John Rawlins

Ethnic Differences in Physiological Cardiac Adaptation to Intense Physical Exercise in Highly Trained Female Athletes

Background— Ethnicity is an important determinant of cardiovascular adaptation in athletes. Studies in black male athletes reveal a higher prevalence of electric repolarization and left ventricular hypertrophy than observed in white males; these frequently overlap with those observed in cardiomyopathy and have important implications in the preparticipation cardiac screening era. There are no reports on cardiac adaptation in highly trained black females, who comprise an increasing population of elite competitors. Methods and Results— Between 2004 and 2009, 240 nationally ranked black female athletes (mean age 21±4.6 years old) underwent 12-lead ECG and 2-dimensional echocardiography. The results were compared with 200 white female athletes of similar age and size participating in similar sports. Black athletes demonstrated greater left ventricular wall thickness (9.2±1.2 versus 8.6±1.2 mm, P<0.001) and left ventricular mass (187.2±42 versus 172.3±42 g, P=0.008) than white athletes. Eight black athletes (3%) exhibited a left ventricular wall thickness >11 mm (12 to 13 mm) compared with none of the white athletes. All athletes revealed normal indices of systolic and diastolic function. Black athletes exhibited a higher prevalence of T-wave inversions (14% versus 2%, P<0.001) and ST-segment elevation (11% versus 1%, P<0.001) than white athletes. Deep T-wave inversions (−0.2 mV) were observed only in black athletes and were confined to the anterior leads (V1 through V3). Conclusions— Systematic physical exercise in black female athletes is associated with greater left ventricular hypertrophy and higher prevalence of repolarization changes than in white female athletes of similar age and size participating in identical sporting disciplines. However, a maximal left ventricular wall thickness >13 mm or deep T-wave inversions in the inferior and lateral leads are rare and warrant further investigation.

Left ventricular hypertrophy in athletes

Participation in regular intensive exercise is associated with a modest increase in left ventricular wall thickness (LVWT) and cavity size. The magnitude of these physiological changes is predominantly determined by a variety of demographic factors which include age, gender, size, ethnicity, and sporting discipline. A small minority of male athletes participating in sporting disciplines involving intensive isotonic and isometric exercise may exhibit substantial increases in cardiac size that overlap with the phenotypic manifestation of the cardiomyopathies. The most challenging clinical dilemma incorporates the differentiation between physiological left ventricular hypertrophy (LVH) (athletes heart) and hypertrophic cardiomyopathy (HCM), which is recognized as the commonest cause of non-traumatic exercise related sudden cardiac death in young (<35 years old) athletes. This review aims to highlight the distribution and physiological upper limits of LVWT in athletes, determinants of LVH in athletes, and echocardiographic methods of differentiating athletes heart from HCM.

PREVALENCE AND SIGNIFICANCE OF T-WAVE INVERSIONS IN PREDOMINANTLY CAUCASIAN ADOLESCENT ATHLETES

AIMS Athletic activity is associated with electrocardiographic T-wave inversions in some adults, resembling those observed in cardiomyopathy. The prevalence and significance of T-wave inversions in adolescent athletes, the group most vulnerable to exercise-related sudden death from cardiomyopathy, is unknown. METHODS AND RESULTS This study evaluated 1710 adolescent athletes and 400 healthy controls. Subjects with T-wave inversions underwent intensive cardiac investigations to identify a potential cause. There was no significant difference in the overall prevalence of T-wave inversions between athletes and controls (4 vs. 3%; P = 0.46). T-wave inversions in leads V1-V3 were largely confined to athletes and controls aged <16 years. Only 0.1% of athletes aged >or=16 years exhibited T-wave inversions beyond V2. T-wave inversions in the inferior and/or lateral leads and deep T-wave inversions occurred infrequently in athletes (1.5 and 0.8%, respectively) and were associated with a high prevalence of left ventricular hypertrophy or congenital cardiac anomalies. Despite intensive investigations, no athlete was diagnosed with a cardiomyopathy. CONCLUSIONS T-wave inversions in V1-V3 are relatively common in athletes <16 years and probably represent the juvenile electrocardiogram pattern. In adolescent athletes, T-wave inversions beyond V2 if >or=16 years, T-wave inversions in the inferior/lateral leads and deep T-wave inversions in any lead are unusual, warranting further investigations for underlying cardiomyopathy.

