The influence of maturation on exercise-induced cardiac remodelling and haematological adaptation.

Cardiovascular and haematological adaptations to endurance training facilitate greater maximal oxygen consumption ( V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ ), and such adaptations may be augmented following puberty. Therefore, we compared left ventricular (LV) morphology (echocardiography), blood volume, haemoglobin (Hb) mass (CO rebreathing) and V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ in endurance-trained and untrained boys (n = 42, age = 9.0-17.1 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 61.6 ± 7.2 ml/kg/min, and n = 31, age = 8.0-17.7 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 46.5 ± 6.1 ml/kg/min, respectively) and girls (n = 45, age = 8.2-17.0 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 51.4 ± 5.7 ml/kg/min, and n = 36, age = 8.0-17.6 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 39.8 ± 5.7 ml/kg/min, respectively). Pubertal stage was estimated via maturity offset, with participants classified as pre- or post-peak height velocity (PHV). Pre-PHV, only a larger LV end-diastolic volume/lean body mass (EDV/LBM) for trained boys (+0.28 ml/kg LBM, P = 0.007) and a higher Hb mass/LBM for trained girls (+1.65 g/kg LBM, P = 0.007) were evident compared to untrained controls. Post-PHV, LV mass/LBM (boys: +0.50 g/kg LBM, P = 0.0003; girls: +0.35 g/kg LBM, P = 0.003), EDV/LBM (boys: +0.35 ml/kg LBM, P < 0.0001; girls: +0.31 ml/kg LBM, P = 0.0004), blood volume/LBM (boys: +12.47 ml/kg LBM, P = 0.004; girls: +13.48 ml/kg LBM, P = 0.0002.) and Hb mass/LBM (boys: +1.29 g/kg LBM, P = 0.015; girls: +1.47 g/kg LBM, P = 0.002) were all greater in trained versus untrained groups. Pre-PHV, EDV (R2adj  = 0.224, P = 0.001) in boys, and Hb mass and interventricular septal thickness (R2adj  = 0.317, P = 0.002) in girls partially accounted for the variance in V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ . Post-PHV, stronger predictive models were evident via the inclusion of LV wall thickness and EDV in boys (R2adj  = 0.608, P < 0.0001), and posterior wall thickness and Hb mass in girls (R2adj  = 0.490, P < 0.0001). In conclusion, cardiovascular adaptation to exercise training is more pronounced post-PHV, with evidence for a greater role of central components for oxygen delivery. KEY POINTS: It has long been hypothesised that cardiovascular adaptation to endurance training is augmented following puberty. We investigated whether differences in cardiac and haematological variables exist, and to what extent, between endurance-trained versus untrained, pre- and post-peak height velocity (PHV) children, and how these central factors relate to maximal oxygen consumption. Using echocardiography to quantify left ventricular (LV) morphology and carbon monoxide rebreathing to determine blood volume and haemoglobin mass, we identified that training-related differences in LV morphology are evident in pre-PHV children, with haematological differences also observed between pre-PHV girls. However, the breadth and magnitude of cardiovascular remodelling was more pronounced post-PHV. Cardiac and haematological measures provide significant predictive models for maximal oxygen consumption ( V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ ) in children that are much stronger post-PHV, suggesting that other important determinants within the oxygen transport chain could account for the majority of variance in V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ before puberty.

Electrocardiographic differentiation between 'benign T-wave inversion' and arrhythmogenic right ventricular cardiomyopathy.

AIMS: To characterize the most common electrocardiographic (ECG) abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), including anterior T-wave inversion (TWI) and to compare the characteristics of TWI in patients with ARVC and in a cohort of young healthy athletes and sedentary individuals. METHODS AND RESULTS: The study population consisted of 162 patients with a definite diagnosis of ARVC and 129 young controls with anterior TWI. Cardiac disease was excluded in all controls after a comprehensive diagnostic work-up. The ECG was abnormal in 131 patients with ARVC (81%). Abnormalities included anterior TWI (n = 82, 51%), QRS duration ratio V2:V5 >1.2 (n = 51, 31%), prolonged terminal S wave activation duration in V2 >55 ms (n = 42, 26%), inferior TWI (n = 30, 18%), and lateral TWI (n = 26, 16%). The J-point preceding anterior TWI was <0.1 mV in 80/82 (98%) patients with ARVC and in 98 (76%) controls. Among the ARVC patients with anterior TWI, 62 (77%) showed at least one additional abnormal feature, most commonly QRS duration ratio V2:V5 > 1.2 (52%) and inferior or lateral TWI (47%). CONCLUSION: The ECG is frequently abnormal in patients with ARVC and anterior TWI is the most common feature. Anterior TWI is usually accompanied by other abnormalities in ARVC, which are uncommon in healthy individuals. J point <0.1 mV preceding anterior TWI is not specific to ARVC and is observed in the majority of healthy individuals, including athletes, indicating a limited role for differentiating physiology or normal variants from ARVC.

