Conditions: Diastolic Dysfunction
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 16
Healthy volunteers: yes

Brief summary:
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:
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.

Arms:
arm 1: 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.

Interventions: intervention 1: Dobutamine stress echo (DSE) intervention 2: Atropine bolus
Intervention descriptions: intervention 1: 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. intervention 2: 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.

Protocol document: