Baruteau, Alban-Elouen

Abstract Background and Aims There is a paucity of data on arrhythmia burden in patients with congenitally corrected transposition of the great arteries (ccTGAs). The present study sought to quantify the incidence of atrial arrhythmia (AA), ventricular arrhythmia (VA), and complete atrioventricular block (CAVB) in patients with ccTGA and identify associated factors. Methods An international, multi-centre, retrospective cohort study was conducted in 29 tertiary hospitals (six countries) between 1990 and 2018. Primary analyses consisted of determining the incidence of a combined outcome consisting of AA, VA, or CAVB, along with its individual components. Factors associated with the different types of arrhythmias were assessed by uni-variable and multi-variable Cox regression analyses. Results A total of 1131 patients with ccTGA were followed for 9.0 (interquartile range 4.0–17.2) years. Cumulative rates of the primary endpoint at 10, 15, and 20 years were 44.5%, 51.0%, and 58.8%, respectively. AA, VA, and CAVB occurred in 2.1, 1.4, and 2.0 cases per 100 person-years, respectively. In multi-variable analyses, surgery/intervention conferred a greater than three-fold higher risk of AA [hazard ratio (HR) 3.01, 95% confidence interval (CI) 1.90–4.78, P < .001]. Furthermore, surgery/intervention was significantly associated with a greater risk of VA (HR 1.73, 95% CI 0.98–3.05, P = .003) and CAVB (HR 3.65, 95% CI 2.20–6.05, P < .001). The left bundle branch block was associated with a higher risk of VA (HR 4.03, 95% CI 1.59–10.23, P = .003) and the right bundle branch block with a higher risk of CAVB (HR 3.71, 95% CI 1.81–7.63, P < .001). Conclusions The arrhythmia burden in patients with ccTGA is substantial, with a high incidence of AA, VA, and CAVB.

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns. Methods: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands. Results: Laterality defects and atrioventricular block at diagnosis were observed in 29.9% and 9.3%, respectively. ccTGA was associated with primary ciliary dyskinesia in 11 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (28.4%), laterality defects (13.6%), and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and dextro-transposition of the great arteries, and 9 familial co-segregation of ccTGA and laterality defects. In one family co-segregation of ccTGA, dextro-transposition of the great arteries and heterotaxy syndrome in 3 distinct relatives was found. In another family, twins both displayed ccTGA and primary ciliary dyskinesia. Conclusions: ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, dextro-transposition of the great arteries, laterality defects and in some cases primary ciliary dyskinesia, strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

Abstract Aims Calmodulinopathies are rare life-threatening arrhythmia syndromes which affect mostly young individuals and are, caused by mutations in any of the three genes (CALM 1–3) that encode identical calmodulin proteins. We established the International Calmodulinopathy Registry (ICalmR) to understand the natural history, clinical features, and response to therapy of patients with a CALM-mediated arrhythmia syndrome. Methods and results A dedicated Case Report File was created to collect demographic, clinical, and genetic information. ICalmR has enrolled 74 subjects, with a variant in the CALM1 (n = 36), CALM2 (n = 23), or CALM3 (n = 15) genes. Sixty-four (86.5%) were symptomatic and the 10-year cumulative mortality was 27%. The two prevalent phenotypes are long QT syndrome (LQTS; CALM-LQTS, n = 36, 49%) and catecholaminergic polymorphic ventricular tachycardia (CPVT; CALM-CPVT, n = 21, 28%). CALM-LQTS patients have extremely prolonged QTc intervals (594 ± 73 ms), high prevalence (78%) of life-threatening arrhythmias with median age at onset of 1.5 years [interquartile range (IQR) 0.1–5.5 years] and poor response to therapies. Most electrocardiograms (ECGs) show late onset peaked T waves. All CALM-CPVT patients were symptomatic with median age of onset of 6.0 years (IQR 3.0–8.5 years). Basal ECG frequently shows prominent U waves. Other CALM-related phenotypes are idiopathic ventricular fibrillation (IVF, n = 7), sudden unexplained death (SUD, n = 4), overlapping features of CPVT/LQTS (n = 3), and predominant neurological phenotype (n = 1). Cardiac structural abnormalities and neurological features were present in 18 and 13 patients, respectively. Conclusion Calmodulinopathies are largely characterized by adrenergically-induced life-threatening arrhythmias. Available therapies are disquietingly insufficient, especially in CALM-LQTS. Combination therapy with drugs, sympathectomy, and devices should be considered.