Precordial exercise mapping: improved diagnosis of coronary artery disease.

Surface mapping of the exercise electrocardiogram (ECG) provides a measure of the precordial area, severity, and time course of ST-segment changes occurring after exercise. Sixteen-lead isopotential surface maps were recorded before and after exercise in 109 patients with probable angina who subsequently underwent coronary arteriography. In addition, exercise ECGs with three orthogonal leads were obtained in 53 of these patients, and with a single unipolar chest lead in all 109. Of the 109 patients, 85 had significant (greater than or equal to 70%) narrowing of at least one major coronary artery. The sensitivities of the precordial surface mapping, orthogonal leads, and single chest lead (V5) when compared with the findings at coronary arteriography were 95%, 68%, and 64% respectively, while the specificities of the three lead systems did not differ significantly. The technique of precordial surface mapping after exercise may easily be applied in clinical practice and requires only conventional equipment available in most hospitals. It effectively aids diagnosis of coronary artery disease.     

Electrocardiographic chest wall mapping in the diagnosis of coronary artery disease.

Chest wall mapping of ST segment changes, inverted U waves, and Q waves using 16 electrocardiographic electrodes was performed at rest and during and after bicycle ergometry in 150 patients presenting with chest pain suggestive of angina. All patients underwent coronary angiography. The presence or absence of appreciable coronary artery disease (greater than or equal to 50% stenosis) was detected with a sensitivity of 98% and a specificity of 88%. The identification of lesions in individual coronary arteries was also possible with a sensitivity and specificity of 87% and 85% respectively for the territory of the left anterior descending and diagonal artery, 71% and 85% respectively for the right coronary artery, and 85% and 80% respectively for the circumflex artery. This test appears to be a reliable non-invasive screening method for selecting patients for angiography.     

Cold pressor test in the rat: medullary and spinal pathways and neurotransmitters

This study was designed to delineate the medullary and spinal pathways mediating the cardiovascular responses to cold pressor test (CPT) and to identify neurotransmitters in these pathways. Experiments were done in barodenervated, urethane-anesthetized, male Wistar rats. The CPT was performed by immersing the limbs and ventral half of the body of the rat in ice-cold water (0.5 degrees C) for 2 min. CPT elicited an immediate increase in mean arterial pressure (MAP), heart rate (HR), and greater splanchnic nerve activity (GSNA). Bilateral blockade of ionotropic glutamate receptors (iGLURs) in the rostral ventrolateral medullary pressor area (RVLM) significantly attenuated the CPT-induced responses. Bilateral blockade of gamma-aminobutyric acid (GABA) receptors, but not iGLURs, in the nucleus ambiguus (nAmb) significantly reduced the CPT-induced increases in HR, but not MAP. Blockade of spinal iGLURs caused a significant reduction in CPT-induced increases in MAP and GSNA, whereas the increases in HR were reduced to a lesser extent. Combination of the blockade of spinal iGLURs and bilateral vagotomy or intravenous atropine almost completely blocked CPT-induced tachycardia. Midcollicular decerebration significantly reduced CPT-induced increases in MAP and HR. These results indicated that: 1) CPT-induced increases in MAP, HR, and GSNA were mediated by activation of iGLURs in the RVLM and spinal cord, 2) activation of GABA receptors in the nAmb also contributed to the CPT-induced tachycardic responses, and 3) brain areas rostral to the brain stem also participated in the CPT-induced pressor and tachycardic responses.     

Delayed diagnosis of symptomatic coronary artery disease in young men

Delay in making the diagnosis of symptomatic coronary artery disease was determined by studying the medical histories of 265 men aged 24.7 to 49.9 (mean 40.1) years with angiographically proven obstructive coronary atherosclerosis. The diagnosis of angina pectoris was delayed three times as often as the diagnosis of myocardial infarction, and for five times as long. The diagnosis of symptomatic coronary artery disease was delayed three and a half times more often in patients less than 35 years of age, than in patients over 45; the average time from presentation with symptoms to diagnosis was 30 times longer in patients under 35 years of age than in patients over 45.     

Accelerated progression of coronary artery disease.

Atheromatous disease of the arteries is progressive and often results in untimely morbidity and premature death. The pathogenesis of the arterial lesion is as complex as its rate of progression is variable and ill understood. In six patients undergoing coronary arteriography, who were being restudied before percutaneous transluminal coronary angioplasty, the angiographic appearance deteriorated considerably over a fairly short period (mean 3.6 months). Although early detection and preventive measures have lowered the incidence of atheromatous disease and improved survival in some patients, rapid progression of the disease remains a serious hazard in others, who, as a group, remain at present unidentifiable.     

Twelve weeks of coronary artery disease.

Osler said the components of the student spirit are humility, confidence, pride and hope. In this retrospective look at 12 weeks spent on a cardiology ward, medical student Paul Fedak recounts his experiences concerning a patient diagnosed with terminal coronary artery disease.     

Noninvasive diagnosis of coronary artery disease using a neural network algorithm

This study examines the utility of neural networks for detecting coronary artery disease noninvasively by using the clinical examination variables and extracting useful information from the diastolic heart sounds associated with coronary occlusions. It has been widely reported that coronary stenoses produce sounds due to the turbulent blood flow in these vessels. These complex and highly attenuated signals taken from recordings made in both soundproof and noisy rooms were detected and analyzed to provide feature set based on the poles and power spectral density function (PSD) of the Autoregressive (AR) method after Adaptive Line Enhancement (ALE) method. In addition, some physical examination variables such as sex, age, body weight, smoking condition, diastolic pressure, systolic pressure and derivation from them were included in the feature vector. This feature vector was used as the input pattern to the neural network. The analysis was studied on one hundred recordings (63 abnormal, 37 normals). The network correctly identified 84% of the subjects with coronary artery disease and 89% of the normal subjects.