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BACKGROUND: Asymptomatic atrial fibrillation (AF) is associated with an increased risk of stroke. The yield of serial electrocardiographic (ECG) screening for AF is unknown. OBJECTIVES: The aim of this study was to determine the frequency of AF detected by serial, 7-day ECG patch screenings in older women identified as having an elevated risk of AF according to the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology)-AF clinical prediction score. METHODS: Postmenopausal women with a 5-year predicted risk of new-onset AF ≥5% according to CHARGE-AF were recruited from the ongoing WHISH (Women’s Health Initiative Strong and Healthy) randomized trial of a physical activity intervention. Participants with AF at baseline by self-report or medical records review were excluded. Screening with 7-day ECG patch monitors was performed at baseline, 6 months, and 12 months from study enrollment. RESULTS: On baseline monitoring, 2.5% of the cohort had AF detected, increasing to 3.7% by 6 months and 4.9% cumulatively by 12 months. Yield of patch screening was higher among participants with a higher (≥10%) CHARGE-AF score: 4.2% had AF detected at baseline, 5.9% at 6 months, and 7.2% at 12 months. Most participants with patch-identified AF never had a clinical diagnosis of AF (36 of 46 [78%]). CONCLUSIONS: Older women with an elevated CHARGE-AF score had a high prevalence of AF on 7-day ECG patch screening. Serial screening over 12 months substantially increased the detection of AF. These data can be useful in helping identify high-risk participants for enrollment in future studies of the management of asymptomatic AF.(Women’s Health Initiative Silent Atrial Fibrillation Recording Study [WHISH STAR]; NCT05366803.)

The risk of myocardial damage after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been controversial. The purpose of this study is to report the incidence of abnormal cardiovascular findings in National Collegiate Athletic Association (NCAA) Division I student-athletes with a history of SARS-CoV-2 infection.This is a case series of student-athletes with SARS-CoV-2 infection and their subsequent cardiac work-up, including troponin level, electrocardiogram, and echocardiogram. Additional testing was ordered as clinically indicated.This study was conducted at a single NCAA Division I institution.Student-athletes were included if they tested positive for SARS-CoV-2 by PCR or antibody testing [immunoglobulin G (IgG)] from April 15, 2020 to October 31, 2020.Cardiac testing was conducted as part of postinfection screening.This study was designed to quantify abnormal cardiovascular screening results and cardiac diagnoses after SARS-CoV-2 infection in Division I collegiate athletes.Fifty-five student-athletes tested positive for SARS-CoV-2. Of these, 14 (26%) had a positive IgG and 41 (74%) had a positive PCR test. Eight abnormal cardiovascular screening evaluations necessitated further testing including cardiac magnetic resonance imaging (cMRI). Two athletes received new cardiac diagnoses, one probable early cardiomyopathy and one pericarditis, whereas the remaining 6 had normal cMRIs.These data support recent publications which recommend the de-escalation of cardiovascular testing such as cardiac MRI or echocardiogram for athletes who have recovered from asymptomatic or mildly symptomatic SARS-CoV-2 infection. Continued follow-up of these athletes for sequelae of SARS-CoV-2 is critical.

OBJECTIVES: This study sought to discover the key determinants of exercise capacity, maximal oxygen consumption (oxygen uptake [Vo2]), and ventilatory efficiency (ventilation/carbon dioxide output [VE/Vco2] slope) and assess the prognostic potential of metabolic exercise testing in hypertrophic cardiomyopathy (HCM). BACKGROUND: The intrinsic mechanisms leading to reduced functional tolerance in HCM are unclear. METHODS: The study sample included 156 HCM patients consecutively enrolled from January 1, 2007 to January 1, 2012 with a complete clinical assessment, including rest and stress echocardiography and cardiopulmonary exercise test (CPET) with impedance cardiography. Patients were also followed for the composite outcome of cardiac-related death, heart transplant, and functional deterioration leading to septal reduction therapy (myectomy or septal alcohol ablation). RESULTS: Abnormalities in CPET responses were frequent, with 39% (n = 61) of the sample showing a reduced exercise tolerance (Vo2 max 34). The variables most strongly associated with exercise capacity (expressed in metabolic equivalents), were peak cardiac index (r = 0.51, p < 0.001), age (r = -0.25, p < 0.01), male sex (r = 0.24, p = 0.02), and indexed right ventricular end-diastolic area (r = 0.31, p = 0.002), resulting in an R(2) of 0.51, p < 0.001. Peak cardiac index was the main predictor of peak Vo2 (r = 0.61, p < 0.001). The variables most strongly related to VE/VCO2 slope were E/E' (r = 0.23, p = 0.021) and indexed left atrial volume index (LAVI) (r = 0.34, p = 0.005) (model R(2) = 0.15). The composite endpoint occurred in 21 (13%) patients. In an exploratory analysis, 3 variables were independently associated with the composite outcome (mean follow-up 27 ± 11 months): peak Vo2 34 (hazard ratio: 3.14; 95% CI: 1.26 to 7.87; p = 0.014), and LAVI >40 ml/m(2) (hazard ratio: 3.32; 95% CI: 1.08 to 10.16; p = 0.036). CONCLUSIONS: In HCM, peak cardiac index is the main determinant of exercise capacity, but it is not significantly related to ventilatory efficiency. Peak Vo2, ventilatory inefficiency, and LAVI are associated with an increased risk of major events in the short-term follow-up.

