@afm

My EP doc ordered 30 day Holter four years ago, and it showed occasional AFib. My AFib occurs at a lower heart rate and I don't have symptoms. I was prescribed Flecainide to use for an AFib episode and Eliquis. My symptoms still continued with and without exercise. I self referred myself to Mayo Cardiology for a complete evaluation. My Echocardiogram showed normal ejection fraction, tricuspid valve regurgitation, mild pulmonary hypertension, VO2 max test was average for my age, but I went into AFib sitting in the lobby after the test. My Cardiologist said the only way to tell what was going on with my heart was to have an invasive right Heart Catheterization with exercise. I was fortunate that Dr Barry Borlaug, a world expert in heart failure, was available to perform the invasive test. The test measured my oxygen and CO2 levels, pressures in my heart during exercise on a supine bicycle where the work load was increased until I could no longer continue. My hemodynamics were normal at rest, but during exercise I dropped my oxygen level , and my wedge pressure increased. My diagnosis was a common type of heart failure called HFpEF. My Cardiologist explained I have type of diastolic heart failure, where the left ventricle is stiff and does not relax well enough to accept the normal flow of blood coming from the left atrium. There is no cure.

Heart failure is associated with AFib. This is why I have moderated my exercise intensity and all my heart values have stabilized. I still jog 5 miles indoors flat, and I keep my heart rate under 120 because I experience arrhythmias and dyspnea when my heart rate goes over 120.

Try purchasing an oximeter and check your oxygen and heart rate when hiking. A smart watch would be very helpful. I have an Apple Watch, Lookee Tech 2 lead ECG. and Oximeter. Both upload data to my Apple Watch. There are other reviews on Smart Watches and Oximeters on Mayo Connect.

The heart has a high demand for oxygen and oxygen levels generally need to be 88-90% or higher at all times. Mine will drop to lows of 82% at high altitudes or on a plane just sitting. I have a portable oxygen concentrator I carry with me when I travel. All my pulmonary function tests are normal.

Everyone is different. My brother is 78 and he has a different type of heart failure, no AFib, and his blood pressure and heart failure are controlled with meds. He does not have exercise restrictions and he continues to hike in the mountains as usual up to 10,000 feet.

I hope you get answers soon.