A previously asymptomatic 32-year o

A previously asymptomatic 32-year old male patient was
admitted to our emergency department with a complaint of
first-time occurring severe palpitation and dizziness which
started 20 minutes ago. On physical examination, he was
lethargic, his skin was pale and diaphoretic, his pulse was
weak, irregular and tachycardic (> 160 beats/min). His
arterial blood pressure was measured 70/30 mmHg and the
remainder of the physical examination was within normal
limits. His medical and family history was unrevealing for
any history of coronary artery disease, unexplained syncope
or sudden death. A 12-lead ECG revealed an irregular, wide
QRS complex tachycardia with delta waves most apparent in
leads V1–V4 and in some narrow QRS beats (Fig. 1). Pre-excitated AF causing haemodynamic compromise was diagnosed
and emergent electrical cardioversion with 200 joules
was performed that restored the sinus rhythm. A subsequent
ECG showed minimal preexcitation with borderline PR
interval of 120 ms, normal ST segment and T waves and
apparently small delta waves only in leads III and aVF