Heart Care Info - Heart Disease Prevention & Treatment

Phidippides Cardiomyopathy: A Review and Case Illustration

JE Trivax, PA Mc Cullough - Clinical Cardiology - Wiley Online Library Phidippides was a Greek messenger who experienced sudden death after running more than 175 miles in two days. In today's world, marathon running and other endurance sports are becoming more popular and raising concern about sudden deaths at these events. ...

Some marathon runners train for years, whereas many others train for 18 to 20 weeks as advised on the Internet or in many widely available books. Marathon training differs drastically among participants in regard to days per week, miles per week, and recovery periods. As a result, marathon runners have different levels of fitness at baseline for the race. Despite different training regimens and fitness levels, in all cases the heart faces increased pressure and volume overload and responds by increasing left ventricular chamber size, thickness, and mass. Running a marathon initiates multiple events within one's body for cardiac injury, including increased release of catecholamines and resultant coronary vasoconstriction, increased heart rate leading to decreased diastolic filling time of the coronary arteries, increased demand for oxygen, changes in free fatty acid metabolism, lactic acidosis, and metabolic derangements.11 During the event, in susceptible individuals the heart is unable to keep up with the demands of marathon running and increasing right heart preload and afterload, and begins to dilate and stretch in response to these hemodynamic changes.12 These changes may be more pronounced in those with less training.13 Right heart dilation and hypokinesis after prolonged strenuous exercise has been observed using cardiac magnetic resonance imaging.8,14 Diastolic dysfunction is frequently observed in both younger and older athletes.15 Multiple cardiac biomarkers are released, including myoglobin, cardiac troponin I, creatine kinase, and creatine kinase myocardial band, and B type natriuretic peptide.16 Volume depletion and reduced renal filtration occurs with elevated blood urea nitrogen, serum creatinine, and cystatin C.17 During the recovery period after the marathon, the cardiac geometric dimensions are restored, and many athletes continue this cycle with training, marathon running, cardiac disturbances, and again cardiac recovery. With this repetitive stretch of the chambers and restoration of the chamber geometry, we believe there are individuals prone to developing chronic structural changes, including chamber dilation and myocardial fibrosis, as a response to the repetitive volume overload and dynamic strain of the heart.18 Approximately one third of individuals after a marathon, irrespective of baseline factors, speed, or conditioning, will have a rise and fall of cardiac troponin and B type natriuretic peptide.8 It is unclear whether this group, in particular, will go on to develop patches of cardiac fibrosis. These changes are asymptomatic and probably occur over many years. However, in those who experience ventricular arrhythmias and/or sudden cardiac death there is this lethal disorder, Phidippides cardiomyopathy. Thus, it is rational to develop risk prediction and screening methods for this disorder to allow counseling for individuals who are considering endurance sports such as marathon running.