TBX5 variants and cardiac phenotype: A systematic review of the literature and a novel variant.

T-Box Transcription Factor 5 (TBX5) variants are associated with Holt-Oram syndrome. Holt-Oram syndrome display phenotypic variability, regarding upper limb defects, congenital heart defects, and arrhythmias. To investigate the genotype-phenotype relationship between TBX5 variants and cardiac disease, we performed a systematic review of the literature. Through the systematic review we identified 108 variants in TBX5 associated with a cardiac phenotype in 277 patients. Arrhythmias were more frequent in patients with a missense variant (48% vs 30%, p = 0.009) and upper limb abnormalities were more frequent in patients with protein-truncating variants (85% vs 64%, p = 0.0008). We found clustering of missense variants in the T-box domain. Furthermore, we present a family with atrial septal defects. By whole exome sequencing, we identified a novel missense variant p.Phe232Leu in TBX5. The cardiac phenotype included atrial septal defect, arrhythmias, heart failure, and dilated cardiomyopathy. Clinical examination revealed subtle upper limb abnormalities. Thus, the family corresponds to the diagnostic criteria of Holt-Oram syndrome. We provide an overview of cardiac phenotypes associated with TBX5 variants and show an increased risk of arrhythmias associated to missense variants compared to protein-truncating variants. We report a novel missense variant in TBX5 in a family with an atypical Holt-Oram syndrome phenotype.

Electrocardiographic Characteristics in 438 Neonates with Atrial Septal Defects.

Arrhythmias and electrocardiographic (ECG) abnormalities are common among patients with atrial septal defects (ASDs). We studied a large cohort of neonates with ASDs to investigate whether ECG abnormalities are present at this early stage or develop later, secondary to hemodynamic changes. We analyzed the echocardiograms and ECGs from the Copenhagen Baby Heart Study, a population-based cohort study. We compared ECG characteristics of 438 neonates with secundum ASDs to 1314 matched controls. In subgroup analyses, we investigated whether electrocardiographic characteristics were associated with age at examination. Neonates with ASDs (median age, 11 days; males, 51%) had longer P-wave durations (58 vs. 56 ms, p < 0.001), PR intervals (100 vs. 96 ms, p < 0.001), and a more rightward-shifted QRS axis (116 vs. 114 degrees, p = 0.032) compared to controls (median age, 10 days; males, 51%). There were no differences between cases and controls in the P-wave area, amplitude, or axis. Subgroup analyses showed that the differences in P-wave duration and PR interval were present in neonates examined in the first week after birth. The difference in the QRS axis was not found in neonates examined this early but was found in neonates examined at age two to four weeks. In conclusion, ASDs are associated with ECG changes from the neonatal phase. The P-wave duration and PR interval are longer in neonates with ASDs when compared to controls as early as the first week after birth, indicating that these changes are not purely secondary, but that neonates with an ASD have altered cardiac electrical activity.ClinicalTrials.gov Identifier NCT02753348 (April 27, 2016).

Atrial Septal Defect: Larger Right Ventricular Dimensions and Atrial Volumes as Early as in the First Month After Birth-a Case-Control Study Including 716 Neonates.

