Abnormal cardiac sensitivity in patients with chest pain and normal coronary arteries

Abstract

The causes of chest pain in patients found to have angiographically normal coronary arteries during cardiac catheterization remain controversial. Cardiac sensitivity to catheter manipulation, pacing at various stimulus intensities and intracoronary injection of contrast medium was examined in several groups of patients who underwent cardiac catheterization. Right heart (especially right ventricular) catheter manipulation and pacing and intracoronary contrast medium provoked chest pain typical of that previously experienced in 29 (81%) of 36 patients with chest pain and angiographically normal coronary arteries and 15 (46%) of 33 symptomatic patients with hypertrophic cardiomyopathy. In contrast, only 2 (6%) of 33 symptomatic patients with coronary artery disease experienced their typical chest pain with these sensitivity tests (p less than 0.001). None of 10 patients with valvular heart disease but without a chest pain syndrome experienced any sensation with these tests. Cutaneous pain threshold testing demonstrated that patients with chest pain and normal coronary arteries had a higher pain threshold to thermal stimulation compared with patients who had coronary artery disease or hypertrophic cardiomyopathy. No relation existed between cardiac sensitivity and cutaneous sensitivity testing. Thus, patients who have chest pain despite angiographically normal coronary arteries may have abnormal cardiac sensitivity to a variety of stimuli. This increased sensitivity may be of causal importance to their chest pain syndrome or may contribute to their perception of ischemia-induced pain. The same phenomenon was also commonly seen in symptomatic patients with hypertrophic cardiomyopathy. Whether this phenomenon represents abnormal activation of pain receptors within the heart or abnormal processing of visceral afferent neural impulses in the peripheral or central nervous system is unknown.

Patients With Syndrome X Have Normal Transmural Myocardial Perfusion and Oxygenation

“…Several studies reproduced typical chest pain in patients with syndrome X with stimulus to the right side of the heart, including right atrial saline infusion and right ventricular pacing. 8,33 In these studies, chest pain may have resulted from mechanical distortion of mechanoreceptors to catheter stimulation. Rosen and colleagues 34 showed that altered ventral neural handling of afferent signals may contribute to the abnormal pain perception in these patients.…”

“…[5][6][7] Moreover, the observation that patients with syndrome X commonly experience their typical chest pain during cardiac catheterization maneuvers (simple catheter movements or saline injection in the heart) has led several investigators to believe that enhanced cardiac pain perception is a central component of the pathophysiology of the syndrome. 8,9 microspheres for the assessment of blood flow, 12 and we have previously used this technique to report resting myocardial blood flow (MBF) in patients with hibernating myocardium. 13 Over the past decade, several investigators have reported on CMR perfusion in cardiac syndrome X with conflicting results.…”

Combination of Variant and Microvascular Angina

“…It has been proposed that mild subendocardial ischemia or a patchy distribution of myocardial ischemia can fail to cause regional wall motion abnormalities and yet cause severe angina, in particular due to the presence of increased painful sensitivity to cardiac stimuli. 15,16 Although typical VA and CSX involve conductive and resistance coronary arteries, respectively, some previous studies suggested that in both conditions functional abnormalities may involve the whole coronary circulation. Thus, in CSX patients functional abnormalities in the epicardial coronary vessels were reported in previous studies showing impaired endothelium-dependent vasodilatory function in response to vasodilator stimuli and increased vasoconstriction in response to a ergonovine test.…”

Angiotensin-Converting Enzyme Inhibitors and 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase in Cardiac Syndrome X

“…The presence of ischemic-like ST-segment changes and abnormalities in myocardial perfusion detected by cardiovascular magnetic resonance during chest pain suggests that the pain could be due to ischemia. 12 However, a number of studies demonstrated that pain can be evoked by electrical stimulation of the right ventricle 13 and failed to show left ventricular dysfunction 14 during angina and ST-segment depression, which generates doubts on the ischemic origin of chest pain, at least in a number of patients found to have normal angiograms. 15,16 SX may well comprise a heterogeneous disorder, and differences between studies may be related to differences in patient selection.…”