RESUMEN
BACKGROUND: Recent guidelines published by the joint European Society of Hypertension/European Society of Cardiology have suggested the inclusion of C-reactive protein (CRP) in the standard assessment of cardiovascular risk in hypertensive patients, but few data are available on the role of CRP in patients with carotid lesions. METHODS: We studied 472 patients, 236 with and 236 without hypertension, sex- and age-matched, with and without early stages of atherosclerosis (e.g. those with an asymptomatic intima-media thickness of >0.9 mm), the influence of all the other traditional cardiovascular risk factors (e.g. older age, male sex, obesity, diabetes, smoking habit, family history of coronary artery disease, dyslipidaemia) and of high-sensitivity CRP levels on cerebrovascular and cardiovascular events in a 5-year follow up. RESULTS: At the end of follow up, patients with hypertension had more events than those without (25% vs 17%, P < 0.05). Proportional hazard analysis revealed in the group of patients without hypertension the presence of baseline carotid lesions (P= 0.02) as predictor of events. In patients with hypertension, the presence of baseline carotid lesions (P= 0.04) and elevated CRP levels (P= 0.02) predicted clinical events. Patients with hypertension also showed a significant relationship between clinical events and quintiles of CRP levels (P < 0.01). CONCLUSION: Beyond the utility of high-sensitivity CRP levels in the prediction of early and late stages of atherosclerosis and subsequently on its association with clinical events, the therapeutic implications of these results remain to be evaluated by further studies.
Asunto(s)
Aterosclerosis/sangre , Aterosclerosis/complicaciones , Proteína C-Reactiva/metabolismo , Hipertensión/sangre , Hipertensión/complicaciones , Anciano , Aterosclerosis/epidemiología , Biomarcadores/sangre , Proteína C-Reactiva/análisis , Estudios de Casos y Controles , Trastornos Cerebrovasculares/sangre , Trastornos Cerebrovasculares/epidemiología , Trastornos Cerebrovasculares/etiología , Femenino , Estudios de Seguimiento , Humanos , Hipertensión/epidemiología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Factores de RiesgoRESUMEN
BACKGROUND: A reduced level of daily activities is thought to be an important determinant of aerobic exercise intolerance in patients with chronic heart failure chronic heart failure; however, few data exist about the relationship between habitual physical activity level and peak aerobic capacity in patients at different clinical stages of left ventricular dysfunction. STUDY OBJECTIVES: The purposes of this study were as follow: (1) to validate a simple interviewer-administered scoring system for evaluation of habitual physical activity level of patients with chronic heart failure and asymptomatic left ventricular dysfunction (ALVD); (2) to determine the relationship between habitual physical activity level and peak aerobic capacity in chronic heart failure and ALVD patients; and (3) to compare habitual activity levels among different New York Heart Association (NYHA) classes in these populations. SETTING: Cardiology division at a tertiary-care hospital. STUDY POPULATION: We studied 167 consecutive patients with chronic heart failure (NYHA class I to III), 40 patients with ALVD, and 52 healthy subjects (HS). MEASUREMENTS AND RESULTS: Habitual physical activity level was evaluated by means of an interview-based activity scoring system considering leisure time and occupational activities and also recent deconditioning events (eg, hospital admissions); a final activity score (AS) ranging from 0.8 to 5 was obtained. All patients and HS performed a symptom-limited cardiopulmonary exercise test up to a respiratory exchange ratio of > or = 1.1. AS was an independent predictor of peak oxygen consumption (VO(2)) in all groups, with a significantly higher VO(2) vs AS relationship slope in the ALVD and HS groups than in the chronic heart failure group. Moreover, AS was found to be significantly lower in chronic heart failure than in ALVD patients and HS (1.6 +/- 0.6 vs 2.2 +/- 0.7 vs 3.5 +/- 1.1, respectively; p < 0.0001), as was peak VO(2) (14.7 +/- 3.7 mL/kg/min vs 20 +/- 4 mL/kg/min vs 33.1 +/- 10 mL/kg/min, respectively; p < 0.0001), but the latter differences were canceled after adjusting for AS values. Significant AS and peak VO(2) reductions were observed in chronic heart failure patients with NYHA class progression from I to III. CONCLUSIONS: Habitual physical activity level is progressively decreased with worsening of heart failure symptoms and is related to peak aerobic capacity in both chronic heart failure and ALVD patients. However, this relationship appears to be weak in patients with chronic heart failure, whereas daily activity is a strong independent predictor of peak aerobic capacity both in ALVD patients and HS. This may be related to the intervention of factors other than skeletal muscle deconditioning in the exercise pathophysiology of chronic heart failure patients.
