Early Diagnosis of Diastolic Dysfunction and Reliability of DSE in Detecting Stress Diastolic Dysfunction

Study Overview
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Brief Summary
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The heart becoming stiff due to increased fibrous tissue or decreased elasticity of the heart tissue is one of the earliest changes caused by heart failure. These changes can be detected by simple non-invasive echocardiogram techniques. However, these techniques usually detect the increased stiffness of the heart only after it has progressed to a significant extent. The investigators hypothesize that if they stress the heart using a Dobutamine infusion and measure the filling pressure using echocardiogram, it will provide them with tools to identify these changes earlier.

Detailed Description
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The heart becoming stiff due to increased fibrous tissue or decreased elasticity of the heart tissue is one of the earliest changes caused by heart failure. These changes can be detected by simple non-invasive echocardiogram techniques. However, these techniques usually detect the increased stiffness of the heart only after it has progressed to a significant extent. The investigators hypothesize that if they stress the heart using a Dobutamine infusion and measure the filling pressure using echocardiogram, it will provide them with tools to identify these changes earlier. The investigators are planning to include people have normal heart function. It is standard procedure to measure cardiac pressure during catheterization. Simultaneously, the investigators will infuse Dobutamine (standard drug used for chemical stress testing, DSE). This drug increases the heart rate and mimics exercise in normal humans who are unable to exercise for various reasons. The investigators would continue to monitor the pressure inside the heart as they infuse Dobutamine and see of there is an increase in filling pressure. The investigators will correlate the invasive pressures with their echo derived measurements. The investigators plan to include 25 veterans in this study. For each individual the study would increase the amount of time they will spend in the Catheterization Lab from 30 to 120 minutes. The entire procedure will be monitored by Advanced Cardiac Life Support (ACLS) certified nurses and doctors.

Official Title
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Early Diagnosis of Diastolic Dysfunction and Reliability of Dobutamine Stress Echo (DSE) in Detecting Stress Diastolic Dysfunction

Conditions
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Diastolic Dysfunction

Intervention / Treatment
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* Drug: Dobutamine stress echo (DSE)
* Drug: Atropine bolus


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Prospectively enroll 25 veterans age range from 18 to 65 who are found to have normal left ventricular (LV) systolic function and no significant coronary artery disease by cardiac catheterization. Subjects identified during routine cardiac testing to have significant diastolic dysfunction may also be enrolled to rule out coronary disease and study DSE -invasive pressure correlations. Exclusion criteria: Patients with LV systolic dysfunction, severe coronary lesions (> 50%), uncontrolled hypertension (BP > 160/100) and significant pulmonary hypertension (PASP > 50 mmHg) would be excluded. Subject will not be included if they have a significant rhythm abnormality, frequent premature ventricular complexes, atrial fibrillation and technical reasons in the catheterization laboratory which preclude the study protocol.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Dobutamine stress echo (DSE)<br>Dobutamine intravenous infusion would be undertaken starting at 10 micrograms/kg per minute in three minute intervals increased to 20, 30, 40 or 50 micrograms/kg per minute or to a peak heart rate response of at least 85% age predicted maximum heart rate. If at the end of the Dobutamine protocol, there is inadequate heart rate response, intravenous atropine boluses of 0.5 milligrams (maximum 1.0 mg) would be used as needed to achieve a heart rate of at least 85% of age predicted maximum heart rate. | Drug: Dobutamine stress echo (DSE)<br>* Dobutamine intravenous infusion would be undertaken starting at 10 micro-grams/kg per minute in three minute intervals increased to 20, 30, 40 or 50 micro-grams/kg per minute or to a peak heart rate response of at least 85% age predicted maximum heart rate.<br>* Other names: Dobutamine hydrochloride;Drug: Atropine bolus<br>* If at the end of the Dobutamine protocol, there is inadequate heart rate response, intravenous atropine boluses of 0.5 milligrams (maximum 1.0 mg) would be used as needed to achieve a heart rate of at least 85% of age predicted maximum heart rate.<br>* Other names: Atropine sulfate;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Left Ventricle Mean Diastolic Pressure | Left ventricle filling pressures were measured using a pigtail catheter inserted into the left ventricle. Measurements of left ventricle pressures were taken at baseline, 3 minutes, 6 minutes, 9 minutes, 12 minutes, and recovery. Change from baseline at recovery reported. | Baseline, recovery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Early Transmitral Velocity/Early Lateral Mitral Velocity (E/E') | Echocardiography was performed at rest and with dobutamine stress at 3 minutes, 6 minutes, 9 minutes, and 12 minutes, to measure differences in E/E' at the septum and lateral mitral annulus. Change from baseline at recovery reported. | Baseline, recovery |