Introduction: The association between poor physical fitness and adverse health outcomes is well-established, but few data are available regarding the association between fitness and health care costs. Hypothesis: Higher fitness is associated with lower overall health care costs. Methods: We studied 1,294 patients (mean 64±12 years) who underwent maximal exercise testing for clinical reasons as part of the Veterans Exercise Testing Study (VETS). Fitness was expressed as the percentage of age-predicted peak METs achieved, and categorized in quartiles. Total and annualized health care costs, derived from the VA Allocated Resource Center, were assessed between 2005 and 2010. Health care costs between quartiles of fitness were compared using ANOVA; multiple regression was used to determine clinical and exercise test predictors of health care costs. Follow-up for all-cause mortality (mean 8.5±5 years) was performed through March 2013. Results: A gradient for reduced health care costs was observed with increased fitness, with subjects in the least-fit quartile having approximately twice the overall costs as those in the fittest quartile (Table). Non-survivors were significantly less fit (6.5±5.1 vs. 9.1±3.5 METs, p Conclusions: Low fitness is associated with a significant burden on the health care system. Improving fitness should be encouraged for its potential to lower health care costs.

Early repolarization, which is characterized by an elevation of the QRS-ST junction (J point) in leads other than V(1) through V(3) on 12-lead electrocardiography, has been associated with vulnerability to ventricular fibrillation, but little is known about the prognostic significance of this pattern in the general population.We assessed the prevalence and prognostic significance of early repolarization on 12-lead electrocardiography in a community-based general population of 10,864 middle-aged subjects (mean [+/-SD] age, 44+/-8 years). The primary end point was death from cardiac causes, and secondary end points were death from any cause and death from arrhythmia during a mean follow-up of 30+/-11 years. Early repolarization was stratified according to the degree of J-point elevation (or = 0.1 mV or0.2 mV) in either inferior or lateral leads.The early-repolarization pattern of 0.1 mV or more was present in 630 subjects (5.8%): 384 (3.5%) in inferior leads and 262 (2.4%) in lateral leads, with elevations in both leads in 16 subjects (0.1%). J-point elevation of at least 0.1 mV in inferior leads was associated with an increased risk of death from cardiac causes (adjusted relative risk, 1.28; 95% confidence interval [CI], 1.04 to 1.59; P=0.03); 36 subjects (0.3%) with J-point elevation of more than 0.2 mV in inferior leads had a markedly elevated risk of death from cardiac causes (adjusted relative risk, 2.98; 95% CI, 1.85 to 4.92; P0.001) and from arrhythmia (adjusted relative risk, 2.92; 95% CI, 1.45 to 5.89; P=0.01). Other electrocardiographic risk markers, such as a prolonged QT interval corrected for heart rate (P=0.03) and left ventricular hypertrophy (P=0.004), were weaker predictors of the primary end point.An early-repolarization pattern in the inferior leads of a standard electrocardiogram is associated with an increased risk of death from cardiac causes in middle-aged subjects.

This chapter discusses research conducted to evaluate the prognostic significance of premature ventricular contractions (PVCs) on a routine electrocardiogram (ECG), and to evaluate their relationship to heart rate, heart failure and sport participation. Identifying parameters to help risk stratify patients and provide prognostic implications can help identify individuals who may benefit from early diagnosis and intervention. Our discussion utilizes research from a large database of computerized 12-lead ECGs, including 45,402 members of the US Veterans Administration, of which 352 were known to have heart failure. In addition, 750 athletes were analyzed. Echocardiograms and treadmill tests were performed on all those with heart failure and echocardiograms were part of the annual physical exam of the college athletes. Briefly, there were 1731 patients with PVCs (3.8%) in the total veteran population. Twentynine of the 352 with heart failure exhibited a PVC (8%) and 5 of the 750 athletes exhibited a PVC (0.7%). Compared to patients without PVCs, those with PVCs had significantly higher all-cause (39% vs. 22%, p 100 bpm) and by the presence or absence of PVCs, mortality increased progressively with heart rate and doubled with the presence of PVCs. Using regression analysis, heart rate was demonstrated to be an independent and significant predictor of PVCs. We identified 352 patients (64 ± 11 years; 7 females) with a history of clinical HF undergoing treadmill testing for clinical reasons at the VAPAHCS (1987-2007). Patients with rest PVCs were defined as having ≥1 PVC on the ECG prior to testing (n=29; 8%).During a median follow-up period of 6.2 years, there were 178 deaths of which 76 (42.6%) were due to CV causes. At baseline, compared to patients without rest PVCs, those with rest PVCs had a lower ejection fraction (EF) (30% vs. 45%) and the prevalence of EF≤35% was higher (75% vs. 41%). They were more likely to have smoked (76% vs. 55%).The all-cause and CV mortality rates were significantly higher in the rest PVCs group (72% vs. 49%, p=0.01 and 45% vs. 20%, p=0.002; respectively). After adjusting for age, beta-blocker use, rest ECG findings, resting heart rate (HR), EF, maximal systolic blood pressure, peak HR and exercise capacity