Asunto(s)
Actividades Cotidianas/clasificación , Prueba de Esfuerzo , Disfunción Ventricular Izquierda/diagnóstico , Adulto , Anciano , Enfermedad Crónica , Metabolismo Energético/fisiología , Femenino , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Disfunción Ventricular Izquierda/fisiopatología , Función Ventricular Izquierda/fisiologíaRESUMEN
We report the case of a VDD single-lead pacemaker implantation through a persistent left superior vena cava in a 48-year-old male patient with recurrent episodes of syncope due to paroxysmal atrioventricular block. VDD lead insertion through the anomalous venous structure led to positioning of the floating sensing dipole into the coronary sinus, in a very large and stable sensed atrial signal due to the close anatomic relationship between the coronary sinus and the left atrium. Shortness of the sensed atrioventricular interval allowed VDD stimulation to occur only in the case of paroxysmal atrioventricular block.
Asunto(s)
Estimulación Cardíaca Artificial , Bloqueo Cardíaco/terapia , Vena Cava Superior , Cateterismo , Humanos , Masculino , Persona de Mediana Edad , Vena Cava Superior/anomalíasRESUMEN
In a previous paper, as the first of a series of three on the importance of characteristics and modalities of physical activity (PA) and exercise in the management of cardiovascular health within the general population, we concluded that, in the population at large, PA and aerobic exercise capacity clearly are inversely associated with increased cardiovascular disease risk and all-cause and cardiovascular mortality and that a doseresponse curve on cardiovascular outcome has been demonstrated in most studies. More and more evidence is accumulated that engaging in regular PA and exercise interventions are essential components for reducing the severity of cardiovascular risk factors, such as obesity and abdominal fat, high BP, metabolic risk factors, and systemic inflammation. However, it is less clear whether and which type of PA and exercise intervention (aerobic exercise, dynamic resistive exercise, or both) or characteristic of exercise (frequency, intensity, time or duration, and volume) would yield more benefit for each separate risk factor. The present paper, therefore, will review and make recommendations for PA and exercise training in the management of cardiovascular health in individuals with cardiovascular risk factors. The guidance offered in this series of papers is aimed at medical doctors, health practitioners, kinesiologists, physiotherapists and exercise physiologists, politicians, public health policy makers, and individual members of the public. Based on previous and the current literature overviews, recommendations from the European Association on Cardiovascular Prevention and Rehabilitation are formulated regarding type, volume, and intensity of PA and regarding appropriate risk evaluation during exercise in individuals with cardiovascular risk factors.
Asunto(s)
Actividades Cotidianas , Enfermedades Cardiovasculares/prevención & control , Terapia por Ejercicio/normas , Ejercicio Físico/fisiología , Obesidad/rehabilitación , Guías de Práctica Clínica como Asunto , Salud Pública , Enfermedades Cardiovasculares/etiología , Humanos , Obesidad/complicaciones , Factores de RiesgoAsunto(s)
Prueba de Esfuerzo , Ejercicio Físico , Insuficiencia Cardíaca/fisiopatología , Adulto , Carbazoles/uso terapéutico , Carvedilol , Niño , Método Doble Ciego , Disnea/etiología , Electrocardiografía , Femenino , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/terapia , Frecuencia Cardíaca , Humanos , Entrevistas como Asunto , Estilo de Vida , Masculino , Persona de Mediana Edad , Propanolaminas/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Análisis de Regresión , Encuestas y Cuestionarios , Factores de Tiempo , Vasodilatadores/uso terapéutico , CaminataRESUMEN
Type-A right atrial thrombosis is characterized by echocardiographic detection of mobile worm-shaped thromboemboli in the right atrium, with a high propensity to embolic dislocation into the pulmonary circulation. This type of thrombus is associated with a very high mortality rate that exceeds 60% in untreated patients. Surgical embolectomy has been proposed as the treatment of choice, but the availability of an experienced surgical staff and the patients' eligibility for surgical treatment cannot be taken for granted. Efficacy of systemic thrombolysis for treatment of type-A right atrial thrombosis has repeatedly been reported during the past few years, with early mortality rates comparable to those of surgical approach. The major advantages of thrombolysis would be ease of administration and independence of patient's hemodynamic status. Our experience confirms these impressions and argues in favor of the routine use of systemic thrombolysis in the presence of a type-A right atrial thrombus, while reserving surgical embolectomy for patients with formal contraindications to thrombolysis.
