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Background— Atrial dilatation and atrial standstill are etiologically heterogeneous phenotypes with poorly defined nosology. In 1983, we described 8-years follow-up of atrial dilatation with standstill evolution in 8 patients from 3 families. We later identified 5 additional patients with identical phenotypes: 1 member of the largest original family and 4 unrelated to the 3 original families. All families are from the same geographic area in Northeast Italy. Methods and Results— We followed up the 13 patients for up to 37 years, extended the clinical investigation and monitoring to living relatives, and investigated the genetic basis of the disease. The disease was characterized by: (1) clinical onset in adulthood; (2) biatrial dilatation up to giant size; (3) early supraventricular arrhythmias with progressive loss of atrial electric activity to atrial standstill; (4) thromboembolic complications; and (5) stable, normal left ventricular function and New York Heart Association functional class during the long-term course of the disease. By linkage analysis, we mapped a locus at 1p36.22 containing the Natriuretic Peptide Precursor A gene. By sequencing Natriuretic Peptide Precursor A , we identified a homozygous missense mutation (p.Arg150Gln) in all living affected individuals of the 6 families. All patients showed low serum levels of atrial natriuretic peptide. Heterozygous mutation carriers were healthy and demonstrated normal levels of atrial natriuretic peptide. Conclusions— Autosomal recessive atrial dilated cardiomyopathy is a rare disease associated with homozygous mutation of the Natriuretic Peptide Precursor A gene and characterized by extreme atrial dilatation with standstill evolution, thromboembolic risk, preserved left ventricular function, and severely decreased levels of atrial natriuretic peptide.

AimsThe aim of this study is to show the feasibility of a biventricular implantable cardioverter-defibrillator [cardiac resynchronization therapy (CRT)–ICD] implantation using an electroanatomic navigation system and a low dose of fluoroscopy. Here four case reports of patients affected by dilated cardiomyopathy, who underwent cardiac resynchronization therapy, are described.Methods and resultsDuring 2010, four patients were admitted to our Cardiology Department for implantation of an CRT–ICD device in primary prevention. All had an ejection fraction of <35% and were in New York Heart Association class III despite optimal medical therapy. The implantations were performed using the EnSite NavX system. All the leads were positioned in the cardiac chambers utilizing the three-dimensional navigation system and only using X-ray to check that the leads had been positioned correctly. To our knowledge, these cases are the first use of an electroanatomic system for implantation of an CRT–ICD device and in all four cases the cannulation of the coronary sinus (CS) was performed only using the mapping system. Electroanatomic navigation made it possible to minimize X-ray exposure during the implantation of the CRT–ICD device; in addition, the mapping system was used to choose the optimum position of the CS catheter using as reference the maximum activation delay between the two ventricles.ConclusionsThe NavX system shows great potential during the implantation of an CRT–ICD device. It seems to be feasible, safe, and extremely beneficial in terms of a reduction in X-ray exposure. Furthermore, there is benefit of more detailed information and accuracy during the CS lead placement.