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Exercise-induced left bundle branch block (EI-LBBB) is an infrequent finding. Its prevalence and prognostic significance are not clear.To evaluate, in a longitudinal study, the prevalence and prognostic significance of EI-LBBB in American war veterans.We evaluated 9,623 patients submitted to an exercise test (ET) in treadmill between 1987 and 2007. The outcomes were compared between those with normal TE, the ones with EI-LBBB and the ones with down-sloping ST-segment. Mortality and causes of death were identified while blinded to the ET results.In this prospective cohort, 6,922 individuals had normal ET results (57.2 ± 11.4 years), 1,739 had abnormal ST-segment depression (62.7 ± 9.8 years), and 38 had EI-LBBB (65.2 ± 11.9 years). The prevalence of EI-LBBB was 0.38%. After 8.8 years, there were 1,699 deaths due to all-cause mortality and 610 cardiovascular (CV) deaths; coronary artery disease and heart failure were more prevalent in patients with EI-LBBB. Patients with EI-BCRE had a hazard ratio of 2.37 (p = 0.002) for all-cause mortality, but it was not significant when adjusted for age or when the CV death was the assessed outcome.EI-LBBB is a rare clinical finding. Individuals with BCRE-EI have higher all-cause mortality when compared to those with normal ET results. However, this fact is explained by the fact that these patients are significantly older and have more associated cardiovascular diseases.

Background: ST depression and T-wave amplitude abnormalities are known to be independent predictors of cardiovascular (CV) death, but a direct comparison between them has not been described. Methods: Analyses were performed on the first electrocardiogram (ECG) digitally recorded on 46,950 consecutive patients at the Palo Alto Veterans Affairs Medical Center since 1987. Females and patients with electrocardiograms exhibiting bundle branch block, left ventricular hypertrophy, electronic pacing, diagnostic Q waves, or Wolff–Parkinson–White syndrome were excluded, leaving 31,074 male patients for analysis (mean age 55 ± 14). There were 1878 (6.0%) cardiovascular deaths (mean follow-up of 6 ± 4 years). Electrocardiograms were classified using Minnesota code according to the degree of ST depression and T-wave abnormality, and the nine possible combinations of ST segment and T-wave abnormalities were recoded for analysis. Results: The combination of major abnormalities in ST segments and T-waves carried the greatest hazard [3.2 (CI 2.7–3.8)]. Minor ST depression combined with more severe T-wave abnormalities carried a hazard of 3.1 (CI 2.5–3.7), whereas minor T-wave abnormalities combined with more severe ST depression carried a hazard of only 1.9 (CI 1.6–2.3). Conclusion: While both ST segment depression and abnormal T-wave amplitude are clinically important, T-wave abnormalities appear to be greater predictors of cardiovascular mortality.

The use of exercise testing for risk stratification of patients with stable heart disease will be discussed in this chapter. This information will be evidence-based by following the ACC/AHA guidelines for Exercise Testing.1

Fourteen male patients with exercise test-induced angina and ST-segment depression underwent treadmill testing on three consecutive days to evaluate the reproducibility of certain treadmill variables. Computerized ST-segment analysis and expired gas analysis, including anaerobic threshold, were evaluated for reproducibility using an intra-class correlation coefficient analysis. Measured oxygen uptake at peak exercise displayed better reproducibility than total treadmill time, the onset of angina, and the gas exchange anaerobic threshold (ATGE). The double product, heart rate, and ST-segment displacement in lead X were found to be reproducible at peak exercise, the onset of angina, and the ATGE. The incorporation of gas exchange analysis can provide accurate physiologic determinants of exercise capacity in patients with angina pectoris. In addition, noninvasive estimates of myocardial oxygen demand and ischemia can be reproducibly determined. These findings have important implications for the design of studies evaluating the effects of an intervention on angina pectoris.