Asunto(s)
Fibrinolíticos/uso terapéutico , Cardiopatías/tratamiento farmacológico , Estreptoquinasa/uso terapéutico , Terapia Trombolítica , Trombosis/tratamiento farmacológico , Activador de Tejido Plasminógeno/uso terapéutico , Anciano , Anciano de 80 o más Años , Femenino , Atrios Cardíacos/diagnóstico por imagen , Cardiopatías/clasificación , Cardiopatías/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Proteínas Recombinantes/uso terapéutico , Trombosis/clasificación , Trombosis/diagnóstico , UltrasonografíaRESUMEN
Twenty-two subjects with Wolff-Parkinson-White (WPW) electrocardiographic pattern performing agonistic physical activity were referred to our laboratory to assess arrhythmogenic risk (group 1). This allowed us to evaluate a less known aspect, namely that of effects of training on the electrophysiologic properties of the atrium and accessory pathway. This was done utilizing a control group of 10 WPW patients who did not perform agonistic physical activity (group 2). All subjects were symptom free, and without signs of associated cardiopathy if we exclude 1 patient of group 1, who presented moderate mitral valve prolapse. Group 1 patients showed significantly higher mean values for basic cycle length (p less than 0.001), atrial effective (p less than 0.04) and functional (p less than 0.02) refractory period, and anterograde effective refractory period of the accessory pathway (p less than 0.02). The different behavior observed in group 1 patients could be explained considering the known influence of training on the equilibrium of the autonomic nervous system. Moreover, it is noteworthy that the two groups did not differ for inducibility of atrial fibrillation (AF). This should be taken into account considering the importance of AF in WPW. In conclusion, our study does not demonstrate any negative electrophysiologic effects of training in patients with WPW.
Asunto(s)
Función Atrial , Electrocardiografía , Deportes , Síndrome de Wolff-Parkinson-White/fisiopatología , Adolescente , Adulto , Fibrilación Atrial/fisiopatología , Ejercicio Físico/fisiología , Femenino , Humanos , Masculino , Factores de RiesgoRESUMEN
Programmed atrial stimulation at five atrial sites was performed to evaluate electrophysiologic atrial properties in 17 control patients (14 M, 3F, mean age 61 +/- 9 years) (Group A) and in 18 patients with paroxysmal atrial fibrillation (13 M, 5 F, mean age 61 +/- 5 years) (Group B) with normal sinus node function. The mean value of the P wave duration was similar in both groups. Programmed atrial stimulation was performed at five atrial sites: high, medium and low lateral wall, and high and low medial wall. We evaluated the following parameters: A) local conduction delay measured at the functional refractory period as the difference between A1-A2 and S1-S2 intervals; B) widening of local electrogram measured at the functional refractory period as the difference between A1-A2 interval measured at the end of each local electrogram and A1-A2 interval measured at the beginning of each local electrogram. We evaluated the mean and the maximum value of the two above-mentioned parameters; C) dispersion of effective refractory period and functional refractory period, determined as the longest minus the shortest refractory period from the range of refractory periods measured in each patient; D) the mean of effective refractory periods and functional refractory periods observed at five atrial sites. Mean and maximum local conduction delay, mean effective and functional refractory periods did not present significant differences in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Fibrilación Atrial/fisiopatología , Adulto , Anciano , Estimulación Eléctrica , Electrocardiografía , Femenino , Atrios Cardíacos/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Periodo Refractario ElectrofisiológicoRESUMEN
In 22 patients (age range 13-40 years) with Wolff-Parkinson-White ECG pattern without evidence of associated cardiomyopathy we measured the anterograde effective refractory period of the accessory pathway (ERP-AP) by extrastimulus method (at twice diastolic threshold) during atrial pacing (100/min). The ERP-AP range was 220-480 ms. There was a significant direct correlation between age and ERP-AP (r = 0.50, p less than 0.01). An ERP-AP less than or equal to 250 ms was found in 4 patients (age less than or equal to 23 years). This is noteworthy in the light of reports that, over the years: (1) typical Wolff-Parkinson-White ECG signs can disappear and (2) the frequency of tachycardic episodes decreases. Our data suggest a lower risk of high ventricular rates during atrial fibrillation with increasing age.
