TUESDAY AFTERNOON, APRIL 17, 1973

2:00 P.M. Scientific Session

Regency Ballroom

25. Drug Influence on Platelet Loss During Extracorporeal Circulation

C. H. MIELKE, JR.,* M. deLEVAL,* J. D. HILL,*

M. F. MACUR* and F. GERBODE, San Francisco, California

Thrombocytopenia, which develops during prolonged extracorporeal circulation, represents the major hazard to this procedure. The potential for serious hemorrhage during prolonged perfusion has led to investigations of the influence of various drugs on platelet loss.

Using labeled platelets (51 Cr) in dogs, we were able to show that the majority of this platelet loss occurs because of storage in the liver during bypass. Once bypass is discontinued, some of the sequestered, labeled platelets return to the circulation with a corresponding reduction in liver radioactivity. Circulating fibrinogen labeled with 1251 remains stable.

Using this animal model we have evaluated several drugs with known influences on platelet function in both the Temptrol bubble and Bramson membrane oxygenators. The influences of Persantine, Aspirin, Sudoxicam and Pluronic F68 were compared on platelet loss during and after bypass.

Persantine inhibited platelet adhesion but not aggregation. Platelet levels were only slightly diminished during and after bypass. Pluronic F68 was similar but less effective. Platelet microaggregation during bypass was effectively inhibited by both agents. Sudoxicam inhibited both platelet aggregation and adhesion. However, the post bypass level of platelets was lower than with the two other agents. Platelet consumption was increased by high doses of aspirin.

*By invitation

26. Electroencephalographic Changes and Cerebral Complications in Open-Heart Surgery

M. WITOSZKA,* H. TAMURA,* R. INDEGLIA* and

F. A. SIMEONE, Providence, Rhode Island

Cerebral dysfunction and behavioral disorders are not uncommon after surgical correction of cardiac lesions. In the past four years encephalograms (EEC) were continuously monitored during open heart surgery in 50 randomly selected patients who survived (Group I) and 50 patients who succumbed during (Group II) and after the procedure (Group III). These data were correlated with clinical evidence of neurological disorders and findings in the brain at autopsy.

*By invitation

Postmortem examinations of the brain were performed in 20 patients. Among 18 of these patients with significant EEG changes fifteen had abnormal findings upon histologic examination of the brain. Evidence of cerebral embolism was found in 60% of autopsy specimens. No correlation between hypotension and histologic abnormalities was observed.

Conclusions:

1. Neurological complications occurred in 52% of patients who survived open heart surgery and in 80% of patients who died.

2. These complications followed intraoperative EEG abnormalities in 28% cases and 35% in the absence of intraoperative EEG changes, postoperative encephalopathy or motor disorders occurred in 62% of the patients.

3. Neuronal degeneration was the most common pathological manifestation of the encephalopatlic syndrome, while frank cerebral necrosis (8 cases) was most often associated with cerebral embolism (80% of the cases).

*By invitation

27. Surgical Experience with Temporary and Permanent A-V Sequential Demand Pacing

JOSH FIELDS,* BAROUTH V. BERKOVITS* and

JACK M. MATLOFF, Los Angeles, California

The hemodynamic advantages of the normal atrioventricular sequence can be maintained in patients with atrial bradytachy-arrhythmias and/or complete heart block by the temporary or permanent use of atrioventricular sequential demand pacing. This pacing modality is achieved with a two-catheter system utilizing a conventional bipolar ventricular catheter and a new, preformed J-shaped bipolar atrial electrode. Temporary use in 12 postoperative cardiac surgical patients with sinus or nodal bradycardia (with and without A-V block) yielded a 12-22 mm Hg increase in blood pressure over that achieved with ventricular pacing. In each case of escape tachyarrhythmia or ectopic activity, the use of A-V sequential pacing achieved capture and maintenance of a stable rate and rhythm without large doses of suppressant drugs.

Permanent A-V sequential demand pacemakers have been implanted for up to three years in 49 patients, 6 following prosthetic valve replacement and 43 with intermittent or constant atrial arrhythmias (17) and bradytachy-arrhythmias (26). Fifteen of these patients also had A-V dissociation. There was dramatic clinical improvement in 44 of these patients, manifest by relief of syncope, control of tachyarrhythmias and relief of congestive heart failure. This latter result was achieved by virtue of increased cardiac outputs. From this experience, it would appear that A-V sequential demand pacing provides the most comprehensive modality of pacing yet available.

*By invitation

28. Experience with Atrial Pacemaker Wires Implanted During Cardiac Operations

NOEL L. MILLS* and JOHN L. OCHSNER, New Orleans,

Louisiana

Two-hundred and seventy-five patients had implantation of a pacemaker wire on the right atrium at the time of cardiac operation. The operations involved were repair of congenital heart defects and valvular and coronary bypass procedures. Forty-three patients had arrhythmias in the postoperative period-the most common being atrial fibrillation, ventricular premature beats, and atrial flutter. A unipolar wire was implanted in all except 8 patients. Bipolar wires were used for patients who had sinus bradycardia at the conclusion of the operation and left while being atrially paced.

The atrial wire was used also in the postoperative period as an exploring electrode to diagnose atrial arrhythmias. Connection of the atrial wire to the chest electrode of the standard electrocardiograph obtains such information that proper diagnosis and prompt treatment could be instituted. In addition, the electrode was used as an atrial pacer for conversion of flutter to normal sinus rhythm, for sinus bradycardia, and for evaluation of coronary bypass grafts.

In 13 patients implantation of the wire was unsuccessful and in 4 the wires were broken on removal. No early or late sequelae were observed. From our experience we advocate the routine use of atrially implanted electrodes for diagnostic and therapeutic use after cardiac operations.

3:30 P.M. Executive Session (Limited to Active and Senior Members) Regency Ballroom

*By invitation

TUESDAY EVENING, APRIL 17, 1973

7:00 P.M. President's Reception

Regency Ballroom

8:00 P.M. President's Dinner and Dancing

Regency Ballroom

Attendance open to all physicians and their ladies. Tickets must be obtained at the Registration Desk by 5:00 P.M. on Monday, April 16, 1973.

Dinner Dress Preferred