Leg workouts may unlock a hidden cause of exercise intolerance in common heart failure

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

All subjects will be \>65 years of age. The controls will be screened carefully for hypertension and cardiac disease, including structural heart and hemodynamically significant obstructive coronary disease, using a history, physical examination, and resting and post-exercise transthoracic echocardiograms. Additional exclusion criteria for this group will include valvular heart disease, atrial flutter/ fibrillation, renal insufficiency, chronic lung disease, regular cigarette smoking within the past 10 years, and cardiovascular medication. Subjects demonstrating greater than moderate levels of activity \> 2 days per week will not be allowed to participate, as chronic high levels of physical activity could potentially impact the primary outcome variables. * HFpEF Inclusion Criteria: * Patients will be \> 65 years old * We will use a modification of the European Guidelines for the diagnosis of HFpEF to select the patient population. * The key components of these guidelines include: * signs and symptoms of heart failure; * b) an ejection fraction \> 0.50; and * c) objective evidence of diastolic dysfunction. To satisfy the first criteria, we will use the Framingham criteria (dyspnea, orthopnea, PND, edema); however we will require objective evidence of congestion including * chest X-ray, * elevated BNP, * or elevated PCWP (pulmonary capillary wedge pressure) or * LVEDP (left ventricular end-diastolic pressure) \> 16 mmHg; for the second, we will accept echo, nuclear or catheter documentation; and for * we will require a depressed tissue Doppler mitral annular velocity \< 7.5 cm/s along with PCWP \> 16 mmHg if available. HFpEF Exclusion Criteria: * underlying valvular or congenital heart disease; * restrictive or infiltrative cardiomyopathy; * acute myocarditis; * NYHA Class IV CHF, or CHF that cannot be stabilized on medical therapy; * other condition that would limit the patient's ability to complete the protocol; * manifest ischemic heart disease. * Patients with CABG or previous history of atrial fibrillation will be allowed to participate, though for safety reasons, patients on Coumadin will be excluded. * All patients must be in sinus rhythm without a left bundle branch block at the time of study, and be off beta blockers or non-dihydropyridine Ca++ blockers for at least 5 half-lives. β blockers will be weaned over 3-5 days and additional doses of vasodilators added to control blood pressure if necessary. Drugs that affect the renin-angiotensin-aldosterone system and diuretics will be maintained.