A narrative review of inherited arrhythmogenic syndromes in young population: role of genetic diagnosis in exercise recommendations.

Sudden cardiac death is a rare but socially devastating event, especially if occurs in young people. Usually, this unexpected lethal event occurs during or just after exercise. One of the leading causes of sudden cardiac death is inherited arrhythmogenic syndromes, a group of genetic entities characterised by incomplete penetrance and variable expressivity. Exercise can be the trigger for malignant arrhythmias and even syncope in population with a genetic predisposition, being sudden cardiac death as the first symptom. Due to genetic origin, family members must be clinically assessed and genetically analysed after diagnosis or suspected diagnosis of a cardiac channelopathy. Early identification and adoption of personalised preventive measures is crucial to reduce risk of arrhythmias and avoid new lethal episodes. Despite exercise being recommended by the global population due to its beneficial effects on health, particular recommendations for these patients should be adopted considering the sport practised, level of demand, age, gender, arrhythmogenic syndrome diagnosed but also genetic diagnosis. Our review focuses on the role of genetic background in sudden cardiac death during exercise in child and young population.

The use of face masks and the impact on heart rate variability during baseline ECG

We compared electrocardiograms (ECGs) findings with one year difference between each other with and without use of face mask at the moment to be tested. The first ECG was done one year before without face mask, and the second ECG with a mask one year later after 3 months of mandatory use for epidemiological COVID-19 pandemic justifications in healthy youth elite athletes.ResultsRegarding heart rate variability (HRV), an increase in RMSSD was recorded when the test was performed with a mask (M): 108.5 ± 90 ms vs. No mask (NM): 72.9 ± 54.2 ms (p <0.002). And also an increase in SDNN, when the test was done with a M: 86.2 ± 47.2 ms vs. NM: 65.9 ± 43.5 ms (p <0.036).ConclusionsThe results on ECG are consistent with the increasing predominance of parasympathetic regulation, which is responsible for regulation of the autonomic loop when the subject is using face mask. (AU)

Arrhythmogenic Cardiomyopathy and Athletes: A Dangerous Relationship.

Arrhythmogenic cardiomyopathy (ACM) is a disease characterized by a progressive replacement of myocardium by fibro-adipose material, predisposing to ventricular arrhythmias (VA) and sudden cardiac death (SCD). Its prevalence is estimated at 1:2000 to 1:5000, with a higher incidence in males, and clinical onset is usually between the 2nd and 4th decade of life. The prevalence of ACM in SCD victims is relatively high, making it one of the most common etiologies in young patients with SCD, especially if they are athletes. Cardiac events occur more frequently in individuals with ACM who participate in competitive sports and/or high-intensity training. In effect, exercise activity can worsen RV function in cases of hereditary ACM. Estimating the incidence of SCD caused by ACM in athletes remains challenging, being reported frequency ranging from 3% to 20%. Here, we review the potential implications of exercising on the clinical course of the classical genetic form of ACM, as well as the diagnostic tools, risk stratification, and the different therapeutic tools available for managing ACM.

Physiological impact of different types of mask at rest

Introduction: Due to the mandatory use of a mask in the context of the Covid-19 pandemic, we set out to evaluate the physiological impact of hypoxia and hypercapnia generated by different masks at rest.MethodsThirty-two competitive adolescent athletes (40% female) were evaluated. Room air and intra-mask measurements were taken at rest while sitting in a chair. A spirometric study was performed and the intra-mask concentration of O2 and CO2 was evaluated, comparing 3 situations: a) Home (H): mask that the subject was wearing from home. b) Surgical (S): surgical mask. c) KN95 mask (KN95).ResultsThe ambient air in the laboratory was: O2: 20.9% and CO2: 544 ± 67 ppm (0.05%); Intra-mask O2: H: 17.8 ± 0.72 %; S: 17.08 ± 0.62 %; KN95: 16.8 ± 0.56 %; (H vs S: ns; H vs NK95: p <0.001; S vs KN95: p <0.002). Intra-mask CO2: H: 1.81 ± 0.52 %; S 1.92 ± 0.35 %; KN95: 2.07 ± 0.36%; (H vs S: ns; H vs NK95: p <0.001; S vs KN95: p <0.012). CO2 levels with KN95 were lower in men 1.97 ± 0.37 % vs 2.2 ± 0.29 % than in women (p<0.04), with a significant correlation between gender and weight (r: 0.98, p: 0.01) and height (r: 0.78, p: 0.01).ConclusionsThe KN95 mask presented a lower concentration of O2, and a higher concentration of CO2 compared to the baseline situation with the surgical masks and those home-made. There is a difference in CO2 between the sexes when the KN95 mask was used, in relation to weight and height. (AU)