Appropriateness, diagnostic value, and outcomes of repeat testing following index echocardiography.

AIMS: Emergency admission to hospital is associated with an economic burden and mortality. Echocardiography is often the first-line cardiovascular imaging investigation. Repeat testing is common; however, there are sparse data on the prevalence, appropriateness, or outcome of repeat testing. METHODS: We performed an electronic database search for patients with emergency admissions to our institution in February 2015. An electronic patient record review of inpatient echocardiograms was undertaken. Indications for echocardiography were classified as appropriate, may be appropriate, or rarely appropriate. One-year follow-up for repeat testing and mortality was investigated. RESULTS: A total of 409 of 2306 (17.7%) unplanned/emergency admissions underwent inpatient echocardiography. Abnormalities were identified in 165/409 (40.3%) of these patients; 154 of 409 (37.7%) had a repeat echocardiogram within the next year. Rarely appropriate indications for echocardiography occurred in 51 (33%) of repeat vs 53 (16%) of index echocardiograms, P < .0001. Repeat testing was associated with a change in findings in 17/154 (11%) patients overall. All of whom had an abnormal index echocardiogram and had an appropriate indication. There was no difference in mean survival time between patients who underwent repeat and those who only underwent a single index echocardiogram (310 days vs 327 days), P = .34. CONCLUSION: Inpatient echocardiography in emergency hospital admissions identifies clinically important pathology. Repeated testing is common within 1 year of hospital admission. New diagnostic findings occurred in 11% of patients and only in patients with appropriate studies and an abnormal index echocardiogram. Identification of methods to reduce repeat testing and implement appropriateness criteria is warranted.

Electrocardiographic anterior T-wave inversion in athletes of different ethnicities: differential diagnosis between athlete's heart and cardiomyopathy.

AIMS: Anterior T-wave inversion (TWI) is a recognized variant in athletes of African/Afro Caribbean origin and some endurance athletes; however, the presence of this specific repolarization anomaly also raises the possibility of cardiomyopathy. The differentiation between physiological adaptation and cardiomyopathy may be facilitated by examining other repolarization parameters, notably the J-point and the ST-segment. METHODS AND RESULTS: We compared the electrocardiogram pattern of anterior TWI in a series of 80 healthy athletes (median age 21 years, 75% males); 95 patients with hypertrophic cardiomyopathy (HCM) (median age 46 years, 75% males), including 26 affected athletes; and 58 patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) (median age 32 years, 71% males), including 9 affected athletes. Athletes and patients were of either white/Caucasian or black/Afro Caribbean descent and showed TWI ≥1 mm in ≥2 contiguous anterior leads (V1-V4). We aimed to identify repolarization patterns for differentiating physiologic from pathologic TWI. After adjustment for age, gender, and ethnicity, J-point elevation <1 mm (but no ST-segment elevation without J-point elevation) in the anterior leads showing TWI and TWI extending beyond V4 remained independent predictors for both ARVC, with OR = 569 (95% CI = 38-8545; P < 0.001) and OR = 6.0 (95% CI = 1.2-37.8; P = 0.03), respectively, and HCM with OR = 227 (95% CI = 12-1620; P < 0.001) and OR = 331 (95% CI = 20-2752; P = 0.001), respectively. In athletes with anterior TWI, the combination of J-point elevation ≥1 mm and TWI not extending beyond V4 excluded a cardiomyopathy, either ARVC or HCM, with 100% sensitivity and 55% specificity. CONCLUSION: The combination of J-point elevation and TWI confined to lead V1-V4 offers the potential for an accurate differentiation between 'physiologic' and 'cardiomyopathic' anterior TWI, among athletes of both white/Caucasian or black/Afro Caribbean descent. Conversely, ST-segment elevation without J-point elevation preceding anterior TWI may reflect cardiomyopathy.

