Sudden Cardiac Death in Athletes: From the Basics to the Practical Work-Up

Comparison of 6-lead smartphone ECG and 12-lead ECG in athletes and a genetic heart disease population

BACKGROUND

Smartphone electrocardiograms (iECGs) are an innovative method of capturing transient arrhythmias that are occasionally experienced by athletes. This study aimed to assess the accuracy of a 6-lead iECG compared with 12-lead ECG in athletes and those with known genetic heart disease (positive controls).

RESEARCH DESIGN AND METHODS

Each participant had a resting 12-lead ECG (supine) and a 30 s 6-lead iECG (seated) taken within 2 h. Manual measurements of heart rate, QTc, and PR intervals, and QRS duration were completed using digital calipers. Bland-Altman analysis was used to assess the quantitative agreement of measurements.

RESULTS

The 6-lead readings for heart rate were faster than the 12-lead in athletes (n = 233) and positive controls (n = 49). All other measurements were shorter in the 6-lead. QTc mean difference was smaller in the positive controls (4.7 ± 26.0 ms) than in athletes (12.5 ± 25.0 ms). The largest difference was in PR intervals, both in athletes (12.8 ± 17.7 ms) and positive controls (7.6 ± 18.9 ms). QRS duration had the smallest mean difference (0.6 ± 9.0 ms in athletes, 1.0 ± 12.7 ms in positive controls).

CONCLUSIONS

The 6-lead readings had reasonable agreement with the 12-lead ECG. A 6-lead iECG is a reasonable option to opportunistically capture arrhythmias that may occur infrequently, but should not replace a 12-lead if available.

Relative utility of portable ECG devices in capturing arrhythmias in athletes

INTRODUCTION

Traditional monitoring of athletes with cardiac symptoms is limited due to sport-specific considerations and the intermittent nature of symptoms. Some portable electrocardiogram (ECG) devices may have more diagnostic utility than traditional monitoring. Their accuracy, advantages, and limitations should be considered when a clinician is considering the most appropriate device for investigation of an athlete's symptoms.

AREAS COVERED

There are six main categories of portable ECG devices: smartwatches, handheld devices, mobile cardiac telemetry (MCT), patches, rings, and chest sensors. The aim of this review is to highlight to a clinician the potential benefits of some devices over others to assist the physician in identifying the most appropriate device. We present peer-reviewed literature on the accuracy of each type of device along with advantages and limitations.

EXPERT OPINION

For a user-initiated capture of an ECG, smartwatches and handheld devices are easy to use and supported by peer-reviewed literature. Rings can also provide a user-initiated ECG, though there is limited evidence to support their usage. For continuous monitoring, patches and MCT are both useful, though there is limited access to these devices. Chest sensors show some promise, although access is currently limited in some countries.

Catheter ablation versus antiarrhythmic drug therapy for sustained ventricular tachycardia in patients with hypertrophic cardiomyopathy

BACKGROUND

Ventricular tachycardia (VT) is the primary cause of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, the strategy for VT treatment in HCM patients remains unclear. This study is aimed to compare the effectiveness of catheter ablation versus antiarrhythmic drug (AAD) therapy for sustained VT in patients with HCM.

METHODS

A total of 28 HCM patients with sustained VT at 4 different centers between December 2012 and December 2021 were enrolled. Twelve underwent catheter ablation (ablation group) and sixteen received AAD therapy (AAD group). The primary outcome was VT recurrence during follow-up.

RESULTS

Baseline characteristics were comparable between two groups. After a mean follow-up of 31.4 ± 17.5 months, the primary outcome occurred in 35.7% of the ablation group and 90.6% of the AAD group (hazard ratio [HR], 0.29 [95%CI, 0.10-0.89]; P = 0.021). No differences in hospital admission due to cardiovascular cause (25.0% vs. 71.0%; P = 0.138) and cardiovascular cause-related mortality/heart transplantation (9.1% vs. 50.6%; P = 0.551) were observed. However, there was a significant reduction in the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation in ablation group as compared to that of AAD group (42.9% vs. 93.7%; HR, 0.34 [95% CI, 0.12-0.95]; P = 0.029).

CONCLUSIONS

In HCM patients with sustained VT, catheter ablation reduced the VT recurrence, and the composite endpoint of VT recurrence, hospital admission due to cardiovascular cause, cardiovascular cause-related mortality, or heart transplantation as compared to AAD.

