Cardio-thoracic Ratio (CTR) for Detection of Left Ventricular Hypertrophy (LVH) in Elderly People

Kim, Sung Hoon; Shin, Yun Jeong; Kang, Hee Suk; Yoon, Hai Gyung; Oh, Mi Kyeong; Cheong, Sang Sig

Abstract

BACKGROUND: Left ventricular hypertrophy (LVH) is closely related with a high death rate, rhythmia, ischemic heart disease, stroke and sudden death. It is known that the prognosis becomes better as LVH regresses. Therefore, it is important to diagnose it correctly with ease in primary care. The authors evaluated the most standard cardio-thoracic ratio (CTR) with respect to LVH oriented towards elderly people whose body habitus changed over time as they had become older, and evaluated the factors which affect the rate of diagnosis including sensitivity and specificity.
METHODS
A total of 231 subjects over 60 years of age who visited a general hospital health promotion center from March 1997 to August 2003, underwent echocardiography and identified not to have heart disease were selected. LV (left vetricular) mass was measured through echocardiography. LV mass was divided by 2.7 times of height (m) by Deveruex's method, and 49.1 g/m2.7 for men and 46.7 g/m2.7 for women were set to be standards of LVH. CTR was obtained by dividing the maximum transverse diameter of the heart by maximum transverse diameter of thorax on chest PA.
RESULTS
CTR was observed on the basis of 0.45, 0.5, 0.55, and the agreement was highest of 0.5 for men and 0.45 for women. However, considering the sensitivity, the specificity, and the positive predictive value, it was thought to be most proper to be set at 0.5 was be standard for both men and women. When diagnosing LVH through chest PA, if 0.5 was set to be standard, false positive become high in women, false negative became high as height increased, and false negative became high as body mass index (BMI) increased. The smoking group showed higher false negative compared to the non- smoking group, and the false negative was higher as the level of hemoglobin increased.
CONCLUSION
When diagnosing LVH through CTR in elderly people, it was appropriate to set 0.5 as a standard, but it is necessary to consider sex, body habitus, BMI, smoking and the level of hemoglobin.