Need for pacing in patients who qualify for an implantable cardioverter-defibrillator: Clinical implications for the subcutaneous ICD.

BACKGROUND: Implantation of the subcutaneous implantable cardioverter-defibrillator (S-ICD) is spreading and has been shown to be safe and effective; however, it does not provide brady-pacing. Currently, data on the need for brady-pacing and cardiac resynchronization therapy (CRT) implantation in patients with ICD indication are limited. METHODS: The Multicenter Automatic Defibrillator Implantation Trial (MADIT)-II enrolled post-MI patients with reduced ejection fraction (EF ≤ 35%), randomized to either an implantable cardioverter-defibrillator (ICD) or conventional medical therapy. Kaplan-Meier analyses and multivariate Cox models were performed to assess the incidence and predictors of pacemaker (PM), or CRT implantation in the conventional arm of MADIT-II, after excluding 32 patients (6.5%) with a previously implanted PM. RESULTS: During the median follow-up of 20 months, 24 of 458 patients (5.2%) were implanted with a PM or a CRT (19 PM, 5 CRT). Symptomatic sinus bradycardia was the primary indication for PM implantation (n = 9, 37%), followed by AV block (n = 5, 21%), tachy-brady syndrome (n = 4, 17%), and carotid sinus hypersensitivity (n = 1, 4%). Baseline PR interval >200 ms (HR = 3.07, 95% CI: 1.24-7.57, p = .02), and CABG before enrollment (HR = 6.88, 95% CI: 1.58-29.84, p = .01) predicted subsequent PM/CRT implantation. Patients with PM/CRT implantation had a significantly higher risk for heart failure (HR = 2.67, 95% CI = 1.38-5.14, p = .003), but no increased mortality risk (HR = 1.06, 95% CI = 0.46-2.46, p = .89). CONCLUSION: The short-term need for ventricular pacing or CRT implantation in patients with MADIT-II ICD indication was low, especially in those with a normal baseline PR interval, and such patients are appropriate candidates for the subcutaneous ICD.

Death with an implantable cardioverter-defibrillator: a MADIT-II substudy.

AIMS: There are limited data regarding factors that identify implantable cardioverter-defibrillator (ICD) patients who will experience either ventricular tachyarrhythmic (VTA) or non-arrhythmic (NA) mortality, and the commonly used clinical classification of sudden cardiac death (SCD) vs. non-sudden cardiac death (NSCD) may not be accurate enough. We aimed to correlate clinical adjudication of mortality events to device interrogation data and to identify risk factors for VTA mortality in Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II). METHODS AND RESULTS: Of the 746 patients who received an ICD in MADIT-II, 44 died from cardiac causes and had available interrogation data at the time of death. Sudden cardiac death vs. NSCD was defined by an adjudication committee. Ventricular tachyarrhythmic and NA arrhythmic deaths were categorized by the presence or absence of ventricular tachycardia or fibrillation (VT/VF) during the terminal event. Mode of death was found to be inaccurate when validated by device interrogation for VTA events: 50% patients adjudicated as SCD did not have a VTA event at the time of death; and 25% of adjudicated NSCD were found to have VT/VF during the mortality event. Multivariate analysis showed that factors independently associated with VTA mortality included: VT/VF >72 h prior to the mortality event [hazard ratio (HR) 8.0; P < 0.001], hospitalization for heart failure (HR 6.7; P = 0.001), and a history of hypertension (HR 4; P = 0.04). CONCLUSION: Current classification of SCD vs. NSCD fails to identify VTA events at the time of death in a significant proportion of patients, and simple clinical parameters can be used to identify ICD recipients with increased risk for VTA mortality.

Prognostic value of average T-wave alternans and QT variability for cardiac events in MADIT-II patients.