Atrial septal defect (ASD) is characterized by a left-to-right shunt causing dilatation of the right atrium and right ventricle as well as pulmonary hyperperfusion. The detection of ASDs often occurs late in childhood or adulthood. Little is known about cardiac structure and function in neonates with ASD.We analyzed neonatal echocardiograms from the Copenhagen Baby Heart Study, a multicenter, population-based cohort study of 27,595 neonates. We included 716 neonates with secundum-type ASDs and matched them 1:1 on sex and age at examination with neonates without ASD from the same birth cohort. Neonates with an ASD (median age 11 days, 52% female) had larger right ventricular (RV) dimensions than matched controls (RV longitudinal dimension end-diastole: 27.7 mm vs. 26.7 mm, p < 0.001; RV basal dimension end-diastole: 14.9 mm vs. 13.8 mm, p < 0.001; and RV outflow tract diameter 13.6 mm vs. 12.4 mm, p < 0.001). Atrial volumes were larger in neonates with ASD compared to controls (right atrial end-systolic volume: 2.9 ml vs. 2.1 ml, p < 0.001; and left atrial end-systolic volume 2.0 ml vs. 1.8 ml, p < 0.001). Tricuspid annular plane systolic excursion was larger in neonates with ASD than in controls (10.2 mm vs. 9.6 mm, p < 0.001). Left ventricular dimensions and function did not differ between neonates with ASD and controls. In conclusion, ASDs were associated with altered cardiac dimensions already in the neonatal period, with larger right ventricular dimensions and larger atrial volumes at echocardiography within the first 30 days after birth.ClinicalTrials.gov Identifier: NCT02753348 (April 27, 2016).

Improved Left Ventricular Structure and Function After Successful Kidney Transplantation.

BACKGROUND/AIMS: Cardiac changes observed in chronic kidney disease patients are of multifactorial origin including chronic uremia, hemodynamics or inflammation. Restoration of renal function by kidney transplantation (KTX) may reverse cardiac changes. Novel echocardiographic methods such as speckle tracking echocardiography (STE) allow early and sensitive detection of subtle changes of cardiac parameters. We evaluated changes of cardiac structure and function after KTX by advanced echocardiographic modalities. METHODS: Thirty-one KTX recipients (female n=11) were evaluated by medical examination, laboratory testing and echocardiography before and after KTX (median follow-up 19 months). Left ventricular (LV) and right ventricular (RV) diameters and function were assessed by echocardiographic standard parameters. Longitudinal 2D strain of the LV (GLPS) and left atrium (LA) was determined by 2D STE. RESULTS: After KTX, median serum creatinine level was 1.3 mg/dl (IQR, 1.2-1.5). Systolic blood pressure decreased significantly after KTX. Echocardiography showed a significant reduction in LV end-diastolic septal and posterior wall thickness and LV mass index after KTX, which was accompanied by an improvement of GLPS. There were no relevant changes in parameters of LA (reservoir, conduit or contractile) function, LV diastolic or RV function after KTX. CONCLUSION: LV hypertrophy reversed after successful KTX and was accompanied by an improvement in longitudinal LV function as assessed by STE. Diastolic function and STE-derived LA function parameters did not change significantly after KTX.

Midterm echocardiographic follow-up of cardiac function after living kidney donation.

BACKGROUND: Living kidney donation (LKD) has become increasingly important as more patients reach end-stage renal disease. While safety of the donor is of utmost importance, recent data have suggested an increased risk for cardiovascular mortality after LKD. Therefore, we assessed the changes of cardiac structure and function after LKD by advanced echocardiographic methods. METHODS: 30 living kidney donors were evaluated by medical examination, laboratory testing, and echocardiography before and after LKD (median follow-up 19.5 months). Left ventricular (LV) and right ventricular (RV) function was assessed by echocardiographic standard indices. Longitudinal 2D strain of the LV and left atrium (LA) was determined by 2D speckle tracking. RESULTS: Serum creatinine increased significantly from 0.80 ± 0.12 mg/dL to 1.18 ± 0.21 mg/ dL (p < 0.001) after LKD. There was a trend to higher blood pressure after LKD, accompanied with significantly higher intake of antihypertensive drugs. Echocardiographic parameters of LV, LA, and RV function did not change significantly after LKD. N-terminal pro-brain natriuretic peptide (NT-proBNP) levels remained within normal ranges after LKD. CONCLUSION: The rise in serum creatinine and blood pressure indicates that patients have a potentially higher cardiac risk after LKD. However, our pilot study found no evidence for detrimental effects of LKD on cardiac structure and function within a relatively short-term follow-up.