Histological findings of the atrioventricular conductive system in street heroin addicts, victims of sudden unexpected death.

A study of the atrioventricular (AV) conducting tissue was considered necessary for the examination of probable histologic changes that could justify the arrhythmias observed in street-heroin addicts. Postmortem coronary angiography and microscopic examination were performed in 50 heroin addicts (group A) and in 50 nonaddicts (group B), all male 16-40 years old. In group A, fatty and/or fibrous tissue replaced the AV node in 50% of cases while in group B in 14%. The main bundle was replaced by fatty and/or fibrous tissue in 44% in group A cases and 10% in group B. Intimal proliferation and fibromuscular dysplasia of the AV arteries in group A were correspondingly 26% and 14% and in group B 6% and 2%. Inflammation with focal and/or diffuse concentration of round cells of the AV node was detected in 54% in group A. These findings could explain a possible arrhythmia mechanism in this population.

A secret pathway of the sinus node artery.

Anatomic and postmortem angiographic findings of a previously unreported case of common origin of the left circumflex (LCX) and the sinus node (SN) arteries, from the left main (LM) coronary artery were demonstrated. Knowledge of this anatomical variation, although it does not give rise to symptoms, is essential for anatomist and mainly for the interventional cardiologists and cardiac surgeons for their procedures.

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.