BACKGROUND: Identifying which patients might benefit the most from ICD therapy remains challenging. We hypothesize that increased T-wave alternans (TWA) and QT variability (QTV) provide complementary information for predicting appropriate ICD therapy in patients with previous myocardial infarction and reduced ejection fraction. METHODS: We analyzed 10-min resting ECGs from MADIT-II patients with baseline heart rate >80 beats/min. TWA indices IAA and IAA90 were computed with the multilead Laplacian Likelihood ratio method. QTV indices QTVN and QTVI were measured using a standard approach. Cox proportional hazard models were adjusted considering appropriate ICD therapy and sudden cardiac death (SCD) as endpoints. RESULTS: TWA and QTV were measured in 175 patients. Neither QTV nor TWA predicted SCD. Appropriate ICD therapy was predicted by combining IAA90 and QTVN after adjusting for relevant correlates. CONCLUSION: Increased TWA and QTV are independent predictors of appropriate ICD therapy in MADIT-II patients with elevated heart rate at baseline.

Prospective evaluation of outcome of Indian patients who meet MADIT II (Multicenter Automatic Defibrillator Implantation Trial) criteria for implantable cardioverter defibrillator implantation: is it appropriate for Indian patients?

BACKGROUND: The MADIT II investigators had concluded that prophylactic use of an ICD improved survival in patients with prior myocardial infarction reduced left ventricular ejection fraction. Whether MADIT II criteria for ICD implantation are appropriate for Indian patients also is unclear and not studied. METHODS: A total of 144 patients, Mean age 56.23 ± 10.9 years who met MADIT II criteria were prospectively followed for 20.78 + 5.9 months. RESULTS: During the follow-up period, 26 (18.1%) patients died. 18 were sudden cardiac deaths and 8 were non SCD deaths. Total mortality did not correlate with Age, NYHA class, NSVT on Holter, PVC >10/hours, QRS width, or use of statins. Multivariate logistic regression model identified the following variables associated with increase all-cause mortality: No use of beta blocker (odd ratio:13.068, p = 0.021), No past revascularization (odd ratio:11.613,p = 0.007) and Increase serum creatinine level (odd ratio: 4.066, p = 0.035). The mortality rate in the present series was comparable with that in the MADIT II conventional therapy group though patient in present study are younger, less diabetic, hypertensive, smokers and better treated with beta-blockers, ACE/ARB and statin. CONCLUSION: Indian patients with prior MI (more than one month back) and left ventricular ejection fraction of 30% or less had a cardiac mortality similar to western population who are not treated with prophylactic ICD. Patients of Indian origin should derive a similar benefit with prophylactic implantation of ICD as per MADIT II criteria as would a western population.

Remote monitoring: Doomed to let down or an attractive promise?

Device interrogation and management are time consuming, representing a relevant burden for pacing centers. In several situations, patients' management requires additional follow up visits. Remote Monitoring (RM) allows an optimal recall management and a rapid diagnosis of device or lead failure, without the need of additional in office visits. Further it allows a significant delay reduction between the adverse event and the reaction to the alarm, shortening the time needed to make a clinical decision. A role in risk-predicting patient-related outcomes has also been shown. RM permits detection of the arrhythmia from 1 to 5 months in advance compared to in-office visits. Importantly, by using specific algorithms with multiparametric analysis, RM has been studied as a potential instrument to identify early patients on risk of worsening HF using specific algorithms. Although the use of RM in HF setting remains controversial, it has been proposed to improve HF clinical outcomes and survival in clinical trials. In this sense, RM success could require a standardization of process within a management model, that may involve different health care professionals. In this review, we examine recent advances of RM providing an update of this tool through different clinical scenarios.

The prediction of ICD therapy in multicenter automatic defibrillator implantation trial (MADIT) II like patients: a retrospective analysis.

OBJECTIVES: MADIT II like patients have not been compared to patients without an electrophysiological study, patients in whom ventricular tachycardia or fibrillation were induced in an electrophysiological study (EPS) and patients without an inducibility in EPS in one study. BACKGROUND: The multicenter automatic defibrillator implantation trial (MADIT) II showed a benefit of ICD implantation in patients with ischemic heart disease. METHODS: We performed a retrospective analysis in 93 patients with an ischemic heart disease and an ejection fraction