Results of a nationally implemented de novo cardiac screening programme in elite rugby players in England.

BACKGROUND/AIM: Screening of young competitive athletes remains a contentious issue. In 2010, a nationwide cardiac screening for all elite rugby players was introduced in England. This provided a unique opportunity to prospectively assess the feasibility and cost-effectiveness of a de novo, ECG-based cardiac screening programme. METHODS: Between 2010 and 2012, 1191 rugby players aged ≥14 years underwent cardiac screening with a health questionnaire, 12-lead ECG and a consultation with a cardiologist. The players with concerning findings on initial evaluation were offered on-site transthoracic echocardiogram (TTE). Athletes were referred for further investigations as deemed necessary. The overall cost of the screening programme was estimated. RESULTS: After initial evaluation, 9.7% of athletes underwent on-site TTE; 8.2% underwent on-site TTE due to ECG anomalies and 1.4% underwent on-site TTE due to concerns on the questionnaire. After TTE, only 2.9% of the total cohort was referred for further evaluation. Two players were diagnosed with potentially serious conditions; one with Wolff-Parkinson-White, who resumed competition after catheter ablation, and one with hypertrophic cardiomyopathy, who withdrew from competition. During a mean follow-up of 52.8±5.5 months, none of the players who were reassured experienced any adverse cardiac events. The total cost of the screening programme was £59 875, which averaged to a cost of £50 per player or £29 938 per condition identified. Application of refined ECG criteria would reduce the ECG false-positive rate to 4.9%. CONCLUSIONS: Preparticipation cardiac screening with 12-lead ECG is feasible. Refinement of the ECG criteria, the use of on-site TTE and expert setting can minimise the burden of unnecessary investigations and reduce costs.

Comparison of electrocardiographic criteria for the detection of cardiac abnormalities in elite black and white athletes.

BACKGROUND: Recent efforts have focused on improving the specificity of the European Society of Cardiology (ESC) criteria for ECG interpretation in athletes. These criteria are derived predominantly from white athletes (WAs) and do not account for the effect of Afro-Caribbean ethnicity or novel research questioning the relevance of several isolated ECG patterns. We assessed the impact of the ESC criteria, the newly published Seattle criteria, and a group of proposed refined criteria in a large cohort of black athletes (BAs) and WAs. METHODS AND RESULTS: Between 2000 and 2012, 1208 BAs were evaluated with history, examination, 12-lead ECG, and further investigations as appropriate. ECGs were retrospectively analyzed according to the ESC recommendations, Seattle criteria, and proposed refined criteria which exclude several specific ECG patterns when present in isolation. All 3 criteria were also applied to 4297 WAs and 103 young athletes with hypertrophic cardiomyopathy. The ESC recommendations raised suspicion of a cardiac abnormality in 40.4% of BAs and 16.2% of WAs. The Seattle criteria reduced abnormal ECGs to 18.4% in BAs and 7.1% in WAs. The refined criteria further reduced abnormal ECGs to 11.5% in BAs and 5.3% in WAs. All 3 criteria identified 98.1% of athletes with hypertrophic cardiomyopathy. Compared with ESC recommendations, the refined criteria improved specificity from 40.3% to 84.2% in BAs and from 73.8% to 94.1% in WAs without compromising the sensitivity of the ECG in detecting pathology. CONCLUSION: Refinement of current ECG screening criteria has the potential to significantly reduce the burden of false-positive ECGs in athletes, particularly BAs.

Reversible de novo left ventricular trabeculations in pregnant women: implications for the diagnosis of left ventricular noncompaction in low-risk populations.

