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Hemodynamics at rest and during supine and sitting bicycle exercise in patients with coronary artery disease
Insights
In patients with coronary artery disease, the sitting position improves left ventricular function during exercise compared to supine. This study highlights the impact of posture on cardiac performance during angina.
Area of Science:
- Cardiology
- Physiology
Background:
- Coronary artery disease (CAD) affects left ventricular (LV) function.
- Hemodynamic responses can vary based on patient positioning.
Purpose of the Study:
- To assess LV function and compare pulmonary capillary wedge pressure (PCWP) and LV end-diastolic pressure (LVEDP) in supine vs. sitting positions.
- To evaluate hemodynamic changes at rest and during exercise in men with CAD.
Main Methods:
- Hemodynamic studies were conducted on 20 men with CAD-induced angina.
- Measurements were taken at rest and during exercise in both supine and sitting positions.
Main Results:
- At rest, sitting position showed lower cardiac index, stroke index, systolic ejection rate index, and LV stroke work index.
- During exercise, the sitting position demonstrated significant increases in stroke index, systolic ejection rate index, and LV stroke work index compared to rest.
- Exercise in the sitting position resulted in lower PCWP and LVEDP compared to the supine position.
Conclusions:
- The sitting position enhances LV function and reduces filling pressures during exercise in patients with CAD and angina.
- Posture significantly influences hemodynamic responses and cardiac performance in this patient population.
Abstract:
To access left ventricular function and compare pulmonary capillary wedge pressure and left ventricular end-diastolic pressure in the supine and sitting positions, 20 men with angina pectoris secondary to coronary artery disease underwent hemodynamic studies at rest and during exercise in the two positions. At rest the values for cardiac index, stroke index, systolic ejection rate index and left ventricular stroke work index were lower in the sitting position; heart rate, left ventricular end-diastolic pressure and pulmonary capillary wedge pressure were similar in the two positions. All patients experienced angina during both exercise periods. At angina during supine exercise, stroke index, systolic ejection rate index and left ventricular stroke work index did not increase significantly from the resting values. In contrast, during sitting exercise, significant increases in these variables were observed. Comparison of data during exercise revealed higher values for heart rate, mean systemic pressure, cardiac index, systolic ejection rate index, left ventricular stroke work index and rate-pressure product and lower values for mean pulmonary capillary wedge pressure (20 +/- 3 versus 27 +/- 3 [mean +/- standard error of the mean] mm Hg, P is less than 0.001), and left ventricular end-diastolic pressure (24+/- 3 versus 31 +/- 3 mm Hg, P is less than 0.02) in the sitting position; stroke index and S-T segment depression were similar during the two exercise periods. Four patients had insignificant increases in left ventricular filling pressure during both exercise periods. Of the 16 patients with abnormal left ventricular filling pressure during supine exercise, only 10 had a similar response during exercise in the sitting position. There was a good correlation between left ventricular end-diastolic pressure and mean pulmonary capillary wedge pressure at rest and during exercise in the two postures.