SUDDEN CARDIAC DEATH RATE IN AN AREA CHARACTERIZED BY HIGH-INCIDENCE OF CORONARY-ARTERY DISEASE AND LOW HARDNESS OF DRINKING-WATER

From January 1992 to January 1993 the incidence of sudden cardiac death among the population of the Media Valle del Serchio area (Tuscany, Italy), composed of a population of 35,000, was found to be twice that of the European average; 32 cases have been reported over this period in that area (9 per 10,000 in the examined year), with a male/female (M/F) ratio of 2.5:1 (23 M, 9 F). In Italy the mean incidence of sudden death was calculated as 6/10,000 and in Europe 5/10,000. In the examined population hypertension was the coronary risk factor present most frequently (87%). A previous diagnosis of coronary artery disease was documented in 21 cases (66%); 5 of these exhibited previous myocardial infarction and 3 previous myocardial infarction associated with left ventricular heart failure. In 7 subjects no previous cardiovascular disorders were discovered. Prodromal symptoms had been reported in 20 cases (62%), which included chest pain in 8 and dyspnea in 8. In the examined geographic area a high prevalence of coronary artery disease was verified through the records of the Public Health Service, which documents the main causes of mortality in Tuscany, and through the hospitalization data and the services provided for ischemic heart disease at the local coronary care unit compared with the national average. Moreover, research was accomplished on physical and chemical properties of drinking water in the same area, and this revealed a very low total hardness due to the paucity of calcium and magnesium salts. In conclusion, this research demonstrated a close relationship between the incidence of sudden death and the incidence of ischemic heart disease in a mountain area with low-hardness drinking water.