ECG screening and Sudden Cardiac Death prevention in endurance athletes
Authors: Ricciardi D , Crispino E , Liporace P , Marchi F , Sanasi L , D'amore M C , Sposito E , Italiano E L , Loiacono G , Gioia F , Picarelli F , Calabrese V , Ussia G P , Grigioni F 
Published: May 2024

Abstract

Introduction
Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport activity. Identifying non-invasive and repeatable risk markers during annual athletes screening remains a crucial goal for the scientific community for the prevention of cardiovascular disease. The ECG, exercise test and spirometry are part of the annual screening program in the sport population over 40 years of age. The Heart Rate Variability (HRV) has been shown to be an independent predictor of mortality in populations with CV disease, but its relationship with SCD has been little explored in those at low risk, including athletes. This study aims to use a 5 minute ECG screening in a specific population of athletes practicing endurance sports and evaluate its clinical repercussions.

Aims
The primary aim of the study is to assess whether morphological and spectral ECG analysis in endurance athletes by the 5-minute 'mini Holter ECG' can add information to the annual screening for the prevention of CV diseases and SCD.

Materials
The study population were selected from Endurance Marathon athletes. A control group was also collected for comparison. The 5 minutes ECG was recorded at rest with the Kardia Mobile 6L™ device that use three electrodes, which allows 6 leads recording. HRV indices were obtained using the Kubios software. A morphological analysis was performed and the HRV parameters were analyzed in the time and frequency domains.

Results
A total of 554 subjects (220 athletes-334 controls, 325 male-229 women) were analyzed. A higher incidence of sinus arrhythmias, LAFB, 1stdegree AVB, J point/ST-segment abnormalities in athletes compared to controls was observed. Athletes had a significantly shorter QTc than the control group (394.87±30.55 ms vs. 407.01±29.09 ms), suggestive of greater protection from malignant ventricular arrhythmias. The HRV PNS (-0.73±1.25 vs -0.21±1.45) and SNS (1.71±1.91 vs 0.58 ± 1.43) indices were also higher and lower in the athlete group than in the control group, suggestive for higher vagal tone. Given the absence of a normality range of standard HRV parameters in the athlete population, values in the normal range of the 5th to 95th percentile were extrapolated in the whole population for the main HRV parameters. The project, therefore, is to evaluate patients with HRV values higher or lower than 5-95 percentile to identify those deserving further clinical investigations and closer follow-up for suspected increased risk of CV disease and SCD.

Conclusions
The 5-minute cardiac Holter, combining a more accurate analysis in terms of morphology and arrhythmias than the 12-lead ECG, allows a greater number of static and dynamic alterations to be detected; moreover, the analysis of HRV could provide even more information, such that it could be considered as a complementary tool during the examination and FUP of athletes. Further long-term prospective studies are needed to correlate alterations in HRV and clinical events.