Asunto(s)
Electrocardiografía , Sistema de Conducción Cardíaco/fisiopatología , Síndrome de Wolff-Parkinson-White/fisiopatología , Adolescente , Adulto , Factores de Edad , Femenino , Humanos , MasculinoRESUMEN
BACKGROUND: Several studies have evidenced that hypertensive patients (pts) with left ventricular hypertrophy (LVH) have an increased incidence of malignant ventricular arrhythmias and sudden death. The purpose of our study was to investigate the prevalence of risky ventricular arrhythmias in uncomplicated hypertensive pts (untreated during last 10 days) in comparison with normotensive ones. In this context, not only the value of left ventricular mass index (LVMI) was taken into account, but also the type of LVH and the related functional behaviour. PATIENTS AND METHODS: 59 untreated mild to moderate essential hypertensives (EH), without symptoms or signs of coronary artery disease, were classified in 3 groups: normal (i.e. without hypertrophy) EH (NEH: 12 pts, 6 M and 6 F, mean age +/- SD 52 +/- 10 yrs), concentric hypertrophic EH (CEH: 30 pts, 15 M and 15 F, mean age +/- SD 59 +/- 10 yrs), and eccentric hypertrophic EH (EEH: 17 pts, 7 M and 10F, mean age +/- SD 60 +/- 10 yrs), according to echocardiographic measurements. Values and duration of arterial hypertension were comparable among the groups. A normotensive, age-matched group was studied as control (C: 21 pts, 11 M and 10 F, mean age +/- SD, 57 +/- 10 yrs). 24-hour Holter electrocardiographic monitoring (ECG-H) and Signal-Averaged electrocardiography (SAECG) were performed seeking to identify the arrhythmogenic risk. Echocardiographic analysis was accomplished by means of a computerized system: LVMI, ratio of LV wall thickness to LV internal radius (relative wall thickness = RWTh), systolic velocity of circumferential fractioning (VCFs), peak of LV relaxation rate (pLVRr) and peak-systolic stress (pSS) were evaluated. RESULTS: Normal LV systolic function was generally found, but both NEH and EEH groups showed a significant reduction in pLVRr in comparison with C and CEH groups (mean values +/- SD: 3.52 +/- 1,3 and 3.40 +/- 0.9 vs 4.92 +/- 0.4 and 4.27 +/- 1.4 sec-1, respectively, p < .05 for both). pSS was significantly higher in EEH and NEH than in CEH and C (mean values +/- SD: 149 +/- 42 and 157 +/- 66 vs 116 +/- 28 and 122 +/- 15 10(3) dynes/cm2, respectively; p < .05 for both). At ECG-H, EEH had a prevalence of potentially malignant ventricular arrhythmias (PMVA: ventricular extrasystoles > or = 30/h; ventricular couplets, > or = 2 episodes/24h, or triplets, > or = 1 episode/24h; R on T), significantly larger than in C (35.3% vs 4.8%, p < .05) and almost significantly larger than in NEH and CEH (8.3% and 10%, respectively). No differences in LVMI were found between EEH with or without PMVA. In respect of functional LV behaviour, the former group showed lower values of VCFs (2.33 +/- 0.6 vs 3.71 +/- 1.32 sec-1, (p < .005) than the latter group. At SAECG, the EEH exhibited again a greater prevalence of abnormal findings than C (35.3% vs 0%, p < 0.5). No correlations were found between ECG-H and SAECG abnormalities, nor between the latter group and LVMI or LV functional indexes. Among pts showing a more pronounced impairment of diastolic function (pLVRr < 4 sec-1), EEH exhibited the highest prevalence of both PMVA (50%) and late potentials (41%). CONCLUSIONS: Our data suggest that uncomplicated mild to moderate essential hypertension may be associated with higher risk of ventricular arrhythmias, particularly when cardiac involvement is characterized by eccentric LVH. On the contrary, in this stage of hypertensive disease, LVMI as well as LV function do not seem to influence the ventricular arrhythmogenesis. The clinical importance of these findings is uncertain, and further studies are needed.