Cardiac adaptation to exercise in adolescent athletes of African ethnicity: an emergent elite athletic population

Background/aims Adult black athletes (BA) exhibit left ventricular hypertrophy (LVH) on echocardiography and marked ECG repolarisation changes resembling those observed in hypertrophic cardiomyopathy (HCM). Limited data are available for adolescent BA, the group most vulnerable to exercise-related sudden cardiac death. Methods Between 1996 and 2011, 245 male and 84 female adolescent BA from a wide variety of sporting disciplines underwent cardiac evaluation including ECG and echocardiography. Athletes exhibiting T-wave inversions and/or echocardiographic LVH were investigated further for quiescent cardiomyopathies. Results were compared with 903 adolescent white athletes (WA) and 134 adolescent sedentary black controls (BC). Results LVH on echocardiography was present in 7% of BA compared to only 0.6% of WA and none of the BC. In the very young (<16 years), 5.5% of BA, but none of the WA, demonstrated LVH. Within the BA group, LVH was more prevalent in men compared to women (9% vs 1.2%, p=0.012). T-wave inversions were present in 22.8% BA, 4.5% WA and 13.4% BC. T-wave inversions in BA occurred with similar frequency in men and women and were predominantly confined to leads V1–V4. T-wave inversions in the lateral leads, commonly associated with cardiomyopathies, were present in 2.4% of BA. On a further evaluation and mean follow-up of 8.3 years, none of the athletes exhibited HCM. Conclusions Athletic training has a pronounced effect on adolescent BA. Black athletes as young as 14 years of age may exhibit left ventricular wall thicknesses of 15 mm and marked repolarisation changes resembling HCM. Male and female BA demonstrate a high prevalence of T-wave inversions.

Coronary Artery Rupture Caused by Stent Infection A Rare Complication

A 62-year-old man with a history of hypertension was admitted with unstable angina. Three years earlier, he had presented with a non–ST-segment–elevation myocardial infarction and had undergone percutaneous coronary intervention with a paclitaxel-eluting stent (3.0×20 mm; Taxus, Boston Scientific, Boston, MA) to the proximal left anterior descending coronary artery (Figure 1A). His initial ECG was normal, and his biomarkers were not elevated. Eight hours into his admission, he became pyrexial and developed chest pain associated with transient anterior ST-segment elevation. Emergency coronary angiography demonstrated aneurysmal dilatation at the proximal edge of the previous stent (Figure 1B). Because he had normal flow (Thrombolysis in Myocardial Infarction grade 3), his pain had settled spontaneously, and there was no evidence of a left ventricular regional wall motion …

60 Ethnic differences in repolarisation patterns and left ventricular remodelling in highly trained male adolescent (14–18 years) athletes

Purpose Studies in adult, black athletes (BA) demonstrate a high prevalence of ECG repolarisation changes and echocardiographic left ventricular hypertrophy (LVH) that may overlap with hypertrophic cardiomyopathy (HCM). The prevalence of ECG repolarisation changes and echocardiographic LVH in adolescent BA, the group most vulnerable to exercise-related sudden death from HCM, is unknown. Methods This study evaluated 219 male adolescent BA (14–18 years, inclusive) with 12-lead ECG and 2-D echocardiography. Results were compared with 1440 male adolescent WA. Athletes with T wave inversions and morphological LVH were invited for further investigation with exercise stress test, 24 h Holter and CMR. Results ST segment elevation was common in both groups but more frequent in BA (63.5% vs 14.9%, p<0.001), while ST segment depression was exceedingly rare. Both T wave inversions (21.5% vs 2.9%, p<0.001) and deep T wave inversions (11% vs 0.3%, p<0.001) were commoner in BA. Black athletes demonstrated greater left ventricular wall thickness (10.4±1.6 vs 9.4±1.2 mm, p<0.001) compared to WA. Twenty-three (10.5%) BA exhibited a left ventricular wall thickness >12 mm vs only 6 (0.4%) WA (p<0.001). None of the athletes exhibited the broader phenotype of HCM on further investigation. In multivariable analysis black ethnicity was the strongest independent predictor for the presence of T wave inversions (OR 3.56, 95% CI 1.56 to 8.13, p=0.003) and LVH (OR 3.17, 95% CI 1.77 to 5.71, p<0.001). Conclusions As with adult athletes, T wave inversions and LVH were more prevalent in adolescent BA compared to WA. These findings have important implications in the pre-participation screening era, particularly in countries with a high proportion of BA competing at elite level, since extrapolation of ECG and echocardiographic criteria, solely derived from Caucasian cohorts, would result in 25.6% of BA requiring further investigations for cardiac pathology.Abstract 60 Figure 1 Bar chart depicting the distribution of left ventricular wall thickness in black and white adolescent athletes.

