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Comparison of atrial pacing and the cold pressor test in patients with angina pectoris
Insights
Maximal atrial pacing effectively provokes angina and myocardial lactate production in patients with coronary artery disease. The cold pressor test is less effective and cannot reliably distinguish between patients with and without coronary artery disease.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Angina pectoris is a common cardiovascular condition.
- Distinguishing between coronary artery disease and other causes of chest pain is clinically important.
Purpose of the Study:
- To compare the efficacy of maximal atrial pacing and the cold pressor test (CPT) in provoking angina pectoris and myocardial metabolic changes.
- To assess the utility of these tests in differentiating patients with and without significant coronary artery disease.
Main Methods:
- A haemodynamic and myocardial metabolic study was conducted.
- Twelve patients with severe coronary artery disease (group I) and 16 with normal coronary angiograms (group II) underwent maximal atrial pacing and CPT.
- Measurements included angina occurrence, myocardial lactate production, coronary sinus flow, and coronary vascular resistance.
Main Results:
- Maximal pacing induced angina in all group I patients and myocardial lactate production in 8/12. In group II, 12/16 experienced chest pain, but only 2 showed lactate production.
- CPT did not induce angina or lactate production in either group.
- Maximal pacing increased coronary sinus flow and decreased coronary vascular resistance in both groups.
- CPT decreased coronary flow and increased resistance in group I, with variable responses in group II.
Conclusions:
- Maximal atrial pacing is a more effective provocative test for angina pectoris than CPT.
- Hemodynamic responses to pacing and CPT differ between patients with and without coronary artery disease.
- CPT's variable response in patients with normal coronary arteries limits its use in diagnosing coronary artery disease.
Abstract:
A haemodynamic and myocardial metabolic study was performed to compare effects of maximal atrial pacing and the cold pressor test (CPT) in patients with angina pectoris. Twelve patients (group I) had angiographically severe coronary artery disease, while 16 patients (group II) had normal coronary angiograms. At maximal pacing, angina developed in all patients in group I, and myocardial lactate production was found in eight of 12 patients. In group II, 12 out of 16 patients experienced chest pain, but only two patients had myocardial lactate production. Neither angina nor myocardial lactate production was present in any patient in either group during CPT. Coronary sinus flow increased and coronary vascular resistance decreased significantly in both groups at maximal pacing (P less than 0.001). At CPT, coronary flow decreased (P less than 0.05) and coronary resistance increased (P less than 0.001) in group I, while individual response was more variable in group II. In conclusion, maximal pacing was a more effective method of provocation of angina pectoris than CPT. The reactions of coronary sinus flow and coronary vascular resistance were different in group I than in group II. However, because of the variability of response in patients with normal coronary arteries, CPT cannot be used to distinguish patients with coronary artery disease from patients with no such disease.