Thiene G

Spin-echo nuclear magnetic resonance for tissue characterisation in arrhythmogenic right ventricular cardiomyopathy.

OBJECTIVE: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disorder characterised clinically by ventricular arrhythmias that can cause cardiac arrest and morphologically by fatty or fibro-fatty myocardial atrophy of the right ventricle. In vivo tissue characterisation without endomyocardial biopsy would be useful. The aim of this study was to investigate the diagnostic accuracy of spin-echo nuclear magnetic resonance (NMR) for tissue characterisation in ARVC. PATIENTS AND METHODS: Twenty three subjects (15 men and eight women, aged 18-49, mean 34) were studied with spin-echo T1-weighted NMR and multislice scan. Fifteen had a clinical diagnosis of ARVC and eight were controls (age and sex matched subjects). Data were independently evaluated by two expert observers. RESULTS: In the control group NMR was always negative (100% specificity). Ten of the 15 patients with ARVC had an abnormal NMR result (67% sensitivity), with areas that had a signal intensity close to that of pericardial or subcutaneous fat. In the remaining five cases the NMR signal was inadequate. Nine patients underwent both NMR and endomyocardial biopsy; biopsy was positive in eight (89%) and NMR was positive in five (56%). CONCLUSIONS: NMR is a useful non-invasive diagnostic tool in the evaluation of fatty replacement in ARVC. The technique can be used with other procedures in the initial diagnostic evaluation and is a useful alternative tool in the long term follow up of patients with ARVC.

Complete transposition of great arteries with coarctation of aorta.

Complete transposition of the great arteries with ventricular septal defect and coarctation or atresia of the aortic arch is a relatively rare anatomoclinical entity and in general not well understood. This association accounted for six out of 50 cases (12%) of our clinical experience and six out of 64 cases (9%) of the post-mortem series of complete transposition. Relevant clinical manifestations were cyanosis, early and pronounced congestive heart failure, with a decrease in amplitude of femoral pulses and, in the most severe cases, isolated left ventricular hypertrophy on the electrocardiogram. Inlet or outlet right ventricular obstruction and pulmonary artery dextroposition are the pathological substrates of unequal partitioning of the blood stream in favour of the pulmonary artery and ductus arteriosus, probably accounting for fetal underdevelopment of the aortic arch. The medical and surgical prognosis of these cases is definitely poor.

Atresia of left atrioventricular orifice. Anatomical investigation in 62 cases.

Sixty-two hearts without a patent exit from the left atrium to the ventricular mass have been studied. All had situs solitus and laevocardia. The material consisted of 32 cases with coexistent aortic atresia and 30 cases with patent aortic root. Five hearts with aortic atresia were biventricular with atrioventricular concordance and imperforate left atrioventricular valves, and 27 hearts were univentricular of right ventricular type, with absent left atrioventricular connection. The anatomy of this group was uniform, with extreme hypoplasia of all the left cardiac segments. Among the cases with patent aortic root, five were biventricular, with atrioventricular concordance and imperforate left atrioventricular valves, and 24 had absent left atrioventricular connection, 15 with univentricular heart of right ventricular type and nine with univentricular heart of left ventricular type. The final heart had double inlet univentricular of left ventricular type with an imperforate left atrioventricular valve. In this second group the aorta was larger in cases with discordant ventriculoarterial connection or in those with double outlet from the main ventricular chamber. A normal sized aorta without aortic arch obstruction was observed in nine instances. These are of great interest in terms of surgical anatomy since definitive palliation may be feasible.

Dysplasia of the atrioventricular valves associated with conduction system anomalies.

Clinical, vectorcardiographic, and echocardiographic data from two siblings with atrial septal defects and dysplasia of the mitral and tricuspid valves are reported. Vectorcardiograms showed that both siblings had abnormal ventricular activation with initial electrical forces directed posteriorly. One sibling died after surgery, and necropsy showed incomplete differentiation of the leaflets and tensor apparatus producing anomalies resembling mitral arcade. Serial histological examination of the conducting tissue showed that the atrioventricular node was located on the left side of the atrial septum, that the central fibrous body and the membranous septum were hypoplastic, and that an accessory nodoventricular pathway originating in the compact node joined the left side of the ventricular septum. This accessory pathway was probably the cause of the unusual ventricular activation. Dysplasia of the mitral and tricuspid valves together with hypoplasia of the central fibrous body and the presence of accessory pathways are probably part of a malformative complex caused by incomplete differentiation of both the cardiac atrioventricular valves and the junctional area.

Anatomy of Tetralogy of Fallot

It was Etienne-Louis Arthur Fallot who, in 1888, first described the clinicopathological correlates of the “maladie bleue” [1]. The lesion that he identified was the association of interventricular communication, sub pulmonary stenosis, biventricular origin of the aorta and hypertrophy of the right ventricle. From the translation in English by Allwork in 1988 [2], come the following significant passages of Fallots original work: n... during the last few years, three cases of a rare and curious disease have passed before our eyes.observed during their lives and afterwards at necropsy, three patients affected by the illness called “maladie bleue”. n n... we thought that the “maladie bleue” was caused by these lesions multiple but constant, so together they constituted a type perfectly defined. n nAll the three patients had... an abnormal interventricular communication and in each of them the ventricular septal defect was in the same place, the superior part of the septum...the pulmonary artery was narrowed and in each there was subarterial as well as valvular stenosis...there was ventricular hypertrophy...the aorta deviated to the right...took equal origin from both ventricles.”

Etiology and pathology of the aortic arch malformations

In the embryo the various vascular systems are continuously modified and adapted to satisfy changing needs [1, 2, 3].