Katsuya Ebe

Electrophysiologic Evaluation of Asymptomatic Patients with the Wolff-Parkinson-White Pattern

In the past 4 years, 34 asymptomatic patients with the Wolff‐Parkinson‐White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 ± 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.

Electrical Storm in Idiopathic Ventricular Fibrillation Is Associated With Early Repolarization

OBJECTIVES This study sought to characterize patients with idiopathic ventricular fibrillation (IVF) who develop electrical storms. BACKGROUND Some IVF patients develop ventricular fibrillation (VF) storms, but the characteristics of these patients are poorly known. METHODS Ninety-one IVF patients (86% male) were selected after the exclusion of structural heart diseases, primary electrical diseases, and coronary spasm. Electrocardiogram features were compared between the patients with and without electrical storms. A VF storm was defined as VF occurring ≥3 times in 24 h and J waves >0.1 mV above the isoelectric line in contiguous leads. RESULTS Fourteen (15.4%) patients had VF storms occurring out-of-hospital at night or in the early morning. J waves were more closely associated with VF storms compared to patients without VF storms: 92.9% versus 36.4% (p < 0.0001). VF storms were controlled by intravenous isoproterenol, which attenuated the J-wave amplitude. After the subsidence of VF storms, the J waves decreased to the nondiagnostic level during the entire follow-up period. Implantable cardioverter-defibrillator therapy was administered to all patients during follow-up. Quinidine therapy was limited, but the patients on disopyramide (n = 3), bepridil (n = 1), or isoprenaline (n = 1) were free from VF recurrence, while VF recurred in 5 of the 9 patients who were not given antiarrhythmic drugs. CONCLUSIONS The VF storms in the IVF patients were highly associated with J waves that showed augmentation prior to the VF onset. Isoproterenol was effective in controlling VF and attenuated the J waves, which diminished to below the diagnostic level during follow-up. VF recurred in patients followed up without antiarrhythmic agents.

Vasoconstrictor effect of endothelin on the canine coronary artery: is a novel endogenous peptide involved in regulating myocardial blood flow and coronary spasm?

We examined the effect of endothelin on the canine coronary artery (N = 20). The left circumflex coronary artery was cannulated and perfused with arterial blood at constant pressure. Coronary blood flow was monitored by an electromagnetic flowmeter. Intracoronary endothelin provoked a vasoconstriction that was dose-dependent. At a dose of 500 pmol, coronary blood flow was reduced remarkably (91.0 +/- 5.4%, n = 4), and endothelin subsequently produced a fall in systemic blood pressure and ST elevation in the electrocardiogram. At a dose of 100 pmol (n = 9), coronary flow decreased from 16.4 +/- 1.5 ml/min to 12.5 +/- 1.5 ml/min (p less than 0.001) and coronary vascular resistance increased from 6.3 +/- 0.8 mm Hg/ml/min to 9.9 +/- 1.9 mm Hg/ml/min (p less than 0.005). A cumulative dose-response curve to endothelin was obtained and the curves were shifted to the right after both verapamil and nifedipine administration. Therefore endothelin has a potent vasoconstrictor action that is attenuated by the calcium-channel blocker.

Increase of scavenger receptor A‐positive monocytes in patients with acute coronary syndromes

To evaluate the utility of the scavenger receptor A (SRA) index (no. SRA+ monocytes observed in 10 high‐power fields of peripheral blood (PB) smear samples, normal upper limit <30) as the indication of disrupted, fissured, or eroded plaque, 225 patients with acute myocardial infarction (AMI), 79 with unstable angina (UA) and 91 with stable angina (SA) were examined. Thrombus was gathered from 95 of 205 sequential AMI patients (46.3%), and classified into platelets, mixed, and two kinds of residual mural thrombus (RMT). RMT was observed in 56 of 169 (33.1%) AMI patients with SRA index ≥30 at hospitalization. The SRA index of 82.4% of AMI, and 75.9% of UA, and 70.3% of SA patients was ≥30 at hospitalization. For 36 AMI patients who initially had an SRA index of <30 at hospitalization, it exceeded 30 within 2 days, and the SRA index rapidly increased in most AMI patients after hospitalization. SRA+ monocytes were considered to differentiate from SRA– monocytes in PB. An abnormally high SRA index is considered to be a useful indication of disrupted or fissured or eroded plaque.