BACKGROUND: Patients with heart failure and chronic anemia frequently demonstrate left ventricular (LV) trabeculations, which may be compatible with the diagnosis of LV noncompaction. We used the pregnancy model, which is characterized by a reversible increase in cardiac preload and other changes in cardiac function, to assess the development of de novo LV trabeculations in women with morphologically normal hearts. METHODS AND RESULTS: One hundred two primigravida pregnant women were evaluated longitudinally with a series of echocardiograms in the first trimester, in the third trimester, and postpartum. Echocardiograms were analyzed according to established guidelines. Increased LV trabeculations and the presence of LV noncompaction were based on established criteria. Pregnancy was associated with an increased heart rate, stroke volume, and cardiac output, as well as increased LV volume and mass. During pregnancy, 26 women (25.4%) developed increased trabeculations. Eight women showed sufficient trabeculations to fulfill criteria for LV noncompaction. During the postpartum follow-up period of 24±3 months, 19 women (73%) demonstrated complete resolution of trabeculations, and 5 showed a marked reduction in the trabeculated layer. CONCLUSIONS: Pregnancy induces de novo LV trabeculations in a significant proportion of women. The results suggest that LV trabeculations occur in response to increased LV loading conditions or other physiological responses to pregnancy and are not specific for LV noncompaction. These factors should be considered in the assessment of individuals with LV trabeculations outside the context of symptoms of heart failure or familial cardiomyopathy.

Relationship between echocardiographic right-ventricular dimensions and signal-averaged electrocardiogram abnormalities in endurance athletes.

AIMS: Regular physical exercise results in physiological cardiovascular changes. Athletes may demonstrate electrocardiographic changes that can also be seen in certain cardiomyopathies such as arrhythmogenic right-ventricular cardiomyopathy (ARVC). The aim of this study was to assess the prevalence of one such electrocardiographic characteristic, the abnormal signal-averaged ECG (SAECG), and to assess the correlation between SAECG parameters and echocardiographic parameters in athletes participating in sporting disciplines with combined strength and endurance components. METHODS AND RESULTS: We evaluated 24 elite athletes and 27 amateur athletes participating in combined high dynamic and high static (HDHS) sports, using an ECG, SAECG, and a transthoracic echocardiogram. The SAECG was regarded as positive for late potentials if one out of three parameters was abnormal. Prolongation of the filtered QRS duration (fQRS) was present in all of the elite athletes, compared with 74.1% of the amateur athletes (P = 0.011). There was a low prevalence of abnormalities in the other two SAECG parameters [low-amplitude signal (LAS) duration and root-mean-square (RMS) voltage]. The percentage of elite athletes and amateur athletes with ≥2 abnormal SAECG parameters was 8.3 and 7.4% (P = 0.99), respectively. Most of the echocardiographic dimensions were significantly greater in the elite athlete group compared with the amateur athletes. There was a moderate positive correlation between the fQRS and right-ventricular dimensions. CONCLUSION: The majority of elite and amateur athletes participating in HDHS sports reveal a prolonged fQRS duration on the SAECG, and according to the 2010 Task Force criteria for the diagnosis of ARVC, these athletes therefore demonstrate late potentials. The extent of fQRS prolongation is positively correlated with RV dimensions. Therefore SAECG findings should be interpreted with caution in endurance athletes.

Postmortem imaging in congenital heart disease: preliminary experience.

BACKGROUND: Despite the importance of the autopsy for quality improvement, autopsy rates have declined dramatically in recent decades due to poor acceptance by families and physicians and high costs to institutions. PURPOSE: To compare postmortem imaging (PMI) with autopsy in patients with congenital heart defects to see if PMI could substitute in some or all cases and to compare costs of the two methods. MATERIAL AND METHODS: Ten patients with congenital heart disease dying in hospital during the study period in whom an autopsy was planned underwent PMI using postmortem magnetic resonance imaging (PMMRI) (6 patients) and postmortem computed tomographic angiography (PMCTA) (10 patients) with permission of the family. Four patients were excluded from PMMR because of metal ECMO cannulas. PMI was interpreted before autopsy using an organ system checklist and results compared to autopsy. The costs of each method were tracked. RESULTS: When both PMMR and PMCTA were performed the PMI findings corresponded closely with autopsy. PMI correctly diagnosed the principal heart defects in all six cases and correctly imaged central vessels, heart valves and chambers, brain, abdominal organs, and bone. Weak points were visualization of the coronary arteries and distinguishing postmortem pulmonary atelectasis from lung pathology. The cause of death by PMI matched autopsy findings in 5/6 cases in which both PMMR and PMCTA were performed and was incomplete in the other five cases. The cost of PMI was about 15% lower than the cost of autopsy. CONCLUSION: PMI provided most gross anatomic cardiac diagnoses available by autopsy in our series of patients with congenital heart defects and the cost appears to be lower.

