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In his latest column, Dr. Paul Thompson offers perspective on the diagnosis and potential overdiagnosis of non-compaction cardiomyopathy in athletes.
Cardiac non-compaction (NC) can produce a form of cardiomyopathy (CM) typified by deep invaginations of the myocardium caused by an arrest of normal myocardial morphogenesis. NCCM was considered to be rare, but is increasingly diagnosed because of the widespread use of cardiac imaging. Patients with NCCM can present with syncope and systemic emboli believed to originate from clotting in the myocardial invaginations.1
Sports cardiologists have suspected that athletes, especially black athletes, have an increased prevalence of imaging evidence of NCCM, but data confirming such a relationship were lacking. De la Chica and colleagues2 evaluated the relationship between physical activity (PA) and the imaging criteria for NCCM in 705 men and women in the Spanish Progression of Early Subclinical Atherosclerosis study (PESA). PA was measured using accelerometry, the gold standard for PA assessment. LV geometry was assessed using cardiac MR.
The diagnosis of NCCM was determined using the Petersen, Jacquier, Grothoff, and Stacey clinical scoring criteria. 1PA was divided into 6 activity groups from the least (0) to the most (5) active. Some of the subjects were very active, but the population was not a population of athletes. The prevalence of NCCM using the most permissive diagnostic criteria (Petersen) was significantly higher in the most active group (30 & 14% in PA group 5 vs 0, respectively).
The prevalence of NCCN was also significantly higher in the most active group using the middle 2 diagnostic criteria (Jacquier & Grothoff), but not different between groups using the most stringent criteria (Stacey). This confirms the clinical impression that more active subjects meet the imaging criteria for NCCM more frequently than the general population. These results should help prevent clinicians from diagnosing NCCM in athletes without supporting data such as a family history of cardiomyopathy, a reduced ejection fraction, or decreased exercise capacity. I have found that athletes can have the excrescences and pits suggestive of NCCM, but that the wall thickness is normal under the “non-compacted” area. In contrast, true NCCM often has wall thinning below the truly non-compacted segment.
Black athletes appear to have more highly trabeculated left ventricles making them more vulnerable to over-diagnosis3 and seem to have the appearance of non-compaction more frequently than whites. I have seen several athletes over my career who were diagnosed with NCCM based on imaging criteria alone and restricted from sports because of the diagnosis. This is never an easy decision, but clinicians should strongly consider the possibility that non-compaction in a healthy athlete, especially a healthy black athlete, is an abnormal image, but not necessarily a disease unless there is other supporting clinical evidence.
One of the most important tenets of medicine is “Do no harm”.An important corollary is “Do not over-diagnose” because it can cause harm. 3