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Diastolic time in congestive heart failure
S E Meiler1, H Boudoulas, D V Unverferth
1Division of Cardiology, Ohio State University College of Medicine, Columbus.
Insights
In heart failure patients, diastolic perfusion time decreases significantly with faster heart rates, potentially worsening subendocardial blood flow and left ventricular dysfunction. This relationship is more pronounced compared to healthy individuals.
Area of Science:
- Cardiology
- Physiology
Background:
- Diastolic perfusion time is crucial for coronary blood flow and subendocardial perfusion.
- Subendocardial ischemia can worsen left ventricular dysfunction in congestive heart failure.
Purpose of the Study:
- To analyze diastolic perfusion time in relation to heart rate in patients with heart failure.
- To compare these relationships with normal control subjects.
Main Methods:
- Analysis of diastolic perfusion time and heart rate in 29 digitalized heart failure patients (group 1), 12 non-digitalized heart failure patients (group 2), and 58 normal controls.
- Statistical correlation analysis (negative exponential and logarithmic) and comparison of regression lines.
Main Results:
- Significant negative correlations between heart rate and diastolic time in both digitalized (r = -0.85) and non-digitalized (r = -0.95) heart failure groups, differing from normal controls.
- Increased diastolic time at 60 bpm (9% in group 1, 7% in group 2) and decreased diastolic time at 120 bpm (10% in both groups) compared to normal subjects.
- Regression lines intersected normal subjects' line at 98 bpm (group 1) and 93 bpm (group 2).
Conclusions:
- Diastolic perfusion time changes relative to heart rate are more pronounced in congestive heart failure.
- Faster heart rates in heart failure patients may impede subendocardial blood flow due to altered diastolic perfusion time dynamics.
Abstract:
Diastolic perfusion time is an important determinant of coronary blood flow and subendocardial perfusion. It has been proposed that subendocardial ischemia may exacerbate and perpetuate left ventricular dysfunction in congestive heart failure. Diastolic perfusion time in relation to heart rate was analyzed in 29 digitalized (group 1) and 12 nondigitalized patients (group 2) with heart failure and in 58 normal control subjects. In group 1 there was a strong negative exponential correlation (r = -0.85) and in group 2 a strong negative logarithmic correlation (r = -0.95) between heart rate and diastolic time; both regressions differed significantly from normal control. There was a 9% increase of diastolic time at a heart rate of 60 bpm in group 1 and a 7% increase in group 2 (both p less than 0.05) compared with normal subjects. The curves intersected the regression line of normal subjects at a heart rate of 98 bpm in group 1 and 93 bpm in group 2. At 120 bpm there was a 10% decrease in diastolic time for both groups with heart failure (both p less than 0.05). Changes in diastolic perfusion time relative to heart rate are more pronounced in congestive heart failure such that at faster heart rates this relationship may further impede subendocardial blood flow.