Long-term outcome with the automatic implantable cardioverter-defibrillator

Abstract

The automatic implantable cardioverter-defibrillator was implanted in 270 patients because of life-threatening arrhythmias over a 7 year period. There was a history of sustained ventricular tachycardia or fibrillation, or both, in 96% of these patients, 80% had one or more prior cardiac arrests and 78% had coronary artery disease as their underlying diagnosis. The average ejection fraction was 34%, and 96% of these patients had had an average of 3.4 antiarrhythmic drug failures per patient before defibrillator implantation. There were four perioperative deaths and eight patients had generator infection or generator erosion, or both, during the perioperative period or during long-term follow-up. Concomitant antiarrhythmic drug therapy was given to 69% of patients. Shocks from the device were given to 58% of patients. and 20% received "problematic" shocks. The device was removed from 16 patients during long-term follow-up for a variety of reasons. There were 7 sudden cardiac deaths and 30 nonsudden cardiac deaths, 18 of which were secondary to congestive heart failure. The actuarial incidence of sudden death, total cardiac death and total mortality from all causes was 1%, 7% and 8%, respectively, at 1 year, and 4%, 24% and 26% at 5 years. The automatic implantable cardioverter-defibrillator nearly eliminates sudden death over a long-term follow-up period in a high risk group of patients. It has an acceptable rate of complications or problems, or both, and most late deaths in these patients are nonsudden and of cardiovascular origin.

Clinical Usefulness of Electrophysiologic Study (EPS)-Guided Risk Stratification for Life-Threatening Arrhythmia in Patients With Heart Failure

“…Because the incidence of sudden death was only 11 of 61 patients without ICD implantation, the main cause of total death depended on the aggravation of heart failure itself. 6,8) This result is concordant with the results in early reports concerning the effect of ICD on an improved prognosis in patients with LV dysfunction, 9,10) which indicated a significant decrease in arrhythmic death but no change in total death in long-term observation. Most likely, ICD therapy could only change the mode of death from arrhythmia to heart failure in some patients.…”

“…Although an ICD therapy is the most powerful therapy for prevention of sudden cardiac death, [6][7][8][9][10] it is practically impossible to assign all heart failure patients to ICD therapy, especially for primary prevention, or in other words, for the patients without previous spontaneous episodes of VT/VF. 3,5,8) In the present study, we focused on the primary prevention of sudden cardiac death in patients with a history of heart failure, and risk stratification was performed based on the findings in Holter-ECG and VT/VF inducibility in EPS.…”

“…[1][2][3][4][5] Importantly, about 1/3 of total deaths was due to a life-threatening arrhythmic event, so that the management of critical ventricular arrhythmia is an important issue in patients with heart failure. [1][2][3][4][5] Recent studies have revealed that usage of an implantable cardioverter defibrillator (ICD) would be superior to any other preventive therapies, including amiodarone, especially in patients with previous history of spontaneous ventricular tachyarrhythmias, ie, secondary prevention, [6][7][8][9][10][11] but ICD cannot be assigned to all patients with heart failure mainly because of its cost-effectiveness. Therefore, practical risk-stratification should be conducted for clinical management of patients with heart failure, especially in the primary prevention of sudden cardiac death.…”

Effect of duration of ventricular fibrillation on defibrillation efficacy in humans.

“…13 Our data should not be extrapolated beyond the 15-second duration of ventricular fibrillation that we evaluated. The difference in defibrillation efficacy between 5 and 15 seconds seen only at 300 V in this study could possibly be observed at higher energies if the duration of fibrillation is longer than 15 seconds. Also, in some patients, longer duration of ventricular fibrillation could possibly result in an inability to defibrillate with any energy.…”

Rise in chronic defibrillation thresholds in nonthoracotomy implantable defibrillator.

“…Operative mortality has been reported to be as high as 5%, with significant morbidity in 8% to 10% of patients. [1][2][3][4][5] Several manufacturers have developed nonthoracotomy lead systems to reduce the risks of implantation.6-8 These systems incorporate transvenous and subcutaneous electrodes in the lead system for shock delivery. Initial experience has been encouraging.9 '10 Although not rigorously evaluated, the chronic defibrillation threshold (DFT) in epicardial patch systems seems to be stable.…”