The clinical features of isolated left circumflex coronary artery disease.

The clinical characteristics of 84 patients with isolated circumflex disease (greater than or equal to 70% luminal stenosis) were reviewed. A total of 66 patients had angina pectoris (mean duration 17.3 months), and 60 had suffered a myocardial infarction. Risk factors averaged 2.2 per patient. In the 84 patients there were 103 discrete circumflex stenoses; 51 stenoses were central (proximal circumflex, obtuse marginal, and intermediate branches), and 52 were peripheral (distal circumflex, posterolateral, and posterior descending branches); 48 were total and 55 were subtotal. Left ventricular function was normal in 21 patients and abnormal in 63 patients, but the mean left ventricular ejection fraction of the group was normal (59 +/- 12%). Eighty-two patients had abnormal electrocardiograms: there were Q waves in 25, RV pattern in 43, ST-T wave abnormalities in 19, left bundle branch block in two, and pacemaker rhythm in one. Inferior abnormalities on the electrocardiogram correlated with peripheral stenoses (p less than .02), and lateral abnormalities on the electrocardiogram correlated with central stenoses (p less than .01). The RV pattern of true posterior infarction was seen in both central and peripheral stenoses. In the 32 patients who underwent thallium scanning, lateral defects were more common with central stenoses, but posterolateral defects occurred similarly in central and peripheral stenoses. Prognosis was good. There were two deaths during the mean follow-up time of 17 months (range 1 to 49). The cumulative survival rate was 100% at 12 months, 97.5 +/- 2.9% at 24 months, and 97.5 +/- 3.6% at 30 months.