Pre-participation medical evaluation in competitive athletes: the experience of an international multisport club

Objective: to assess the effectiveness of a tailored Pre-Participation Medical Examination (PPME) prior to sport practice for athletes competing in team sports, has been suggested as a useful tool for an early identification and treatment of multiple disorders. Design: Among 2008 and 2018 a total of 2570 athletes from 12 to 35 years old from 12 different team sports disciplines were evaluated by the PPME of Football Club Barcelona. Methods: The PPME included: medical history, anthropometric data, physical examination, baseline 12-lead ECG, a maximal stress test, a 2D-Doppler chocardiography and an extensive orthopaedic evaluation. Results: In 495 of the 2574 athletes (19.2%), the PPME identified pathologies that require a specific treatment or a closed follow-up. The most frequent medical conditions documented in young athletes were neurological, psychological and psychiatric disorders whereas in adults the most prevalent were respiratory and immunological pathologies. Two athletes were considered inadequate to compete due to severe cardiovascular diseases whereas seven required a specific treatment for their cardiovascular diseases in order to be considered eligible for sports competition. Additionally, a large proportion of athletes (958, 37.2%) reported previous musculoskeletal sport-related injuries being bone fractures and joint injuries the most frequent ones.Conclusions: The Football Club Barcelona PPME was effective in identifying latent pathologies and musculoskeletal sport-related injuries in a significant proportion of young and adult athletes competing in team sports. The identification of these medical conditions allowed to provide an early and specific treatment and to implement strategic ad hoc preventive programs.

COVID-19: Analysis of cavitary air inspired through a mask, in competitive adolescent athletes

Introduction: Due to the mandatory use of a mask in the context of the COVID-19 pandemic, and the authorization to do outdoor sports in Catalonia, we set out to evaluate the physiological impact of the hypoxia and hypercapnia generated by the mask during aerobic exercise.Methods46 adolescent competitive athletes (35 women, 11 men) were evaluated. Measurements were taken of ambient air, at rest intra-mask, and during a stress test intra-mask. The concentration of O2 and CO2 intra-mask and the O2 Saturation were evaluated.ResultsThe O2 of ambient air in the laboratory: 20.9%; Basal intra-mask O2: 18.0±0.7% and intra-mask O2 during exercise: 17.4±0.6% (p<0.0001). The CO2 was: 0.05±0.01% environmental; baseline intra-mask: 1.31±0.5%, and during exercise intra-mask: 1.76±0.6% (p<0.0001). Baseline O2 saturation with mask was 98.4±0.6% and immediately after exercise was 97.1±2.8% (p<0.03). During the exercise intra-mask, 30% of the young athletes exceeded 2% of CO2 and 22% breathed oxygen with a concentration lower than 17%.ConclusionsThe use of masks generate hypercapnic hypoxia during exercise. One third of the subjects exceed the CO2 threshold of 2%. (AU)

Cardiac adaptation to endurance exercise training: Differential impact of swimming and running.

