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The relationship between left ventricular function assessed by multigated radionuclide test and cardiopulmonary
Eliezer Klainman1, Gershon Fink, Joseph Lebzelter
1Institute of Pulmonary Medicine, Exercise Physiology Unit, Rabin Medical Center, Beilinson Campus, Petah Tiqva.
Study Objectives:
To compare the oxygen pulse curve (O(2)P-C) as measured during cardiopulmonary exercise testing (CPET) with left ventricular (LV) ejection fraction (LVEF) rest-exercise response as measured by multigated equilibrium (99m)Tc radionuclide cineangiography (MUGA) in patients with different degrees of ischemic heart disease (IHD).
Patients:
Forty-six patients (39 men and 7 women; mean plus minus 1 SD age, 59.2 plus minus 11 years) with IHD, with no hypertrophic, valvular, or pericardial disease.
Methods:
A supine bicycle ergometer with increments of 25 W every 2 min was used for MUGA, and an electronically braked cycle ergometer was used for upright symptoms-limited CPET. Exercise was increased by 10 to 20 W/min until the target heart rate (HR) was reached (similar peak HR for both studies).
Measurements And Results:
The O(2)P-C was scored on a 10-point scale as follows: type A, normal curve (10 points); type B, normal-shaped curve with low values (8 points); type C, low and flat curve (5 points); type D, descending curve (3 points). Findings for the MUGA study were classified into four groups by the degree of ischemic response: group 1 (control), normal diastolic function (n = 10), LVEF > 55%, LVEF during exercise minus LVEF at rest [DeltaLVEF] greater-than-or-equal 5%; group 2, mild ischemia (n = 10), LVEF > 55%, < 0 DeltaLVEF < 5%, diastolic dysfunction at exercise (prominent "A" waves); group 3, LV dysfunction (n = 9), LVEF < or = 35% at rest; and group 4, significant ischemia (n = 17), LVEF > 55%, DeltaLVEF < 0, diastolic dysfunction. A highly significant relationship between the O(2)P-C score and the MUGA grouping was observed by Fisher's Exact Test and Pearson's linear regression line (p < 0.001; R = - 0.89).
Conclusions:
Exercise-responded O(2)P-C might serve as a good noninvasive, physiologically based, parameter to distinguish between IHD patients with normal and impaired LV function.