Disclosures – L. Brent Mitchell, MD Industry Disclosures Study Disclosures • Guidant • AVID • Medtronic • CIDS • St. Jude • MUSTT • Cambridge Heart • SCD-HeFT • General Electric • DINAMIT • RAFT
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment CRT CRT CRT pacemaker defibrillator
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment CRT CRT CRT pacemaker defibrillator
ICDs and CRTs for Dummies The Implantable Defibrillator – Michel Mirowski (1980) Mirowski M et al. N Engl J Med 303:322-4, 1980
ICDs and CRTs for Dummies
ICDs and CRTs for Dummies Risk Stratification for ICD Higher SCD Risk Potential ICD FILTER Patients Lower SCD Risk
ICDs and CRTs for Dummies Sudden Cardiac Death Overall ASHD risk Factors Manifest ASHD EF <0.35 VT/VF survivor 0 10 20 30 40 0 100 200 300 Events/year (thousands) Events/year (%) Modified from Myerburg et al Ann Intern Med 119:1187-1197, 1993
ICDs and CRTs for Dummies Touch Pad Question 1 In meta-analysis of secondary prevention trials of ICD therapy versus medical therapy in patients with prior life-threatening ventricular tachyarrhythmias, use of the ICD is associated with a reduction in all-cause mortality of: 1. 10% 2. 20% 3. 30% 4. 50%
ICDs and CRTs for Dummies All-Cause Mortality – ICD versus Amio STUDY N RR AVID 1016 0.62 (0.47-0.81) CIDS 659 0.82 (0.61-1.10) CASH 191 0.83 (0.52-1.33) OVERALL 1866 0.73 (0.59-0.89) 0 0.5 1 1.5 2 RELATIVE RISK Connolly et al: Eur Heart J 21:2071, 2000
ICDs and CRTs for Dummies Secondary Prevention ICDs – Effect of LVEF LVEF 35% LVEF > 35% 60 60 50 50 Amio % Mortality % Mortality 40 40 30 30 Amio ICD 20 20 ICD 10 10 0 0 0 1 2 3 4 5 0 1 2 3 4 5 Years Years Connolly et al. Eur Heart J 21:2071-78, 2000
ICDs and CRTs for Dummies Sudden Cardiac Death Overall ASHD risk Factors Manifest ASHD EF <0.35 VT/VF survivor 0 10 20 30 40 0 100 200 300 Events/year (thousands) Events/year (%) Modified from Myerburg et al Ann Intern Med 119:1187-1197, 1993
ICDs and CRTs for Dummies All-Cause Mortality - ICD versus Control heterogeneity STUDY N RR p = 0.0005 196 0.41 (0.26 – 0.69) MADIT CABG – PATCH 900 1.08 (0.84 – 1.39) MUSTT 514 0.46 (0.34 – 0.62) CAT* 104 2.16 (0.46 – 10.22) MADIT – II 1232 0.71 (0.55 – 0.92) 103 0.92 (0.51 – 1.66) AMIOVIRT COMPANION 903 0.57 (0.40 – 0.81) DEFINITE 458 0.65 (0.40 – 1.09) 674 1.08 (0.76 – 1.55) DINAMIT SCD-HeFT 1676 0.77 (0.62 – 0.96) All Trials 7253 0.76 (0.63 – 0.91) 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0.2 RELATIVE RISK Nanthakumar et al. J Am Coll Cardiol 44:2166-72, 2004
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD 10 Trials 0.76 (0.63-0.91) CRT treatment CRT CRT CRT pacemaker defibrillator
ICDs and CRTs for Dummies Who Should Receive an ICD? Patients at a annual risk of sudden death that exceeds the hazard of having an ICD Provided that the patient agrees with the goal of preventing sudden death Preferably in a scenario where use of the ICD has been proven effective in an RCT
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment CRT CRT CRT pacemaker defibrillator
Cardiac Dyssynchrony Effects of Abnormal Activation Sequences • atrioventricular asynchrony • negative LA - LV: LA contraction against closed MV • long LA - LV: late diastolic MR decreases LV filling time • interventricular asynchrony • decreased LV filling time • septum recruited to RV ejection • intraventricular asynchrony • some LV contraction before aortic valve opening • some LV contraction after aortic valve closure • wasted work stretching noncontracting regions • uncoordinated papillary muscles leads to MR • decreased diastolic LV filling time • intramural asynchrony • contraction is non-transmural
ICDs and CRTs for Dummies All-Cause Mortality – CRT vs Control Class III/IV Pts STUDY N RR MUSTIC SR 58 3.00 (0.13 – 70.7) MUSTIC AF 43 2.19 (0.09 – 50.9) MIRACLE 453 0.74 (0.36 – 1.53) COMPANION 925 0.85 (0.66 – 1.09) CARE HF 813 0.67 (0.53 – 0.86) All Trials 2292 0.76 (0.64 – 0.90) 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0.2 RELATIVE RISK RAFT Investigators
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical 5 Trials 0.76 (0.64-0.90) ICD CRT treatment CRT CRT CRT pacemaker defibrillator
ICDs and CRTs for Dummies Who Should Receive CRT? Patients with symptomatic CHF, low LVEF and evidence of contractile dys-synchrony Unfortunately, at present, CRT response occurs in only 2/3 treated patients CRT is often associated with reversal of adverse LV remodelling (importance?)
