Long-term follow-up of patients initially diagnosed with syndrome X

The clinical course of 30 patients (27 women and 3 men) diagnosed with syndrome X (angina pectoris, positive exercise test and normal coronary arteries) was evaluated during 5-year follow up. Patients were divided at the control examination into 2 groups according to the median value of the heart rate/blood pressure product variation from rest to the first stage of a modified Bruce protocol, as follows: group 1 ≤ 1,050 (n = 15) and group 21,050 mm Hg X beats/min (n = 15). All patients were followed at 6-month intervals during a mean follow-up of 60 ± 8 months. During follow-up, chest pain was unchanged in 20 patients, decreased in severity and frequency in 9 (7 in group 1, and 2 in group 2), and disappeared in 1 in group 2; 3 patients in group 1 had prolonged episodes of anginal chest pain (>30 minutes) that needed hospitalization. In group 2, 7 patients developed systemic hypertension, 4 had a progression of exercise-induced left bundle branch block to constant left bundle branch block, and 4 continued to develop rate-dependent block during exercise, but at a reduced heart rate. In the latter 8 patients, left ventricular ejection fraction at rest during follow-up decreased significantly from 61 ± 6% to 51 ± 8% (p <0.02). Therefore, during follow-up, patients in group 1 remained clinically stable or improved, whereas it was possible to identify 2 subgroups among those in group 2: a subgroup who became clearly hypertensive, and a subgroup who had a progressive reduction in left ventricular function and a progression of intraventricular conduction disturbances. In conclusion, syndrome X comprises patients with possible myocardial ischemia, borderline hypertension and early stage cardiomyopathy.