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A Clinical Angiographic Study of the Arterial Blood Supply to the sinus Node: DiscussionThe nature of the blood supply to the sinoatrial node influences the clinical expression of sinoatrial ischemia in coronary heart disease. Fainting, syncope, and cardiac arrhythmias have been described as characteristic clinical features of acute infarction because of transient ischemia of the sinus node. In our clinical angiographic study, which to our knowledge is the first to describe the incidence of atheroma of the sinus node artery, 307 of the 309 patients (99.3 percent) had angiographically normal sinus node arteries free of atheroma. The two patients with atheromatous sinus node arteries showed no evidence of sinus node dysfunction. With the exception of two other cases in whom the normal sinus node artery arose from the distal portion of a severely stenotic left circumflex artery and who showed clinical sinus node dysfunction during the acute phase of myocardial infarction, there was no correlation between the origin of the sinus artery or its anatomic variation and sinus node dysfunction. To date this is the first study to our knowledge to demonstrate this lack of correlation. (more…)

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  • Evidence of temporary sinus node dysfunction was found in two patients. One with inferolateral infarction had critical stenosis of the left circumflex artery with the SNA arising from its posterior portion. The other patient, with a subendocardial infarction, had severe three vessel disease, and a posterior SNA arising distal to the severe stenosis. Sinus bradycardia (<55 beats/min) during the first six hours of myocardial infarction was noted in nine patients, seven with inferior and two with inferolateral infarction, but the SNA was not involved in the infarction process. Nearly all patients had supraventricular or ventricular extrasystoles in the first 24 to 36 hours of infarction, although all received prophylactic lignocaine. buy zoloft online
    The sinus node arteries in 307 of the 309 patients were angiographically atheroma free. Two hundred sixty-one of our 309 patients had a right dominant coronary arterial system (posterior descending artery originating from the right coronary artery), 45 had a left dominant coronary arterial system (posterior descending artery originating from the left circumflex), and three had a balanced type with two posterior descending arteries, one arising from the right coronary artery and one from the left circumflex. (more…)

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  • A Clinical Angiographic Study of the Arterial Blood Supply to the sinus NodeKnowledge of the course of the arteries irrigating the sinus node is important for better understanding of cardiac physiology and from a surgical point of view. Many post-mortem and a few angiographic studies have demonstrated that the sinus node artery (SNA) originates from the right coronary artery in approximately 60 percent of hearts and from the left circumflex in the remaining 40 percent.’ In a previous study we found that 27 percent of the SNAs originating from the left circumflex coronary artery were posterior, ie, passed backward in the region of the left atrium between the atrial appendage and the left superior pulmonary vein before reaching the atrial septum. In the present angiographic and clinical study we demonstrate the characteristic variations of the SNA and attempt to correlate sinus node dysfunction with the angiographic findings. (more…)

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