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Relation of changes in left ventricular peak filling rate during exercise to exercise performance in systemic
1Department of Internal Medicine, Allegheny University, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, USA.
Insights
Abnormal left ventricular (LV) diastolic filling during exercise, measured by peak filling rate (PFR), is linked to reduced exercise performance in patients with coronary artery disease (CAD). Improving PFR during exercise may enhance exercise capacity.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Systemic hypertension and coronary artery disease (CAD) are associated with impaired left ventricular (LV) diastolic function at rest and reduced exercise tolerance.
- Diastolic filling abnormalities may persist during exercise, potentially impacting exercise performance.
Purpose of the Study:
- To investigate the relationship between changes in LV peak filling rate (PFR) during exercise and exercise performance.
- To determine if impaired diastolic filling during exertion contributes to reduced exercise capacity in patients with hypertension and CAD.
Main Methods:
- Rest and exercise radionuclide angiograms were performed on 55 subjects: 20 with hypertension, 15 with prior myocardial infarction (CAD), and 20 controls.
- Peak filling rate (PFR) at rest and during peak exercise was measured in end-diastolic volume per second (EDV/s).
- Exercise performance was assessed by peak workload and exercise time.
Main Results:
- Patients with CAD exhibited reduced PFR at rest and significantly smaller increments in PFR during exercise compared to hypertensive subjects and controls.
- The increase in PFR during exercise was positively correlated with exercise performance (r = 0.49, p < 0.0002).
- CAD patients showed lower peak workload and exercise time compared to hypertensive subjects and controls.
Conclusions:
- Alterations in LV diastolic filling during exercise are significant determinants of exercise performance.
- Impaired LV diastolic function during exertion, as indicated by PFR, plays a crucial role in limiting exercise capacity in patients with CAD.
Abstract:
Patients with systemic hypertension and coronary artery disease (CAD) often manifest abnormalities at rest in left ventricular (LV) diastolic function and reduced exercise tolerance. It is possible that abnormalities in filling persist during exercise and are partially related to abnormal exercise tolerance. We examined rest and exercise peak filling rate (PFR) to determine if changes in PFR during exercise influence exercise performance. We studied 20 patients with systemic hypertension who had no evidence of CAD (negative thallium-201 stress imaging) and 15 patients with prior myocardial infarction, preserved ejection fraction, and no ischemia by thallium-201 stress imaging. Results were compared with 20 normal subjects. All 55 subjects had rest and exercise radionuclide angiograms Peak workload, exercise time, and LV ejection fraction were reduced in subjects with CAD (57 +/- 24 W, 7.41 +/- 2.91 min, and 60 +/- 9%) compared with subjects with hypertension (72 +/- 21 W, 9.69 +/- 3.03 min, and 70 +/- 6%, p <0.05) and controls (80 +/- 30 W, 10.82 +/- 3.50 min, and 67 +/- 6%, p <0.05). PFR at rest was reduced in CAD subjects (2.40 +/- 0.70 end-diastolic volume per second [EDV/s]) compared with those with hypertension (2.89 +/- 0.70 EDV/s, p <0.02) and controls (3.23 +/- 0.52 EDV/s, p <0.0002). The increments in PFR during exercise were reduced in CAD patients (+1.76 +/- 0.95 EDV/s) compared with hypertensive subjects (+2.93 +/- 1.7 EDV/s) and controls (+3.22 +/- 1.4 EDV/s, p <0.05). The increment in PFR during exercise was related to exercise performance (r = 0.49, p <0.0002). These findings suggest that alterations in LV diastolic filling during exercise are important determinants of exercise performance.