Jonathan H. Kim

Performance of the 2010 European Society of Cardiology criteria for ECG interpretation in athletes

Background The European Society of Cardiology (ESC) recently published revised criteria for ECG interpretation in the athlete. Objective To examine the performance of the 2010 ESC ECG criteria in a population of athletes undergoing preparticipation cardiovascular disease screening. Methods University athletes (n=508) underwent routine medical history/physical examination and ECG before athletic participation. Transthoracic echocardiography (TTE) was also performed on each participant to detect or exclude cardiac findings with relevance to sport participation. Screening test statistics were calculated to determine the performance of the 2010 ESC criteria, and the performance of the 2010 criteria was compared with the 2005 criteria. Results Application of the 2010 ESC criteria, compared with the 2005 criteria, reduced the number of participants with abnormal ECG findings from 83/508 (16.3%) to 49/508 (9.6%). The reduction in the number of abnormal ECGs was driven by the reclassification of participants with isolated QRS voltage criteria for left ventricular hypertrophy from abnormal to normal. Of the 49 participants with abnormal ECGs, 14/49 (29%) had a single ECG abnormality and 35/49 (71%) had two or more abnormalities. The use of the 2010 criteria was associated with improved specificity (reduction in the false positive rate) and preserved sensitivity when compared with the 2005 criteria. Conclusion Application of the 2010 ESC criteria for ECG interpretation in the athlete improves the accuracy of an ECG-inclusive preparticipation screening strategy by reducing the rate of false positive ECGs.

Blood Pressure and Left Ventricular Hypertrophy During American-Style Football Participation

Background— Hypertension, a strong determinant of cardiovascular disease risk, has been documented among elite, professional American-style football (ASF) players. The risk of increased blood pressure (BP) and early adulthood hypertension among the substantially larger population of collegiate ASF athletes is not known. Methods and Results— We conducted a prospective, longitudinal study to examine BP, the incidence of hypertension, and left ventricular remodeling among collegiate ASF athletes. Resting BP and left ventricular structure were assessed before and after a single season of competitive ASF participation in 6 consecutive groups of first-year university athletes (n=113). ASF participation was associated with significant increases in systolic BP (116±8 versus 125±13 mm Hg; P<0.001) and diastolic BP (64±8 mm Hg versus 66±10 mm Hg; P<0.001). At the postseason assessment, the majority of athletes met criteria for Joint National Commission (seventh report) prehypertension (53 of 113, 47%) or stage 1 hypertension (16 of 113, 14%). Among measured characteristics, lineman field position, intraseason weight gain, and family history of hypertension were the strongest independent predictors of postseason BP. Among linemen, there was a significant increase in the prevalence of concentric left ventricular hypertrophy (2 of 64 [3%] versus 20 of 64 [31%]; P<0.001) and change in left ventricular mass correlated with intraseason change in systolic BP (R=0.46, P<0.001). Conclusions— Collegiate ASF athletes may be at risk for clinically relevant increases in BP and the development of hypertension. Enhanced surveillance and carefully selected interventions may represent important opportunities to improve later-life cardiovascular health outcomes in this population.

Regression of "gray zone" exercise-induced concentric left ventricular hypertrophy during prescribed detraining.

To the Editor: Left ventricular hypertrophy (LVH) may develop in response to exercise training. In extreme cases, exercise-induced LVH (EI-LVH) may be difficult to differentiate from clinically relevant conditions such as hypertrophic cardiomyopathy (HCM). A valuable clinical pathway integrating

Impact of American-Style Football Participation on Vascular Function

Although hypertension is common in American-style football (ASF) players, the presence of concomitant vascular dysfunction has not been previously characterized. We sought to examine the impact of ASF participation on arterial stiffness and to compare metrics of arterial function between collegiate ASF participants and nonathletic collegiate controls. Newly matriculated collegiate athletes were studied longitudinally during a single season of ASF participation and were then compared with healthy undergraduate controls. Arterial stiffness was characterized using applanation tonometry (SphygmoCor). ASF participants (n = 32, 18.4 ± 0.5 years) were evenly comprised of Caucasians (n = 14, 44%) and African-Americans (n = 18, 56%). A single season of ASF participation led to an increase in central aortic pulse pressure (27 ± 4 vs 34 ± 8 mm Hg, p <0.001). Relative to controls (n = 47), pulse wave velocity was increased in ASF participants (5.6 ± 0.7 vs 6.2 ± 0.9 m/s, p = 0.002). After adjusting for height, weight, body mass index, systolic blood pressure, and diastolic blood pressure, ASF participation was independently predictive of increased pulse wave velocity (β = 0.33, p = 0.04). In conclusion, ASF participation leads to changes in central hemodynamics and increased arterial stiffness.

