Radionuclide angiographic assessment of global and segmental left ventricular function at rest and during exercise after coronary artery bypass graft surgery
Left ventricular ejection fraction (LVEF) was measured by radionuclide angiography at rest and during supine bicycle exercise before and 3 months after coronary artery bypass graft surgery (CABG) in 20 patients with chronic stable angina. The right anterior oblique gated first-pass technique was used to assess LVEF response to maximal exercise (Wmax), while the left anterior oblique equilibrium-gated technique was used to assess LVEF and relative LV volume changes during graded submaximal exercise. Mean LVEF was unchanged at rest after CABG by both the first-pass (60 +/- 12% vs 60 +/- 12%) and equilibrium-gated (61 +/- 13% vs 62 +/- 13%) measurements. At Wmax, mean first-pass LVEF was significantly higher postoperatively than preoperatively (63 +/- 17% vs 53 +/- 17%; p less than 0.01) with a higher Wmax (750 +/- 182 vs 590 +/- 202 kpm/min; p less than 0.001) and higher rate-pressure product (302 +/- 59 vs 222 +/- 57 units; p less than 0.001). Similarly, equilibrium-gated LVEF levels during graded exercise, using stepwise regression analysis, were significantly higher postoperatively than preoperatively (p less than 0.001); at the highest graded work load, they averaged 63 +/- 19% postoperatively and 53 +/- 17% preoperatively, with higher work loads (500 +/- 190 vs 417 +/- 155; p less than 0.05) and higher rate-pressure products (271 +/- 55 vs 207 +/- 53; p less than 0.001). The increase in exercise LVEF after surgery was due to a marked decrease in the ratio, relative to resting values, of counts-based end-systolic volumes during submaximal exercise (preoperatively 1.91 +/- 1.04; postoperatively 1.14 +/- 0.46; p less than 0.01). The five subjects in whom LVEF decreased significantly during exercise postoperatively all had one or more blocked or stenosed grafts. This study documents, by two independent radionuclide techniques, an improved LVEF during exercise at an increased maximal work capacity and rate-pressure product 3 months after successful CABG.
- Research Organization:
- Cardiology Service, Alfred Hospital, Melbourne, Victoria, Australia
- OSTI ID:
- 6766309
- Journal Information:
- Circulation; (United States), Vol. 66:5
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
GRAFTS
EVALUATION
HEART
SCINTISCANNING
RADIOPHARMACEUTICALS
DIAGNOSTIC USES
BLOOD CIRCULATION
CARDIOVASCULAR DISEASES
CORONARIES
EXERCISE
PATHOLOGY
PATIENTS
ARTERIES
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
COUNTING TECHNIQUES
DIAGNOSTIC TECHNIQUES
DISEASES
DRUGS
LABELLED COMPOUNDS
ORGANS
RADIOISOTOPE SCANNING
TRANSPLANTS
USES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550901 - Pathology- Tracer Techniques
551001 - Physiological Systems- Tracer Techniques