Asunto(s)
Arritmias Cardíacas/etiología , Hipertensión/complicaciones , Hipertrofia Ventricular Izquierda/complicaciones , Adulto , Anciano , Ecocardiografía , Electrocardiografía , Electrocardiografía Ambulatoria , Femenino , Corazón/fisiopatología , Ventrículos Cardíacos , Humanos , Hipertensión/clasificación , Hipertensión/fisiopatología , Hipertrofia Ventricular Izquierda/diagnóstico , Hipertrofia Ventricular Izquierda/fisiopatología , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
The case of a 83-year-old patient undergoing DDD pacemaker implantation for sick sinus syndrome with postimplant detection of advanced interatrial conduction block is described. At nominal AV interval programming values (175 ms), absence of P wave following an atrial spike was observed, and the presence of an interatrial conduction disturbance was demonstrated by a Doppler transmitral flow pattern analysis and transesophageal ECG recording. AV interval lengthening up to 300 ms resulted in proper timing of atrial and ventricular contractions. Awaiting for conclusive data about biatrial pacing, interatrial conduction blocks can be managed in some cases by proper programming of conventional DDD systems.
Asunto(s)
Nodo Atrioventricular/fisiopatología , Bloqueo Cardíaco/terapia , Marcapaso Artificial , Anciano , Anciano de 80 o más Años , Electrocardiografía , Bloqueo Cardíaco/diagnóstico , Bloqueo Cardíaco/fisiopatología , Humanos , MasculinoRESUMEN
The purpose of this study was to evaluate the wavelength index (WLI) at three atrial sites in a group of 23 patients with recurrent episodes of lone paroxysmal atrial fibrillation (LPAF) and a control group (n = 20). All patients underwent programmed atrial stimulation (paced cycle length = 600 ms) at high, medium, and low lateral right atrial wall. P wave duration, sinus cycle length, and corrected sinus node recovery time were not significantly different between the two study groups. WLI was calculated according to the following formulas: atrial effective refractory period (AERP)/duration of atrial extrastimulus electrogram (A2) or AERP/A2 + atrial latency; and atrial functional refractory period (AFRP)/A2. WLI was significantly shorter in LPAF than in the control group at each of the paced atrial sites independently of the formula used. Duration of premature atrial electrogram appeared to play the major role in determining the difference in WLI between patients with paroxysmal atrial fibrillation and the control group.
