Age-related fibromuscular dysplasia in the human left ventricle papillary muscles arteries.

We describe histologically cases of patients between 31 and 60 years of age who had fibromuscular dysplasia (FMD) in the tunica media (TM) of the left ventricle papillary muscles (PM) arteries. We also compared them with our previous findings in subjects younger than 30 years of age. We examined histologically samples taken from the tip of the anterior PM of the left ventricle in 200 healthy male hearts. In 33 cases (16.5 %), FMD was in the TM. We divided these cases into three subgroups (A, B, C) based on the degree of replacement of smooth muscle cells by fibrous tissue, and thus identified 17, 11 and 5 cases, respectively. Until the age of 41, the typical lesions were often localized within the TM. Beyond that age, the fibrous tissue increased in the TM wall and in the surrounding area of the vessels, causing dysfunction of the PM. Degenerative lesions, as well as inflammatory infiltration, were found after the age of 53. The findings of this study will be useful to cardiologists and cardiac surgeons, in pointing out that, after the age of 44 years old, some PM and their supporting valves may present a degree of dysfunction.

Histological recognition and classification of the atrioventricular node artery variants: a new approach.

BACKGROUND: There is a controversy in the literature concerning the origin, course, and distribution of the atrioventricular (AV) node artery. METHODS: Postmortem coronary angiography, dissection, and microscopic examination were performed in 100 human hearts specimens, providing anatomical, histological, and postmortem angiographic features of the AV node artery. RESULTS: Two anatomical types of AV node artery, depending on its length (long-short), were found. "Long-length" (LL) AV node artery supplied with blood almost all the AV conducting tissue in 72 cases. It consisted of a horizontal and descending part ending in two branches. "Short-length" (SL) AV node artery had only a horizontal part, perfusing exclusively the AV node and several times the nonpenetrating main bundle of His. In 67 of 100 cases, the AV arteries were arising from the right coronary artery, distal to the posterior descending (PD) artery. The AV node artery never originated from the PD artery. In 54 of 100 cases, it passed under the coronary sinus (CS) and in the remaining 46 it passed underneath the right atrium endocardium. CONCLUSIONS: The above-described postmortem coronary angiographic findings are essential for interventional cardiologists and cardiac surgeons. Damage to the LL or SL type of AV node artery may cause severe or limited AV conduction abnormalities, respectively. Furthermore, the course of AV node artery under the CS makes it susceptible to injuries provoked by diagnostic or therapeutic procedures involving the CS area.

Histologic findings in left ventricle papillary muscle arteries from human hearts.

We describe original histologic findings of left ventricle papillary muscle (LVPM) arteries in people under 30 years of age. We examined 666 samples taken from the tip, mid-portion and base of papillary muscles in 56 males and 55 females, as well as several samples from the rest of the left ventricle. The number of smooth muscle cells (SMC) in the tunica media of the LVPM arteries led us to divide the samples examined into three groups: (i) group 1, 355 samples (53%) with a normal number of SMC and a normal lumen (the number of group 1 samples increased from the tip (21%) to the base (47%)); (ii) group 2, 252 samples (38%) with a mild to moderately increased number of SMC (the number of these samples decreased from the tip (44%) to the base (22%)); and (iii) group 3, 59 samples (9%) with abundant SMC that were more than twofold greater in size and number of normal arteries, in contrast with the other two groups. The shape of the SMC in group 3 samples was round and the extremely narrow, centrally located lumen of these SMCE had a round or oval shape. These changes were restricted only to papillary muscle arteries and the number of group 3 samples decreased from the tip (63%) to the mid-portion (37%). No inflammatory reaction or chronic ischemic changes were found in the LVPM arteries and surrounding area. The SMC changes in groups 2 and 3 were found in subjects aged more than 2 months. These findings will provide anatomists, cardiologists, pathologists and physiologists with valuable knowledge and will trigger further investigation into the etiology of the structural changes observed and their evolution with age.

Original histologic findings in arteries of the right ventricle papillary muscles in human hearts.

In this study we describe original histologic findings of the right ventricle papillary muscle (PM) arteries in people under 30 years old. We examined 666 samples taken from the tip, mid-portion, and base of the PM in 56 males and 55 females, as well as samples from the rest of the right ventricle. The amount of smooth muscle cell (SMC) fibers in the tunica media (TM) led to their division into three groups: Group 1: 351 samples (53%); normal amount, normal lumen. The amount of SMCs increased from the tip (20%) to the base (48%). Group 2: 226 samples (34%); mild to moderately increased amount of SMCs, with narrowness, eccentric displacement, and uneven lumen shape. They decreased from the tip (42%) to the base (23%). Group 3: 89 samples (13%), with abundant SMCs that duplicated the arterial size, contrary to the other two groups. Their shape was round and their extremely narrow, centrally located lumen had a round or oval shape. These changes were restricted only to PM arteries and decreased from the tip (65%) to the mid-portion (35%). This type of artery predominated compared to the other two groups, probably because of the narrow lumen. No inflammatory reaction or chronic ischemic changes were found in the PM and its arteries. The SMC changes in groups 2 and 3 were found in subjects older than 2 months. The above findings will provide anatomists, cardiologists, and physiologists with valuable knowledge.