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Relation between exercise-induced left ventricular wall motion abnormalities and coronary artery disease in
M Pepi1, A Maltagliati, M Berti
1Istituto di Cardiologia dell'Universitá degli Studi, Fondazione I. Monzino IRCCS, Milan, Italy.
Insights
Hypertension affects heart function during exercise, particularly with coronary artery disease. Lowering blood pressure with nifedipine can alter left ventricular wall motion in patients with significant coronary stenoses.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Hypertension Research
Background:
- Hypertension can impair coronary circulation and the heart's metabolic reserve.
- Understanding left ventricular (LV) function during exercise in hypertensive patients with coronary stenosis is crucial.
Purpose of the Study:
- To determine if exercise-induced global and regional LV function in hypertensive patients relates to coronary stenosis.
- To investigate if lowering diastolic pressure affects LV dynamics in these patients.
Main Methods:
- 35 hypertensive patients undergoing coronary angiography performed exercise echocardiography before and after nifedipine.
- LV ejection fraction and regional wall motion were assessed at multiple phases.
- Patients were categorized into those with normal coronary arteries (n=21) and significant stenosis (n=14).
Main Results:
- LV ejection fraction slightly decreased in patients with stenosis during exercise, unlike those with normal arteries.
- Most patients with stenosis (13/14) showed LV wall motion abnormalities.
- Nifedipine altered LV wall motion in 7/14 patients with stenosis, with effects varying by the number of affected vessels.
Conclusions:
- Exercise-induced LV dynamics in hypertensive patients are primarily dictated by significant coronary artery disease.
- Rapid blood pressure reduction does not affect LV dynamics in patients without coronary disease.
- In hypertensive patients with coronary stenoses, blood pressure reduction can normalize, worsen, or shift ischemia-induced wall motion abnormalities.
Abstract:
In hypertension, several factors disturb coronary circulation and the metabolic reserve of the heart. This study was undertaken to test whether in hypertensive patients global and regional left ventricular (LV) function is related during exercise to the presence of significant coronary stenosis and whether lowering of coronary perfusion pressure through rapid normalization of the diastolic pressure may modify the dynamics of the left ventricle. Thirty-five patients with mild to moderate hypertension undergoing coronary angiography for the evaluation of chest pain were included in the study; upright bicycle exercise echocardiography tests were performed without therapy and 1 day later 1 h after sublingual administration of nifedipine. LV ejection fraction and regional wall motion scores were evaluated and compared at baseline, peak exercise, immediate postexercise, and recovery phases in each test through digital on-line storing of echocardiographic images. Twenty-one patients had normal coronary arteries (group 1) and 14 significant coronary stenoses (group 2); age, gender, heart rate, blood pressure, left ventricular diameter and mass index, and ejection fraction were similar in the two groups. At peak exercise LV ejection fraction slightly increased in group 1, whereas it slightly decreased in group 2 (both during the test without therapy and after nifedipine administration). All patients in group 1 had normal left ventricular wall motion during exercise; 13 of 14 patients in group 2 had LV wall motion abnormalities at peak exercise. Nifedipine did not produce any effect on LV regional wall motion in group 1, but it induced significant changes in LV regional wall motion in seven patients in group 2. Changes in LV wall motion between the two test groups were related to the number of the stenotic coronary vessels: the normal exercise test before and after therapy and the two normalized tests after nifedipine administration were in fact observed in patients with one-vessel disease, whereas worsening or changes in the site of ischemia were observed only in patients with multivessel disease. Regional and global left ventricular dynamics during exercise is mainly dependent on the existence of significant coronary artery disease. Rapid decrease of blood pressure does not alter the regional dynamics of the left ventricle during exercise in patients without coronary artery disease, but it may induce normalization, worsening, or changes in the site of wall motion abnormalities in hypertensives with significant coronary stenoses.