Unravelling the grey zone: cardiac MRI volume to wall mass ratio to differentiate hypertrophic cardiomyopathy and the athlete's heart.

BACKGROUND: Differentiating physiological left ventricular hypertrophy (LVH) in athletes from pathological hypertrophic cardiomyopathy (HCM) can be challenging. This study assesses the ability of cardiac MRI (CMR) to distinguish between physiological LVH (so-called athlete's heart) and HCM. METHODS: 45 patients with HCM (71% men and 20% athletic) and 734 healthy control participants (60% men and 75% athletic) underwent CMR. Quantitative ventricular parameters were used for multivariate logistic regression with age, gender, sport status and left ventricular (LV) end-diastolic volume (EDV) to ED ventricular wall mass (EDM) ratio as covariates. A second model added the LV EDV : right ventricular (RV) EDV ratio. The performance of the model was subsequently tested. RESULTS: LV EDM was greater in patients with HCM (74 g/m2) compared with healthy athletes/non-athletes (53/41 g/m2), while LV EDV was largest in athletes (114 ml/m2) as compared with non-athletes (94 ml/m2) and patients with HCM (88 ml/m2). The LV EDV : EDM ratio was significantly lower in patients with HCM compared with healthy controls and athletes (1.30/2.39/2.25, p<0.05). The LV EDV : RV EDV ratio was significantly greater in patients with HCM (1.10) than in healthy participants (non-athletes/athletes 0.94/0.93). The regression model resulted in high sensitivity and specificity levels in all and borderline-LVH participants (as defined by septal wall thickness). Corresponding areas under the receiver operator characteristic (ROC) curves were 0.995 (all participants) and 0.992 (borderline-LVH participants only). Adding the LV EDV : RV EDV ratio yielded no additional improvement. CONCLUSIONS: A model incorporating the LV EDV : EDM ratio can help distinguish HCM from physiological hypertrophy in athletes. This also applies to cases with borderline LVH, which present the greatest diagnostic challenge in clinical practice.

Physiological right ventricular adaptation in elite athletes of African and Afro-Caribbean origin.

BACKGROUND: Regular, intensive exercise results in physiological biventricular cardiac adaptation. Ethnicity is an established determinant of left ventricular remodeling; black athletes (BAs) exhibit more profound LV hypertrophy than white athletes (WAs). Right ventricular (RV) remodeling has not been characterized in BAs, although the issue is pertinent because BAs commonly exhibit ECG anomalies that resemble arrhythmogenic RV cardiomyopathy. METHODS AND RESULTS: Between 2006 and 2012, 300 consecutive BAs (n=243 males) from 25 sporting disciplines were evaluated by use of ECG and echocardiography. Results were compared with 375 WAs and 153 sedentary control subjects (n=69 blacks). There were no ethnic differences between RV parameters in control subjects. Both BAs and WAs exhibited greater RV dimensions than control subjects. RV dimensions were marginally smaller in BAs than in WAs (proximal outflow tract, 30.9±5.5 versus 32.8±5.3 mm, P<0.001; longitudinal dimension, 86.6±9.5 versus 89.8±9.6 mm, P<0.001), although only 2.3% of variation was attributable to ethnicity. RV enlargement compatible with diagnostic criteria for arrhythmogenic RV cardiomyopathy was frequently observed (proximal outflow tract ≥32 mm; 45.0% of BAs, 58.5% of WAs). Anterior T-wave inversion was present in 14.3% of BAs versus 3.7% of WAs (P<0.001). Marked RV enlargement with concomitant anterior T-wave inversion was observed in 3.0% of BAs versus 0.3% of WAs (P=0.005). Further investigation did not diagnose arrhythmogenic RV cardiomyopathy in any athlete. CONCLUSIONS: Physiological RV enlargement is commonly observed in both black and white athletes. The impact of ethnicity is minimal, which obviates the need for race-specific RV reference values. However, in the context of frequent ECG repolarization anomalies in BAs, the potential for erroneous diagnosis of arrhythmogenic RV cardiomyopathy is considerably greater in this ethnic group.

