Early Detection of Diastolic Dysfunction and the Role of Lifestyle Measures in Its Treatment

Introduction:

Diastolic dysfunction (DD) accounts for >50% of all heart failure (DHF) hospitalizations and this number is increasing with age, obesity and diabetes.

There are no proven treatments for DHF apart from blood pressure control.

Aim:

If diagnosed early, is this reversible with lifestyle changes; namely, aerobic exercise and weight reduction?

Methods:

We will screen veterans presenting to the medicine, cardiology and pulmonary services with dyspnea. We will perform echocardiography with Doppler which non-invasively measures cardiac filling and diastolic dysfunction. Treadmill exercise echo will be performed to quantify DD.

Bruce treadmill protocol description/ procedure: Exercise is performed on a treadmill. The test starts at 2.74 km/hr (1.7 mph) and at a gradient (or incline) of 10%. At three minute intervals the incline of the treadmill increases by 2%, and the speed increases as shown in the table below.

Stage Speed (mph) Gradient:

• 1.7 10
• 2.5 12
• 3.4 14
• 4.2 16
• 5.0 18
• 5.5 20
• 6.0 22
• 6.5 24
• 7.0 26
• 7.5 28

Subject exercise study:

For physical exercise to have a beneficial effect on cardiac function, we suggest the following:

• Type of Exercise
• Walking - outdoors or treadmill
• Running or jogging
• Cycling - outdoors or stationary

Duration of Exercise:

Initial 2-3 minute gradual warm-up period. Roughly 30 minutes of continuous exercise 5 times a week.

Finally a few minutes of gradual cool-down before terminating exercise.

Intensity of Exercise:

Target exercise at a "moderately significant exertion".

We will demonstrate what is adequate in the beginning and periodically throughout the 6 months of the study.

"Maximum age predicted heart rate (MPHR)" is calculated as 220 minus subject's age. Then we would like to sustain roughly about 70 to 85% of MPHR for 25-30 minutes.

"Successful" Exerciser: Subjects who are able to adhere to the required intensity and duration of exercise for the majority (about 75% or more) of the time; averaging 150 minutes/ week on self reporting.

Inclusion criteria

• Patients with dyspnea/shortness of breath
• Age 40-65 years of age
• Sedentary lifestyle (<150 minutes of exercise/week)
• Echocardiographic evidence of early diastolic dysfunction: mitral E/A <0.9, OR resting E/E' between 8-15 cm/s, OR post-exercise E/E' >13 cm/s.

Exclusion criteria

• Age <40 years or >65 years
• Coronary Artery Disease by angiography or evidence of ischemia on a stress test
• Systolic Dysfunction (LV Ejection fraction <50%)
• Congestive Heart Failure Functional Class III or IV
• Moderate to severe COPD (FEV <80% predicted)
• Moderate to severe valvular heart disease, except tricuspid regurgitation
• Inability to get heart rate >/= 85% of maximum predicted heart rate
• Uncontrolled hypertension (systolic BP>140mmHg, diastolic BP>90mmHg) despite medical therapy
• On echocardiogram, RV systolic pressure >60mmHg that suggests severe pulmonary hypertension
• On echocardiogram, left atrial size> 6.5 cm or left atrial volume > 35 ml/BSA