Objectives: High-intensity training has been associated with bi-ventricular and bi-atrial remodelling and a potentially increased risk of arrhythmias. Most of the evidence is based on endurance disciplines mainly involving the lower part of the body, while few data is available on upper body disciplines. The purpose of this study was to compare chronic cardiac remodelling induced by running and swimming as well as the acute response of ventricular and atrial performance after an upper-body and a lower-body endurance race. Methods: Standard and speckle tracking echocardiographic assessment of left ventricle, right ventricle and both atria was performed at baseline and immediately after a 9.5 km open-water swimming race in 26 healthy men and before and after a 35 km-trail-running race in 21 male runners. Results: No significant differences were observed in baseline ventricular dimensions. However, both right ventricular and atrial systolic deformation were greater in runners. This group also showed slightly larger atrial volumes as compared to swimmers. After the race, right ventricular dilatation was observed in both groups, but only runners showed a decrease in right ventricular deformation and a decrease in atrial volumes and deformation. Significant increases in atrial deformation without reduction in atrial volumes were observed only in swimmers after the race. Conclusions: Right ventricular and atrial remodelling is different depending on the endurance training discipline. Long-distance running races induce a greater impairment in right ventricular performance and atrial function compared to endurance swimming competitions.

COVID-19 and mask in sports

INTRODUCTION: Due to the mandatory use of a mask, and the authorization to do outdoor sports in Catalonia, we aimed to assess the physiological impact of the hypercapnia hypoxia generated by the masks during aerobic sports practice. METHODS: Eight subjects (2 women, 6 men) were assessed at baseline with and without a mask, and immediately after a 21-flex test performed following the Ruffier protocol with a mask. Measures of HR (heart rate), concentration of O2 and CO2 inside the mask and SatO2 were assessed. The test was carried out in ambient air in squares in the city of Barcelona. RESULTS: A decrease in O2 was recorded, and when comparing the, baseline 20.9%, baseline mask 18.3%, post-exercise 17.8% (p < 0.001). An increase in CO2 in the three preconditions (464, 14162, 17000ppm; p < 0.001). Basal saturation O2 was 97.6±1.5% and post exercise 92.1±4.12% (p 0.02). CONCLUSIONS: The use of masks in athletes causes hypoxic and hypercapnic breathing as evidenced by increased effort during exercise. The use of masks during a short exercise with an intensity around 6-8 METS, decreases O2 by 3.7% and increases the CO2 concentration by 20%

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Aortic root remodelling in competitive athletes.

BACKGROUND: Controversy remains about the cut-off limits for detecting aortic dilatation in athletes, particularly in large-sized individuals. The allometric scaling model has been used to obtain size-independent measurements in cardiovascular structures in the general population. AIM: The purpose of this study was to validate the use of allometric scaling in the measurement of the aortic root for competitive athletes and to offer reference values. METHODS: This was a cross-sectional study that analyses the dimensions of aortic root found in the echocardiogram performed as part of pre-participation sports screening in competitive athletes between 2012-2015. Beta exponents were calculated for height and body surface area in the whole cohort. In order to establish whether a common exponent could be used in both genders the following model was assessed y = axb*exp(c*sex). If a common exponent could not be applied then sex-specific beta exponents were calculated. RESULTS: Two thousand and eighty-three athletes (64% men) were included, from a broad spectrum of 44 different sports disciplines, including basketball, volleyball and handball. The mean age was 18.2 ± 5.1 years (range 12-35 years) and all athletes were Caucasian, with a training load of 12.5 ± 5.4 h per week. Indexed aortic root dimension showed a correlation with ratiometric scaling by body surface area (r: -0.419) and generated size independence values with a very light correlation with height (r: -0.084); and with the allometric scaling by body surface area (r: -0.063) and height (r: -0.070). The absolute value of aortic root was higher in men than in women (p < 0.001). These differences were maintained with allometric scaling. CONCLUSION: Size-independent aortic root dimension values are provided using allometric scaling by body surface area and height in a large cohort of competitive athletes. Aortic root values were larger in men than in women, both in absolute values and after allometric scaling. The use of these indexed aortic reference ranges can be useful for the early detection of aortic pathologies.

