Author + information
- Received April 26, 1983
- Revision received January 9, 1984
- Accepted January 13, 1984
- Published online June 1, 1984.
- Raymond G. McKay, MDb,a,
- Julian M. Aroesty, MD, FACC,
- Gary V. Heller, MD, PhD,
- Kenneth J. Silverman, MD, FACC,
- J. Anthony Parker, MDc,
- Ann V. Als, MD,
- Patricia C. Come, MD,
- Gerald M. Kolodny, MD and
- William Grossman, MD, FACC
- ↵aAddress for reprints: Raymond G. McKay, MD, Cardiovascular Division, Beth Israel Hospital, 330 Brookline Avenue, Boston, Massachusetts 02215.
To assess the relation between extent of ischemia and the magnitude of hemodynamic changes, 25 patients (5 with normal coronary arteries and 20 with significant coronary obstructive disease) were studied with rapid atrial pacing and thallium scintigraphy at the time of cardiac catheterization. Hemodynamic variables were measured before, during and after maximal pacing. Thallium was injected intravenously during maximal pacing and scans in three standard views were obtained immediately in the catheterization laboratory, with delayed scans obtained 4 hours after the cessation of pacing. The three thallium scans were each subdivided into five segments, and a thallium score was obtained on the basis of the total number of segments that were hypoperfused. Each patient was assigned a total thallium score corresponding to thallium defects at maximal pacing, as well as a redistributed thallium score corresponding to the difference between thallium score at maximal pacing and that 4 hours later.
With pacing, patients with normal coronary arteries demonstrated no significant change in baseline hemodynamic variables, whereas patients with coronary artery disease exhibited a decrease in cardiac index, an increase in systemic vascular resistance, a widening of arteriovenous oxygen difference, an increase in pulmonary capillary wedge pressure and mean pulmonary artery pressure during maximal pacing and an increase in left ventricular end-diastolic pressure immediately after pacing. There was a significant correlation (Spearman rank r = 0.64, p < 0.01) between redistributed thallium score and an increase in left ventricular end-diastolic pressure in the postpacing period. Moreover, there was an even higher correlation (Spearman rank r = 0.90, p < 0.001) between total thallium score and the postpacing increase in end-diastolic pressure.
It is concluded that in patients with coronary artery disease the magnitude of pacing-induced hemodynamic changes reflects both the amount of myocardial tissue at ischemic jeopardy and the total mass of hypoperfused myocardium during maximal pacing stress.
↵b Dr. McKay is a 1983-1984 Merck Fellow of the American College of Cardiology.
↵c Dr. Parker is the recipient of a Research Career Development Award 5 K04 HL00465 from the National Heart, Lung, and Blood Institute. A preliminary report of this work was presented at the Annual Scientific Sessions of the American Heart Association in Dallas, Texas in November 1982.
This study was supported, in part, by Grant HL 28939 from the National Heart, Lung, and Blood Institute, Bethesda, Maryland and by Research Training Grant HL07374 from the United States Public Health Service, Bethesda, Maryland.
- Received April 26, 1983.
- Revision received January 9, 1984.
- Accepted January 13, 1984.
- American College of Cardiology Foundation