Effects of Sixty-Minute Race-Pace Running on Cardiac Stress Biomarkers in Recreational Distance Runners

Sudden cardiac death (SCD) in athletes is generally rare, but a serious complication of cardiovascular events during exercise. Although regular intensive physical exercise is thought to be a key to a healthy life, unsuspected pathologies might lead to SCD during or after physical activity. Cardiac dysfunction and elevated cardiac markers have been reported after prolonged exercise. We sought to clarify the cardiac marker levels and hydration status in healthy, middle-aged male subjects for 24 hours after running sixty-minute at race-pace. The participants were 47.4±1.7 years old, had peak oxygen consumption of 47.1±1.2ml/kg/min, and regularly running 70.5±6.4km/week. Blood biomarkers were performed before, immediately after, at the fourth and twenty-fourth hours after running. Compared to initial values, creatine kinase (before:161.2±22.5U/L, 24 hours after:411.9±139.7U/L, p<0.001) and CK-MB (before:4.3±0.7ng/ml, 24 hours after:10.1±3.0ng/ml, p<0.001) were significantly elevated immediately after running and remained significantly high for 24 hours. In addition, Troponin-I (before:5.0±1.1ng/l, 4 hours after:81.5±29.9ng/l, p<0.001) and NT-proBNP (before: 31.2±5.3pg/ml, immediately after: 64.4±8.5pg/ml, p<0.01) were significantly elevated immediately after running and returned to baseline levels in 24 hours. The sixty-minute running caused significant dehydration, but athletes were rehydrated at the 4th hour in their voluntary hydration behavior. As the individual data were analyzed, it was interesting to see that some of the athletes had critical biomarker levels without any cardiac symptom. Our findings indicate that race-pace sixty-minute running may induce a possible transient silent myocardial injury in apparently healthy master runners. Detailed pre-participation screening of these athletes may be necessary to reduce the risk of SCD.

The Prevalence of Cardiovascular Diseases in Paralympic Athletes

Paralympic participants represent a special subset of athletes. Although sudden cardiac death in this group is a rare event, it should be underlined that, in particular, Paralympians with movement restrictions have a higher prevalence of coronary heart disease. Numerous reports have focused on comparing athletes with spinal cord injury (SCI) and the ones with non-spinal cord injury-NSCI. The first group is more prone to develop arrhythmias, arterial hypertension, hyperlipidaemia including atrial fibrillation and atrial flutter, and this group potentially may have a higher risk of cardiovascular mortality. In ECGs of the disabled athletes with SCI, we more often find changes typically established as consequences of exercise training, such as T-wave inversions. The potential differences in the cardiovascular status of disabled athletes may depend not only on the class of impairment, but also on the discipline of sport and environmental conditions, which makes the analysis relatively complex. The paper analyses up-to-date articles discussing the cardiovascular problems in disabled athletes, pointing to scarce data in several fields of interest. Previous studies on the frequency of abnormalities of the cardiovascular system in Paralympic athletes highlighted the need to intensify preventive cardiology care for this group of athletes, and some activities could be proposed for sportsmen and sportswomen in this group, including more frequent screening ECG, application of 24 h ECG Holter monitoring, echocardiography and cardiological care. Due to the relatively few data available and existing discrepancies in this area, further research is necessary.

Cardiac Biomarkers and Autoantibodies in Endurance Athletes: Potential Similarities with Arrhythmogenic Cardiomyopathy Pathogenic Mechanisms

The “Extreme Exercise Hypothesis” states that when individuals perform training beyond the ideal exercise dose, a decline in the beneficial effects of physical activity occurs. This is due to significant changes in myocardial structure and function, such as hemodynamic alterations, cardiac chamber enlargement and hypertrophy, myocardial inflammation, oxidative stress, fibrosis, and conduction changes. In addition, an increased amount of circulating biomarkers of exercise-induced damage has been reported. Although these changes are often reversible, long-lasting cardiac damage may develop after years of intense physical exercise. Since several features of the athlete’s heart overlap with arrhythmogenic cardiomyopathy (ACM), the syndrome of “exercise-induced ACM” has been postulated. Thus, the distinction between ACM and the athlete’s heart may be challenging. Recently, an autoimmune mechanism has been discovered in ACM patients linked to their characteristic junctional impairment. Since cardiac junctions are similarly impaired by intense physical activity due to the strong myocardial stretching, we propose in the present work the novel hypothesis of an autoimmune response in endurance athletes. This investigation may deepen the knowledge about the pathological remodeling and relative activated mechanisms induced by intense endurance exercise, potentially improving the early recognition of whom is actually at risk.