Electrocardiographic right and left bundle branch block patterns in athletes: Prevalence, pathology, and clinical significance

Differentiating benign electrocardiographic (ECG) patterns in athletes from those representative of underlying cardiac pathology is both clinically relevant and challenging. Complete right (RBBB) and left (LBBB) bundle branch block are relatively rare in asymptomatic athletic populations, and current expert consensus guidelines recommend further clinical investigation upon detection of either ECG pattern. However, present data suggest that typical RBBB is not associated with structural cardiac pathology and may alternatively represent an ECG marker of exercise-induced right ventricular remodeling. In accordance with current guidelines, the presence of asymptomatic LBBB in athletes is not associated with normal exercise physiology and more likely indicative of underlying cardiac pathology. While long-term outcomes for asymptomatic athletes with RBBB or LBBB remain unknown, current evidence regarding these ECG patterns should be considered to improve the specificity of future athlete-specific ECG interpretation guidelines.

Progenitor Cells and Clinical Outcomes in Patients With Heart Failure

Background Endogenous regenerative capacity, assessed as circulating progenitor cell (PC) numbers, is an independent predictor of adverse outcomes in patients with cardiovascular disease. However, their predictive role in heart failure (HF) remains controversial. We assessed the relationship between the number of circulating PCs and the pathogenesis and severity of HF and their impact on incident HF events. Methods and Results We recruited 2049 adults of which 651 had HF diagnosis. PCs were enumerated by flow cytometry as CD45med+ blood mononuclear cells expressing CD34, CD133, vascular endothelial growth factor receptor-2, and chemokine (C-X-C motif) receptor 4 epitopes. PC subsets were lower in number in HF and after adjustment for clinical characteristics in multivariable analyses, a low CD34+ and CD34+/CXCR+ cell count remained independently associated with a diagnosis of HF (P<0.01). PC levels were not significantly different in reduced versus preserved ejection fraction patients. In 514 subjects with HF, there were 98 (19.1%) all-cause deaths during a 2.2±1.5-year follow-up. In a Cox regression model adjusting for clinical variables, hematopoietic-enriched PCs (CD34+, CD34+/CD133+, and CD34+/CXCR4+) were independent predictors of all-cause death (hazard ratio 2.0, 1.6, 1.6-fold higher mortality, respectively; P<0.03) among HF patients. Endothelial-enriched PCs (CD34+/VEGF+) were independent predictors of mortality in patients with HF with preserved ejection fraction only (hazard ratio, 5.0; P=0.001). Conclusions PC levels are lower in patients with HF, and lower PC counts are strongly and independently predictive of mortality. Strategies to increase PCs and exogenous stem cell therapies designed to improve regenerative capacity in HF, especially, in HF with preserved ejection fraction, need to be further explored.

Strenuous Exercise and Cardiovascular Disease Outcomes

Purpose of ReviewThis review summarizes several issues at the forefront of recent controversies involving the appropriate exercise dose including epidemiologic data describing mortality trends in those who engage in high levels of physical activity and recent observational data suggesting adverse cardiovascular outcomes among long-term endurance athletes.Recent FindingsThe benefits of habitual and moderate levels of exercise on cardiovascular disease outcomes in the general population have been well established. However, recent data have questioned whether higher doses of physical and athletic activity are associated with adverse cardiovascular outcomes.SummarySpecifically in regard to adverse cardiovascular outcomes, the evidence and limitations of the available data associating veteran endurance athletes with an increased risk of atrial fibrillation, exercise-induced arrhythmogenic cardiac remodeling, and accelerated coronary atherosclerosis will be discussed. This review will also provide a conceptual framework in the context of the clinical management of athletic patients and will highlight key areas of future research that may resolve many of these controversial issues.

Physical Activity, Endurance Exercise, and Excess—Can One Overdose?

