Coronary sinus

We examined the effects of selective activation of histamine Hj receptors on coronary hemodynamics in two groups patients with atypical chest pain and normal coronary arteries, and patients with vasospastic angina [48]. Selective Hj receptor stimulation was achieved by infusing histamine intravenously (0.5 pg/kg/min) for 5 min after pretreatment with cimetidine to antagonize the H2 receptors. Heart rate was kept constant (100 beats/min) by coronary sinus pacing. 

The AV node lies directly above the insertion of the septal leaflet of the tricuspid valve and anterior to the ostium of the coronary sinus. It is part of the AV junction area, which is divided into three regions. The transitional cells, or nodal approaches, connect the atrial myocardium to the compact portion of the AV node. The slowest conduction time occurs within the AV node [8]. At its distal end, the compact portion of the AV node enters the central fibrous body, becoming the penetrating portion, or His-bundle [9]. 

Transcoronary venous injection is performed with a catheter system threaded percutaneously into the coronary sinus. Initial studies in swine have confirmed the feasibility and safety of this approach [121]. This delivery method has also been used to deliver skeletal myoblasts to scarred myocardium in cardiomyopathy patients [120]. With intravascular ultrasound guidance, this approach allows the operator to extend a catheter and needle away from the pericardial space and coronary artery into the adjacent myocardium. To date, human feasibility studies have had a good safety profile. This technique is limited, however, by coronary venous tortuosity, lack of site specific targeting, and its own technically challenging nature. Unlike the transendocardial approach, in which cells are... 

Beneath the activation of the coagulation system, it has been demonstrated that platelet activation in the coronary sinus of patients undergoing coronary intervention is significant (26). 

Tortolani, A.J., Powell, S.R., Misik, V., Weglicki, W.B., Pogo, G.J., and Kramer, J.H. 1993. Detection of alkoxyl and carbon-centered free radicals in coronary sinus blood from patients undergoing elective cardioplegia. Free Radical Biol. Med. 14 421 126. 

Benedict et al. (1986) modified the electrical induction of thrombosis by use of two Doppler flow probes proximal and distal to the needle electrode in order to measure changes in blood flow velocity. The electrical current was stopped at 50 % increase in flow velocity and thrombosis then occurred spontaneously. The important role of serotonin was demonstrated by increases in coronary sinus serotonin levels just prior to occlusion. 

Coronary blood flows through the cardiac muscle in arteries, capillaries and veins and returns to the heart via the coronary sinus. Extraction of oxygen from coronary blood is high and, when oxygen requirements increase, blood flow must also rapidly increase to supply the extra oxygen needed. 

The cardiac effects of intracoronary infusion of cocaine have been studied in dogs and humans (42). The procedure can be performed safely and does not alter coronary arterial blood flow. The effects of direct intracoronary infusion of cocaine on left ventricle systolic and diastolic performance have been studied in 20 patients referred for cardiac catheterization for evaluation of chest pain. They were given saline or cocaine hydrochloride (1 mg/minute) in 15-minute intracoronary infusions, and cardiac measurements were made during the final 2-3 minutes of each infusion. The blood cocaine concentration obtained from the coronary sinus was 3.0 pg/ml, which is similar in magnitude to the blood-cocaine concentration reported in abusers who die of cocaine intoxication. Minimal systemic effects were produced. The overall results were that cocaine caused measurable deterioration of left ventricular systolic and diastolic performance. 

Right Atrium Receives deoxygenated blood from the vena cava and coronary sinus and pumps blood into the right ventricle through the tricuspid valve... 

J. W. West, T. Kobayashi and F. S. Anderson, Effects of selective coronary embolization on coronary blood flow and coronary sinus venous blood oxygen saturation in dogs, Circ Res 10,722-738 (1962). 

Bagger JP, Botker HE. Thomassen A, Nielsen TT. Effects of ranolizine on ischemic threshold, coronary sinus blood flow, and myocardial metabolism in coronary artery disease. Cardiovasc Drugs Ther 1997 11 479M84. 

The cardiac catheterization procednre reqnires vascnlar access, nsually obtained percutaneonsly at brachial or femoral arteries or veins. Left-sided catheterization provides access to the aorta, left ventricle, and left atrinm. Right-sided catheterization enables the right side of the heart, coronary sinus, pulmonary arteries, and pulmonary wedge position to be reached. Left-sided catheterization is used for coronary angiography and ventriculography, whereas rightsided catheterization is nsed for determination of cardiac performance parameters. 

Coronary blood flow is closely tied to oxygen needs of the heart. Changes in oxygen balance lead to very rapid changes in coronary blood flow. Although a number of mediators may contribute to these changes, the most important ones are likely to be adenosine, other nucleotides, nitric oxide, prostaglandins, CO2, and H. Adenosine, which is formed from adenosine triphosphate (ATP) and adenosine monophosphate (AMP) under conditions of ischemia and stress, is a potent vasodilator that links decreased perfusion to metabolically induced vasodilation, or reactive hyperemia. The synthesis and release of adenosine into coronary sinus venous effluent occur within seconds of coronary artery occlusion, and about 30% of the hyperemic response can be blocked by metabolic blockers of adenosine. " ... 

The Mechanism ofMn-SOD Release into Serum in Patients with Acute Myocardial Infarction. Figure 19 shows the difference in serum Mn-SOD levels between samples taken from the ascending portion of the aorta and samples taken from the coronary sinus immediately following reperfusion in four patients with anterior myocardial infarction. In all cases the Mn-SOD levels were higher in the coronary sinus than in the aorta. This suggests that the noted elevations of serum Mn-SOD originated in cardiac tissue. 

Fig. 19. Difference in serum Mn-SOD levels in aortic and coronary sinus blood in acute anterior myocardial infarction.

FIGURE 5.2 Typical PA and lateral chest X-ray after implantation of CRT-D system. Note the course of the LV lead via the coronary sinus to reach the lateral epicardial wall of the left ventricle, which is posterior as viewed in the lateral projection. (RA, right atrial lead with tip in right atrial appendage RV, ICD lead with tip in right ventricular apex LV, left ventricular lead with tip at the mid-lateral wall of the left ventricle.)... 

FIGURE 6.1 Initiation of atrial fibrillation (AF) with ectopic beats arising from the left superior pulmonary vein (PV). Shown are three surface leads (I, aVF, and VI), five intracardiac electrograms form the coronary sinus (CS prox to CS distal) and five electrograms from a catheter in the left superior PV (PV1 through PV5). After a sinus beat, a premature PV potential appears on PV3, which initiates AF (arrow). 

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