Cardiac performance after an endurance open water swimming race.

PURPOSE: Endurance exercise competitions have shown a transient negative effect on global right ventricular (RV) performance. Most published studies are based on terrestrial sports. The aim of our study was to evaluate the cardiac effects after an open water swimming race. METHODS: We evaluated 33 healthy swimmers (mean age 40.9 ± 7.2) participating in a 9.5 km open water swimming race. All subjects underwent a standard transthoracic echocardiography including an evaluation of dimensions and myocardial ventricular deformation. Echocardiography was performed 24 h before and within the first hour of arrival at the finish line. Cardiac troponin I (cTn I), NT-ProBNP and leukocytes were also evaluated. RESULTS: No changes in left ventricle (LV) ejection fraction or LV global longitudinal strain were observed. A significant increase in RV end-diastolic area (RVEDA) was noted after the race (RVEDA at baseline 15.12 ± 1.86; RVEDA after race 16.06 ± 2.27, p < 0.05), but no changes were seen in RV fractional area change or RV global longitudinal strain. Cardiac biomarkers and leukocytes significantly increased. No association was detected between the increase in cTn I or NT-proBNP and the RV acute dilatation or LV performance. A significant association was observed between cTn I and leukocytes (r = 0.375, p < 0.05). CONCLUSIONS: An acute RV dilatation but without an impairment in RV deformation was observed after participating in an endurance swimming race. The correlation between the increase in cTn I and leukocytes, but not with ventricular performance, may support the hypothesis of an exercise-induced increase in myocardial sarcolemmal permeability due to an inflammatory response rather than myocardial injury.

Cardiopulmonary resuscitation and use of the automatic external defibrillator in sport / Reanimación cardiopulmonar y uso del desfibrilador externo automático en el deporte

Cardiac arrest during sport practice is a low-incidence event, however, as it is commonly seen witnessed to have a high survival rate compared to general non-hospital cardiac arrest. The objective of this review is to analyze the special characteristics, give recommendations for the installation of automatic external defibrillators and the elaboration of an adequate medical action plan for each sports center (AU)

La parada cardiaca durante la práctica de deporte es un evento de baja incidencia, sin embargo, al ser habitualmente presenciado presenta una tasa de supervivencia elevada si se compara con el paro cardiaco extra-hospitalario en general. El objetivo de esta revisión es analizar las características especiales, dar recomendaciones para la instalación de desfibriladores externos automáticos y elaboración de un plan de acción médica adecuado a cada centro deportivo (AU)

Exaggerated blood pressure response to exercise and late-onset hypertension in young adults.

INTRODUCTION: Exaggerated blood pressure response (EBPR) during exercise has been associated with an increased risk of incidental systemic hypertension and cardiovascular morbidity; however, there is no consensus definition of EBPR. We aimed to determine which marker best defines EBPR during exercise and to predict the long-term development of hypertension in individuals younger than 50 years. PATIENTS AND METHODS: We reviewed 107 exercise tests performed in 1992, applied several reported methods to define EBPR at moderate and maximum exercise, and contacted the patients by telephone 20 years after the test to verify hypertension status. Finally, we determined which definition best predicted incidental hypertension at 20-year follow-up. RESULTS: The mean age of the participants at the time of exercise testing was 25.7±11.1 years. Logistic regression showed a significant association of diastolic blood pressure of more than 95 mmHg at peak exercise and systolic pressure more than 180 mmHg at moderate exercise with new-onset hypertension at 20-year follow-up [odds ratio: 6.3 (2.09-18.9) and odds ratio: 7.09 (2.31-21.7), respectively]. If EBPR was present, as defined by at least one of these parameters, the probability of incidental later onset hypertension was 70%. CONCLUSION: In our population, diastolic blood pressure of more than 95 mmHg at maximum exercise or systolic blood pressure more than 180 mmHg at moderate-intensity exercise (100 W) were the best predictors of new-onset hypertension at long-term follow-up. Individuals with EBPR according to these criteria should be monitored closely to detect the early development of hypertension.

