A man with chest pain and a broad QRS complex tachycardia

A 50 year old man with “heavy” chest pain was referred urgently from a local district hospital to the cardiothoracic centre because a broad QRS complex tachycardia had been noticed on electrocardiogram (ECG). The chest pain was intermittent and had started two hours before presentation. He was a cigarette smoker and his medical history included asthma and a myocardial infarction eight years earlier, for which no invasive treatment was carried out. In the past year he had experienced frequent episodes of chest pain in the early morning, but did not report exertional angina. On examination, the patient was tachycardic with a heart rate of 160 beats/min but with a normal blood pressure of 125/75 mm Hg. Physical examination was otherwise unremarkable. ECGs were recorded after referral. Figure 1 shows an ECG recorded while the patient had chest pain, and figure 2 when he was free of pain.