Childhood obesity: impact on cardiac geometry and function.

OBJECTIVES: The aim of our study was to assess geometric and functional changes of the heart in obese compared with nonobese children and adolescents. BACKGROUND: Obesity in children and adolescents has increased over the past decades and is considered a strong risk factor for future cardiovascular morbidity and mortality. Obesity has been associated with myocardial structural alterations that may influence cardiac mechanics. METHODS: We prospectively recruited 61 obese (13.5 ± 2.7 years of age, 46% male sex, SD score body mass index, 2.52 ± 0.60) and 40 nonobese (14.1 ± 2.8 years of age, 50% male sex, SD score body mass index, -0.33 ± 0.83) consecutive, nonselected Caucasian children and adolescents. A standardized 2-dimensional (2D) echocardiography and 2D speckle-tracking analysis was performed in all children. Furthermore, blood chemistry including lipid and glucose metabolism was assessed in all children. RESULTS: Compared with nonobese children, blood pressure, low-density lipoprotein cholesterol, and parameters of glucose metabolism were significantly increased in obese children, whereas high-density lipoprotein cholesterol was significantly lower. Compared with nonobese children, obese children were characterized by enlarged left- and right-sided cardiac chambers, thicker left ventricular walls, and, consequently, increased left ventricular mass. Despite a comparable left ventricular ejection fraction, decreased tissue Doppler-derived peak systolic velocity and regional basoseptal strain were found in obese children compared with nonobese children. Beyond that, 2D speckle tracking-derived longitudinal (-18.2 ± 2.0 vs. -20.5 ± 2.3, p < 0.001) and circumferential (-17.0 ± 2.7 vs. -19.5 ± 2.9, p < 0.001) strain of the left ventricle was reduced in obese children compared with nonobese children. Diastolic function was also impaired in obese compared with nonobese children. Both longitudinal strain and circumferential strain were independently associated with obesity. CONCLUSIONS: The results of this study demonstrate that childhood obesity is associated with significant changes in myocardial geometry and function, indicating an early onset of potentially unfavorable alterations in the myocardium.

Validity of the surface electrocardiogram criteria for right ventricular hypertrophy: the MESA-RV Study (Multi-Ethnic Study of Atherosclerosis-Right Ventricle).

OBJECTIVES: The study aimed to assess the diagnostic properties of electrocardiographic (ECG) criteria for right ventricular hypertrophy (RVH) measured by cardiac magnetic resonance imaging (cMRI) in adults without clinical cardiovascular disease. BACKGROUND: Current ECG criteria for RVH were based on cadaveric dissection in small studies. METHODS: MESA (Multi-Ethnic Study of Atherosclerosis) performed cMRIs with complete right ventricle (RV) interpretation on 4,062 participants without clinical cardiovascular disease. Endocardial margins of the RV were manually contoured on diastolic and systolic images. The ECG screening criteria for RVH from the 2009 American Heart Association Recommendations for Standardization and Interpretation of the ECG were examined in participants with and without left ventricular (LV) hypertrophy or reduced ejection fraction. RVH was defined using sex-specific normative equations based on age, height, and weight. RESULTS: The study sample with normal LV morphology and function (n = 3,719) was age 61.3 ± 10.0 years, 53.5% female, 39.6% Caucasian, 25.5% African American, 21.9% Hispanic, and 13.0% Asian. The mean body mass index was 27.9 ± 5.0 kg/m(2). A total of 6% had RVH, which was generally mild. Traditional ECG criteria were specific (many >95%) but had low sensitivity for RVH by cMRI. The positive predictive values were not sufficiently high as to be clinically useful (maximum 12%). The results did not differ based on age, sex, race, or smoking status, or with the inclusion of participants with abnormal LV mass or function. Classification and regression tree analysis revealed that no combination of ECG variables was better than the criteria used singly. CONCLUSIONS: The recommended ECG screening criteria for RVH are not sufficiently sensitive or specific for screening for mild RVH in adults without clinical cardiovascular disease.

Isolated left ventricular noncompaction in sub-Saharan Africa: a clinical and echocardiographic perspective.