Prevention of sudden death in adolescent athletes: Incremental diagnostic value and cost-effectiveness of diagnostic tests.

Introduction Pre-participation screening in athletes attempts to reduce the incidence of sudden death during sports by identifying susceptible individuals. The objective of this study was to evaluate the diagnostic capacity of the different pre-participation screening points in adolescent athletes and the cost effectiveness of the programme. Methods Athletes were studied between 12-18 years old. Pre-participation screening included the American Heart Association questionnaire, electrocardiogram, echocardiogram, and stress test. The cost of test was established by the Catalan public health system. Results Of 1650 athletes included, 57% were men and mean age was 15.09 ± 1.82 years. Positive findings were identified as follows: in American Heart Association questionnaire 5.09% of subjects, in electrocardiogram 3.78%, in echocardiogram 4.96%, and in exercise test 1.75%. Six athletes (0.36%) were disqualified from participation and 10 (0.60%) were referred for interventional treatment. Diagnostic capacity was assessed by the area under the curve for detection of diseases that motivated disqualification for sport practice (American Heart Association questionnaire, 0.55; electrocardiogram, 0.72; echocardiogram, 0.88; stress test, 0.57). The cost for each athlete disqualified from the sport for a disease causing sudden death was €45,578. Conclusion The electrocardiogram and echocardiogram were the most useful studies to detect athletes susceptible to sudden death, and the stress test best diagnosed arrhythmias with specific treatment. In our country, pre-participatory screening was cost effective to detect athletes who might experience sudden death in sports.

Gender influence on the adaptation of atrial performance to training.

BACKGROUND: High-intensity training has been associated with atrial remodelling and arrhythmias in men. Our purpose was to analyse atrial performance in female endurance athletes, compared to male athletes and controls. METHODS: This was a cross-sectional study. We included four groups: female athletes, females controls, male athletes and male controls. Left (LA) and right atrial (RA) volumes and function were assessed using 2D and speckle-tracking echocardiography to determine peak atrial strain-rate at atrial (SRa) and ventricular contraction (SRs), as surrogates of atrial contractile and reservoir function, respectively. ANOVA and Bonferroni's statistical tests were used to compare variables among groups. RESULTS: We included 82 subjects, 39 women (19 endurance athletes, 20 controls) and 43 men (22 endurance athletes, 21 controls). Mean age was similar between groups (36.6 ± 5.6 years). Athletes had larger bi-atrial volumes, compared to controls (women, LA 27.1 vs. 15.8 ml/m2, p < 0.001; RA 22.31 vs. 14.2 ml/m2, p = 0.009; men, LA: 25.0 vs. 18.5 ml/m2, p = 0.003; RA 30.8 vs. 21.9 ml/m2, p < 0.001) and lower strain-rate (women, LASRa -1.60 vs. -2.18 s-1, p < 0.001; RASRa -1.89 vs. -2.38 s-1, p = 0.009; men, LASRa -1.21 vs. -1.44 s-1, p = 1; RASRa -1.44 vs. -1.60 s-1, p = 1). However, RA indexed size was lower and bi-atrial deformation greater in female athletes, compared to male athletes. CONCLUSIONS: The atria of both male and female athletes shows specific remodelling, compared to sedentary subjects, with larger size and less deformation at rest, particularly for the RA. Despite a similar extent of remodelling, the pattern in women had greater bi-atrial myocardial deformation and smaller RA size.

