Jerzy P. Dubiel

Technetium 99m stannous pyrophosphate myocardial imaging in patients with and without left ventricular aneurysm.

To further explore the usefulness of technetium 99m pyrophosphate (99mTc-PYP) myocardial imaging and test its validity in the diagnosis of acute myocardial infarction, 99mTc-PYP myocardial scintigrams were performed in 50 patients. Out of 28 patients with acute myocardial infarction, myocardial scintigrams demonstrated localized activity in the 15 patients with transmural, and diffuse activity in the 13 patients with subendocardial myocardial infarction. Twenty-two patients with significant coronary artery disease documented by coronary angiography but without acute myocardial infarction were also studied. Nine of ten patients with clinical evidence of left ventricular aneurysm from previous myocardial infarction and definite left ventricular dyskinesis had positive scintigrams with activity localized to the site of the wall motion abnormality. Two of five patients without definite aneurysm but with left ventricular akinesis also had localized uptake in the involved area of the left ventricle. Seven patients with normal left ventricular wall motion had negative scintigrams. These findings suggest caution in interpreting positive 99mTc-PYP scintigrams as being indicative of acute myocardial infarction when evidence of a left ventricular aneurysm is also present.

Limited clinical diagnostic specificity of technetium-99m stannous pyrophosphate myocardial imaging in acute myocardial infarction.

To test the sensitivity and specificity of technetium-99m stannous pyrophosphate myocardial imaging in the diagnosis of acute myocardial infarction, myocardial scintigrams were performed in 115 patients. Positive scintigrams were found in all 48 patients with acute myocardial infarction; uptake was localized in 29 patients with transmural infarction and diffuse in 2 patients with transmural infarction and in the remaining 17 patients with subendocardial myocardial infarction. Positive scintigrams were also found in 31 of 67 patients without clinical evidence of acute myocardial infarction. Diffusely positive scintigrams were found in 3 of 3 patients with unstable angina pectoris, 7 of 30 patients with stable angina pectoris, 4 of 13 patients who had undergone aortocoronary bypass surgery, 4 of 4 patients with congestive cardiomyopathy and 1 patient studied 1 day after direct current cardioversion. Localized uptake of 99mTc-pyrophosphate was found in 9 of 10 patients with left ventricular aneurysm and in 3 of 13 patients after aortocoronary bypass surgery. All four patients with atypical chest pain and two patients with pericarditis had normal scintigrams. Our data confirm the previously reported sensitivity of 99mTc-pyrophosphate imaging in detection of acute myocardial infarction but indicate that positive scintigrams are not specific for this entity.

Cold pressor thallium-201 myocardial scintigraphy in the diagnosis of coronary artery disease

Thallium-201 myocardial scintigraphy was performed during cold pressor stimulation in 36 patients aged 36 to 69 years. Thirty-one patients had coronary artery disease and 5 patients did not, as confirmed by coronary cineangiography. Thallium-201 (1.5 to 2 mCi) was injected at 30 seconds of the cold pressor stimulation. The product of systolic pressure X heart rate increased from a baseline of 77.4 +/- 16 (standard deviation [SD]) to 103.6 +/- 17 at 30 seconds of the cold pressor test (p less than 0.0005). Transient perfusion deficits developed in 24 of 31 patients with coronary artery disease (sensitivity 77%), and all 5 patients without coronary artery disease had normal scintigrams. The sensitivity in detecting coronary artery disease was 40% in patients with 1 vessel disease, 91% in patients with 2 vessel disease, and 100% in patients with 3 vessel disease. Exercise electrocardiograms (available in 29 of 36 patients) were positive for ischemia in 18 of 24 patients with coronary artery disease and in 1 of 5 patients without coronary artery disease (sensitivity 75% and specificity less than 80%). Exercise thallium-201 scintigrams, obtained in 16 patients, were positive in 11 patients with coronary artery disease and positive cold pressor thallium-201 scintigrams. Five patients without coronary artery disease and with normal cold pressor thallium-201 scintigrams had normal exercise thallium-201 scintigrams. Coronary cineangiography performed during cold pressor stimulation in 6 patients who had positive cold pressor and exercise thallium-201 scintigrams did not show coronary spasm. Our data indicate that cold pressor thallium-201 scintigraphy offers promise as a noninvasive test in the diagnosis of coronary artery disease and may be used in patients in whom exercise testing is not feasible.

Left ventricular response to exercise in regular runners and controls: A radionuclide evaluation

Radionuclide angiography was performed during upright exercise to compare left ventricular function in nine regular runners to nine age-matched, healthy controls. Heart rate, blood pressure, left ventricular ejection fraction (LVEF), end diastolic volume index (EDVI), end systolic volume index (ESVI), and stroke volume index (SVI) were measured at rest and at 40%, 60%, 80%, and 100% of maximum work capacity (mean maximal workload [KPM ± SD] was 1,773 ± 157 in runners and 1,260 ± 324 in controls). The resting data of runners and controls were similar. There were no significant differences in heart rate, systolic blood pressure, and LVEF between runners and controls during exercise. SVI and EDVI were higher in runners during exercise (P<0.05). ESVI was lower in controls at a 60% level of exercise (P<0.05). The data indicate that an early and sustained increase in the diastolic volume of the left ventricle is important for enhanced cardiac performance of regular runners during exercise