What Can Cause a Heart of Stone ?
I saw a 72-year-old distance runner in March 2016 for new onset atrial fibrillation. He was a reasonably good runner who had run a marathon (26.2 miles) in 3 hours and 27 minutes at age 50. I treated his atrial fibrillation with anticoagulation and pill-in-the-pocket diltiazem and flecainide for several years, but he ultimately underwent ablation with resolution of this arrhythmia.
Three years later he had a bike accident with a right rib fracture. He had a CT performed because his ascending aorta looked widened. The CT of the aorta was normal, but the CT showed extensive coronary artery calcification (CAC). A subsequent CAC score was enormously high at 2125.
We (1) and others (2) have reported increased CAC score in lifelong endurance athletes. The mechanism is not known but may relate to the observation that exercise acutely and transiently raises parathyroid hormone levels.(3) There are other possibilities including the possibility that the turbulence of increased heart rates during exercise accelerates the atherosclerotic process. (4) At any rate, just about everyone now agrees that endurance athletes have increased amounts of CAC, but the significance and their prognosis is unknown.
I scheduled an exercise stress test to make sure that he did not have ischemia. He was able to exercise into Bruce stage IV and to a heart rate of 155 bpm. He had 1 mm of ST segment depression but it resolved in 1 minute after exercise so I concluded it was a false positive test.
This man was still biking 50 miles 2–3 times per week and swimming the other days. But his lipids had never been bad, so I was concerned that his CAC score was higher than one would expect even for an endurance athlete. I obtained a calcium value which was 10.2 (nl=8.7–10.5) and a parathyroid hormone (PTH) level which was 64 (nl=14–64). His PTH should not be that high when the calcium was also high, so I referred him to endocrinology. The values were repeated on December 5, 2019 and were Ca = 9.5, PTH = 100. Parathyroid/thyroid imaging done in January with I 123 sodium iodide and technetium 99 sestamibi showed “excess sestamibi activity at the lower pole of the left lobe of the thyroid suggesting a parathyroid adenoma or hyperplasia”. He is scheduled for parathyroid surgery.
The points of this case are to think of hyperparathyroidism if CAC are higher than one would expect from hypercholesterolemia or exercise training alone. Also, I am a simple cardiologist, but if the Ca is high normal and the PTH is high normal, that is not right and requires more evaluation.
1. Aengevaeren VL, Mosterd A, Braber TL, et al. Relationship between lifelong exercise volume and coronary atherosclerosis in athletes. Circulation. 2017;136(2):138–148. doi: 10.1161/CIRCULATIONAHA.117.027834 [doi].
2. DeFina LF, Radford NB, Barlow CE, et al. Association of all-cause and cardiovascular mortality with high levels of physical activity and concurrent coronary artery calcification. JAMA Cardiol. 2019. doi: 10.1001/jamacardio.2018.4628 [doi].
3. Barry DW, Kohrt WM. Acute effects of 2 hours of moderate-intensity cycling on serum parathyroid hormone and calcium. Calcif Tissue Int. 2007;80(6):359–365. doi: 10.1007/s00223–007–9028-y [doi].
4. Lin J, DeLuca JR, Lu MT, et al. Extreme endurance exercise and progressive coronary artery disease. J Am Coll Cardiol. 2017;70(2):293–295. doi: S0735–1097(17)37339–4 [pii].