Contraindicaciones cardiológicas para la práctica deportiva / Cardiological contraindications in sports

La muerte súbita en el deporte está causada en la mayoría de ocasiones por enfermedades cardiacas. El objetivo del cribado pre-participativo es poder identificar a los individuos que requieran un tratamiento específico para continuar el deporte o el cese de la práctica deportiva. La evidencia científica actual se basa en recomendaciones de expertos que en algunos casos son controvertidas y en ocasiones poco prácticas. Esta revisión tiene como objetivo dar un enfoque actualizado y pragmático de las recomendaciones en los deportistas con cardiopatía

In most cases, sudden death in sports is caused by heart disease. The aim of preparticipation screening is to identify individuals who require specific treatment to continue the sport or stop practicing it. Current scientific evidence is based on expert recommendations that in some cases are controversial and sometimes impractical. This review aims to present an updated and pragmatic approach to the recommendations in athletes with heart disease

Fibrosis miocárdica y extrasistolia ventricular. Caso clínico / Myocardial fibrosis and premature ventricular contraction. A clinical case

La extrasistolia ventricular aislada es un hallazgo común en la prueba de esfuerzo de algunos deportistas. No hay evidencia científica extensa en el manejo de esta situación, particularmente cuando es un hallazgo en un individuo asintomático sin antecedentes. En este caso se presenta un deportista asintomático, sin antecedentes, de 26 años, jugador de rugby profesional, con 2 extrasístoles ventriculares en la fase de recuperación de la prueba de esfuerzo (una con imagen de bloqueo de rama derecha y la otra izquierda), pruebas complementarias cardiológicas normales (Holter, ecocardiograma doppler, ECG señal promediada, tomografía coronaria) excepto el hallazgo de fibrosis transmural del ventrículo izquierdo en la resonancia cardiaca, así como la toma de decisión en relación a la aptitud deportiva en el contexto de la escasa evidencia científica disponible en estos casos (AU)

An isolated premature ventricular contraction is a common finding in some athletes. There is no extensive scientific evidence on the management of this situation, particularly when it is a finding in an asymptomatic individual with no history. The case is presented on a 26 year-old asymptomatic athlete, a professional rugby player, with no history, who had two premature ventricular contractions in the recovery phase of the effort test (one with an image of a right bundle branch block and the other with a left block). Complementary cardiological tests (Holter, Doppler echocardiogram, ECG signal averaged ECG, and coronary tomography) were normal, except for finding a left ventricular transmural fibrosis in the cardiac resonance. There is scarce scientific evidence available for decision-making in relation to sports aptitude in the context of these cases

Influence of gender on right ventricle adaptation to endurance exercise: an ultrasound two-dimensional speckle-tracking stress study.

BACKGROUND: Characteristic right ventricle (RV) remodelling is related to endurance exercise in male athletes (MAs), but data in female athletes (FAs) are scarce. Our aim was to evaluate sex-related influence on exercise-induced RV remodelling and on RV performance during exercise. METHODS: Forty endurance athletes (>10 training hours/week, 50% female) and 40 age-matched controls (<3 h moderate exercise/week, 50% female) were included. Echocardiography was performed at rest and at maximum cycle-ergometer effort. Both ventricles were analysed by standard and speckle-tracking echocardiography. RESULTS: Endurance training induced similar structural and functional cardiac remodelling in MAs and FAs, characterized by bi-ventricular dilatation [~34%, left ventricle (LV); 29%, RV] and normal bi-ventricular function. However, males had larger RV size (p < 0.01), compared to females: RV end-diastolic area (cm2/m2): 15.6 ± 2.2 vs 11.6 ± 1.7 in athletes; 12.2 ± 2.7 vs 8.6 ± 1.6 in controls, respectively, and lower bi-ventricular deformation (RV global longitudinal strain (GLS) (%): -24.0 ± 3.6 vs -29.2 ± 3.1 in athletes; -24.9 ± 2.5 vs -30.0 ± 1.9 in controls, and LVGLS: -17.5 ± 1.4 vs -21.9 ± 1.9 in athletes; -18.7 ± 1.2 vs -22.5 ± 1.5 in controls, respectively, p < 0.01). During exercise, the increase in LV function was positively correlated (p < 0.01) with increased cardiac output (∆%LV ejection fraction, r = +0.46 and ∆%LVGLS, r = +0.36). Improvement in RV performance was blunted at high workloads, especially in MAs. CONCLUSION: Long-term endurance training induced similar bi-ventricular remodelling in MAs and FAs. Independently of training load, males had larger RV size and lower bi-ventricular deformation. Improvement in RV performance during exercise was blunted at high workloads, especially in MAs. The potential mechanisms underlying these findings warrant further investigation.

