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Stored Electrograms (stored + electrogram)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

A Coroner's Request for Closure: The Value of the Stored Electrogram

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2006
IRENE H. STEVENSON
Pacemaker diagnostics can be useful to troubleshoot both during life and after death. A 58-year old man with a single chamber ventricular pacemaker and a previous His bundle ablation died suddenly. Interrogation of his pacemaker revealed the cause of death not as pacemaker malfunction, but a fatal ventricular arrhythmia. [source]

Predictors of All-Cause Mortality for Patients with Chronic Chagas' Heart Disease Receiving Implantable Cardioverter Defibrillator Therapy

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2007
AUGUSTO CARDINALLI-NETO M.D., Ph.D.
Background: Implantable Cardioverter Defibrillators (ICD) have sporadically been used in the treatment of either Sustained Ventricular Tachycardia (VT) or Ventricular Fibrillation (VF) in Chagas' disease patients. This study aimed at determining predictors of all-cause mortality for Chagas' disease patients receiving ICD therapy. Methods and Results: Ninety consecutive patients were entered the study. Mean left ventricular ejection fraction was 47 ± 13%. Twenty-five (28%) patients had no left ventricular systolic dysfunction. After device implantation, all patients were given amiodarone (mean daily dose = 331, 1 ± 153,3 mg), whereas a B-Blocking agent was given to 37 (40%) out of 90 patients. Results: A total of 4,274 arrhythmias were observed on stored electrogram in 64 (71%) out of 90 patients during the study period; SVT was observed in 45 out of 64 (70%) patients, and VF in 19 (30%) out of 64 patients. Twenty-six (29%) out of 90 patients had no arrhythmia. Fifty-eight (64%) out of 90 patients received appropriate shock, whereas Antitachycardia Pacing was delivered to 58 (64%) out of 90 patients. There were 31 (34%) deaths during the study period. Five patients were lost to follow up. Sudden cardiac death affected 2 (7%) out of 26 patients, whereas pump failure death was detected in the remaining 24 (93%) patients. Number of shocks per patient per 30 days was the only independent predictor of mortality. Conclusion: Number of shocks per patient per 30 days predicts outcome in Chagas' disease patients treated with ICD. [source]

Mechanisms of Ventricular Fibrillation Initiation in MADIT II Patients with Implantable Cardioverter Defibrillators

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2008
RYAN ANTHONY M.D.
Background:The availability of stored intracardiac electrograms from implantable defibrillators (ICDs) has facilitated the study of the mechanisms of ventricular tachyarrhythmia onset. This study aimed to determine the patterns of initiation of ventricular fibrillation (VF) in Multicenter Automatic Defibrillator Implantation Trial (MADIT) II patients along with associated electrocardiogram (ECG) parameters and clinical characteristics. Methods:Examination of stored electrograms enabled us to evaluate the rhythm preceding each episode of VF and to calculate (intracardiac) ECG parameters including QT, QT peak (QTp), coupling interval, and prematurity index. Results:Sixty episodes of VF among 29 patients (mean age 64.4 ± 2.5 years) were identified. A single ventricular premature complex (VPC) initiated 46 (77%) episodes whereas a short-long-short (SLS) sequence accounted for 14 (23%) episodes. Of the 29 patients studied, 23 patients had VF episodes preceded by a VPC only, two patients with SLS only, and four patients with both VPC and SLS-initiated episodes. There were no significant differences between initiation patterns in regards to the measured ECG parameters; a faster heart rate with SLS initiation (mean RR prior to VF of 655 ± 104 ms for SLS and 744 ± 222 ms for VPC) approached significance (P = 0.06). The two patients with SLS only were not on ,-blockers compared to 83% of the VPC patients. Conclusion:Ventricular fibrillation is more commonly initiated by a VPC than by a SLS sequence among the MADIT II population. Current pacing modes designed to prevent bradycardia and pause-dependent arrhythmias are unlikely to decrease the incidence of VPC-initiated episodes of VF. [source]

Temporary Disturbances of the QT Interval Precede the Onset of Ventricular Tachyarrhythmias in Patients with Structural Heart Diseases

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2002
BJÖRN HENRIK DIEM
DIEM, B.H. et al.: Temporary Disturbances of the QT Interval Precede the Onset of Ventricular Tach-yarrhythmias in Patients with Structural Heart Diseases. An increase in sinus rate prior to ventricular tachyarrhythmias has been demonstrated in previous studies. There is no clear data available concerning changes in ventricular de- and repolarization prior to ventricular tachyarrhythmias, especially in patients with structural heart disease. Therefore, the aim of this study was to analyze the QT and QTc interval (Bazett's formula immediately before the onset of ventricular tachyarrhythmias in stored electrograms of patients with ICDs. The study analyzed 228 spontaneous ventricular tachyarrhythmia episodes in 52 patients (mean age 64 ± 10 years, 49 men, 3 women) and compared them with 146 electrograms of baseline rhythm recorded during regular ICD follow-up. Mean ventricular cycle length (CL), QT interval, and QTc were measured before the onset of ventricular tachyarrhythmia and during baseline rhythm. Prior to ventricular tachyarrhythmias onset, CL was significantly shorter than during baseline rhythm (714 ± 139 vs 828 ± 149 ms, P < 0.0001). By contrast, the QT interval (430 ± 67 ms) and QTc interval (518 ± 67 ms) were significantly prolonged before the onset of ventricular tachyarrhythmias as compared to baseline rhythm (QT 406 ± 67 ms, QTc 450 ± 61 ms; P < 0.0001). CL, QT, and QTc changes were independent of concomitant treatment with antiarrhythmic drugs. Ventricular tachyarrhythmias are preceded by a significant prolongation of the QT and QTc intervals. This phenomenon may represent a greater than normal disparity of repolarization recovery times possibly facilitating the development of ventricular tachyarrhythmias. [source]