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MADIT II Patients (madit + ii_patient)

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Medical Sciences	100%

Selected Abstracts

Obesity As a Risk Factor for Sustained Ventricular Tachyarrhythmias in MADIT II Patients

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2007
GRZEGORZ PIETRASIK M.D.
Background: Obesity, as defined by body mass index ,30 kg/m2, has been shown to be a risk factor for cardiovascular disease. However, data on the relationship between body mass index (BMI) and the risk of ventricular arrhythmias and sudden cardiac death are limited. The aim of this study was to evaluate the risk of ventricular tachyarrhythmias and sudden death by BMI in patients after myocardial infarction with severe left ventricular dysfunction. Methods: The risk of appropriate defibrillator therapy for ventricular tachycardia or ventricular fibrillation (VT/VF) by BMI status was analyzed in 476 nondiabetic patients with left ventricular dysfunction who received an implantable cardioverter defibrillator (ICD) in the Multicenter Automatic Defibrillator Implantation Trial-II (MADIT II). Results: Mean BMI was 27 ± 5 kg/m2. Obese patients comprised 25% of the study population. After 2 years of follow-up, the cumulative rates of appropriate ICD therapy for VT/VF were 39% in obese and 24% in nonobese patients, respectively (P = 0.014). In multivariate analysis, there was a significant 64% increase in the risk for appropriate ICD therapy among obese patients as compared with nonobese patients, which was attributed mainly to an 86% increase in the risk of appropriate ICD shocks (P = 0.006). Consistent with these results, the risk of the combined endpoint of appropriate VT/VF therapy or sudden cardiac death (SCD) was also significantly increased among obese patients (Hazard Ratio 1.59; P = 0.01). Conclusions: Our findings suggest that in nondiabetic patients with ischemic left ventricular dysfunction, a BMI ,30 kg/m2 is an independent risk factor for ventricular tachyarrhythmias. [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]

Abnormal P-Wave Morphology Is a Predictor of Atrial Fibrillation Development and Cardiac Death in MADIT II Patients

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2010
Fredrik Holmqvist M.D., Ph.D.
Background: Several ECG-based approaches have been shown to add value when risk-stratifying patients with congestive heart failure, but little attention has been paid to the prognostic value of abnormal atrial depolarization in this context. The aim of this study was to noninvasively analyze the atrial depolarization phase to identify markers associated with increased risk of mortality, deterioration of heart failure, and development of atrial fibrillation (AF) in a high-risk population with advanced congestive heart failure and a history of acute myocardial infarction. Methods: Patients included in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) with sinus rhythm at baseline were studied (n = 802). Unfiltered and band-pass filtered signal-averaged P waves were analyzed to determine orthogonal P-wave morphology (prespecified types 1, 2, and 3/atypical), P-wave duration, and RMS20. The association between P-wave parameters and data on the clinical course and cardiac events during a mean follow-up of 20 months was analyzed. Results: P-wave duration was 139 ± 23 ms and the RMS20 was 1.9 ± 1.1 ,V. None of these parameters was significantly associated with poor cardiac outcome or AF development. After adjustment for clinical covariates, abnormal P-wave morphology was found to be independently predictive of nonsudden cardiac death (HR 2.66; 95% CI 1.41,5.04, P = 0.0027) and AF development (HR 1.75; 95% CI 1.10,2.79, P = 0.019). Conclusion: Abnormalities in P-wave morphology recorded from orthogonal leads in surface ECG are independently predictive of increased risk of nonsudden cardiac death and AF development in MADIT II patients. Ann Noninvasive Electrocardiol 2010;15(1):63,72 [source]

The Clinical Implications of Cumulative Right Ventricular Pacing in the Multicenter Automatic Defibrillator Trial II

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2005
JONATHAN S. STEINBERG M.D.
Introduction: This study was designed to assess whether right ventricular pacing in the implantable cardioverter defibrillator (ICD) arm of the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II was associated with an unfavorable outcome. Methods and Results: Data on the number of ventricular paced beats were available in 567 (76%) of 742 MADIT II patients with ICDs. The number of ventricular paced beats over the total number of beats showed a bimodal distribution with patients being predominantly paced or nonpaced. Therefore, patients were dichotomized at 0,50% and 51,100% of cumulative pacing with median pacing rate 0.2% and 95.6%, respectively. Endpoints included new or worsening heart failure, appropriate ICD therapy for VT/VF, and the combined endpoint of heart failure or death. Clinical features associated with frequent ventricular pacing included age ,65 years, advanced NYHA heart failure class, LVEF < 0.25, first degree AV and bundle branch block, and amiodarone use. During follow-up, 119 patients (21%) had new or worsened heart failure, 130 (23%) had new or worsened heart failure or death, and 142 (25%) had appropriate therapy for VT/VF. In comparison to patients with infrequent pacing, those with frequent pacing had significantly higher risk of new or worsened heart failure (hazard ratio = 1.93; P = 0.002) and VT/VF requiring ICD therapy (HR = 1.50; P = 0.02). Conclusions: Patients in MADIT II who were predominantly paced had a higher rate of new or worsened heart failure and were more likely to receive therapy for VT/VF. These results suggest the deleterious consequences of RV pacing, particularly in the setting of severe LV dysfunction. [source]

A Prognostic Index Relating 24-Hour Ambulatory Blood Pressure to Cardiac Events in Ischemic Cardiomyopathy Following Defibrillator Implantation

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2008
LANFRANCO ANTONINI M.D.
Background:We assessed the role of left ventricular ejection fraction and of ambulatory blood pressure monitoring (ABPM) to predict cardiac death and heart failure in patients with defibrillator fulfilling MADIT II criteria. ABPM variables assessed included: mean 24 hours diastolic and systolic blood pressure, mean 24 hours heart rate, and pulse pressure. Methods:We studied 105 consecutive patients (age 67 ± 11), all with a defibrillator and ejection fraction , 30%). Results:At 1-year follow-up, there were 29 events (25%), three cardiac deaths, and 26 hospitalizations for heart failure. Age, creatinine, mean 24 hours diastolic blood pressure, and mean 24 hours systolic blood pressure (but not ejection fraction) were associated with events. A prognostic index (PI) was built by age and ABPM variables, according to the formula (120 , age) + (mean 24 hours diastolic blood pressure + mean 24 hours systolic blood pressure). Receiver operating characteristic curves showed the best cutoff for PI = 220 (sensitivity 81%, specificity 71%, positive predictive value 56%, negative predictive value 88%). Cox regression analysis confirmed the significant association between lower PI (< 220) and clinical events (HR 4.8, 95% CI 1.8,12.3, P = 0.0001 for PI). Overall, 12% of patients with high PI values (, 220 n = 71) had clinical events at 12-month follow-up, compared with 61% of patients with low PI (< 220 n = 34) (P < 0.0001). Conclusion:The PI built by mean 24 hours diastolic and systolic blood pressure and age could be a simple method to stratify risk of cardiac death and acute heart failure in MADIT II patients, in whom ejection fraction, uniformly depressed, is not predictive. [source]