Acute, Exercise Dose-Dependent Impairment in Atrial Performance During an Endurance Race: 2D Ultrasound Speckle-Tracking Strain Analysis.

OBJECTIVES: This study sought to understand and characterize the acute atrial response to endurance exercise and the influence of the amount of exercise performed. BACKGROUND: Endurance exercise seems to be recognized as a risk factor for developing atrial arrhythmia. Atrial geometrical and functional remodeling may be the underlying substrate. METHODS: Echocardiography was performed in 55 healthy adults at baseline and after a 3-stage trail race: a short race (S) (14 km), n = 17; a medium race (M) (35 km), n = 21; and a long race (L) (56 km), n = 17. Analysis consisted of standard, speckle-tracking assessment of both the left ventricle (LV) and right ventricle (RV) and both the left atrium (LA) and the right atrium (RA): a-wave strain (Sa) and strain rate (Ra) as a surrogate for atrial contractile function and s-wave strain (St) and strain rate (SR) as reservoir function. RESULTS: After the race, RA reservoir function decreased in group M (Δ% SRs: -12.5) and further in group L (Δ% SRs: -15.4), with no changes in group S. RA contractile function decreased in group L (Δ% SRa: -9.3), showed no changes in group M (Δ% SRa: +0.7), and increased in group S (Δ% SRa: +14.8). A similar trend was documented in LA reservoir and contractile function but with less pronounced changes. The decrease in RA reservoir after the race correlated with the decrease in RV global longitudinal strain (GLS) (Δ% RVGLS vs. RASt and RASRs: +0.44; p < 0.05 and +0.41, respectively; p < 0.05). CONCLUSIONS: During a trail-running race, an acute exercise-dose dependent impairment in atrial function was observed, mostly in the RA, which was related to RV systolic dysfunction. The impact on atrial function of long-term endurance training might lead to atrial remodeling, favoring arrhythmia development.

Impacto del aire enrarecido de una cueva mediterránea en humanos, a nivel cardiovascular / Effect of rarefied air in a Mediterranean cave at cardiovascular level in humans

Introducción: Estudio de la adaptación fisiológica en personas respirando aire enrarecido en una sima. Objetivo: Investigar la capacidad arritmogénica del aire enrarecido y las alteraciones del sistema nervioso autónomo (simpático y parasimpático). Establecer unos niveles de corte más allá de los cuales hay que tomar medidas preventivas. Método: Veinticinco espeleólogos, 6 de ellos pertenecientes a cuerpos profesionales de rescate, sometidos a controles en reposo en el exterior, respirando aire de composición normal (NA), y un control subterráneo, también en reposo, respirando aire enrarecido de origen natural (RA) en un espacio confinado (O2: 13,38 ± 1,5% y CO2: 2,23 ± 0,31%). Monitorizados mediante control Holter cardíaco y presión arterial. Resultados: Pulso cardíaco de reposo (NA: 81,9 ± 15,1 latidos vs. RA: 83,8 ± 17,3 latidos en RA; p ≤ 0,58). Presión arterial sistólica (NA: 130,3 ± 17,2 mmHg vs. RA: 140,2 ± 21,3 mmHg; p ≤ 0,0003). Presión arterial diastólica (NA: 78,2 ± 11,0 mmHg vs. RA: 85,5 ± 11,2 mmHg; p ≤ 0,0002). Variabilidad cardíaca: RMSSD (NA: 25,9 ± 13,8 ms vs. RA: 36,9 ± 17,8 ms; p ≤ 0,003); NN50 (NA: 49,0 ± 66,2 latidos vs. RA: 111,7 ± 102,8 latidos; p ≤ 0,003); pNN50 (7,5 ± 11,3% en NA vs. 15,9 ± 15,8% en RA; p ≤ 0,0013). Análisis de Fourier: TP (NA: 1.759,5 ms2 vs. RA: 2.611,5 ms2; p < 0,04); HF (NA: 301,5 ± 329,4 ms2 vs. RA: 662,3 ± 762,8 ms2; p ≤ 0,02). Se detecta un incremento de los acontecimiento arrítmicos cuando comparamos la hora que incluye la prueba 1 (HNA) con aire de proporciones normales versus la hora que incluye la prueba 2 (HRA) con aire enrarecido. Hay una clara correlación estadística de eventos arrítmicos en ambas situaciones: (latidos ectópicos en RA) = 2,9859 × (latidos ectópicos en NA) + 1,5622; n = 24; r = 0,814; p < 0,0001. Conclusiones:La exposición al aire enrarecido en reposo de tan solo 10 min provoca una respuesta presora de la presión arterial sistólica y diastólica, comparada con aire normal. La variabilidad cardíaca, en situación de reposo estandarizada, muestra una respuesta de tipo parasimpático, con el aumento de los parámetros rMSSD y HF cuando los sujetos están sometidos a una atmósfera de aire enrarecido. En este caso, compuesto por 13% de O2 y 2,5% de CO2. En aire enrarecido, como el de la sima estudiada, los sujetos presentaban el triple de fenómenos arrítmicos que cuando realizan una tarea con carga similar en aire estándar

