Related Experiment Videos
Hemodynamic changes during ventricular pacing in patients with complete heart block and aortic and mitral valvular
Insights
Increasing heart rate in complete heart block (CHB) patients with valvular disease can improve ventricular function. Pacing to near-normal rates benefits CHB patients with specific valve issues, aiding cardiac performance.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Cardiovascular Hemodynamics
Background:
- Complete heart block (CHB) often results in slow ventricular rates, impacting cardiac function.
- Valvular heart disease can further complicate cardiac performance in CHB patients.
- Ventricular function improvement is typically indicated by reduced left ventricular end-diastolic pressure (LVEDP) and volume, and increased contractility.
Purpose of the Study:
- To investigate the impact of increasing heart rate on ventricular function in CHB patients, particularly those with coexisting valvular heart disease.
- To compare hemodynamic responses to ventricular pacing in CHB patients with normal valves versus those with valvular lesions.
Main Methods:
- Hemodynamic studies were conducted on patients with CHB and valvular heart disease, as well as those with CHB and normal valves.
- Measurements were taken at slow, idioventricular rates and after increasing heart rate to near-normal levels via ventricular pacing.
- Key hemodynamic parameters including LVEDP, left atrial pressure, and ventricular stroke work were analyzed.
Main Results:
- In CHB patients with mitral stenosis, increased pacing heart rate normalized elevated LVEDP with minimal increase in left atrial pressure.
- In CHB patients with aortic stenosis, pacing improved cardiac function primarily through LVEDP reduction, though left ventricular stroke work decreased.
- In CHB patients with aortic insufficiency, pacing normalized elevated ventricular filling pressures and reduced regurgitant stroke volume.
Conclusions:
- Increasing heart rate via ventricular pacing can significantly benefit CHB patients with valvular lesions that increase LVEDP and end-diastolic volume.
- The specific valvular lesion influences the hemodynamic response to heart rate augmentation in CHB patients.
- Hemodynamic evaluation is crucial for tailoring pacing therapy in CHB patients with coexisting valvular heart disease.
Abstract:
Increasing the heart rate to near normal in patients with complete heart block (CHB) and slow ventricular rates may lead to greater improvement in ventricular function than when the heart rate is increased from normal to more rapid heart rates. Improvement in ventricular function is usually manifested by a decrease in left ventricular end-diastolic pressure (LVEDP) and volume and by an increase in contractility. In patients with both CHB and valvular heart disease improvement in ventricular function during pacing may be modified by the nature of the valvular disease. Hemodynamic data from six patients with both valvular heart disease and CHB were compared with those from ten patients with CHB and normal cardiac valves. Hemodynamic studies were performed at slow or idioventricular rates and again after increasing the heart rate to more nearly normal levels by ventricular pacing. When obstruction to left ventricular inflow (mitral stenosis) co-existed with CHB, increasing the heart rate resulted in a reduction of an elevated LVEDP to normal. This resulted in only a small increase in left atrial pressure in spite of a striking increase in the mean left atrial-ventricular gradient. When obstruction to left ventricular outflow prevailed (aortic stenosis), improvement in cardiac function was manifested mainly by a decrease in LVEDP and was accompanied by a decrease in left ventricular stroke work. When a large regurgitant volume (aortic insufficiency) was added to a ventricle which has enlarged subsequent to CHB, there was striking elevation in ventricular filling pressures which returned to more nearly normal levels when the heart rate was increased. This was accompanied by a reduction in regurgitant stroke volume in the patient in whom it was measured. Thus, an increase in heart rate may be especially beneficial to those patients with CHB who also have valvular lesions which contribute to an increase in LVEDP and end-diastolic volume. Careful hemodynamic evaluation is helpful in determining appropriate therapy in these patients.