in clinical practice. No clinical disadvantages were observed during 16 month clinical follow-up periods. Positive remodeling may potentially cause late-acquired ISA.