Opinion statementAlthough moderate levels of exercise reduce cardiovascular morbidity and mortality in the general population, recent data have questioned whether higher doses of physical activity are associated with diminished health benefits and adverse outcomes. This review focuses on several issues at the center of this controversy including epidemiologic data describing mortality trends in those who engage in high levels of physical activity and recent observational data suggesting adverse cardiovascular outcomes among long-term endurance athletes. Specifically for the endurance athlete, the evidence and limitations of the available data associating veteran endurance athletes with an increased risk of atrial fibrillation, pathologic, and arrhythmogenic cardiac remodeling and accelerated coronary atherosclerosis will be discussed. This review will also provide practitioners involved in the care of athletes and highly active patients a conceptual framework for these contemporary controversies and will highlight key areas of uncertainty that will require future research.

High‐Sensitivity Troponin I Levels and Coronary Artery Disease Severity, Progression, and Long‐Term Outcomes

Background The associations between high‐sensitivity troponin I (hsTnI) levels and coronary artery disease (CAD) severity and progression remain unclear. We investigated whether there is an association between hsTnI and angiographic severity and progression of CAD and whether the predictive value of hsTnI level for incident cardiovascular outcomes is independent of CAD severity. Methods and Results In 3087 patients (aged 63±12 years, 64% men) undergoing cardiac catheterization without evidence of acute myocardial infarction, the severity of CAD was calculated by the number of major coronary arteries with ≥50% stenosis and the Gensini score. CAD progression was assessed in a subset of 717 patients who had undergone ≥2 coronary angiograms >3 months before enrollment. Patients were followed up for incident all‐cause mortality and incident cardiovascular events. Of the total population, 11% had normal angiograms, 23% had nonobstructive CAD, 20% had 1‐vessel CAD, 20% had 2‐vessel CAD, and 26% had 3‐vessel CAD. After adjusting for age, sex, race, body mass index, smoking, hypertension, diabetes mellitus history, and renal function, hsTnI levels were independently associated with the severity of CAD measured by the Gensini score (log 2 ß=0.31; 95% confidence interval, 0.18–0.44; P<0.001) and with CAD progression (log 2 ß=0.36; 95% confidence interval, 0.14–0.58; P=0.001). hsTnI level was also a significant predictor of incident death, cardiovascular death, myocardial infarction, revascularization, and cardiac hospitalizations, independent of the aforementioned covariates and CAD severity. Conclusions Higher hsTnI levels are associated with the underlying burden of coronary atherosclerosis, more rapid progression of CAD, and higher risk of all‐cause mortality and incident cardiovascular events. Whether more aggressive treatment aimed at reducing hsTnI levels can modulate disease progression requires further investigation.

Marital Status and Outcomes in Patients With Cardiovascular Disease

Background Being unmarried is associated with decreased survival in the general population. Whether married, divorced, separated, widowed, or never‐married status affects outcomes in patients with cardiovascular disease has not been well characterized. Methods and Results A prospective cohort (inception period 2003–2015) of 6051 patients (mean age 63 years, 64% male, 23% black) undergoing cardiac catheterization for suspected or confirmed coronary artery disease was followed for a median of 3.7 years (interquartile range: 1.7–6.7 years). Marital status was stratified as married (n=4088) versus unmarried (n=1963), which included those who were never married (n=451), divorced or separated (n=842), or widowed (n=670). The relationship between marital status and primary outcome of cardiovascular death and myocardial infarction was examined using Cox regression models adjusted for clinical characteristics. There were 1085 (18%) deaths from all causes, 688 (11%) cardiovascular‐related deaths, and 272 (4.5%) incident myocardial infarction events. Compared with married participants, being unmarried was associated with higher risk of all‐cause mortality (hazard ratio [HR]: 1.24; 95% confidence interval [CI], 1.06–1.47), cardiovascular death (HR: 1.45; 95% CI, 1.18–1.78), and cardiovascular death or myocardial infarction (HR: 1.52; 95% CI, 1.27–1.83). Compared with married participants, the increase in cardiovascular death or myocardial infarction was similar for the participants who were divorced or separated (HR: 1.41; 95% CI, 1.10–1.81), widowed (HR: 1.71; 95% CI, 1.32–2.20), or never married (HR: 1.40; 95% CI, 0.97–2.03). The findings persisted after adjustment for medications and other socioeconomic factors. Conclusions Marital status is independently associated with cardiovascular outcomes in patients with or at high risk of cardiovascular disease, with higher mortality in the unmarried population. The mechanisms responsible for this increased risk require further study.