Angina pectoris with angiographically normal coronary arteries: A clinical, hemodynamic, and metabolic study

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Abstract
Seventy‐six patients with anginalike chest pain (ALCP) and angiographically normal coronary arteries (NCA) had a study of the myocardial metabolism at rest and during maximal atrial pacing. The results were compared with pain characteristics, electrocardiogram, left ventricular, and coronary hemodynamic data. Coronary blood flow (CBF) was measured by continuous ther‐modilution. At maximal paced heart rate, the study of the myocardial metabolism distinguished two groups: (1) a first group of 50 patients whose lactate extraction coefficient was equal to or exceeded 9 % and was considered as normal (Gr. I, K ≥9%); (2) a second group of 26 patients whose lactate extraction coefficient was below 9% (Gr. II, K<9%), significant of myocardial ischemia. In group I (K≥9%), chest pain was usually atypical (typical in only 25 % of cases) and rapid atrial pacing most often caused neither pain nor ECG changes. The hemodynamic and angiographic study showed minor alterations of the left ventricular cavity in 50% of cases. In group II (K<9%), chest pain was typical in 50% of the patients and maximal atrial pacing most often caused chest pain (85%) and ST‐segment depression (80%). In almost every case, the left ventricular and the coronary angiograms were normal. Only in this group, which had clinical, electrical, and metabolic signs of myocardial ischemia, could the diagnosis of angina pectoris with angiographically normal coronary arteries be upheld. However, resting CBF, % increase in CBF for an identical myocardial oxygen demand, and coronary resistances remained comparable in the two groups and no different from a group of 10 control subjects. This study confirms that myocardial ischemia occurs during rapid atrial pacing in 30% of patients with ALCP and NCA, with no obvious explanation, since coronary hemodynamics remain normal. In the remaining 70% of patients where no myocardial ischemia can be demonstrated minor forms of cardiomyopathy or mitral valve prolapse can often be shown.

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