@article {662, title = {Echocardiographic features of the right heart in sleep-disordered breathing: the Framingham Heart Study.}, journal = {Am J Respir Crit Care Med}, volume = {164}, year = {2001}, month = {2001 Sep 15}, pages = {933-8}, abstract = {

The effect of sleep-disordered breathing (SDB) on right heart structure and function is controversial. Studies of patients referred for evaluation of possible sleep apnea have yielded conflicting results, and the impact of SDB on the right heart has not been investigated in the general population. We examined the echocardiographic features of subjects with SDB at the Framingham Heart Study site of the Sleep Heart Health Study. Of 1,001 polysomnography subjects, 90 with SDB defined as a respiratory disturbance index (RDI) score > 90th percentile (mean RDI = 42) were compared with 90 low-RDI subjects (mean RDI = 5) matched for age, sex, and body mass index. Right heart measurements, made without knowledge of clinical status, were compared between groups. The majority of the subjects were male (74\%). After multivariable adjustment, right ventricle (RV) wall thickness was significantly greater (p = 0.005) in subjects with SDB (0.78 +/- 0.02 cm) than in the low-RDI subjects (0.68 +/- 0.02 cm). Right atrial dimensions, RV dimensions, and RV systolic function were not found to be significantly different between subjects with SDB and the low-RDI subjects. We conclude that in this community-based study of SDB and right heart echocardiographic features, RV wall thickness was increased in subjects with SDB. Whether the RV hypertrophy observed in persons with SDB is associated with increased morbidity and mortality remains unknown.

}, keywords = {Adult, Age Factors, Aged, Cohort Studies, Cross-Sectional Studies, Data Interpretation, Statistical, Echocardiography, Female, Forced Expiratory Volume, Humans, Hypertrophy, Right Ventricular, Linear Models, Male, Middle Aged, Obesity, Observer Variation, Polysomnography, Prospective Studies, Sex Factors, Sleep Apnea Syndromes, Ventricular Function, Right, Vital Capacity}, issn = {1073-449X}, doi = {10.1164/ajrccm.164.6.2001092}, author = {Guidry, U C and Mendes, L A and Evans, J C and Levy, D and O{\textquoteright}Connor, G T and Larson, M G and Gottlieb, D J and Benjamin, E J} } @article {6063, title = {Common genetic variation near the connexin-43 gene is associated with resting heart rate in African Americans: a genome-wide association study of 13,372 participants.}, journal = {Heart Rhythm}, volume = {10}, year = {2013}, month = {2013 Mar}, pages = {401-8}, abstract = {

BACKGROUND: Genome-wide association studies have identified several genetic loci associated with variation in resting heart rate in European and Asian populations. No study has evaluated genetic variants associated with heart rate in African Americans.

OBJECTIVE: To identify novel genetic variants associated with resting heart rate in African Americans.

METHODS: Ten cohort studies participating in the Candidate-gene Association Resource and Continental Origins and Genetic Epidemiology Network consortia performed genome-wide genotyping of single nucleotide polymorphisms (SNPs) and imputed 2,954,965 SNPs using HapMap YRI and CEU panels in 13,372 participants of African ancestry. Each study measured the RR interval (ms) from 10-second resting 12-lead electrocardiograms and estimated RR-SNP associations using covariate-adjusted linear regression. Random-effects meta-analysis was used to combine cohort-specific measures of association and identify genome-wide significant loci (P<=2.5{\texttimes}10(-8)).

RESULTS: Fourteen SNPs on chromosome 6q22 exceeded the genome-wide significance threshold. The most significant association was for rs9320841 (+13 ms per minor allele; P = 4.98{\texttimes}10(-15)). This SNP was approximately 350 kb downstream of GJA1, a locus previously identified as harboring SNPs associated with heart rate in Europeans. Adjustment for rs9320841 also attenuated the association between the remaining 13 SNPs in this region and heart rate. In addition, SNPs in MYH6, which have been identified in European genome-wide association study, were associated with similar changes in the resting heart rate as this population of African Americans.

CONCLUSIONS: An intergenic region downstream of GJA1 (the gene encoding connexin 43, the major protein of the human myocardial gap junction) and an intragenic region within MYH6 are associated with variation in resting heart rate in African Americans as well as in populations of European and Asian origin.

}, keywords = {Adult, African Americans, Aged, Arrhythmias, Cardiac, Connexin 43, Electrocardiography, Female, Genetic Variation, Genome-Wide Association Study, Genotype, Heart Rate, Humans, Male, Meta-Analysis as Topic, Middle Aged, Polymorphism, Single Nucleotide, Rest, United States}, issn = {1556-3871}, doi = {10.1016/j.hrthm.2012.11.014}, author = {Deo, R and Nalls, M A and Avery, C L and Smith, J G and Evans, D S and Keller, M F and Butler, A M and Buxbaum, S G and Li, G and Miguel Quibrera, P and Smith, E N and Tanaka, T and Akylbekova, E L and Alonso, A and Arking, D E and Benjamin, E J and Berenson, G S and Bis, J C and Chen, L Y and Chen, W and Cummings, S R and Ellinor, P T and Evans, M K and Ferrucci, L and Fox, E R and Heckbert, S R and Heiss, G and Hsueh, W C and Kerr, K F and Limacher, M C and Liu, Y and Lubitz, S A and Magnani, J W and Mehra, R and Marcus, G M and Murray, S S and Newman, A B and Njajou, O and North, K E and Paltoo, D N and Psaty, B M and Redline, S S and Reiner, A P and Robinson, J G and Rotter, J I and Samdarshi, T E and Schnabel, R B and Schork, N J and Singleton, A B and Siscovick, D and Soliman, E Z and Sotoodehnia, N and Srinivasan, S R and Taylor, H A and Trevisan, M and Zhang, Z and Zonderman, A B and Newton-Cheh, C and Whitsel, E A} }