[Implantation of a transvenous defibrillation system in isolated persistent left superior vena cava]

A 49-year-old man, an alcoholic for the past 7 years, complained of dizziness, palpitations and exertional dyspnoea (NYHA stage III). Physical examination revealed peripheral cyanosis, slightly raised jugular venous pressure, râles in the lung bases, a loud systolic murmur, maximal over the apex, and an enlarged palpable liver.

Results of biochemical tests were unremarkable. The ECG showed sinus rhythm, 1 degree AV block and signs of left ventricular hypertrophy. Chest radiogram demonstrated cardiac dilatation and probably absent right superior vena cava (SVC). Long-term ECG monitoring during episodes of dizziness and one syncope revealed self-limited periods of unifocal ventricular tachycardia. Echocardiography and angiography showed bilateral ventricular dilatation with an ejection fraction reduced to 20%, as well as mild mitral and moderate tricuspid regurgitation but normal cardiac valves, suggesting a dilated cardiomyopathy. Coronary angiography was normal. No myocarditis was revealed on myocardial biopsy. The patient declined electrophysiological investigation.

Amiodarone caused higher degree AV block. A temporary pacemaker lead was inserted via the persistent left SVC, amiodarone discontinued and later a pacemaker-defibrillator system (ICD) implanted, previous digital subtraction angiography having demonstrated a left SVC and absent right SVC. The transvenous electrode had been placed via the left subclavian vein, left SVC (anode), coronary sinus, right atrium into the right ventricle (cathode), and the pacemaker-defibrillator implanted subpectorally. Stable electrode position and correct ICD function has been documented over 2 years. 4 months after implantation bursts of ventricular tachycardia recurred every few minutes that responded to renewed amiodarone administration.

Good long-term results can be obtained with ICD electrodes implanted via a persistent LSVC.