Asunto(s)
Fibrilación Atrial/fisiopatología , Sistema de Conducción Cardíaco/fisiopatología , Fibrilación Atrial/diagnóstico , Función del Atrio Derecho/fisiología , Estimulación Cardíaca Artificial , Estudios de Casos y Controles , Electrofisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Periodo Refractario Electrofisiológico/fisiologíaRESUMEN
The mechanism(s) responsible for the release of brain natriuretic peptide (BNP), a cardiac hormone of ventricular origin, are still not completely understood. We measured plasma atrial natriuretic peptide (ANP) and BNP in 15 subjects (10 men, mean age 67 +/- 3 years) with a dual chamber pacemaker and unimpaired heart function during ventricular pacing, which is known to induce an increase in atrial pressure and plasma ANP concentration. Under ECG monitoring, all subjects received sequential atrioventricular pacing for 30 minutes and ventricular pacing for 30 minutes, at the same rate of 80 beats/min. Arterial pressure and plasma BNP and ANP levels were measured every 10 minutes throughout the study. Ventricular pacing led to atrioventricular dissociation in eight subjects and to retrograde ventriculo-atrial conduction in seven. Arterial pressure remained unchanged in all subjects. In the group with atrioventricular dissociation, plasma ANP increased from 10.14 +/- 0.58 to 16.72 +/- 0.92 fmol/mL at the 60th minute (P < 0.0001), whereas plasma BNP did not change at all (from 1.26 +/- 0.07 to 1.16 +/- 0.09 fmol/mL). In the group with retrograde conduction, plasma ANP concentration doubled (from 10.95 +/- 1.66 to 21.40 +/- 1.51 fmol/mL, P < 0.0001), BNP increased 1.5-fold (from 1.16 +/- 0.06 to 1.64 +/- 0.14 fmol/mL, P < 0.001), and the ANP:BNP ratio augmented from 10:1 to 13.4:1. These results indicate that the release of ANP and BNP is regulated by different mechanisms, supporting the view that there is a dual natriuretic peptide system, comprising ANP from the atria and BNP from the ventricles.
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Factor Natriurético Atrial/sangre , Estimulación Cardíaca Artificial/métodos , Proteínas del Tejido Nervioso/sangre , Marcapaso Artificial , Anciano , Arritmias Cardíacas/sangre , Arritmias Cardíacas/fisiopatología , Nodo Atrioventricular/fisiología , Presión Sanguínea/fisiología , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Péptido Natriurético Encefálico , Función Ventricular/fisiologíaRESUMEN
Signal-averaged P wave of 42 patients with lone paroxysmal atrial fibrillation (PAF) and 29 normal subjects (N) were recorded, using three orthogonal leads and analyzed in the time and frequency (entire P wave or a 100-ms segment ranging from 75 ms before to 25 ms after the end of P wave) domains. PAFs were divided into a group of 12 having > or = 2 attacks a month (HF) and a group of 30 having < or = 2 attacks a year (LF). Statistically significant differences were absent with regard to ages of PAF and N; ages of HF, LF, and N at the time of signal-averaged ECG; ages of HF and LF at the time of the first arrhythmic episode; and elapsed times from the first episode. Length of P wave and some frequency-domain parameters were found to be significantly correlated with age. PAF showed a significantly longer duration of P wave in the frontal plane using the time-domain analysis. Frequency analysis was found to be useful in evaluating the influence of attack frequency. HF showed significantly higher values of some frequency-domain parameters than LF and N, while the three groups did not differ for time-domain analysis. P wave duration and frequency content of the three orthogonal leads proved to be significantly different in PAF and N. Right and left atrial echocardiographic dimensions proved to be higher (even if within normal limits) in HF than in LF and N. Results suggest that frequency analysis should be performed on the entire P wave.
Asunto(s)
Fibrilación Atrial/fisiopatología , Electrocardiografía , Atrios Cardíacos/patología , Factores de Edad , Fibrilación Atrial/diagnóstico por imagen , Fibrilación Atrial/patología , Ecocardiografía , Electrocardiografía/instrumentación , Electrocardiografía/estadística & datos numéricos , Electrocardiografía Ambulatoria , Electrodos , Femenino , Análisis de Fourier , Atrios Cardíacos/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Procesamiento de Señales Asistido por Computador , Factores de TiempoRESUMEN
There is now clear scientific evidence linking regular aerobic physical activity to a significant cardiovascular risk reduction, and a sedentary lifestyle is currently considered one of the five major risk factors for cardiovascular disease. In the European Union, available data seem to indicate that less than 50% of the citizens are involved in regular aerobic leisure-time and/or occupational physical activity, and that the observed increasing prevalence of obesity is associated with a sedentary lifestyle. It seems reasonable therefore to provide institutions, health services, and individuals with information able to implement effective strategies for the adoption of a physically active lifestyle and for helping people to effectively incorporate physical activity into their daily life both in the primary and the secondary prevention settings. This paper summarizes the available scientific evidence dealing with the relationship between physical activity and cardiovascular health in primary and secondary prevention, and focuses on the preventive effects of aerobic physical activity, whose health benefits have been extensively documented.