Hypertension and Smoking Are Associated With Reduced Regional Left Ventricular Function in Asymptomatic Individuals
This journal article describes a study using magnetic resonance imaging tagging in 1,184 asymptomatic participants in the Multi-Ethnic Study of Atherosclerosis to determine their regional myocardial function and to test the hypothesis that traditional risk factors for coronary artery disease, including hypertension, hypercholesterolemia, diabetes mellitus, and smoking, are associated with abnormalities of regional left ventricular (LV) function. Regional LV function was quantified by analyzing peak systolic circumferential strain in regions corresponding to the left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) territories. Current or former smokers had lower strains in the LAD and RCA regions. The LAD region peak systolic mid-wall circumferential strain (Ecc) values for nonsmokers, former smokers, and current smokers were -15.6 +/- 4.2, -15.1 +/- 4.1, and -14.6 +/- 4.2, respectively. In the adjusted analyses, current smokers had a significantly lower adjusted mean change in systolic strain when compared with never smokers in the LAD and RCA regions. In the LCX region, lower Ecc was observed only in participants who smoked 40 or more pack-years when compared with those who smoked less. The relationships between smoking and regional LV function were seen in the mid-wall and at the LV apical levels, and they remained unaltered after adjustment for coronary calcium in the corresponding coronary regions or after excluding from analysis participants with Q-wave abnormalities. However, they were diminished after adjustment for LV mass. The combination of increased diastolic blood pressure (DBP) with smoking was associated with a substantially lower mid-wall circumferential strain in the LAD territory when compared with the relationships with each risk factor individually. The association between DBP and Ecc was stronger in smokers of 20 or more pack-years than in nonsmokers. Conversely, the association between smoking and Ecc was more prominent in hypertensive than in normotensive participants. A similar combined effect of DBP and cigarette smoking was noted for the RCA region, although of borderline significance. The article also presents findings for other risk factors. Reduced regional LV function was associated with diastolic hypertension and cigarette smoking in a population of asymptomatic people without a history of cardiac disease. This relationship was strongest with the combination of DBP and cigarette smoking. 24 references, 5 figures, and 4 tables. (Author Abstract Modified)