Introduction: Study of physiological adaptation in people breathing rarefied air in a cave. Objective: To investigate the arrhythmogenic capacity of rarefied air and changes the autonomic nervous system (sympathetic and parasympathetic). To establish cutoff levels beyond which preventive measures must be taken. Method: The study included 25 cavers, monitored by ECG Holter and blood pressure measurements in 2 situations at rest, one outside the cave breathing normal air composition (NA), and the other underground, breathing rarefied air of natural origin (RA) in a confined space (O2: 13.38 ± 1.5% and CO2: 2.23 ± 0.31%). Results: Resting heart rate (NA: 81.9 ± 15.1 beats per minute (bpm) vs. RA: 83.8 ± 17.3 bpm; P ≤ .58). Systolic blood pressure (NA: 130.3 ± 17.2 mmHg vs. RA: 140.2 ± 21.3 mmHg; P ≤ .0003). Diastolic blood pressure (NA: 78.2 ± 11.0 mmHg vs. RA: 85.5 ± 11.2 mmHg; P ≤ .0002). Heart rate variability: RMSSD (NA: 25.9 ± 13.8 ms vs. RA: 36.9 ± 17.8 ms; P ≤ .003), NN50 (NA: 49.0 ± 66.2 bpm vs. RA: 111.7 ± 102.8 bpm; P ≤ .003); pNN50 (NA: 11.3% ± 7.5 vs. RA: 15.9 ± 15.8%; P ≤ .0013). Fourier analysis: TP (NA: 1,759.5 ms2 vs. RA: 2,611.5 ms2; P ≤ .04); HF (NA: 301.5 ± 329.4 ms2 vs. RA: 662.3 ± 762.8 ms2; P ≤ .02). An increase in arrhythmic events is detected when comparing the hour that included test 1 (HNA) in normal air with the hour that included test 2 (HRA) with rarefied air. There is a correlation of arrhythmic events in both situations: (ventricular ectopic beats in RA) = 2.9859 × (ventricular ectopic beats NA) + 1.5622; n = 24; r = 0.814; P<0001. Conclusions: Exposure to RA at rest for 10 minutes causes a pressor response in systolic and diastolic blood pressure compared to normal air (NA). Heart rate variability in a standardised situation and rest shows a parasympathetic response, with increased rMSSD and HF parameters when subjects are subjected to an atmosphere of RA. In RA, the subjects had three times more arrhythmic events when compared to NA