Extensive myocardial bridging in the left anterior descending coronary artery was found in a 46 year old survivor of sudden cardiac near-death. Positron emission tomography and dobutamine stress echocardiography revealed ischaemia in the myocardium distal to the bridging. Spasm was excluded as cause of the ischaemia by intracoronary infusion of acetylcholine. Further evaluation of the haemodynamic importance of the bridging using intracoronary Doppler flow velocity measurements revealed an abnormal flow reserve. Dobutamine stress during coronary angiography caused increased mechanical compression during diastole. This was accompanied by multiple premature ventricular contractions. After a debridging operation the flow velocity reserve was normal. The abnormalities found during dobutamine stress had disappeared. Unexpectedly, a spasm was inducible. This may have been due to local oedema or scar formation after the operation. For the evaluation of the haemodynamic importance of myocardial bridging, intracoronary Doppler flow velocity measurements and angiography during dobutamine stress may be helpful in clinical decision making. (Heart 1997;77:280-282) Keywords: dobutamine stress; coronary flow reserve; myocardial bridging; sudden cardiac death Sudden cardiac death in young and middle aged subjects may be caused by (congenital) abnormalities of the coronary arteries. In this report a case of extreme myocardial bridging was found as the precipitating factor for ventricular arrhythmia in a survivor of sudden cardiac near-death.Case A 46 year old man collapsed during lunch in a factory canteen. Cardiopulmonary resuscitation was started immediately. On the arrival of the ambulance ventricular fibrillation was present. After defibrillation, sinus rhythm and adequate circulation were established. In the hospital the heart rate was 50 beats/min, blood pressure 130/70 mm Hg, and the patient respired spontaneously.

Intracoronary acetylcholine infusion is safe, but may lead to serious adverse reactions. Care should be taken especially in patients younger than 60 years of age. Routine use of acetylcholine infusion can thus only be justified if it has important prognostic significance. This has to be proven further in large prospective studies.

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