Should axis deviation or atrial enlargement be categorised as abnormal in young athletes? The athlete's electrocardiogram: time for re-appraisal of markers of pathology.

AIMS: The 2010 European Society of Cardiology (ESC) guidelines for electrocardiogram (ECG) interpretation in athletes are associated with a relatively high false positive rate and warrant modification to improve the specificity without compromising sensitivity. The aim of this study was to investigate whether non-specific anomalies such as axis deviation and atrial enlargement in isolation require further assessment in highly trained young athletes. METHOD AND RESULTS: Between 2003 and 2011, 2533 athletes aged 14-35 years were investigated with 12-lead ECG and echocardiography. Electrocardiograms were analysed for non-training-related (Group 2) changes according to the 2010 ESC guidelines. Results were compared with 9997 asymptomatic controls. Of the 2533 athletes, 329 (13%) showed Group 2 ECG changes. Isolated axis deviation and isolated atrial enlargement comprised 42.6% of all Group 2 changes. Athletes revealed a slightly higher prevalence of these anomalies compared with controls (5.5 vs. 4.4%; P = 0.023). Echocardiographic evaluation of athletes and controls with isolated axis deviation or atrial enlargement (n = 579) failed to identify any major structural or functional abnormalities. Exclusion of axis deviation or atrial enlargement reduced the false positive rate from 13 to 7.5% and improved specificity from 90 to 94% with a minimal reduction in sensitivity (91-89.5%). CONCLUSION: Isolated axis deviation and atrial enlargement comprise a high burden of Group 2 changes in athletes and do not predict underlying structural cardiac disease. Exclusion of these anomalies from current ESC guidelines would improve specificity and cost-effectiveness of pre-participation screening with ECG.

Clinical significance of electrocardiographic right ventricular hypertrophy in athletes: comparison with arrhythmogenic right ventricular cardiomyopathy and pulmonary hypertension.

AIMS: Pre-participation cardiovascular screening of young athletes may prevent sports-related sudden cardiac deaths. Recognition of physiological electrocardiography (ECG) changes in healthy athletes has improved the specificity of screening while maintaining sensitivity for disease. The study objective was to determine the clinical significance of electrocardiographic right ventricular hypertrophy (RVH) in athletes. METHODS AND RESULTS: Between 2010 and 2012, 868 subjects aged 14-35 years (68.8% male) were assessed using ECG and echocardiography (athletes; n = 627, sedentary controls; n = 241). Results were compared against patients with established right ventricular (RV) pathology (arrhythmogenic right ventricular cardiomyopathy, n = 68; pulmonary hypertension, n = 30). Sokolow-Lyon RVH (R[V1]+S[V5orV6] > 1.05 mV) was more prevalent in athletes than controls (11.8 vs. 6.2%, P = 0.017), although RV wall thickness (RVWT) was similar (4.0 ± 1.0 vs. 3.9 ± 0.9 mm, P = 0.18). Athletes exhibiting electrocardiographic RVH were predominantly male (95.9%), and demonstrated similar RV dimensions and function to athletes with normal electrocardiograms (RVWT; 4.0 ± 1.1 vs. 4.0 ± 0.9 mm, P = 0.95, RV basal dimension; 42.7 ± 5.2 vs. 42.1 ± 5.9 mm, P = 0.43, RV fractional area change; 40.6 ± 7.6 vs. 42.2 ± 8.1%, P = 0.14). Sensitivity and specificity of Sokolow-Lyon RVH for echocardiographic RVH (>5 mm) were 14.3 and 88.2%, respectively. Further evaluation including cardiac magnetic resonance imaging did not diagnose right ventricular pathology in any athlete. None of the cardiomyopathic or pulmonary hypertensive patients exhibited voltage RVH without additional ECG abnormalities. CONCLUSION: Electrocardiographic voltage criteria for RVH are frequently fulfilled in healthy athletes without underlying RV pathology, and should not prompt further evaluation if observed in isolation. Recognition of this phenomenon should reduce the burden of investigations after pre-participation ECG screening without compromising sensitivity for disease.

