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document
Mechanisms underlying the lack of effect of implantable cardioverter-defibrillator therapy on mortality in high-risk patients with recent myocardial infarction : insights from the Defibrillation in Acute Myocardial Infarction Trial ( DINAMIT ) . BACKGROUND although implantable cardioverter-defibrillators ( ICDs ) lower mortality in stable patients with low ejection fraction late after myocardial infarction , randomized trials of ICD versus control subjects implanted early after myocardial infarction do not show mortality benefit . Our objective was to investigate possible mechanisms underlying the lack of mortality benefit in the Defibrillation in Acute Myocardial Infarction Trial ( DINAMIT ) . METHODS AND RESULTS this is a secondary analysis of the prospective randomized clinical trial . Outpatients with recent ( 6 to 40 days ) acute myocardial infarction , left ventricular dysfunction ( ejection fraction < 35 % ) , and low heart rate variability were randomized to ICD ( n=311 ) or to standard medical therapy ( n=342 ) . In a competing-risks analysis , those factors that increased the risk of arrhythmic death also increased the risk of nonarrhythmic deaths . After adjustment for these factors , receiving an ICD was associated with a decreased risk of arrhythmic death ( hazard ratio , 0.33 ; 95 % confidence interval , 0.15 to 0.71 ) but an increase in nonarrhythmic death ( hazard ratio , 1.70 ; 95 % confidence interval , 1.00 to 2.80 ) . In an adjusted time-dependent analysis , patients receiving an ICD and having appropriate ICD therapy had a 15.1 % yearly hazard of mortality compared with 5.2 % in ICD patients with no appropriate therapy ( P < 0.001 ) . The reduction in sudden death in ICD patients was completely offset by increased nonarrhythmic deaths , which were greatest in patients receiving ICD shock therapy ( hazard ratio , 6.0 ; 95 % confidence interval , 2.8 to 12.7 ) . CONCLUSIONS in patients receiving ICDs early after myocardial infarction , those factors that are associated with arrhythmia requiring ICD therapy are also associated with a high risk of nonsudden death , negating the benefit of ICDs in this setting .
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Intervention_Physical
implantable cardioverter-defibrillator therapy
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Intervention_Physical
implantable cardioverter-defibrillators
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Intervention_Physical
ICD
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Intervention_Physical
ICD
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Intervention_Control
standard medical therapy
48528
Outcome_Mortality
mortality
48529
Outcome_Mortality
mortality
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Outcome_Mortality
risk of arrhythmic death
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Outcome_Mortality
risk of nonarrhythmic deaths
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Outcome_Mortality
risk of arrhythmic death
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Outcome_Mortality
nonarrhythmic death
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Outcome_Mortality
yearly hazard of mortality
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Outcome_Mortality
sudden death
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Outcome_Mortality
nonarrhythmic deaths
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Outcome_Mortality
nonsudden death
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Participant_Condition
recent myocardial infarction
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Participant_Condition
stable patients with low ejection fraction late after myocardial infarction
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Participant_Condition
Outpatients with recent ( 6 to 40 days ) acute myocardial infarction , left ventricular dysfunction ( ejection fraction < 35 % ) , and low heart rate variability
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Participant_Condition
patients receiving ICDs early after myocardial infarction