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Title: Ethnic differences in cardiac adaptation to exercise
Author: Rawlins, John
Awarding Body: King's College London (University of London)
Current Institution: King's College London (University of London)
Date of Award: 2013
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Regular participation in intense physical activity induces characteristic physiological ECG and echocardiographic changes. These are well described in Caucasian athletes (WA). Male black athletes (MBAs) demonstrate a higher prevalence of repolarisation anomalies and a greater maximal left ventricular wall thickness (mLVWT). The longitudinal significance of this is unclear. There is no published data on female black athletes (FBAs). Methods Between 1996 and 2010, 1144 elite BAs (21% female) underwent a standard pre-participation screen, including a 12-lead EGG and 2-D trans-thoracic echocardiogram. These were compared with 2059 similar WAs (12% female), 259 sedentary black controls (BCs; 54% female), and 52 black patients with hypertrophic cardiomyopathy (HCM). Any healthy subject exhibiting a mLVWT of >11mm (females) or >13mm (males), underwent comprehensive examination to look for phenotypic features of HCM. Male athletes were followed up for 69.7±29.6 months. Results BAs demonstrated a greater mLVWT (Females 9.2±1.2mm vs. 8.6±1.2mm, P<0.001: Males 10.6 ±1.6mm vs. 10.0±1.2, P<0.001) than WA and BC subjects. Eight FBA (3%) exhibited a mLVWT >11mm (12 to 13mm) compared with none of the FWA. T wave inversions (TWI) were present in 82.7% of HCM patients, 22.8% MBAs, 14% FBAs, 10.1% BCs, 3.7% MWA and 2% FWA (P<0.001). The major determinant of TWI in healthy subjects was black ethnicity. In BAs, TWI were confined predominately to the anterior leads (V1-4). Anterior TWI were infrequent amongst BCs (4.2%) and HCM patients (3.8%). TWI in the lateral leads were frequently seen amongst HCM patients(79.6%), but rare in all healthy individuals. During follow-up, one MBA survived a cardiac arrest, and two athletes (one MBA and one MWA) were diagnosed with HCM. Conclusion: Systematic physical exercise in BAs is associated with greater LV hypertrophy and higher prevalence of TWI than in similar WAs. However, a mLVWT >13mm (females) or >16mm (males) or deep TWI in the inferior/lateral leads are rare and warrant investigation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available