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Pathologic findings related to the lead system and repeated defibrillations in patients with the automatic
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Autopsy findings reveal that automatic implantable cardioverter-defibrillator leads can cause localized myocardial injury. Multiple defibrillations, while rare, may also contribute to these localized pathologic changes.
Area of Science:
- Cardiovascular Pathology
- Medical Device Analysis
Background:
- Automatic implantable cardioverter-defibrillators (AICDs) are crucial for managing life-threatening arrhythmias.
- Understanding the long-term pathologic effects of AICD lead placement and defibrillation is essential for patient safety.
Purpose of the Study:
- To evaluate the autopsy findings related to AICD lead placement and defibrillation.
- To assess myocardial and pericardial changes associated with intravascular and intrapericardial leads.
- To investigate the impact of multiple defibrillations on cardiac tissue.
Main Methods:
- Autopsy examination of 25 patients who received AICD lead implantation.
- Histopathologic analysis of myocardial and pericardial tissues.
- Correlation of pathologic findings with defibrillation history and lead presence.
Main Results:
- Acute pericarditis was universal, leading to localized fibrosis around the apical patch lead.
- Thrombus formation occurred in relation to the superior vena cava and right ventricular leads.
- Defibrillation-related myocardial changes, including contraction band necrosis and myocyte loss, were observed in 7 patients, primarily under the patch electrode, affecting <2% of myocardial mass.
Conclusions:
- AICD lead systems can induce localized pericarditis and fibrosis.
- Multiple defibrillations result in localized myocardial injury, predominantly beneath the patch electrode.
- The observed pathologic changes are generally localized and affect a small portion of the myocardium.
Abstract:
The purpose of the present study was to examine at autopsy the effect of multiple defibrillations on the myocardium and the pathologic consequences of short- and long-term placement of the intravascular and interpericardial leads of the automatic implantable cardioverter-defibrillator. Twenty-five patients were examined at autopsy; 8 of them underwent lead implantation only and 17 received both leads and the automatic implantable cardioverter-defibrillator. Twelve patients (48%) died of ventricular tachycardia or ventricular fibrillation; seven (28%) died of other causes. Acute pericarditis occurred in all patients, resulting in a localized, progressive fibrosis around the apical patch lead without giving rise to pericardial restriction. Thrombus formation was associated with the superior vena cava spring electrode in four patients (17%) and the right ventricular rate-sensing electrode in one patient (4%). Asymptomatic pulmonary emboli occurred in two patients (8%). In one patient who underwent defibrillation 59 times, superior vena cava changes consisted of vein wall destruction, fibrosis and thrombus formation. Pathologic changes under the apical patch related to defibrillation were observed in seven patients; two of these had fewer than 5 defibrillations, one had 8 defibrillations and four had 21 to 74 defibrillations. These changes consisted of contraction band necrosis in four patients, vacuolar cytoplasmic clearing and loss of myocytes confined to the myocardium under the patch electrode in five patients who had multiple defibrillations. The observed pathologic changes were estimated to affect less than 2% of the total myocardial mass. Thus, the automatic implantable cardioverter-defibrillator lead system and multiple defibrillations result in localized myocardial injury confined to the tissue under the patch electrode.(ABSTRACT TRUNCATED AT 250 WORDS)