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Hemodynamic parameters during dynamic exercise in patients with silent myocardial ischemia in the presence or absence
J Yoshida1, M Yokota, T Miyahara
1Department of Clinical Laboratory Medicine, Nagoya University Hospital, Japan.
Insights
Patients with left ventricular hypertrophy experienced significantly higher left ventricular filling pressures during exercise-induced myocardial ischemia. This suggests severe ischemia alone may not cause chest pain in these individuals.
Area of Science:
- Cardiology
- Exercise Physiology
- Myocardial Ischemia Research
Background:
- Silent myocardial ischemia is often asymptomatic.
- Left ventricular hypertrophy (LVH) can alter cardiac function.
- Understanding hemodynamic responses during ischemia is crucial.
Purpose of the Study:
- To investigate hemodynamic differences during exercise-induced myocardial ischemia in patients with and without left ventricular hypertrophy.
- To determine if LVH influences the severity of left ventricular filling pressure abnormalities during silent ischemia.
Main Methods:
- Assessed hemodynamic parameters, specifically left ventricular filling pressure, during supine leg exercise.
- Compared responses in two groups: 10 patients without LVH (Group I) and 10 with LVH (Group II).
- Ensured comparable baseline characteristics and exercise levels across groups, with no angina reported.
Main Results:
- Left ventricular filling pressure increased significantly from rest to peak exercise in both groups.
- Group II (with LVH) demonstrated significantly greater increases in left ventricular filling pressure at peak exercise compared to Group I (p < 0.01).
- Patients with asymptomatic silent myocardial ischemia showed varied left ventricular filling dynamics, with severe abnormalities in the LVH group.
Conclusions:
- Asymptomatic silent myocardial ischemia can occur with normal or mildly abnormal left ventricular filling dynamics.
- Patients with coexistent left ventricular hypertrophy may exhibit severely abnormal left ventricular filling dynamics during exercise without experiencing chest pain.
- Severe ischemia and/or ventricular wall stretching are necessary but not sufficient conditions for the manifestation of chest pain during myocardial ischemia.
Abstract:
Hemodynamic parameters during supine leg exercise-induced myocardial ischemia were investigated in ten patients without left ventricular hypertrophy (group I), and in ten patients with left ventricular hypertrophy (group II). Both groups of patients had previously been diagnosed as having totally asymptomatic silent myocardial ischemia. Both groups were comparable in age, sex, left ventricular ejection fraction at rest, and extent of coronary artery disease. All of the patients exercised to the same extent without angina or its usual equivalent. Left ventricular filling pressure increased from 4 +/- 2 mmHg at rest to 11 +/- 3 mmHg at peak exercise in group I, and from 7 +/- 4 mmHg at rest to 19 +/- 7 mmHg at peak exercise in group II. Left ventricular filling pressure at peak exercise was significantly greater in group II than in group I (p < 0.01). Totally asymptomatic silent myocardial ischemia can be seen with either normal or mildly abnormal left ventricular filling dynamics during exercise. In addition patients with coexistent left ventricular hypertrophy can have severely abnormal left ventricular filling dynamics during exercise without ischemic cardiac pains. Therefore, severe ischemia and/or stretching of the ventricular wall may be necessary, but not sufficient, for the occurrence of chest pain.