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[In patients with heart failure, do implantable cardioverter-defibrillators delay death or save lives?]
Massimo Zoni Berisso1, Luigi Delfino, Stefano Viani
1Divisione di Cardiologia E.O. Ospedali Galliera Via Volta, 8 16128 Genova. zoni.berisso@galliera.it
Insights
Automatic implantable cardioverter-defibrillators (ICDs) reduce sudden arrhythmic death (SD) in heart failure patients. However, ICDs do not prolong survival in severe heart failure, though they benefit those with moderate dysfunction.
Area of Science:
- Cardiology
- Medical Devices
- Public Health
Context:
- Heart failure is a major public health concern in Western countries, leading to high rates of cardiac death and rehospitalization.
- Sudden arrhythmic death (SD) is a primary cause of mortality in heart failure patients, with incidence varying by New York Heart Association (NYHA) functional class.
- Automatic implantable cardioverter-defibrillators (ICDs) have shown efficacy in reducing SD in at-risk populations.
Purpose:
- To investigate the survival benefit of ICD implantation in patients with severe heart failure.
- To compare the efficacy of ICDs in prolonging survival across different severities of left ventricular dysfunction in heart failure patients.
Summary:
- ICD implantation in severe heart failure, despite reducing SD incidence, did not improve 1- and 2-year survival rates.
- Patients with moderate left ventricular dysfunction receiving ICDs experienced prolonged survival and reduced SD incidence.
- Perioperative risks and ventricular arrhythmia rates for ICD implantation were comparable across heart failure severity groups, with slightly higher rates in severe cases.
Impact:
- ICD implantation is beneficial for prolonging survival in heart failure patients with moderate left ventricular dysfunction.
- The current evidence does not support ICD implantation solely for survival benefit in patients with the most severe heart failure.
- Further research is needed to clarify the role of ICDs in primary prevention of SD in heart failure patients.
Abstract:
Heart failure is one of the most important public health problems in western countries because of its frequent association with cardiac death and with rehospitalization. Patients with heart failure generally die of sudden arrhythmic death (SD) and progressive pump failure with a SD incidence inversely related to the severity of the underlying heart disease. SD occurs approximately in one half of the patients in New York Heart Association (NYHA) functional classes II-II/III and in one third of those in NYHA classes III/IV-IV, respectively. In the last decade, numerous studies have shown that the automatic implantable cardioverter-defibrillator (ICD) significantly reduces the incidence of SD in those patients who are identified as being at risk. Unfortunately, little is known on whether the ICD actually prolongs the survival of the subgroup of patients with most severe heart failure. The main reasons for such a paucity of information are the small number of available studies, the unavailability of randomized and controlled investigations and the difficulty in comparing the results of such studies owing to the lack of homogeneity. In patients with severe heart failure, both the perioperative mortality and morbidity related to transvenous ICD implantation are similar to those of patient subgroups with moderate or slight heart failure. The defibrillation threshold at implantation and the frequency of intractable ventricular arrhythmias during follow-up (2% of all ICD implantations) are slightly higher than in the patient subgroup with moderate or no heart failure. In the patient subgroup with severe heart failure or with a very poor left ventricular function, ICD implantation is unable to prolong the 1- and 2-year survival despite a clear reduction in the incidence of SD. On the other hand, in the patient subgroup with moderate left ventricular dysfunction, ICD implantation prolongs survival and reduces the incidence of SD. No information is available regarding the primary prevention of SD in patients with heart failure.