BACKGROUND: Isolated left ventricular noncompaction (ILVNC) is a cardiomyopathy caused by intrauterine failure of the myocardium to compact. Common clinical complications are heart failure, arrhythmias, and cardioembolism. A paucity of data exists relating to clinical and echocardiographic features of ILVNC in Africans. METHODS AND RESULTS: This study is a single-center, prospective case-control study, whereby subjects attending a dedicated cardiomyopathy clinic were screened for and diagnosed with ILVNC, provided they had no other associated structural heart disease and fulfilled all the accompanying echocardiographic criteria: (1) end-systolic ratio of noncompacted layer to compacted layer >2, (2) presence of >3 prominent apical trabeculations, and (3) deep intertrabecular recesses that fill with blood from the ventricular cavity visualized using color Doppler ultrasound. Fifty-four subjects were identified, age 45.4±13.1 years (mean±SD), 95% confidence interval 3.6 to 10.2, 55.6% male, and 63.0% New York Health Association Class II, and prevalence of LVNC in our clinic was 6.9%, 95% confidence interval 3.6 to 10.2. Heart failure because of systolic dysfunction was the most common clinical presentation (53 subjects, 98.1%). Left ventricular end-diastolic diameter was 61.4±7.2 mm (mean±SD) and ejection fraction 26.7±11.9% (mean±SD). Common sites of noncompaction were the apical (100%), midinferior (74.1%), and midlateral (64.8%) walls. Right ventricular noncompaction occurred in 12 subjects (22.2%). Pulmonary hypertension was documented in 45 cases (83.3%). Right ventricular dilation was noted in 40 subjects (74.1%), while right ventricular function was depressed in 32 (59.3%). Tricuspid S' was 9.6±2.8 cm/s (mean±SD). No echocardiographic features suggestive of ILVNC were noted in a healthy control group of African descent. CONCLUSIONS: ILVNC in patients of African descent can be characterized by biventricular abnormality and pulmonary hypertension, in addition to isolated left-sided abnormality.

Electrocardiographic evidence for right heart strain in asymptomatic children living in Tibet--a comparative study between Han Chinese and ethnic Tibetans.

OBJECTIVE: To compare ethnic Tibetan children with Han Chinese migrants for signs of right ventricular strain using electrocardiography (ECG) that would suggest chronic hypoxia at altitudes of 3500 to 4500 m above sea level. METHODS: One hundred thirty-five asymptomatic school children aged 7 to 12 years were assessed for height, weight, and blood pressure and underwent a single ECG at 2 centers at 3500 and 4500 m. A questionnaire was given to parents to provide demographic data with relevant medical history. RESULTS: There was a high prevalence of right ventricular strain on ECG for both Tibetan and Han children (33%) with no significant difference between the 2 ethnic groups or sexes. CONCLUSIONS: Other studies showing higher observed rates of symptomatic chronic altitude sickness in Han Chinese children suggest that other extracardiologic factors play a role in the pathogenesis of the disease.

ECG observations in Tibetan and Han residents of Lhasa.

In order to compare the prevalence of electrocardiographic (ECG) abnormalities suggestive of right ventricular hypertrophy in native and immigrant populations residing at high altitude, a retrospective review was undertaken of data obtained from a random survey of healthy volunteers and persons with chronic mountain sickness (CMS). All persons included in the survey were ambulatory volunteers from the general community who were evaluated at the Tibet Institute of Medical Science in Lhasa, where the elevation is 3,658 meters. The 74 residents of Lhasa, whose ECGs were studied, included 30 healthy Tibetan natives of Lhasa; 24 healthy Han (Chinese) immigrants, born at or near sea level, who had migrated to high altitude as children or adults; and 20 persons with symptoms of CMS. The ECGs of all subjects were reviewed for predetermined criteria suggestive of right ventricular hypertrophy, which were found to be present in 17% of healthy Tibetan natives, 29% of healthy Han immigrants, and 50% of CMS patients. The Han subjects who had migrated as children presented evidence of right ventricular hypertrophy more commonly than did adult immigrants. The overwhelming majority (90%) of persons with CMS were Han. Thus, the frequency of ECG abnormalities consistent with right ventricular hypertrophy was similar in healthy young Tibetan and Han men, but these abnormalities were less common in Tibetan natives than in Han who had migrated to high altitude as children or in CMS patients. The prevalence of ECG evidence of right ventricular hypertrophy increased with duration of high altitude residence among Han.