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.

Methods
We studied the coronary arteriograms and the medical records of 309 consecutive patients who underwent coronary arteriography in our hospital. Two hundred thirty-two were males and 77 females whose ages ranged from 19 to 70 years (mean, 51). Coronary arteriography was performed using either the Sones or Judkins technique in standard projections.
Results
Two hundred five patients had ischemic heart disease, and the remaining 104 (54 females and 50 males) had valvular heart disease. Eleven of the patients with valvular heart disease were found to have significant coronary artery disease in addition, but no history of acute myocardial infarction. Seventy-nine of the 205 patients who were catheterized for ischemic heart disease had a history of acute myocardial infarction between one month and six years previously, mean 14 ±9.3 months. Of the remaining 126 patients, not one had a history of faintness or syncope. Of the 79 patients with a history of acute myocardial infarction, 29 showed ECG patterns of inferior infarction, 16 of inferolateral infarction, 22 of anterior infarction and five of extensive anterolateral infarction. The remaining seven patients had ECG changes of subendocardial ischemia only. Eighteen of the 79 patients with a history of acute myocardial infarction had some degree of conduction abnormalities during their hospitalization in the acute phase. The abnormalities were first-degree atrioventricular (AV) block in six patients, second-degree Mobitz 1 iW block in seven patients, second-degree Mobitz 2 in two patients, and third-degree block in three patients. Eight of these patients needed temporary pacing wires, but none required a permanent pacemaker.