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Diastolic filling in acute left ventricular dysfunction: role of the pericardium
S J Lavine1, C A Campbell, R A Kloner
1Division of Cardiology, Harper Hospital, Wayne State University, Detroit, Michigan.
Insights
Congestive heart failure alters diastolic filling patterns, mimicking constrictive pericarditis. Ischemic left ventricular dysfunction in dogs showed altered filling dynamics, not influenced by pericardiectomy.
Area of Science:
- Cardiology
- Physiology
- Experimental Medicine
Background:
- Patients with congestive heart failure (CHF) and elevated left ventricular filling pressures exhibit abnormal diastolic filling patterns.
- This abnormal pattern, characterized by early diastolic filling redistribution, superficially resembles constrictive pericarditis.
- The underlying mechanisms for these observed diastolic filling changes in CHF require elucidation.
Purpose of the Study:
- To investigate the mechanisms behind abnormal diastolic filling patterns in ischemic left ventricular dysfunction.
- To compare diastolic filling characteristics in a canine model of CHF with those seen in constrictive pericarditis.
Main Methods:
- A canine model of ischemic left ventricular dysfunction was created using repeated coronary microsphere embolization.
- Measurements included left ventricular pressures (systolic, end-diastolic, dP/dt), echocardiographic areas, and diastolic filling fractions.
- Data were collected at baseline, during progressive embolization, and after thoracotomy and pericardiectomy.
Main Results:
- Coronary microembolization led to progressive left ventricular dilation and reduced systolic function.
- Diastolic filling fractions at 1/3 and 1/2 of diastole initially declined but significantly increased after embolization.
- These filling pattern changes were independent of thoracotomy or pericardiectomy.
Conclusions:
- Ischemic left ventricular dysfunction significantly alters diastolic filling dynamics, characterized by a shift towards earlier filling.
- The observed diastolic filling abnormalities in this CHF model are intrinsic to left ventricular dysfunction, not extrinsic pericardial effects.
- This study provides insights into the mechanisms of diastolic dysfunction in heart failure.
Abstract:
Patients with congestive heart failure and elevated left ventricular filling pressures demonstrate an abnormal pattern of diastolic filling that is characterized by a redistribution of diastolic filling to early diastole with reduced reliance on late diastolic filling. The diastolic filling pattern superficially resembles that which is seen with constrictive pericarditis. To examine potential mechanisms for these clinical findings, a model of ischemic left ventricular dysfunction was produced in seven dogs by repeated coronary microsphere embolization, producing a dilated left ventricle with reduced systolic function. Measurements of left ventricular systolic and end-diastolic pressures, rate of rise of left ventricular pressure (dP/dt) and echocardiographic end-diastolic and end-systolic areas were obtained at baseline, during intermediate embolization (moderate left ventricular systolic dysfunction, dilation and mild increases in left ventricular end-diastolic pressure), postembolization (further embolization resulting in severe left ventricular systolic dysfunction, dilation and marked increases in left ventricular end-diastolic pressure), after thoracotomy and after pericardiectomy. The filling fraction at 1/3 and 1/2 of diastole and the time constant of left ventricular pressure decline were also determined. Repetitive coronary microembolization caused progressive left ventricular dilation and decreasing systolic function, which did not change after opening the chest or pericardium. The filling fraction at 1/3 and 1/2 of diastole declined with intermediate embolization (12.0 +/- 5.6% and 23.1 +/- 10.8%, respectively) as compared with baseline values (29.0 +/- 11.9%, 42.9 +/- 15.6%, p less than 0.05). After embolization, there was an increase in the 1/3 and the 1/2 filling fraction (47.5 +/- 8.9%, 72.0 +/- 6.0%, respectively, p less than 0.01) as compared with baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)