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[Sudden death of a patient with a pacemaker caused by heart rupture in a "cloisonné" pericardium]
R Maendely1, M Aldakar, B d'Hautefeuille
1Service de Rythmologie et de Stimulation cardiaque, Hôpital Jean-Rostand, Ivry.
Insights
Myocardial infarction (MI) can cause pacemaker malfunction due to reduced action potential amplitude, leading to life-threatening arrhythmias. This case highlights pacemaker failure and fatal outcomes following MI and defibrillator use.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Myocardial infarction (MI) frequently causes bradycardia, necessitating cardiac pacing.
- MI can decrease endocardial action potential amplitude, impairing pacemaker detection of spontaneous ventricular activity.
Observation:
- A patient with coronary heart disease and syncope due to third-degree AV block post-MI developed pacemaker "electrical stunt" after defibrillation.
- Secondary necrosis extension led to pacemaker malfunction and ventricular fibrillation.
Findings:
- Defective pacemaker firing occurred due to "electrical stunt" after defibrillator shock.
- The patient experienced ventricular fibrillation, followed by asystole and death from disordered conduction.
Implications:
- Pacemaker malfunction is a critical risk in MI patients, especially with right ventricular pacing.
- This case underscores the potential for fatal arrhythmias and conduction disorders in complex cardiac scenarios.
Abstract:
Myocardial infarction is sometimes accompanied by bradycardia requiring either temporary or permanent cardiac pacing. In addition an MI reduces the amplitude of endocardial action potentials which produces the conditions for defective detection of spontaneous ventricular complexes by the pacemaker. In this particular condition, the competing cardiac rhythm which arises frequently causes malignant arrhythmias which are potentially fatal. This danger is increased even further by endocardial stimulation of the right ventricle with myocardial infarction of the right ventricle. We have reported in this paper the instructive case of a patient with coronary heart disease, hospitalized for third degree AV block with syncope which developed following a massive postero-diaphragmatic MI, but with few symptoms. After secondary extension of the necrotic area, the artificial pacemaker implanted manifested defective firing which resulted in development of ventricular fibrillation. The latter was controlled by cardioversion, but the patient died from disordered conduction after 30 seconds of complete asystole. For one minute, the pacemaker did not stimulate the ventricle because of "electrical stunt to the myocardium", caused by the shock from the defibrillator. Anatomical examination (at autopsy) confirmed the cardiac rupture.