I should preface all this by saying a few things: I have a history of infrequent episodes of heart palpitations that have since been determined to be a benign combination of isolated PACs and PVCs. I also occasionally have lightheaded spells, but do have high blood pressure, and the anxiety attacks, which most likely cover the cause of those. I am a collegiate athlete and in shape in every other way, but have always noticed that compared to other people with equal amounts of training as me I am way behind. (I am a 21 yr old male, who runs 50-70 miles per week with regular VO2 workouts with a 5k PR of 17:26). I also tend to have a much higher heart rate down at my easy jogging pace than most other people. (My recovery pace is like 8 flat-ish and it's like 180bpm, but I can race a 5:10 mile with a heart rate around 195-200, most people on my team recovery at their respective recovery paces down around 120-130 bpm).
Basically, after feeling some of those palpitations I went and got an echocardiogram (amongst other things) done. It showed that my LV diameter, wall thickness, and blood volume were all normal both diastolic and systolic. However, the EF% was a little on the low side for someone my age, with a 52% reading. My fractional shortening was also a little low down at 22%. Now, a couple of things have been suggested to me. One was that sometimes athletes have bigger, stronger hearts and that in order for my resting stroke volume to get down to everyone else’s level I would have to put out a lower EF%, which would go way farther up when running. But I don’t think this is the case because my diastolic volume is only at 117, which is actually not even at the average, let alone higher up. The other suggested explanation I’ve gotten from people is that my high blood pressure could be causing this. I’m not so sure this is it either, because it’s really just borderline high and if it really were the blood pressure I would think the toll it took on the heart through the years might have already produced other, far worse symptoms like an enlarged heart or thickened walls, but it didn’t.
Numbers from the echo: 4.9 cm diastolic diameter, 3.8cm systolic diameter, 22% FS, 117ml diastolic volume, 56.2 ml systolic volume, EF% 52, Stroke Volume 60.8, LVPW thickness .82cm, IVP thickness .88
So, my questions are the following:
-Can you have some form of systolic dysfunction without ending up with an enlarged heart or an EF% lower than 50?
-Could I have systolic dysfunction that is being controlled by my exercise, which is why I have been able to have an EF% in the low 50’s and no structural remodeling?
-Is systolic dysfunction even dangerous if it is not causing the EF to go any lower than this and not causing any restructuring in the heart?
-Can high blood pressure cause systolic dysfunction or just diastolic dysfunction?
-Why is my resting pulse rate still around 58 even though my heart is only getting 52% of its relatively low (117 diastolic) starting blood volume out with each beat? Doesn’t the body want/need to have a higher cardiac output?
-I’ve heard heart failure is largely progressive and comes in waves of episodic periods after periods of stability. Could it be that this is me and I’m just coming out of a wave of “stability,” or would such a period likely not have me at a point where I have no structural problems and an EF% of 52?
-Could this be a diastolic problem I might have, because I read that the average end diastolic volume is 163, so if I had that as my total instead of 117 and I had the same stroke volume of 60.8 my EF% would be 62 instead of 52? Is the reason my diastolic volume is lower because I cannot maintain my stroke volume if my heart weighed more (from more diastolic blood volume)? Could this be the body’s way of protecting itself, where it knows it can only produce a stroke volume in the normal range of 55-100 if the heart has a lower preload to begin with?
Again, I apologize that I am such a nervous person, but asking questions is just part of how I work through my anxiety and any answers provided, especially those from any doctors or cardiologists on here will be greatly appreciated. Thanks.