Social Determinants of Health Including Child Opportunity Index Leading to Gaps in Care for Patients With Significant Congenital Heart Disease.

BACKGROUND: Gaps in care (GIC) are common for patients with congenital heart disease (CHD) and can lead to worsening clinical status, unplanned hospitalization, and mortality. Understanding of how social determinants of health (SDOH) contribute to GIC in CHD is incomplete. We hypothesize that SDOH, including Child Opportunity Index (COI), are associated with GIC in patients with significant CHD. METHODS AND RESULTS: A total of 8554 patients followed at a regional specialty pediatric hospital with moderate to severe CHD seen in cardiology clinic between January 2013 and December 2015 were retrospectively reviewed. SDOH factors including race, ethnicity, language, and COI calculated based on home address and zip code were analyzed. GIC of >3.25 years were identified in 32% (2709) of patients. GIC were associated with ages 14 to 29 years (P<0.001), Black race or Hispanic ethnicity (P<0.001), living ≥150 miles from the hospital (P=0.017), public health insurance (P<0.001), a maternal education level of high school or less (P<0.001), and a low COI (P<0.001). Multivariable analysis showed that GIC were associated with age ≥14 years, Black race or Hispanic ethnicity, documenting <3 caregivers as contacts, mother's education level being high school or less, a very low/low COI, and insurance status (C statistic 0.66). CONCLUSIONS: One-third of patients followed in a regional referral center with significant CHD experienced a substantial GIC (>3.25 years). Several SDOH, including a low COI, were associated with GIC. Hospitals should adopt formal GIC improvement programs focusing on SDOH to improve continuity of care and ultimately overall outcomes for patients with CHD.

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.

The influence of training status and parasympathetic blockade on the cardiac rate, rhythm, and functional response to autonomic stress.

Apnea (breath-holding) elicits co-activation of sympathetic and parasympathetic nervous systems, affecting cardiac control. In situations of autonomic co-activation (e.g., cold water immersion), cardiac arrhythmias are observed during apnea. Chronic endurance training reduces resting heart rate in part via elevation in parasympathetic tone, and has been identified as a risk factor for development of arrhythmias. However, few studies have investigated autonomic control of the heart in trained athletes during stress. Therefore, we determined whether heightened vagal tone resulting from endurance training promotes a higher incidence of arrhythmia during apnea. We assessed the heart rate, rhythm (ECG lead II), and cardiac inotropic (speckle-tracking echocardiography) response to apnea in 10 endurance trained and 7 untrained participants. Participants performed an apnea at rest and following sympathetic activation using post-exercise circulatory occlusion (PECO). All apneas were performed prior to control (CON) and following vagal block using glycopyrrolate (GLY). Trained participants had lower heart rates at rest (p = 0.03) and during apneas (p = 0.009) under CON. At rest, 3 trained participants exhibited instances of junctional rhythm and 4 trained participants developed ectopy during CON apneas, whereas 3 untrained participants developed ectopic beats only with concurrent sympathetic activation (PECO). Following GLY, no arrhythmias were noted in either group. Vagal block also revealed increased cardiac chronotropy (heart rate) and inotropy (strain rate) during apnea, demonstrating a greater sympathetic influence in the absence of parasympathetic drive. Our results highlight that endurance athletes may be more susceptible to ectopy via elevated vagal tone, whereas untrained participants may only develop ectopy through autonomic conflict.

Adaptation of Left Ventricular Twist Mechanics in Exercise-Trained Children Is Only Evident after the Adolescent Growth Spurt.

