Amano K, Sakamoto T, Sugimoto T
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo.
J Cardiol. 1989 Mar;19(1):219-30.
To clarify the hemodynamic state of an apparently small heart; i.e., a small cardiac silhouette on chest radiography, chest radiographic and echocardiographic studies, physical fitness tests (a battery of tests consisting of vertical jump, side step, floor push-up, and modified Harvard step test) and graded uninterrupted bicycle exercise test were performed. 1. The cardiothoracic ratio (CTR) in 3,461 newly-enrolled university students (18.7 +/- 1.2 years old: mean +/- SD) distributed normally and the mean value +/- SD was 40.2 +/- 3.6%. No difference was observed between male and female students. 2. A small heart was defined as one having a cardiothoracic ratio (CTR) less than or equal to 35% which comprised the lower 10% of the normal distribution. There was no significant difference in results of physical fitness tests between students with small heart (n = 134) and normal controls (n = 136, 45% less than or equal to CTR less than or equal to 50%). 3. A maximal bicycle exercise test was performed in 14 male students with small heart (S: CTR = 31.9 +/- 2.1%) and nine normal controls (C: CTR = 46.5 +/- 1.0%). a) Body weight (S: 57 +/- 7, C: 69 +/- 8 kg, p less than 0.001) were less in students with small heart; Body height was similar in both categories (S: 171 +/- 5, C: 175 +/- 7 cm, NS). b) All controls finished 200 W workload, whereas all students with small heart ceased exercise earlier than the control subjects (three at 125 W, three at 150 W, eight at 175 W). c) Resting heart rate was higher in cases with small heart (S: 92 +/- 14, C: 77 +/- 10 beats/min, p less than 0.02). Left ventricular end-diastolic dimension was smaller in small heart (S: 39 +/- 4, C: 48 +/- 4 mm, p less than 0.001). d) During exercise, blood pressure and oxygen intake at the same workload were similar in both groups, but peak oxygen uptake was higher in the controls (S: 43 +/- 5, C: 50 +/- 7 ml/kg/ml, p less than 0.05). Heart rate and blood lactate concentration were higher throughout exercise in students with small heart (lactate at 175 W; S: 12.7 +/- 1.6, C: 7.8 +/- 2.0 mmol/L, p less than 0.001) (heart rate at 175 W; S: 194 +/- 6, C: 173 +/- 21 beats/min, p less than 0.05). We concluded that hemodynamic conditions at rest and during low grade exercise are preserved in students with small heart.(ABSTRACT TRUNCATED AT 400 WORDS)
为明确心脏外形看似较小患者的血流动力学状态，即胸部X线片上心影较小者，我们进行了胸部X线和超声心动图检查、体能测试（包括纵跳、侧步、俯卧撑和改良哈佛台阶试验的一组测试）以及递增式不间断自行车运动试验。1. 3461名新入学大学生（年龄18.7±1.2岁：均值±标准差）的心胸比（CTR）呈正态分布，均值±标准差为40.2±3.6%。男女学生之间未观察到差异。2. 心脏较小定义为心胸比（CTR）小于或等于35%，此比例占正常分布的下10%。心脏较小的学生（n = 134）与正常对照组（n = 136，45%≤CTR≤50%）在体能测试结果上无显著差异。3. 对14名心脏较小的男性学生（S组：CTR = 31.9±2.1%）和9名正常对照者（C组：CTR = 46.5±1.0%）进行了最大自行车运动试验。a）心脏较小的学生体重较轻（S组：57±7，C组：69±8 kg，p<0.001）；两组身高相似（S组：171±5，C组：175±7 cm，无显著性差异）。b）所有对照者完成了200 W的工作量，而所有心脏较小的学生比对照者更早停止运动（3人在125 W时停止，3人在150 W时停止，8人在175 W时停止）。c）心脏较小的患者静息心率较高（S组：92±14，C组：77±10次/分钟，p<0.02）。心脏较小者左心室舒张末期内径较小（S组：39±4，C组：48±4 mm，p<0.001）。d）运动期间，两组在相同工作量时的血压和摄氧量相似，但对照组的峰值摄氧量较高（S组：43±5，C组：50±7 ml/kg/ml，p<0.05）。心脏较小的学生在整个运动过程中的心率和血乳酸浓度较高（175 W时的乳酸浓度；S组：12.7±1.6，C组：7.8±2.0 mmol/L，p<0.001）（175 W时的心率；S组：194±6，C组：173±21次/分钟，p<0.05）。我们得出结论，心脏较小的学生在静息和低强度运动期间的血流动力学状况得以维持。（摘要截选至400字）