49 Ethnic variation in QT interval among highly trained athletes

Background Studies in Caucasian (white) athletes indicate that a significant proportion exhibit an isolated prolonged corrected QT interval (QTc), raising concerns for potentially false diagnoses and disqualification from competitive sport. The prevalence of prolonged QTc interval in athletes of African/Afro-Caribbean (black) descent is unknown. However, this ethnic group generally exhibits a high proportion of ECG repolarisation changes and increased left ventricular wall thickness, that may impact on QTc. Aim We aimed to assess the impact of ethnicity on QTc in young elite athletes. Methods We assessed 3035 elite athletes, aged 14–35 years, who were participating at national and international level in a variety of sporting disciplines. Athletes were evaluated with ECG and 2D echocardiography. Athletes diagnosed with structural heart disease or hypertension were excluded from analysis. Results Demographic and cardiological results are summarised in Abstract 49 table 1. Black male athletes exhibited shorter QTc than white male athletes, but QTc was similar among black and white female athletes. Bivariate analysis revealed that none of T wave inversions, ST segment elevation, or left ventricular wall thickness were associated with QTc. No ethnic difference was observed in prevalence of QT prolongation, as defined by ESC Sports Consensus criteria (male >440 ms; female >460 ms).Abstract 49 Table 1 Characteristics of athletes evaluated Black Male (n=901) White Male (n=1652) Black Female (n=122) White Female (n=360) Mean Age, years 22±5 17±4 21±5 18±4 Mean Heart Rate, bpm 61±12 56±10 63±10 59±9 Mean QRS duration, ms 88±14 96±10 84±10 88±9 Mean LV wall thickness, mm 10.6±1.6 9.4*±1.2 9.2±1.2 7.9*±2.9 ST segment elevation, n (%) 570 (63.3%) 406 (24.6%) 20 (16.3%) 64 (17.8%) T wave inversions, n (%) 204 (22.6%) 66* (4.0%) 18 (14.6%) 15* (4.2%) Mean QTc (Bazetts), ms 393±26 404*±20 407±25 412±27 QTc >440 ms, n (%) 20 (2.2%) 49 (3.0%) 13 (10.6%) 39 (10.9%) QTc >460 ms, n (%) 4 (0.4%) 7 (0.4%) 1 (0.8%) 5 (1.4%) Means presented as mean ± SD.* p<0.001 white vs black athletes. Conclusion Despite demonstrating a higher prevalence of repolarisation changes and morphological left ventricular hypertrophy, black athletes do not exhibit a longer QTc than white counterparts. Based on ESC Sports Consensus criteria, prevalence of a long QTc in black and white athletes is similar, obviating the need for ethnicity specific criteria for defining a long QTc.

059 Relationship between exercise related blood pressure response and differences in magnitude of left ventricular hypertrophy between African/Afro-Caribbean (black) athletes and Caucasian athletes

Purpose Participation in regular physical exercise is associated with a greater magnitude of left ventricular hypertrophy in male athletes of African/Afro-Caribbean origin (black athletes) compared with athletes of Caucasian origin of similar age and size, participating in similar exercise disciplines. The precise genetic, biochemical and physiological mechanisms for these differences is unknown. However, the role of exercise related blood pressure response as a determinant of exercise induced left ventricular hypertrophy has not been investigated. Aim The study sought to investigate whether there were differences in exercise related blood pressure response in black athletes and Caucasian athletes. Method Between 2004 and 2007, 300 black athletes and 300 whites athletes (mean age 20±5 years) participating at regional or national level underwent echocardiographic evaluation. Of these 54 black athletes (18%) and 12 white athletes (4%) exhibited a LV wall thickness >12 mm indicating LVH. Black and Caucasian athletes with left ventricular hypertrophy of >12 mm were subject to exercise stress testing with simultaneous blood pressure recording using the Bruce protocol. All athletes were exercised to the point of volitional exhaustion. Results Black athletes exhibited a greater mean left ventricular wall thickness compared with white athletes (11.3±1 mm; range 13–16 mm v. 10±1.5 mm; range 13–14 mm: p<0.0001). The blood pressure responses to exercise are tabulated below (Abstract 59 Table 1). There were no significant differences in blood pressure response to exercise between black athletes and white athletes. Abstract 59 Table 1 Shows the comparison in mean systolic BP response to different stages of the Bruce stress test in black athletes and white athletes Stages of Bruce exercise stress test Mean systolic BP (mmHg) (black athletes, N=54) Mean systolic BP (mmHg) (white athletes, N=12) p Value Resting BP 112±7.2 110±8 Non-significant Stage 1 126±10.1 130±12.4 Non-significant Stage 2 141±9.8 147±12.6 Non-significant Stage 3 160±12.4 155±11 Non-significant Stage 4 178±9.3 172±11.5 Non-significant Stage 5 189±18.4 183±15.8 Non-significant Conclusion The greater magnitude of left ventricular hypertrophy in blacks is not explained by a difference in exercise related blood pressure response.

