Background-Platelets are the key to thrombus formation and play a role in the development of atherosclerosis.

Sixty-five members of three families with limb girdle muscular dystrophy (LGMD) underwent neurological, cardiological, and ancillary investigations. Thirty-five individuals were diagnosed as having slowly progressive autosomal dominant LGMD. Symmetrical weakness started in the proximal lower limb muscles, and gradually upper limb muscles also became affected. Early contractures of the spine were absent. Contractures of elbows and Achilles tendons were either minimal or late. Serum creatine kinase activity was normal to moderately elevated. Electromyogram and muscle biopsy were consistent with a mild muscular dystrophy. Cardiological abnormalities, found in more than one-half the patients, included dysrhythmias and atrioventricular (AV) conduction disturbances presenting as bradycardia, syncopal attacks necessitating pacemaker implantation, and sudden cardiac death. There was a significant relation between the severity of AV conduction disturbances and age. In nearly all patients, neuromuscular symptomatology preceded cardiological involvement. The early recognition of this previously not described, autosomal dominant LGMD with life-threatening cardiac involvement offers an opportunity for therapeutic intervention.

SUMMARY The mitral annulus is the point at which the atrial and ventricular walls meet the base of the mitral valve cusps. The suggestion that a variant of this arrangement termed "disjunction" was associated with prolapse of the leaflets prompted examination of the mitral atrioventricular junctions in seven normal hearts and six with prolapse owing to floppy mitral valves. A complete cord-like ring of connective tissue that encircled the atrioventricular junction and into which the three components were inserted at the same point was found in only one heart. The remaining hearts all showed a mixture of segments in which either the three components were inserted into a cord or simply met. Disjunction, defined as a separation of the atrial wall-mitral valve junction from the other component, the left ventricular wall, can occur both with and without a cord-like annulus. There was no significant difference in the number of segments around the left atrioventricular junction which showed disjunction in hearts with normal or prolapsing leaflets.The feature termed disjunction is an anatomical variation of the normal morphological characteristics of the left atrioventricular junction. atrial wall-mitral valve junction and the left ventricular attachment.9 They argued that this anomalous feature, through a process of hypermobility of the tension apparatus, could lead to floppiness of the leaflets. This group, however, studied only limited histological sections from a large number of hearts to demonstrate the significant association between so-called "disjunction" and floppy and prolapsed leaflets.It seemed to us that it was important to test their hypothesis by examining in detail the entire atrioventricular junction in a smaller number of hearts. This report describes our findings. Patients and methodsWe examined 13 hearts obtained an necropsy. The mitral valve was normal in seven (from 3 men and 4 women) and floppy in six (from 4 men and 2 women). The specimens of normal hearts came from a group aged 66-80 years (mean 71-9) and those with floppy valves came from a group aged 56-89 years (mean 69-5).

Transluminal coronary angioplasty was performed in a 51 year old man with a localised narrowing of the proximal segment of the left anterior descending coronary artery. Initial inflations with a small size balloon catheter were unsuccessful. A second attempt, during the same procedure, using a larger calibre catheter relieved the obstruction but produced a dissection. Angina pectoris reappeared approximately three months later. Another attempt to relieve the obstruction by angioplasty, five months after the initial procedure, induced ST segment elevation before angioplasty, followed by ventricular fibrillation and death. The necropsy showed a split in the pre-existent sclerotic plaque and a dissecting aneurysm of the media. A proliferation of fibrocellular tissue filled the false channel and almost totally occluded the pre-existent arterial lumen. The observation suggests that wall laceration with exposure of smooth muscle cells to blood may have initiated the excessive fibrocellular tissue response. This event may be the underlying pathogenetic mechanism for the occurrence of early restenosis after transluminal coronary angioplasty.