Sugrue, D.

Using the records linkage system of the Mayo Clinic and of the Rochester Epidemiology Project, which accesses diagnostic data on the entire population of Olmsted County, Minnesota, we identified 45 new cases of idiopathic dilated cardiomyopathy (DCM) and 19 new cases of hypertrophic cardiomyopathy (HCM) among county residents for the years 1975-1984. Overall age- and sex-adjusted incidence rates were 6.0/100,000 and 2.5/100,000 person-years, respectively. The incidence of DCM doubled from 3.9/100,000 in the first 5 years to 7.9/100,000 person-years in the last 5 years of study. The corresponding change for HCM was from 1.4 to 3.6/100,000 person-years. Age- and sex-adjusted prevalence rates as of January 1, 1985, for DCM and HCM were 36.5/100,000 and 19.7/100,000 population, respectively. The prevalence of DCM in persons less than 55 years old was 17.9/100,000, over a third of whom were New York Heart Association functional Class III or IV at diagnosis. These estimates may be of value in determining the potential use of health care resources, particularly cardiac transplantation.

Summary To determine the relationship of left ventricular function and ventricular tachycardia, 48 hour ECG monitoring and technetium-99m gated equilibrium radionuclide angiography were performed in 84 consecutive patients with hypertrophic cardiomyopathy and sinus rhythm. Measurements of ejection fraction (EF), peak ejection rate (PER, edv/s), peak filling rate (PFR, edv/s) and time to peak filling rate (PFR, ms) were derived from radionuclide activity time curves generated from data acquired in list-mode. Left ventricular function was compared in patients with and without ventricular tachycardia. Left ventricular ejection fraction was significantly lower in 16 patients with ventricular tachycardia compared to 68 patients without (67 ± 17 vs 78 ± 10, P < 0.05) and time to peak filling rate was significantly prolonged (152 ± 32 vs 120 ± 36, P < 0.05). Thus patients with hypertrophic cardiomyopathy at greatest risk of sudden death had significant impairment of systolic and diastolic left ventricular function.