[Successful defibrillation by disconnection of superior vena cava electrode for high defibrillation threshold: a case...

Area of Science:

• Cardiology
• Electrophysiology

Background:

• A 72-year-old male patient diagnosed with dilated cardiomyopathy and sustained ventricular tachycardia was undergoing amiodarone treatment.
• The patient presented with loss of consciousness, and electrocardiography revealed a 2:1 atrioventricular block.

Observation:

• Electrophysiological study induced various ventricular tachyarrhythmias, including ventricular tachycardia and ventricular fibrillation.
• An implantable cardioverter-defibrillator (ICD) was implanted for arrhythmia management.
• Defibrillation threshold testing revealed inability to terminate ventricular fibrillation with maximal ICD output (31J).

Findings:

• Standard adjustments in electrode polarity and position failed to achieve stable defibrillation.
• Successful defibrillation was ultimately accomplished only after disconnecting the superior vena cava electrode.

Implications:

• This case underscores the complexity of achieving effective defibrillation in challenging patient populations.
• It highlights the potential need for unconventional approaches, such as lead modification, in ICD therapy.
• Further research into optimizing ICD lead configurations and defibrillation strategies is warranted.