Dear patient

thanks for your health concerns. Given the history, the main thing that needs to be ruled out is cardiac disease as the pulmonologist indicates that pulmonary function tests are normal. The function of the pacemaker needs to be checked as sometimes inadequate settings can create what we call pacemaker syndrome with a weak heart muscle. Since the symptoms are exertional, the best course would be to reproduce them with exercise, on a treadmill or recumbent bike, and take a look at the heart with echocardiogram(ultrasound of the heart) to see how it reacts with stress

hope this brings some initial insight wish you the best

Dr Brenes Salazar MD
Cardiology
Mayo Clinic MN

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thank you for the additionsl information. there would be a couple of steps that we could have in mind for patients with similar concerns. If the heart ultrasound was performed at rest, it has very little value since we want to look for the changes with exercise. then, as i said an exercise stress echocardiogram would be in order. Another test that would be quite useful is a cardiopulmonary oxygen consumption test in which the patient exercises and you can see both the heart and lung response. If none of that workup is revealing the ultimate test is doing a right heart catheterization to check pressures and oxygen levels of the heart and lungs; even more, those same pressures can br measured as he exercises on a recumbent bike. Exercise induced pulmonary hypertension, exercise induced diastolic dysfunction are very incapacitating entities that only give subtle hints on badic testing and can be unmasked this way

hope that brings further guidance, yours truly

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