Muerte subita

Muerte súbita
Muerte natural inesperada causada dentro de un corto periodo de tiempo a partir de la aparicion de sintomas en una persona sin condicion patologica previa
Intervalo de tiempo menor a una hora
Causada más frecuente por Taquiarritmia ventricular sostenida
* Causas
* Anormalidades cardiacas estructurales (+frecuente)
* Enfermedad coronaria
* Cardiomiopatia* Enfermedad valvular
* Falla en el sistema de conducción
* Desencadenantes
* Isquemia
* Cambios hemodinamicos
* Cambios en SNA
* Anormalidades electrolíticas
* Drogas
Sintomas iniciales: palpitaciones, dolor torácico, disnea

Efectos electrofisiológicos de Isquemia
* Acidosis intracelular y extracelular
* Perdida de la integridad demembrana salida de K y entrada de Ca
* Disminucion en la amplitud y velocidad del PA
* Se prolonga el periodo refractario canales rapidos Na y lentos Ca permanecen inactivos
* Arritmias de Reentrada

Ischemic Heart Disease
CORONARY ATHEROSCLEROSIS
In survivors of cardiac arrest, CHD is present in 40 to 86 percent of patients, depending on age and gender of thepopulation.61 Patients with known coronary heart disease accounted for 20 to 34 percent of SCDs in the Framingham cohort.9 SCD was the first symptom of CHD in approximately 10 percent of all coronary events.
Although the majority of patients who suffer SCD have severe multivessel coronary disease, fewer than half of the patients resuscitated from ventricular fibrillation evolve evidence of myocardial infarction byelevated cardiac enzymes, and less than 20 percent have Q-wave myocardial infarction.48 Holter monitoring at the time of arrest infrequently shows evidence of ischemic ECG changes before the event.46,62In postmortem examinations and in catheterization studies, there was a significant (75 to 85 percent) stenosis in at least two major coronary arteries in as many as 76 percent of patients. Detailedpathologic studies confirm the presence of acute coronary arterial lesions (plaque fissure, plaque hemorrhage, and thrombosis) in up to 95 percent of patients who die suddenly, but only a fraction have total occlusion.31,63
Coronary collateralization may play an important role in the presentation of coronary artery disease as SCD. It is hypothesized that chronic ischemia may be a stimulus fordevelopment of coronary collaterals, which, in turn, could have a protective effect during acute coronary occlusion. The mitigating effect of coronary collateralization is supported by a study of exercise testing in 894 healthy men followed for a mean of 12.7 years. In this study, the initial coronary event was acute myocardial infarction or SCD in 73 percent of those with a normal stress test result,as opposed to 20 percent of those with an abnormal stress test result.64 These findings might also be related to ischemic preconditioning, which is associated with reductions in ventricular fibrillation (VF) in animal models.65
NONATHEROSCLEROTIC DISEASE OF THE CORONARY ARTERIES
Several nonatherosclerotic diseases of the coronary arteries are associated with increased risk of SCD precipitated bycardiac ischemia. Congenital coronary artery anomalies, found in approximately 1 percent of all patients undergoing angiography and in 0.3 percent of patients undergoing autopsy, have been complicated by SCD, often exercise-related, in up to approximately 30 percent of patients.66Origin of the left main coronary artery from the right aortic sinus or origin of the right coronary artery from theleft coronary sinus are the variants most frequently associated with SCD.
Life-threatening ventricular arrhythmias and SCD have been described in patients with coronary artery spasm (Prinzmetal or variant angina). Significant arrhythmias during attacks of variant angina have been documented in these patients.67 Calcium channel blockers are effective in many patients in preventing coronary spasm...