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment CRT CRT CRT pacemaker defibrillator
ICDs and CRTs for Dummies All-Cause Mortality – CRT-D versus Med Rx STUDY N HR COMPANION 903 0.64 (0.48-0.86) 0 0.5 1 1.5 2 HAZARD RATIO Bristow MR et al: N Engl J Med 350:2140-50, 2004
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment CRT CRT CRT pacemaker defibrillator
ICDs and CRTs for Dummies All-Cause Mortality – CRT versus CRT-D STUDY N RR MIRACLE ICD II 186 1.19 (0.17-8.26) CONTAK CD 490 0.69 (0.33-1.45) MIRACLE ICD 474 0.66 (0.39-1.11) All Trials 1150 0.69 (0.45-1.04) 0 0.5 1 1.5 2 RELATIVE RISK RAFT Investigators
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment CRT CRT CRT 3 Trials 0.69 (0.45-1.04) pacemaker defibrillator
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical 5 Trials 0.76 (0.64-0.90) ICD 10 Trials 0.76 (0.63-0.91) CRT treatment CRT CRT CRT 3 Trials 0.69 (0.45-1.04) pacemaker defibrillator
ICDs and CRTs for Dummies Available Platforms No ICD ICD No medical ICD CRT treatment ? CRT CRT CRT pacemaker defibrillator
Multicentre Automatic Defibrillator Implantation Trial – Cardiac Resynchronization Therapy (MADIT - CRT) COMPARISON: composite of all-cause mortality and HF events comparing ICD with CRT versus ICD only on background of optimal medical Rx PATIENTS: ischemic (NYHA Class I or II) CCM or nonischemic (NYHA Class II) CCM LVEF ≤ 0.30, QRSd ≥ 0.13 sec in sinus rhythm for whom ICD is planned DESIGN: double-blind, randomized, parallel-group clinical trial target 1820 patients, 3:2 randomization designed as sequential monitoring trial Moss AJ et al. N Engl J Med 361:xxx-xxx, 2009
Multicentre Automatic Defibrillator Implantation Trial – Cardiac Resynchronization Therapy (MADIT - CRT) Primary outcome – CHF event / all-cause mortality ICD 40 HR = 0.75 (95% CI: 0.62 – 0.91) p = 0.003 Cumulative Incidence 30 20 CRT-ICD 10 0 0 1 2 3 4 Years of Follow-up Moss AJ et al. N Engl J Med 361:1329-38, 2009
Resynchronization in Ambulatory Heart Failure (RAFT) COMPARISON: composite of total mortality / CHF hospitalization comparing pts receiving a CRT ICD to those receiving an ICD alone PATIENTS: planned 1800 pts with Class II / III CHF (only Class II after Feb 2006) with an indication for an ICD and LVEF ≤ 0.30 and QRSd ≥ 0.12 (≥ 0.20 if paced) on optimal medical therapy “double - blind”, parallel -group RCT (1:1) DESIGN: 85% power for 25% RRR from 11% control rate Tang AS et al. N Engl J Med 363:2385-95, 2010
Resynchronization in Ambulatory Heart Failure (RAFT) Primary outcome – CHF hospitalization / mortality ICD HR = 0.75 (95% CI: 0.64 – 0.87) 60 p < 0.001 50 Cumulative Incidence 40 CRT-ICD 30 20 10 0 0 1 2 3 4 5 6 Years of Follow-up Tang AS et al. N Engl J Med 363:2385-95, 2010
Resynchronization in Ambulatory Heart Failure (RAFT) Secondary outcome – all-cause mortality 50 ICD Cumulative Incidence HR = 0.75 (95% CI: 0.62 – 0.91) p = 0.003 40 30 CRT-ICD 20 10 0 5 0 1 2 3 4 6 Years of Follow-up Tang AS et al. N Engl J Med 363:2385-95, 2010
Resynchronization in Ambulatory Heart Failure (RAFT) Subgroup Analysis HR permanent AF / AFL p = 0.14 sinus / atrial paced QRSd < 150 ms p = 0.003 QRSd ≥ 150 ms QRSd paced ≥ 200 ms LBBB p = 0.046 RBBB IVCD PACED LVEF < 0.20 p = 0.05 LVEF ≥ 0.20 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 CRT – ICD better ICD better Tang ASL et al. N Engl J Med 363:2385-95, 2010
ICDs and CRTs for Dummies Who Should Receive CRT - Defibrillator? Patients with symptomatic CHF, low LVEF and evidence of contractile dys-synchrony that have an annual risk of sudden death that exceeds the hazard of having an ICD Provided that the patient agrees with the goal of preventing sudden death and understands that symptom improvement occurs in only 2/3 treated patients Preferably in a scenario where use of CRT- ICD has been proven effective in an RCT
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