High R wave as a risk factor for cardivoascular and all-cause mortality. A 45-year follow-up of 13 cohorts of the Seven Countries Study

Abstract

Objectives: To study the role of high R waves predicting cardiovascular (CVD) and all-cause mortality in a male middle-aged population followed-up 45 years.

Material and methods: A total of 7985 CVD-free men aged 40-59 years were enrolled in 13 cohorts in seven countries (USA, Finland, the Netherlands, Italy, Serbia, Greece, Japan) and high R waves were classified by Minnesota Code 3.1 (as a dichotomous variable) from baseline resting otherwise normal ECG at entry examination together with other personal characteristics. Cox models were solved to detect the possible predictive role of high R waves for CVD and all-cause mortality.

Results: In Cox models high R waves were predictive of 45-year major CVD deaths with a hazard ratio of 1.17 (95% confidence intervals of 1.03-1.33) after adjustment for 6 major CVD risk factors (age, systolic blood pressure, serum cholesterol, cigarette smoking, physical activity and body mass index). The predictive role of high R wave was less evident for 45-year all-cause mortality and after adjustment for the 6 covariates the HR of high R wave lost its significance. A multiple logistic model indicated that body mass index, serum cholesterol, systolic blood pressure and mainly vigorous physical activity were directly related to high R wave prevalence while heart rate, subscapular skinfold, laterality index and shoulder pelvis shape did so in an inverse way.

Conclusion: High R waves seem associated with an excess CVD mortality in a 45-year follow-up of middle-aged men, while their role is diluted when the end-point is all-cause mortality.

Keywords: 45-year follow-up; All-cause mortality; CVD mortality; High R wave; Minnesota code 3.1; Seven Countries Study.