"Myo-cardiomyopathy" is commonly associated with the A8344G "MERRF" mutation.

The objective of the study was to better characterize the clinical phenotype associated with the A8344G "MERRF" mutation of mitochondrial DNA. Fifteen mutated patients were extensively investigated. The frequency of main clinical features was: exercise intolerance and/or muscle weakness 67 %, respiratory involvement 67 %, lactic acidosis 67 %, cardiac abnormalities 53 %, peripheral neuropathy 47 %, myoclonus 40 %, epilepsy 40 %, ataxia 13 %. A restrictive respiratory insufficiency requiring ventilatory support was observed in about half of our patients. One patient developed a severe and rapidly progressive cardiomyopathy requiring cardioverter-defibrillator implantation. Five patients died of overwhelming, intractable lactic acidosis. Serial muscle MRIs identified a consistent pattern of muscle involvement and progression. Cardiac MRI showed non-ischemic late gadolinium enhancement in the left ventricle inferolateral part as early sign of myocardial involvement. Brain spectroscopy demonstrated increased peak of choline and reduction of N-acetylaspartate. Lactate was never detected in brain areas, while it could be documented in ventricles. We confirm that muscle involvement is the most frequent clinical feature associated with A8443G mutation. In contrast with previous reports, however, about half of our patients did not develop signs of CNS involvement even in later stages of the disease. The difference may be related to the infrequent investigation of A8344G mutation in 'pure' mitochondrial myo-cardiomyopathy, representing a bias and a possible cause of syndrome's underestimation. Our study highlights the importance of lactic acidosis and respiratory muscle insufficiency as critical prognostic factors. Muscle and cardiac MRI and brain spectroscopy may be useful tools in diagnosis and follow-up of MERRF.

Mild Beckwith-Wiedemann and severe long-QT syndrome due to deletion of the imprinting center 2 on chromosome 11p.

We report on a young woman admitted to our Cardiology Unit because of an episode of cardiac arrest related to a long-QT syndrome (LQTS). This manifestation was part of a broader phenotype, which was recognized as a mild form of Beckwith-Wiedemann syndrome (BWS). Molecular analysis confirmed the diagnosis of BWS owing to a maternally inherited deletion of the centromeric imprinting center, or ICR2, an extremely rare genetic mechanism in BWS. The deletion interval (198 kb) also included exons 11-16 of the KCNQ1 gene, known to be responsible for LQTS at locus LQT1. No concomitant mutations were found in any other of the known LQT genes. The proposita's mother carries the same deletion in her paternal chromosome and shows manifestations of the Silver-Russell syndrome (SRS). This report describes the smallest BWS-causing ICR2 deletion and provides the first evidence that a paternal deletion of ICR2 leads to a SRS-like phenotype. In addition, our observation strongly suggests that in cases of LQTS due to mutation of the KCNQ1 gene (LQT1), an accurate clinical genetic evaluation should be done in order to program the most appropriate genetic tests.

Lead extraction: a new effective tool to overcome fibrous binding sites.

We report the case of a 50 year-old woman referred for extraction of an infected biventricular implantable cardioverter defibrillator (ICD) who underwent device and leads extraction. Due to adhesions at the level of the subclavian-innominate vein angle, manual traction with locking stylet was ineffective. A new mechanical sheath provided with a stainless steel bladed tip, the Evolution Mechanical Dilator Sheath (Cook Medical), was successfully used to complete lead extraction. As far as we know, this is the first report on the use of this new tool; its safety should be ascertained by increasing the number of cases but its simple use and its low cost make the Evolution Mechanical Dilator Sheath a new interesting tool that can be added to the instruments available for lead extraction.