The four auricular arrhythmias, premature systoles, paroxysmal tachycardia, flutter, and fibrillation, have been investigated in over 200 dogs by three methods: (1) high speed cinematography, (2) cathode-ray oscillography, and (3) multiple-channel electrocardiography. The hitherto unexplored body of the left auricle has been surgically exposed and thoroughly studied. Results indicate that all four arrhythmias are of unitary origin and may occur from one ectopic focus. The resulting arrhythmia depends largely upon the rate of discharge from that focus. There is no circus movement. Corroborative observations have been made on the arrhythmias in man. This conception of the auricular arrhythmias simplifies the understanding of their mechanism.S INCE the classic studies of Lewis and his associates' on the nature of the auricular arrhythmias, comparatively little has been published on this phase of the subject. Levi is believed that his experiments established the following concepts concerning the mechanisms of the auricular arrhythmias:1. That auricular flutter is due to a regular circus movement in the auricles which sweeps around the openings of the venae cavae. The main impulse usually travels in a counterclockwise direction up the right auricle, circling the superior vena cava, then down the left auricle, and around the inferior vena cava, thus completing the circus. Regular daughter waves are sent off the main wave to the remainder of the auricles.2. Auricular fibrillation is due to a circus movement of the same general type as that of auricular flutter, but in this instance the impulse pursues a tortuous and redundant path around the venae cavae and sends off irregular daughter waves to the remainder of the auricles.3. Paroxysmal auricular tachycardia is of a different nature. Lewis believed that a rapidly discharging ectopic focus in the auricle is responsible for the arrhythmia; no circus movement is present. Other investigators, however, do favor circus movement as the mechanism of auricular tachycardia. The evidence that Lewis gathered with regard to circus movement appeared so complete that his conclusions have been accepted as fact in most modern textbooks of physiology, cardiology, and medicine.For the past three years we have been taking high-speed, colored cinematographs of the auricles of the intact dog's heart. A Western Electric Fastax 16-mm. camera was used with which films were taken at speeds up to 2,000 frames per second. When films taken at 2,000 frames per second are projected at eight frames per second the motion of the auricles is slowed 250 times. Auricular events that occur in one second take four minutes to view on the screen. A magnifying lens is used which enlarges the auricle 100 or more times on projection. By careful photographic technic, and lighting the field with twelve RSP-2 photospot incandescent lamps, excellent pictures are obtained showing the most minute detail of auricular activity. By means of such pictures, the auricular contraction wave can actually be seen for the first...

The results of 160 infrainguinal bypasses with arm vein grafts were analyzed. Seventy-three arteriograms were reviewed to identify early and late graft defects; arteriographic findings paralleled those described for saphenous vein grafts. Intimal fibrosis during the first postoperative year, observed in 16 grafts, was the most common defect. Aneurysmosis and elongation were rare, resulting in two graft replacements. Patency and limb salvage rates were calculated for 88 single-length femorodistal bypass grafts; the other 72 were inflow (eight) or outflow (22) jump grafts, sequential (eight) and composite autogenous vein grafts (34). The primary and secondary patency rates for single-length grafts were 74% and 80% at 1 year and 51% and 57% at 5 years, respectively. The limb salvage rate at 5 years was 82%. The survival rate for all patients was 44% at 5 years. These findings reconfirm our use of arm veins as bypass grafts when the saphenous vein is unavailable.

Unheralded occlusions more typical of prosthetic graft failure tempered the initial enthusiasm and effectiveness of vein allografts. All autogenous options must be exhausted to complete distal, secondary revascularization before resorting to nonautogenous conduits. Use of allograft veins must be viewed with continued skepticism.

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Two hundred forty-three bypasses to paramalleolar arteries were performed in 224 extremities of 208 patients since 1971; 166 were implanted in men (68%) and 77 in women (32%). The median age was 73 years. Gangrene (61%), nonhealing ulcer (15%), rest pain (22%), and trauma (2%) were the indications for bypass. Usual risk factors were noted: diabetes (65%), smoking (51%), heart disease (46%), and hypertension (45%). The extent of occlusive disease dictated three graft configurations: long grafts originating in arteries proximal to the adductor tendon (n = 111), short grafts originating at or below the popliteal artery (n = 88), and jump grafts originating near the distal end of a previous femorodistal bypass (n = 44). The association between diabetes (incidence 80%) and gangrene (75%) in patients with short grafts was statistically significant (p less than 0.01). The 2-year secondary patency rate of long in situ grafts was 92% compared with 72% for other autogenous vein long grafts. The limb salvage rate for all autogenous vein long grafts was 90% at 3 years. The secondary patency rate at 3 years for short grafts was 81% and the limb salvage rate was 80%. There were four amputations with patent grafts. Primary and secondary patency rates of jump grafts were similar (53%), whereas the limb salvage rate was 89% at 2 years. Patency and limb salvage rates of rarely employed nonautogenous conduits were less than 35% at 1 year (long grafts). Bypass grafts to the ankle and foot are effective and durable and should be performed with autogenous vein.