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[Heart involvement in progressive external ophthalmoplegia (Kearns-Sayre syndrome): electrophysiologic, hemodynamic
Insights
Kearns-Sayre syndrome, a mitochondrial disorder, often presents with progressive external ophthalmoplegia (PEO) and significant atrioventricular conduction defects. Early detection via endomyocardial biopsy can reveal mitochondrial cardiomyopathy in PEO patients.
Area of Science:
- Cardiology
- Neurology
- Mitochondrial Medicine
Context:
- Kearns-Sayre syndrome (KSS) is a rare multisystem disorder.
- It is characterized by progressive external ophthalmoplegia (PEO), pigmentary degeneration of the retina, and cardiac conduction abnormalities.
- KSS is considered a systemic mitochondrial disorder.
Purpose:
- To investigate the prevalence and characteristics of atrioventricular conduction defects in patients with PEO.
- To identify mitochondrial abnormalities in the myocardium of affected individuals.
Summary:
- A prospective study examined 6 patients with PEO and mitochondrial myopathy.
- ECG revealed conduction defects in 5 patients, including complete heart block requiring a pacemaker.
- Myocardial biopsies showed mitochondrial abnormalities, suggesting mitochondrial cardiomyopathy.
Impact:
- Atrioventricular conduction defects are common in PEO patients.
- Endomyocardial biopsy can diagnose mitochondrial cardiomyopathy in these patients.
- Findings highlight the cardiac implications of mitochondrial disorders.
Abstract:
The Kearns-Sayre syndrome is combined with a progressive external ophthalmoplegia (PEO), retinal pigmentary degeneration and heart block. In some patients, progression of incomplete forms has been described and potentially fatal conduction disturbances may occur. The disease is considered as a systemic mitochondrial disorder. As part of an ongoing prospective study 6 patients (3 female, 3 male; age 32 +/- 9 years) with PEO and typical ultrastructural changes of a mitochondrial myopathy in their skeletal muscle were examined. The ECG disclosed atrio/intraventricular conduction defects in 5 patients: 1 patient had a third degree AV block which was treated by a pacemaker. Another patient had left anterior fascicular block with complete right bundle branch block. In 3 other patients an incomplete right bundle branch block was registered. In 1 patient, His-bundle electrography disclosed a block distal to His by atrial high rate pacing before and after i.v. injection of ajmaline; prophylactically a pacemaker was implanted. The mean HV-interval increased significantly under ajmaline by 44% in patients with sinus rhythm. Hemodynamic studies were normal in 5 patients at rest; only 1 patient was abnormal during exercise. Myocardial biopsy demonstrated mitochondrial abnormalities such as variability in shape and size. In 4 patients concentric cristae mitochondriales were seen. Our results suggest that atrioventricular conduction defects are common in patients with PEO. By means of endomyocardial catheterbiopsy a mitochondrial cardiomyopathy could be detected.