Silent myocardial ischaemia and life threatening ventricular arrhythmias

In a retrospective study of four patients with paroxysmal ventricular tachycardia (VT) induced by silent ischaemia (SI) one case was related to transmural SI secondary to coronary artery spasm and the other cases to subendocardial SI related to non-dynamic coronary artery stenosis. In one patient it was possible simultaneously to document the presence of myocardial ischaemia preceding VT using two independent markers: ECG and thallium scintigraphy. The common feature was attacks of fast polymorphic VT with fainting and intermediate cardiac arrest as the sole clinical manifestation. Attacks at rest occurred in both types of patients, whereas exercise induced attacks were an inconstant feature of SI-VT in non-dynamic coronary artery stenosis. VT suppression was accomplished by anti-ischaemic intervention in three patients: by calcium antagonist medication in the patient with coronary artery spasm, by coronary artery surgery in two cases of non-dynamic artery stenosis. The risk of underdiagnosing SI-VT is discussed. Screening of patients with the aborted cardiac arrest syndrome by ambulatory ECG-monitoring and repeated symptom-limited exercise-ECG is recommended.