113 Cardiocascular screening for sinister cardiac disorders in non-athletic young individuals using a mobile cardiac screening unit

Objectives The vast majority of sudden cardiac deaths (SCD) in young individuals occur in the absence of antecedent symptoms. Most deaths are due to hereditary or congenital cardiac abnormalities which can be diagnosed during life and therapeutic interventions are available to minimise the risk of SCD. In most Western countries screening of competitive athletes is supported by numerous sporting governing bodies. However, in the non-athletic population screening is confined only to those individuals with cardiovascular symptoms in the context of a family history of premature cardiac disease. Based on this strategy, most non-athletic individuals at risk of SCD would not be identified. In this study we assessed the impact of screening on the health service. Methods Over a 3-month period 2671 subjects (mean age 18.8 years; range 14–35 years) were screened with a health questionnaire (HQ), and 12-lead electrocardiography (ECG). Screening was performed using a mobile trailer equipped with ECG and echocardiography machines and manned by cardiac physiologists and a cardiologist. The HQ related to symptoms suggestive of cardiovascular disease and a family history of premature SCD. ECGs were analysed by skilled cardiologists in accordance with the ESC sports cardiology consensus. Individuals with abnormalities on the HQ and/or ECG were investigated further with echocardiography performed on site. Individuals warranting further investigation even after this were referred for 24 h Holter monitoring and exercise stress testing. Results Of the total 2671 individuals screened, 2415 (90.4%) had an entirely normal ECG with the remaining 256 (9.6%) requiring on site echocardiography. A further 163 individuals (6.1%) were reassured following echocardiography. Thus a total of 96.5% of all individuals screened were able to leave the mobile cardiac screening unit reassured that no cardiac disorder could be identified in one visit. Only 93 individuals (3.5%) required further investigation after ECG and echocardiography. Preliminary screening identified 16 individuals (0.59%) with cardiac disorders which could prove potentially fatal in five individuals (0.19%) (Brugada ECG pattern: n=2; Wolff-Parkinson-White: n=1; hypertrophic cardiomyopathy: n=1; right ventricular outflow tract ventricular tachycardia (RVOT-VT): n=1). Conclusions Extrapolation of this data suggests large scale screening of non-athletic individuals (even in an expert setting) would be associated with a significant number of individuals (3.5%) requiring further investigation even after ECG and echocardiography. However, a huge proportion of individuals screened (96.5%) can be reassured in one visit. This is of particular relevance when considering that these individuals subsequently do not require primary and/or secondary care review.

114 The prevalence of ECG abnormalities in young non-athletic individuals raises concerns regarding implementation of a nationwide screening program:

Objectives Pre-participation screening of competitive athletes, combining 12-lead ECG with a health questionnaire and physical examination, has been demonstrated to reduce the incidence of sudden cardiac death (SCD) over a long term follow up period. Paradoxically, the vast majority of SCD occur in the non-athletic population and in the absence of antecedent symptoms. In the UK, screening for sinister cardiac disorders is confined only to those individuals with symptoms, or in the context of a family history of premature cardiac disease. In this study we analysed the prevalence of ECG abnormalities in young non-athletic individuals. Methods Between April 2006 and November 2009, 2619 subjects (mean age 18.3 years; range 14–35; 80% male) were investigated with a health questionnaire and 12-lead ECG. The questionnaire related to symptoms suggestive of cardiovascular disease and a family history of premature cardiovascular disease and/or SCD. The 12-lead ECGs were analysed for specific abnormalities as described in the European Society of Cardiology sports cardiology consensus. Specific criteria for an abnormal ECG analysed include P wave abnormalities suggesting left or right atrial enlargement; QRS abnormalities suggesting left ventricular hypertrophy, interventricular conduction delay and frontal plane axis deviation; and ST segment depression and T wave flattening or inversion. Results Of the 2619 individuals investigated a total of 505 (19.3%) individuals demonstrated one or more abnormalities on the 12-lead ECG. The abnormal findings are summarised in the table below: Number of individuals Percentage of individuals (%) Isolated LA enlargement 47 1.8 Isolated RA enlargement 61 2.3 Left axis deviation (−30 to −90a) 32 1.2 Right axis deviation (>120a) 135 5.2 Left ventricular hypertrophy 605 23.1 Left bundle branch block 2 0.08 Right bundle branch block 7 0.27 ST depression (two or more leads) 5 0.19 T wave inversion (two or more leads) 42 1.6 Conclusions These results demonstrate that there is a high prevalence of ECG abnormalities when applying the ESC sports cardiology consensus criteria to young non-athletic individuals. Many of these abnormalities are non-specific in isolation and warrant further investigations to be carried out. This has significant implications on the feasibility and cost-effectiveness of a national cardiovascular screening programme for sinister cardiac disease.