Electrical remodeling of the atrium during rapid atrial pacing was significantly attenuated by verapamil. This suggests that electrical remodeling of the atrium is triggered by the high calcium influx during rapid atrial pacing rates.

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1 Angiotensin converting enzyme (ACE) is thought to be the main enzyme to convert antiotensin I to the vasoactive angiotensin II. Recently, in the human heart, it was found that the majority of angiotensin II formation was due to another enzyme, identi®ed as human heart chymase. In the human vasculature however, the predominance of either ACE or non-ACE conversion of angiotensin I remains unclear. 2 To study the e ects of ACE-and chymase-inhibition on angiotensin II formation in human arteries, segments of internal mammary arteries were obtained from 37 patients who underwent coronary bypass surgery. 3 Organ bath experiments showed that 100 mM captopril inhibited slightly the response to angiotensin I (pD 2 from 7.09+0.11 ± 6.79+0.10, P50.001), while 100 mM captopril nearly abolished the response to [pro 10 ] angiotensin I, a selective substrate for ACE, and the maximum contraction was reduced from 83+19% ± 23+17% of the control response (P=0.01). A signi®cant decrease of the pD 2 of angiotensin I similar to captopril was observed in the presence of 50 mM chymostatin (pD 2 from 7.36+0.13 ± 6.99+0.15, P50.039), without in¯uencing the maximum response. In the presence of both inhibitors, e ects were much more pronounced than either inhibitor alone, and a 300 times higher dose was needed to yield a signi®cant contraction response to angiotensin I. 4 These results indicate the presence of an ACE and a non-ACE angiontensin II forming pathway in human internal mammary arteries.

An alternative way to revascularize coronary vessels is described, using arterial conduits without extracorporeal circulation. The heart is exposed via a small thoracotomy over the fifth left intercostal space. A thoracoscope is introduced into the thorax, to assist in the harvesting of the left internal mammary artery (LIMA). In selected patients with two or three vessel disease, the same procedure can be achieved on the right side, harvesting the right internal mammary artery to revascularize the right coronary artery. The gastroepiploic artery can be easily reached and used to revascularize the posterior descending artery, through a mini-subxiphoid median laparotomy. This technique was used to revascularize 30