Fulminant type 1 diabetes mellitus and fulminant viral myocarditis. A case report and literature review.

A 35-year-old Japanese woman was admitted with coma following flu-like symptoms. She was diagnosed with diabetic ketoacidosis and fulminant type 1 diabetes (FT1D) and received intravenous infusion of insulin and saline. The next day, the ketoacidosis disappeared, and she recovered consciousness. However, extensive ST-segment elevations in the electrocardiogram appeared with a positive troponin test, and the patient developed pulmonary edema on day 3. An echocardiogram showed globally reduced wall motion of the left ventricle and mild pericardial effusion. Despite medical therapy with intravenous furosemide, carperitide, and catecholamines, her cardiac function deteriorated rapidly, with the left ventricular ejection fraction decreasing to 26% within 7 hours, and progressed to cardiogenic shock that afternoon. The patient received mechanical circulatory support for 4 days with intra-aortic balloon pumping and percutaneous cardiopulmonary support, and recovered fully from circulatory failure. A paired serum antibody test showed a significantly elevated titer against parainfluenza-3 virus, indicating a diagnosis of fulminant viral myocarditis. She was discharged on multiple daily insulin injection therapy, and her subsequent clinical course has been uneventful. In summary, we present a case of concurrent FT1D and fulminant viral myocarditis. Parainfluenza-3 viral infection was confirmed serologically and was considered to be a cause of both the FT1D and fulminant myocarditis.

Experimental Study About Removal of the Implanted Tined Polyurethane Ventricular Lead by Radiofrequency Waves Through the Lead

Polyurethane pacemaker leads are: widely used nowadays. However, only a few studies have been done to investigate the fixation mechanism of polyurethane leads. To elucidate how pacemaker leads are fixed at the early phase after Implantation, polyurethane‐insulated fined ventricular leads were implanted in seven mongrel dogs. One to 4 months later. lips of the leads were anchored among the trabeculae and the distal part of the leads were encapsulated by whitish fibrous tissue. It was found that not organized thrombi, but cell reaction with various states of inflammatory cells was responsible for forming the fibrous tissue. We attempted to remove the lead In‐delivering radiofrequency wave through the lead. However, no lead could be removed.

A case of central diabetes insipidus associated with cardiac dysfunction

Central diabetes insipidus (CDI) results from a deficiency of arginine vasopressin (AVP) secretion. It is treated by replacement therapy with the synthetic AVP analogue desmopressin. To prevent heart failure in patients with CDI accompanied by cardiac dysfunction, controlling sodium and water intake is essential, using the minimum effective dose of desmopressin.

Scavenger receptor A index and coronary thrombus in patients with acute ST elevation myocardial infarction

To examine the relationship between the scavenger receptor A (SRA) index (the number of SRA+ cells observed in 10 high power fields of peripheral blood (PB) smear samples; normal upper limit <30) and coronary thrombus, 389 thrombi obtained from 393 patients with acute ST elevation myocardial infarction were examined. Thrombi were classified into platelets (PT), mixed (MT), fibrin‐rich (FT) and organizing thrombi (OT); 387, 269, 57 and 29 cases were detected, respectively. Patients were divided into group A (PT only, 89 cases), B (containing MT and PT but not FT, 243 cases), and C (containing FT, 57 cases). SRA+ cells had infiltrated into all FT cases and 147 of the 269 MT, but no PT. At hospitalization, the SRA index exceeded 30 in 276 patients. PT was observed in 274 cases, and MT and FT (residual mural thrombus; RMT) observed in 230. Infarct‐related coronary artery was thought to be totally and rapidly occluded by PT that had formed as a result of severe stenosis due to extrusion of plaque content or growth of RMT. An abnormal increase of SRA+ cells is considered to be a useful finding to detecting the presence of PT and, probably, RMT.