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Biomedical subjects

Ning Qi

Publications and source records attributed to Ning Qi.

5 recordsLinked to original sources
PubMed2006

Right ventricular abnormalities in sickle cell anemia: evidence of a progressive increase in pulmonary vascular resistance.

OBJECTIVE: To assess the effects of sickle cell anemia (SCA) on the right ventricle (RV). STUDY DESIGN: Echocardiograms of 32 children with SCA were compared with age-matched healthy controls. RV measurements included diastolic area index, fractional area change, free-wall mass index, ejection time corrected for heart rate (ET(c)), and tricuspid regurgitation (TR) gradient. RESULTS: SCA subjects had elevated RV ETc (mean +/- standard deviation, 0.369 +/- 0.030 sec vs 0.351 +/- 0.022 sec; P < .01), diastolic area index (19.9 +/- 2.4 cm(2)/m(2) vs 13.2 +/- 2.1 cm(2)/m(2); P < .01) and free-wall mass index (33.2 +/- 4.4 g/m(2) vs 23.9 +/- 4.3 g/m(2); P < .01), whereas RV fractional area change (37 +/- 8% vs 36 +/- 4%) was not different from controls. Although RV diastolic area index in SCA paralleled the normal range over time, RV free-wall mass index continued to gradually rise throughout childhood (r = .42; P < .05). TR gradients > 2.5 m/sec, consistent with pulmonary hypertension, were found in 5 (16%) of SCA subjects, all older than 9 years. CONCLUSIONS: RV preload and systolic function do not worsen during childhood in SCA; however, RV mass index and the prevalence of pulmonary hypertension increase consistent with rising pulmonary vascular resistance.

Adolescent↗
PubMed2004

Normal right and left ventricular mass development during early infancy.

The average newborn's right ventricular mass, indexed to body surface area, is approximately 20% above the adult level, consistent with in utero physiologic hypertrophy. In contrast, the left ventricular mass index is underdeveloped by about 30% at birth, resulting in a ratio of right to left ventricular mass that is nearly 75% higher than at maturity. Left ventricular mass index increases rapidly during the first 2 weeks of life and then more slowly thereafter, whereas the right ventricular mass index decreases steadily during the first 4 months of life.

Adult↗
PubMed2004

Echocardiographic assessment of the right ventricular stress-velocity relationship under normal and chronic overload conditions.

UNLABELLED: The effects of chronic volume or pressure overload on the velocity of right ventricular ejection have not been previously well defined. We hypothesized that, as formerly shown for the left ventricle, there would be a direct relationship between the velocity of ejection and an estimate of systolic wall stress. METHODS: Echocardiograms of asymptomatic patients, not on cardiac medications, with either an isolated secundum atrial septal defect > or = 5 mm in diameter or isolated pulmonic stenosis with a peak instantaneous pressure gradient > or = 20 mmHg, were reviewed. Forty-one patients with an atrial septal defect and 34 with pulmonary stenosis met criteria, and were compared to age-matched normal controls. Total subjects were 127 with ages ranging from 1 day to 54 years. Right ventricular monoplane ejection fraction, ejection time corrected for heart rate (ETc), mean normalized systolic ejection rate (MNSERc) and meridianal peak-systolic wall stress (WSps) were measured. RESULTS: Compared to controls, ejection fractions were not significantly different, but WSps averaged 81% and 110% higher, ETc 8% and 9% longer, and MNSERc 5% and 9% slower in the atrial septal defect and pulmonary stenosis groups, respectively. Among all subjects WSps had a significant linear correlation with ETc (r = 0.61, P < 0.01), MNSERc (r =-0.46, P < 0.01), and ejection fraction (r =-0.19, P < 0.05). CONCLUSIONS: Increases in WSps cause an incremental slowing of MNSERc in the right ventricle, with a relationship that is linear over a wide range of normal and abnormal loading conditions.

Adolescent↗