Abstract submitted for 25th World Congress of Internal Medicine - CANCUN, Mexico, June 2000
Importance of Heart Rate and Pulse×Mass Index
for the assessment of Cardiovascular Risk
Web posted: January 2000
Enrique Sánchez-Delgado*, Asociación
Nicaragüense de Medicina Interna, and Heinz Liechti, Laboratorios
Solka, Managua, Nicaragua
Abstract: The importance of resting heart rate (RHR) as a cardiovascular risk factor (CVRF) has been increasingly recognized since the studies of Framingham and Göteborg, reinforced by the success of Betablockers in coronary heart disease. Recently, heart rate variability, chronotropic incompetence (CI) and heart rate recovery (HRR) after exercise, have demonstrated to be predictors of mortality. In all mammals, the slower the pulse, the longer the lifespan, and viceversa.
Obesity is recognized as a major CVRF. Years ago, we observed an apparent relation of 3:1 (72:24) between RHR and body mass index (BMI). Then we developed the Pulse×Mass Index (PMI) and compared it both with the studies on obesity and mortality and with the calculation of the absolute cardiovascular risk according to Framingham.
Based on our investigations, a pulse×mass index of 0.7-1.0 would be ideal [Resting Heart Rate×Body Mass Index1730, or 72×24]. The PMI reflects overweight, stress, sympathetic stimulation, oxidative metabolic rate, hyperinsulinemia, inflammatory activity, physical fitness and side effects of drugs like water retention, potent vasodilation and tachycardia. The therapeutic interventions should improve the treated CVRF without increasing, or better reducing PMI, while improving CI and HRR.
In a pilot group of 30 patients, PMI has a highly significant correlation with the calculation of the absolute cardiovascular risk according to Framingham (r=0.94; p<0.05), especially in patients over 40 years, despite the PMI being more sensitive for younger patients.
Moreover we also observed, that if the relation of 3:1 between pulse and BMI was maintained proportional as BMI increases, then the enlarged mortality becomes predictable -e.g., for a BMI of 33 and a theoretically corresponding pulse of 99 (1/3), the pulse×mass index (33×99÷1730) is 1·9 or almost two-fold, corresponding with the known doubling of mortality with this BMI. The same tendency is found for every increase of BMI and pulse.
Analyzing recent studies like the ones from Calle et al. in USA, Bender et al. in Germany, and Erikssen et al. in Norway, we observe that in the cases where both BMI and RHR are given, the real calculated PMI corresponds very closely to the real, empirically observed mortality. When only BMI is given, if we assume a theoretical relation of 3:1 between RHR and BMI, we observe that the calculated theoretical PMI, has also an overall very close correlation with the real mortality in the different subgroups.
Therefore, pulse×mass index, a widely accessible
index of physical signs, can contribute together with the known
risk factors, to a more complete assessment of cardiovascular
risk. The traditional risk factors (smoking, hypertension, diabetes,
cholesterol), are not enough to explain many cases of CHD. PMI
can be a good candidate as a complement to fill the gap.
Tel: 00505-278-1031
e-mail:
heinz-liechti@scientist.com
ciencia_farma@latinmail.com