BACKGROUND: The extent of structural cardiac remodeling in response to endurance training is maturity dependent. In adults, this structural adaptation is often associated with the adaptation of left ventricular (LV) twist mechanics. For example, an increase in LV twist often follows an expansion in end-diastolic volume, whereas a reduction in twist may follow a thickening of the LV walls. While structural cardiac remodeling has been shown to be more prominent post-peak height velocity (PHV), it remains to be determined how this maturation-dependent structural remodeling influences LV twist. Therefore, we aimed to (1) compare LV twist mechanics between trained and untrained children pre- and post-PHV and (2) investigate how LV structural variables relate to LV twist mechanics pre- and post-PHV. METHODS: Left ventricular function and morphology were assessed (echocardiography) in endurance-trained and untrained boys (n = 38 and n = 28, respectively) and girls (n = 39 and n = 34, respectively). Participants were categorized as either pre- or post-PHV using maturity offset to estimate somatic maturation. RESULTS: Pre-PHV, there were no differences in LV twist or torsion between trained and untrained boys (twist: P = .630; torsion: P = .382) or girls (twist: P = .502; torsion: P = .316), and LV twist mechanics were not related with any LV structural variables (P > .05). Post-PHV, LV twist was lower in trained versus untrained boys (P = .004), with torsion lower in trained groups, irrespective of sex (boys: P < .001; girls: P = .017). Moreover, LV torsion was inversely related to LV mass (boys: r = -0.55, P = .001; girls: r = -0.46, P = .003) and end-diastolic volume (boys: r = -0.64, P < .001; girls: r = -0.36, P = .025) in both sexes. CONCLUSIONS: A difference in LV twist mechanics between endurance-trained and untrained cohorts is only apparent post-PHV, where structural and functional remodeling were related.

Echocardiographic surveillance of aortic valve stenosis: towards a standardized approach.

BACKGROUND AND AIM OF THE STUDY: Severe symptomatic aortic stenosis (AS) portends a poor prognosis, and there is growing evidence that even mild disease carries significant morbidity. Systematic echocardiographic monitoring of asymptomatic disease is therefore essential to optimize the effectiveness of interventions. Inconsistencies exist, however, between different guidelines, and this may lead to inefficient resource utilization or, conversely, to inadequate monitoring. The study aim was to assess the appropriateness of AS surveillance echocardiography at the authors' institution. An additional aim was to document AS progression patterns in a contemporary British population, for which few data currently exist. METHODS: British, European, and North American guidelines relating to echocardiographic surveillance of asymptomatic AS were examined. A retrospective analysis of practice at the authors' institution was conducted, with timing of surveillance compared to guidelines. Progression was documented by monitoring the effective orifice area (EOA) and peak pressure gradient (PPG). RESULTS: Mean progression rates were consistent with published data (deltaEOA = -0.15 +/- 0.49 cm2/year; deltaPPG = +6.67 +/- 24.76 mmHg/year), with wide variation, and poor correlation between surveillance interval and disease progression. Progression of mild AS was significantly faster than severe AS (deltaEOA = -0.33 +/- 0.53 versus +0.04 +/- 0.41 cm2/year, respectively; p < 0.001). Of 169 echocardiograms evaluated, 60.9% were appropriately timed, 33.1% were early, and 6.0% were late. Surveillance of mild AS was less often appropriate than that of moderate or severe AS (12.0% versus 78.3% versus 84.7% appropriate, respectively; p < 0.001). On extrapolating these results nationally, an excess expenditure of pound 4.6 million (US$ 6.0 million) per year was estimated for this indication alone. CONCLUSION: Echocardiographic surveillance of asymptomatic AS is often non-compliant with published guidance, which may be attributable to ambiguities and conflicts between different guidelines. The variable natural history of AS necessitates systematic surveillance at all stages of the disease spectrum, which in turn requires unambiguous, standardized guidelines to minimize variation in quality of care, while providing a clear framework to maximize the impact of investigations.

Differentially Private Occupancy Monitoring from WiFi Access Points.

Accurately monitoring the number of individuals inside a building is vital to limiting COVID-19 transmission. Low adoption of contact tracing apps due to privacy concerns has increased pervasiveness of passive digital tracking alternatives. Large arrays of WiFi access points can conveniently track mobile devices on university and industry campuses. The CrowdMap system employed by the University of Southern California enables such tracking by collecting aggregate statistics from connections to access points around campus. However, since these devices can be used to infer the movement of individuals, there is still a significant risk that even aggregate occupancy statistics will violate the location privacy of individuals. We examine the use of Differential Privacy in reporting statistics from this system as measured using point and range count queries. We propose discretization schemes to model the positions of users given only user connections to WiFi access points. Using this information we are able to release accurate counts of occupants in areas of campus buildings such as labs, hallways, and large discussion halls with minimized risk to individual users' privacy.