Coexistent HCN4 and GATA5 rare variants and Atrial Fibrillation in a large Spanish Family

BACKGROUND

Familial association of atrial fibrillation (AF) can involve single gene variants related to known arrhythmogenic mechanisms; however, genome-wide association studies often disclose complex genetic variants in familial and non-familial AF, making it difficult to relate to known pathogenetic mechanisms.

METHODS

The finding of 4 siblings with AF led to studying 47 members of a family. Long-term Holter monitoring (298 hours average) ruled out silent AFWhole-exome sequencing was performed and variants shared by the index cases were filtered and prioritized according to current recommendations. HCN4 currents (IHCN4) were recorded in Chinese hamster ovary cells expressing human p.P1163H and/or native Hcn4 channels using the patch-clamp technique and topologically associated domain analysis of GATA5 variant carriers were performed.

RESULTS

The clinical study diagnosed 2 more AF cases. Five family members carried the heterozygous p.P1163H, HCN4 variant, 14 the intronic 20,61040536,G,A GATA5 rare variant, and 9 carried both variants (HCN4+GATA5). Five of the 6 AF cases (onset age ranging 33-70 years) carried both variants and one the GATA5 variant alone. Multivariate analysis showed that the presence of HCN4+GATA5 variants significantly and independently increased AF risk [OR=32.740 (1.812-591.408)] and not age, hypertension or overweight. Functional testing showed that IHcn4 generated by heterozygous p.P1163H were normal. Topologically associating domain analysis suggested that GATA5 could affect the expression of many genes, including those encoding microRNA-1.

CONCLUSION

The coincidence of two rare gene variants was independently associated with AF, but functional studies do not allow the postulation of the arrhythmogenic mechanism(s) involved.

Design and rationale of a multicentre, randomised, double-blind, placebo-controlled clinical trial to evaluate the effect of vitamin D on ventricular remodelling in patients with anterior myocardial infarction: the VITamin D in Acute Myocardial Infarction (VITDAMI) trial

INTRODUCTION

Decreased plasma vitamin D (VD) levels are linked to cardiovascular damage. However, clinical trials have not demonstrated a benefit of VD supplements on left ventricular (LV) remodelling. Anterior ST-elevation acute myocardial infarction (STEMI) is the best human model to study the effect of treatments on LV remodelling. We present a proof-of-concept study that aims to investigate whether VD improves LV remodelling in patients with anterior STEMI.

METHODS AND ANALYSIS

The VITamin D in Acute Myocardial Infarction (VITDAMI) trial is a multicentre, randomised, double-blind, placebo-controlled trial. 144 patients with anterior STEMI will be assigned to receive calcifediol 0.266 mg capsules (Hidroferol SGC)/15 days or placebo on a 2:1 basis during 12 months.

PRIMARY OBJECTIVE

to evaluate the effect of calcifediol on LV remodelling defined as an increase in LV end-diastolic volume ≥10% (MRI).

SECONDARY OBJECTIVES

change in LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, diastolic function, sphericity index and size of fibrotic area; endothelial function; plasma levels of aminoterminal fragment of B-type natriuretic peptide, galectin-3 and monocyte chemoattractant protein-1; levels of calcidiol (VD metabolite) and other components of mineral metabolism (fibroblast growth factor-23 (FGF-23), the soluble form of its receptor klotho, parathormone and phosphate). Differences in the effect of VD will be investigated according to the plasma levels of FGF-23 and klotho. Treatment safety and tolerability will be assessed. This is the first study to evaluate the effect of VD on cardiac remodelling in patients with STEMI.

ETHICS AND DISSEMINATION

This trial has been approved by the corresponding Institutional Review Board (IRB) and National Competent Authority (Agencia Española de Medicamentos y Productos Sanitarios (AEMPS)). It will be conducted in accordance with good clinical practice (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use - Good Clinical Practice (ICH-GCP)) requirements, ethical principles of the Declaration of Helsinki and national laws. The results will be submitted to indexed medical journals and national and international meetings.

TRIAL REGISTRATION NUMBER

NCT02548364; Pre-results.

[Assessment of resident training in laparoscopic surgery based on a digestive system anastomosis model in the laboratory]

BACKGROUND

The complexity of laparoscopic surgery makes specific training out of the operating rooms necessary to shorten learning curves and to minimise morbidity rates. Our aim was to analyse the increase in laparoscopic skills after completion of a laboratory training program.

MATERIAL AND METHODS

Prospective study of surgical resident training based on anastomosis performance on an "endotrainer". The program consisted of 4 weeks per year (20h per week) between 2004 and 2007. The outcome measures were the time and number of anastomosis necessary to perform a proper anastomosis. Upon completion, the anastomosis was checked by both trainee and evaluator and quality was assessed. Time and technical failures (loose suture, edge eversion, leakage) were recorded.

RESULTS

Twelve surgical residents were trained. They performed 189 jejuno-jejunal anastomoses (JJA), mean 15.8 per resident and 197 gastro-jejunal anastomoses (GJA), mean 16.4 per resident. The performance mean time was 72.7 min for JJA and 87.2 for GJA. There was a marked reduction in time from the beginning to completion of training. The percentage of flawed anastomosis decreased with training: 26.6%, 21.8%, 17.1%, 17%, 16.1% and 10.5% after 20, 40, 60, 80, 100 and 120 h, respectively. Bearing in mind reduction in both performance time and flawed anastomosis rate, it appears that after 70 h of training the learning curve reaches a plateau zone.

CONCLUSIONS

Intestinal anastomosis (either JJA or GJA) performed in "endotrainer" is a suitable model for laparoscopic training, without the need of live animals. After a training period of 70 hours, the improvement seems of little benefit.

[Surgical resident training program in minimally invasive surgery experimental laboratory (CENDOS)]

INTRODUCTION

The rapid development of laparoscopic surgery makes resident training programmes necessary.

OBJECTIVE

To analyse the results of a structured programme of laparoscopic training in an experimental laboratory.

MATERIAL AND METHOD

From 2003 until 2007, we trained 11 general surgery residents for 20 h every 3 months, for three years. The practice consisted of suture and anastomosis in Endo-Trainer with animal organs, as well as laparoscopic techniques in live animals. In the Endo-Trainer practice we evaluated the time and quality of anastomosis performance. In laparoscopic techniques (cholecystectomy and anti-reflux surgery) a task table was evaluated, from 0 (no errors) to 100 (severe lesion).

RESULTS

In total, 314 anastomosis were performed by the 11 residents, with a median of 28.5 per resident (24-42). The mean time for the first gastro-jejunal anastomosis was 135 min (100-140) and 65 min (57.5-105) for the first jejunal-jejunal anastomosis. Maximum learning was achieved after 45 training hours. There were no appreciable differences between both types of anastomosis. There was inadequate anastomosis quality due to leakage in 17.1% during the learning period and 13.7% during the consolidation period. In the animal, 172 procedures were performed. In cholecystectomy and anti-reflux surgery the mean scores were 2.4 and 5.6 points, respectively. In the remaining procedures, subjectively evaluated by the monitors, the quality was adequate in 65%, deficient in 22% and highly deficient in 13%.

CONCLUSIONS

This structured programme of laparoscopic skills based on intestinal anastomosis allows for quicker resident training.