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Cardiac histologic findings in patients with life-threatening ventricular arrhythmias of unknown origin
Insights
Serious ventricular arrhythmias in patients with normal heart anatomy were often linked to underlying histologic abnormalities, challenging the notion of primary electrical heart disease. Myocardial biopsies revealed common issues like hypertrophy and fibrosis.
Area of Science:
- Cardiology
- Pathology
- Electrophysiology
Background:
- Ventricular arrhythmias with normal cardiac anatomy are often presumed idiopathic or primary electrical disorders.
- Endomyocardial biopsy is a diagnostic tool for evaluating myocardial tissue.
- Understanding the underlying pathology is crucial for effective treatment strategies.
Observation:
- Percutaneous endomyocardial biopsy was performed on 12 patients (aged 9-57) presenting with serious ventricular arrhythmias and normal cardiac structure/function.
- Histologic examination of myocardial tissue was conducted using light microscopy.
- Biopsies were taken from the right ventricle (10 patients) and left ventricle (2 patients).
Findings:
- Histologic abnormalities were identified in 11 out of 12 patients.
- Common findings included myocardial cellular hypertrophy (7 patients) and interstitial fibrosis (5 patients).
- Other abnormalities observed were endocardial fibrosis (2 patients), degenerative changes (1 patient), and increased interstitial cellularity (1 patient).
- One patient showed acute lymphocytic myocarditis.
Implications:
- The high prevalence of histologic abnormalities suggests that "idiopathic" ventricular arrhythmias may often have an underlying structural or inflammatory cause.
- These findings challenge the concept of primary electrical heart disease.
- Further investigation into myocardial pathology is warranted for patients with ventricular arrhythmias and seemingly normal cardiac anatomy.
Abstract:
Percutaneous endomyocardial biopsy (right ventricle in 10, left ventricle in 2) was performed in 12 patients, aged 9 to 57 years, with serious ventricular arrhythmias occurring in the setting of normal cardiac anatomy and mechanical function. Light microscopic examination of tissue revealed histologic abnormalities in 11 patients, including myocardial cellular hypertrophy in 7, interstitial fibrosis in 5, endocardial fibrosis in 2, myocardial degenerative changes in 1 and increased interstitial cellularity in 1. One patient had histologic evidence of acute lymphocytic myocarditis. Thus, a majority of patients with serious ventricular arrhythmias and normal cardiac anatomy had histologic abnormalities, bringing into question the concept of primary electrical heart disease or idiopathic ventricular tachycardia.