Doctors are trained to identify cardiac murmurs and to make a judgement about whether these are benign, or whether they signify underlying heart disease. The study profiled in this edition of the FastFact aims to determine whether this assessment has any value by reviewing pre-competition medical assessment (PMCA) findings in 15141 student-athletes.1
A retrospective analysis of 15 141 adolescents aged 12–19 who had received a pre-competition medical assessment (including a history, examination and ECG) was performed. Participants who had an abnormality found during this assessment also underwent an echocardiogram. Cardiac auscultation was conducted with the participant standing, supine, and supine with Valsalva. When a murmur was detected, clinicians classified these as being either physiological or pathological. Pathological murmurs were characterised as being grade 3/6 systolic or greater, of harsh character, those that increased with Valsalva, any diastolic murmur, radiating, click/gallop/splitting, crescendo–decrescendo or holosystolic. Participants with murmurs were compared with a comparison group without murmurs. The primary outcome was echocardiogram-detected structural heart disease associated with sudden cardiac death (SCD).
A total of 905 participants were found to have a cardiac murmur (mean age 15.8; 58% male). This group was compared to a control (no murmur found) group of 4333 participants (mean age 15.8; 55% male). Of those with a murmur, 743 (82%) murmurs were described as physiological and 162 (18%) as pathological. Twenty-five (2.8%) participants with murmurs and 61 (1.4%) participants without murmurs were subsequently found to have evidence of structural heart disease on echocardiogram. The majority of these patients had relatively minor abnormalities. For example, the most common finding was a bicuspid aortic valve. Only three (0.3%) participants in the murmur group were diagnosed with a condition associated with SCD (hypertrophic cardiomyopathy). Of these, two participants had physiological murmurs, one had a pathological murmur. It should be noted that all three of these patients had an abnormal ECG. The positive predictive value of physiological versus pathological murmurs for identifying any structural heart disease was 2.4% versus 4.3% (p=0.21), respectively. The positive predictive value of having any murmur versus no murmur for identifying structural heart disease was 2.8% versus 1.4% (p=0.003), respectively.
As the authors illustrate, this is the largest study that has investigating the accuracy of cardiac auscultation for the detection of structural heart disease in children or adolescents. It demonstrates that characterising a cardiac murmur as being either physiological or pathological does not help identify those at risk of SCD. In fact, the detection of a murmur (of any kind) had poor correlation with the presence of a structural abnormality. As a result, the study’s findings have some important implications for the PCMA. The authors suggest a practical algorithm for further assessment whereby clinicians should arrange an ECG whenever a murmur is detected. If the ECG is then abnormal further appropriate cardiac testing should then be arranged (as per current consensus guidelines).
As with most of the papers that are highlighted in our FastFacts this paper has not specifically investigated football players. It has also only included adolescents aged 12-19 years of age, based in one region of the United States. As a result, whether these results can be extrapolated to all football players is unknown.
1. Austin AV, Owens DS, Prutkin JM, et al. Do ‘pathologic’ cardiac murmurs in adolescents identify structural heart disease? An evaluation of 15 141 active adolescents for conditions that put them at risk of sudden cardiac death. British Journal of Sports Medicine Published Online First: 15 January 2021. doi: 10.1136/bjsports-2019-101718