This 36-year-old man is presenting to the Emergency Department with palpitation, anterior chest discomfort, dyspnea and presyncope. The symptoms had started 45 min earlier. During the previous 4 weeks he had experienced 2 similar episodes that had terminated spontaneously without treatment. They appeared to be related to emotional upset at work. When free of palpitation, his exercise tolerance is normal and he has no cardiac symptoms. In his late twenties the patient had suffered from sarcoidosis of his eyes and lungs, treated successfully with steroids. He has had no recurrence in the past 6 years:

• Wide QRS tachycardia with right bundle branch block pattern. Ventricular rate 292/min
• Consider ventricular tachycardia or atrial flutter with 1:1 conduction

At the clinical condition of the patient appeared stable, the Emergency attending physician administered 2 IV injections of Adenosine (6 mg and 12 m). The arrhythmia remained unchanged. No flutter waves were noted during Adenosine challenge. The patient underwent successful DC cardioversion:

• Sinus rhythm, 95/min
• Right bundle branch block

Comments: Following restoration of sinus rhythm the patient became symptom-free. Physical examination, echocardiogram and coronary angiography were normal. Cardiac MRI demonstrated a “lesion in the mid-lower interventricular septum compatible with inflammation or scar”, possibly due to sarcoidosis. The LV ejection fraction was 50%. A gallium scan was negative. EP studies were carried out. A tachyarrhythmia could not be induced. The EP consultants felt that arrhythmia in the Emergency Dept. was most likely ventricular tachycardia. A single chamber cardioverter defibrillator was implanted.