Biomedical subjects

Igor Lipchenca

Publications and source records attributed to Igor Lipchenca.

5 recordsLinked to original sources

PubMed2004

Long-term outcome of patients who received implantable cardioverter defibrillators for stable ventricular tachycardia.

INTRODUCTION: Evidence is inconclusive concerning the role of implantable cardioverter defibrillators (ICDs) to treat patients with hemodynamically stable ventricular tachycardia (VT). The goal of this study was to estimate future risk of unstable ventricular arrhythmias in patients who received ICDs for stable VT. METHODS AND RESULTS: We reviewed complete ICD follow-up data from 82 patients (age 66.1 +/- 11.3 years; left ventricular ejection fraction 32.3%+/- 11.2%; mean +/- SD) who received ICDs for stable VT. During the follow-up period of 23.6 +/- 21.5 months (mean +/- SD), 15 patients (18%) died, and 10 (12%) developed unstable ventricular arrhythmia, 8 of whom had the unstable arrhythmia as the first arrhythmia after ICD placement. Estimated 2- and 4-year survival in the whole group was 80% and 74%, respectively. Estimated 2- and 4-year probability of any VT and unstable VT was 67% and 77% and 11% and 25%, respectively. There were no differences in age, ejection fraction, sex, underlying heart disease, cycle length, symptoms, baseline electrophysiologic study results, or QRS characteristics of qualifying VT between patients who developed unstable ventricular arrhythmia and patients who did not. Twenty-nine patients (35%) had at least one inappropriate shock, and 11 (13%) underwent further surgery for ICD-related complications. CONCLUSION: Patients who present with hemodynamically stable VT are at risk for subsequent unstable VT. ICD treatment offers potential salvage of patients with stable VT who subsequently develop unstable VT/ventricular fibrillation, although complications and inappropriate shocks are considerable. No predictors could be found for high and low risk for unstable arrhythmias. These findings support ICD treatment for stable VT survivors.

Aged↗

PubMed2003

Managing pacemaker safety alerts: experience with three successive models of a single manufacturer.

This report describes the experience of a large pacemaker center during three successive replacement operations due to safety alerts involving three models from the same manufacturer. Between March 1993 and May 1999, 210 patients were implanted with three DDD pacemaker models (Sorin Biomedica, Saluggia, Italy) that were subsequently subject to safety alerts. Pacemaker records were reviewed for complications related to device malfunction, and those secondary to the replacement procedure. Pacemaker malfunction was observed in 16.4% of units despite much lower estimates from the company (range 1-4%). With the exception of one, all units were replaced. Malfunctions were discovered in 7 of 20 pacemakers following an urgent call for follow-up issued as a result of the alert. Twenty units implanted as substitutes for those replaced following the first alert turned out to be subject to the third alert. Significant clinical consequences of malfunction occurred in 5.3% of patients including a near fatal event in one case, while complications related to the replacement procedure occurred in 8.3% of patients, including one fatality. On the issuance of a safety alert, failure rates in a particular center may be higher than published by the manufacturer, and should prompt action by the center to weigh local incidence of device failure against complications of replacement procedures. When device failure mechanism is not entirely clear, particularly in cases of successive model failures, replacement devices from a different manufacturer should be considered.

Adolescent↗

PubMed2002

Inhibition of biventricular pacemakers by oversensing of far-field atrial depolarization.

This report describes two patients who exhibited far-field oversensing of the P wave by the ventricular channel of a DDD biventricular pacemaker implanted for the treatment of congestive heart failure. Oversensing probably occurred secondary to slight displacement of the left ventricular lead in the coronary venous system. Long-term reliable pacing was restored by decreasing the sensitivity of the ventricular channel.

Aged↗

PubMed2002

ST-segment deviation following implantable cardioverter defibrillator shocks: incidence, timing, and clinical significance.

ST-segment analysis is frequently used during surgical procedures, while ST deviation is considered a sign of myocardial injury. ST deviations were reported following transthoracic and epicardial electrical shocks. The prevalence, timing, and clinical significance of ST-segment deviation following endocardial ICD shocks are discussed in this article. Twenty-eight patients undergoing 125 shock episodes during ICD implantation or testing were included. A 12-lead ECG was recorded at baseline, continuously during the first 3-10 seconds, 1 minute after test shocks, 3-10 seconds and 1 and 5 minutes after each shock given to terminate VF. ST deviation was diagnosed when the ST-segment was displaced > or = 1 mm in at least one lead compared to baseline. ST-segment deviations were observed after 49 (39%) of all shock episodes in 17 (61%) of patients. ST elevation was observed after 30 (24%) of all shock episodes, and ST depression after 31 (25%). Following 13 shock episodes in seven patients, ST-elevation and depression were observed. ST depressions occurred more frequently after shocks given to terminate VF than after lower energy test shocks (28% vs 18% respectively, P = 0.045). However, there was no significant difference in the prevalence of ST elevations between the lower or higher energy shocks. No adverse clinical events were observed in patients with or without postshock ST-segment deviation. ST-segment deviation following endocardial ICD shocks is a frequent phenomenon, occurring acutely and resolving during the first few minutes postshock. It mayhave no prognostic implications.

Defibrillators, Implantable↗

PubMed2002

Multiple pulse generator malfunctions with a dual chamber pacemaker.

The aim of this study was to evaluate the dual chamber uni/bipolarpacemaker Minidual 50, manufactured by Sorin Biomedica. Between 1995 and 1998, 66 Minidual 50 models were implanted at the Heart Institute. During the follow-up period of 33 +/- 12.8 months (range 0-50 months), total function loss in seven (10.6%) units and false threshold measurement of sensing and pacing in three (4.5%) patients were observed. Average time from implantation to malfunction was 37 months (range 28-42). Malfunction was unrelated to battery status and could not be predicted by any measures obtained during the pacemaker follow-up period. Kaplan Meyer survival curve predicted a 70% 4-year malfunction-free survival of that pacemaker model. Given this high rate of total malfunction and the unpredictable nature of its occurrence, the authors recommend the replacement of all remaining Minidual 50 units at risk, at least in dependent patients.

Adult↗