Left ventricular involvement in right ventricular dysplasia/cardiomyopathy.

OBJECTIVE: To characterize pathological features of left ventricular (LV) involvement in right ventricular dysplasia/cardiomyopathy (RVD/C). DESIGN: Retrospective morphological case study. SETTING: Two referral-based university medical centres. MATERIALS: Seventeen hearts were studied: 15 from sudden cardiac deaths outside hospital and two explanted hearts, one removed for intractable arrhythmias and the other for right-sided heart failure. The subjects (three female) were aged 16 to 60 years. MAIN RESULTS: All had typical right ventricular features of RVD/C and morphological evidence of LV wall involvement, seven with microscopic changes only. Of 10 hearts with gross and microscopic lesions, nine had large or laminar segments involved. The LV free wall was affected in all cases and the ventricular septum (VS) in 15. Sixteen hearts were hypertrophied. In involved areas, the LV or VS walls were of 'normal' thickness or slightly thinned. Five histological patterns of involvement were recognized, of which four were found in the LV. More severe LV involvement was seen in the hearts of older patients. Complete transmural fatty replacement of the myocardium was not observed, nor were the LVs aneurysmal. Minimal or mild focal aggregates of inflammatory cells were seen in nine hearts and moderate inflammatory changes in two. Inflammation was usually associated with myocyte atrophy and only rarely with myonecrosis. CONCLUSIONS: This study suggests that patients with RVD/C who live long enough will likely have LV free wall involvement with frequent VS involvement. Pathologists may miss LV involvement on gross examination. It should be sought diligently in patients dying of the condition or receiving transplants for heart failure. Appropriate histological sections from both free wall and septum must be examined.

Intra-atrial course of the right coronary artery and its branches.

OBJECTIVE: To illustrate and describe an anomaly of right coronary artery (RCA) course. SETTING: Postmortem examination of cardiac tissue. DESIGN AND PATIENTS: Three cases where the RCA had an intracavitary position in the right atrium are described. Additionally, light microscopic analysis of random sections of posterior right atrium from 100 consecutive autopsy cases was undertaken. MAIN RESULTS: Each of the index cases was an incidental finding at autopsy. In two cases, the RCA, after passing the acute angle of the heart (epicardially), entered the right atrium posteriorly and ran subendocardially for distances of 1.5 and 3.0 cm, respectively. In the third case, the RCA entered the right atrial cavity 2.5 cm from its origin and ran subendocardially for 2.0 cm. In all three cases, the RCA exited the atrial cavity and once again attained an epicardial course. In the first two cases, the RCA ran 1.0 cm above the atrioventricular groove, rather than in its normal location at the annulus. The random sections of right atrial wall showed that medium calibre arterial branches of the RCA also commonly run in subendocardial positions (29 of 100 cases) and sometimes project into the atrial cavity (five of 29 cases). CONCLUSIONS: The genesis of this epicardial coronary anomaly is unclear, but may relate to the 'higher' than normal course of the artery in these cases, in concert with the normal thinness of the right atrial wall, and the tendency for even medium calibre arteries to assume this subendocardial location. Despite the benign outcome of the index cases described here, the authors believe that this intracavitary course of the RCA could pose special technical problems during coronary artery catheterization and bypass grafting.

Right atrial myxoma originating from the eustachian valve.

An unusual case of multiple right atrial myxomas arising from the interatrial septum and the Eustachian valve is reported. The literature contains reports of only one other patient with a right atrial myxoma originating from the Eustachian valve.

Right ventricular dysplasia: morphological findings in 13 cases.

OBJECTIVE: To characterize the pathological features of right ventricular dysplasia (RVD). DESIGN: Retrospective morphological case study. SETTING: Three referral-based university medical centres. PATIENTS: Thirteen subjects (one female) aged 16 to 55 years including 10 necropsy hearts from sudden deaths out of hospital, one explant heart and two partial right ventricular resections from patients with intractable ventricular tachycardia. MAIN RESULTS: Most hearts showed hypertrophy and localized or generalized dilatation of the right ventricle. Transillumination revealed myocardial thinning of variable configuration usually conforming to regions of dilatation. Common sites of involvement were apex, infundibular region and posterobasal wall. Histologically, focal or extensive segments of right ventricular myocardium were absent or replaced. Three patterns were found: right ventricle markedly thinned, epicardium and endocardium contiguous, virtually no intervening tissue; wall normal thickness or thinned, myocardium almost totally replaced by fat; and wall normal or thin, myocardium largely replaced by fat with scattered residual myocardial cells and fibrous tissue (the predominant pattern). Endocardial fibrosis was present in eight cases and focal mononuclear cell infiltrates in 10. Electron microscopy in two cases showed nonspecific findings. CONCLUSIONS: RVD has gross and microscopic features which permit its recognition. While a majority of cases are likely congenital (genetic or acquired in utero), the possibility of postnatally acquired conditions (inflammatory, toxic, ischemic) inducing RVD must be explored. The incidence and importance of RVD as a cause of sudden death can only be assessed by continued systematic and detailed studies of patients with recurrent ventricular tachycardia and of hearts, especially from sudden death victims. Although uncommon, RVD should be considered in the differential diagnosis of arrhythmia and sudden death by both clinicians and pathologists.

Atherosclerosis in internal mammary arteries selected for coronary artery bypass grafting.

Atheromas are infrequent in the internal mammary artery (IMA) which is now the conduit of choice for coronary artery bypass grafting (CABG). Described are two cases of significant atherosclerotic stenosis near the distal ends of IMAs selected for CABG.

Rupture of both left ventricular papillary muscles following acute myocardial infarction.

A 77-year-old woman collapsed shortly after arrival at the emergency department and attempts at resuscitation were unsuccessful. Autopsy revealed an evolving recent transmural myocardial infarct in the posterolateral free wall of the left ventricle with rupture of both papillary muscles. No well documented description of post infarction dual papillary muscle rupture was found in the literature.

Death following coronary angiography in a young woman with isolated left coronary ostial stenosis.

A 35-year-old woman with angina of five years duration underwent elective cardiac catheterization and coronary angiography which revealed left main stenosis. Immediately afterwards, the patient became distressed, hypotensive and bradycardic. She died despite emergency percutaneous transluminal coronary angioplasty and resuscitative efforts. Autopsy confirmed isolated left coronary ostial stenosis due to the combination of a congenital abnormality of the ostium and initial segment of left main coronary artery, together with a superimposed myointimal flap bridging the ostium. A unique association was an abnormal configuration of the ostia of the branches of the aortic arch.

Accessory tissue of the tricuspid valve protruding into the left ventricle through a septal defect.

We report the pathologic findings in 13 cases with accessory tissue originating from the tricuspid valve and protruding into the left ventricular outflow tract through a ventricular septal defect (VSD). In eight cases the accessory tissue formed a pouch, the walls of which were similar to the tissue of the normal tricuspid valve. In five cases, papillarylike masses of young connective tissue formed the accessory tissue. The degree of left ventricular outflow tract obstruction was mild in five cases, intermediate in five, and severe in three. Adhesions to the rims of the VSD causing obstruction of the VSD were seen in ten cases. Associated anomalies were present in all cases. The most frequent associated anomalies other than the tricuspid valvular anomalies and the VSDs were transposition of the great arteries and a variety of vascular anomalies.