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Right ventricular dysfunction is not uncommon in adults with congenital heart disease. In congenital heart disease, unlike acquired heart disease, the right ventricle is not always the subpulmonary ventricle: it may support the systemic circulation as it does in patients with transposition complexes. The result is chronic right ventricular pressure overload. In contrast, pulmonary valve regurgitation -a frequent problem after surgical repair of the tetralogy of Fallot- imposes a volume overload on the right ventricle. Over time, both conditions may lead to right ventricular dysfunction and often this becomes a major clinical concern. Clearly, a thorough understanding of right ventricular anatomy and physiology is a necessity for those caring for patients with congenital heart disease. This article provides an overview of right ventricular morphology and the adverse effects of right ventricular dysfunction in adults with congenital heart disease.

Introduction and Objectives: Retrograde aortocoronary dissection is an unusual complication of coronary angioplasty. Our study provides new structural details of the aortic sinuses and the proximal portions of the coronary arteries, which enable better understanding of several clinical features associated with this complication., Methods: We studied eight aortic sinus specimens from patients with structural ischemic heart disease using dissection, histologic analysis, and scanning electron microscopy, and compared findings with those in eight control specimens., Results: We observed the following features: a) in 10 specimens (71%), the left coronary artery diameter was greater than the right; b) the angle that the ascending aorta made with the left coronary artery was acute, whereas that with the right coronary artery was closer to a right angle, thereby possibly providing a better approach for catheterization; c) in contrast to those of the right coronary artery, the periostial wall and sinotubular junction of the left coronary artery were formed by more smooth muscle cells and by a dense matrix of collagen type-I fibers, and d) the aortic sinuses and coronary arteries in structural ischemic heart disease specimens displayed structural alterations that affected the aortic tunica media and the collagen distribution at the sinotubular junction., Conclusions: The morphological and structural differences observed between right and left sides suggest that the left aortic sinus is more resistant to traction and is, therefore, less prone to iatrogenic dissection. Structural ischemic heart disease is a risk factor that increases the likelihood of aortocoronary dissection.

Concomitant with the development of catheter ablation techniques for the treatment of atrial arrhythmias, there has been renewed interest in the morphologic arrangement of the cardiac conduction system. The first descriptions of the anatomy of the nodes and atrioventricular conduction system appeared nearly 100 years ago. Since then the subject has been controversial, possibly because of the early researchers' imprecise knowledge of histology. The components and structure of the specific conduction system in humans are similar to those found in commonly used laboratory animals. The conduction system is composed of specialized myocytes. Its atrial components, the sinus node and the atrioventricular node, are in contact with atrial myocardium. The His bundle penetrates the right fibrous trigone, then divides into two specialized ventricular bundle branches (right and left), which also are surrounded by a fibrous sheath that separates the specialized myocytes from the ordinary myocardium. Only at the distal ramifications of the bundle branches do the fibrous sheaths disappear, allowing continuity with the ventricular myocardium. Knowledge of the specialized myocardium can help in the development of potentially useful therapies for some forms of cardiac arrhythmia.