Abstracts 125
Experiences with a Lens Mitral Valve Prosthesis,
I~REDI~RIC~; S. CROSS, M.D.. F.A.c.c. and RICHARD D.
Jo\I:s. PI~.I).. Cleveland, Ohio.
Although the ball-valve prostheses available at the
present time are functioning satisfactorily in thou-
sands of patients, there is still need for the continued
improvement of artificial heart valves. The prc-sent
report describes a valve consisting of a fenticular
closure within a titanium cage which offers several
significant advantages. ‘l’he fens requires a shorter
excursion than does a ball of equivalent diameter;
thus the valve may be made shorter (about half the
height of the ball cage). The reduced bulk of the cage
permits insertion of fens prostheses with larger orifice
size than is possible with the ball design. The silicone
rubbrr lenticufar closure, reinforced with a thin
titanium ring, weighs only a fourth to a third as much
as a ball of comparable diameter. The reduced mass
of a lens compared with a ball decreases inertial
effects during the opening and closing phases of valve
function. Further dynamic advantage has been
achieved by adjusting the density of the lens to ap-
proximately the specific gravity of blood.
Pressure gradients measured across the lenticufar
valve are not different than those for a ball valve of
equal orifice size at flow rates of up to 40 L./min. of
water. Simultaneous left atria1 and left ventricular
pressure tracings in cineangiography demonstrate ex-
cellent function of the valve in vivo. There is less
chance for aortic outflow obstruction with the lens
mitral valve, and less chance for ventricular arrhyth-
mias. The valve has been functioning in patients and
experimental animals for periods up to two years.
Follow-up studies are available on over 100 patients,
and the results of these studies will be presented.
The Permanent Transvenous Electrode-Catheter
Pacemaker for Treatment of Heart Block, SIMON
DACK. M.D.? F.A.c.c., ROBERTS. LITWAK, M.D., F.A.C.C.
and HOWARD GADBOYS, M.D., F.A.c.c., New York,
N. Y.
This paper presents our results of long term pacing
of the heart by a transvenous bipolar electrode-
catheter wedged into the apex of the right ventricle
via the left cephalic or subclavian vein and connected
to a generator implanted subcutaneously in the left
pectoral area through the same incision. This simple
operation performed under local anesthesia and under
fluoroscopic control obviates the necessity of a thora- cotomy for sewing the electrodes into the left epicardial
surface. Fifty-five cases of heart block treated by this method
of permanent endocardial pacing in the period from
October 1965 to October 1966 are compared with 91
VOLUME 19, TANUARY 1967
cases treated by rhoracotomy and epicardial pacing
during the fleriod Prom September 1962 to October
1965. Our early and long term folfo\v-up rcsufts with
the new method indicarc that prroperativ? fjrepara-
tion is simpler and >horter and temf’orary rransvc-
nous pacing prr’op,eratiVely is usually not rrquired i operative and early mortality is louver (2.4 vs. 8.8’zj;),
and postoperative complications are greatly reduced.
Furthermore. the incidence of flacemaker failure
due to electrode or wire breakage or generator failurr.
which was quite high with the epicardial pacrmaket
(427, in 1.5 yr.? 75Th in 3 yr.), has been much fo\ver
with the endocardiaf pacemaker (1473; in 1 yr.).
Modification of the technic of implanting and fixing
the electrode-catheter has lowered this incidence
even further so that only occasionally does the catheter
tip have to be repositioned because of faulty pacing.
This method is now recommended routinely for the
treatment of patients with chronic heart block com-
plicated by Stokes-Adams syndrome, heart failure, or
severe bradycardia.
Surgical Correction of a Taussig-Bing Malforma-
tion: Report of 3 Cases, GEORGE R. DAICOFF. M.D.
and JOHN W. KIRKLIN. M.D., F.A.c.c.. Rochester.
Minn.
Three patients underwent intracardiac repair of the
congenital cardiac anomaly in which the aorta arose
from the right ventricle and the pulmonary artery
straddled a ventricular septal defect, thereby facing
both the right and left ventricles. This malformation is
commonly known as the Taussig-Bing heart. The
purpose of this report is to emphasize the unique sur-
gical implications of this condition and to indicate a
method of successful repair. The clinical features,
cardiac catheterization data and angiocardiograms
will be discussed.
The essential features of the operation were as
follows: (1) patch closure of the ventricular septaf
defect to complete the transposition of the pulmonary
artery to the left ventricle, (2) intraatrial venous
transposition as described by Mustard. and (3) repair
of associated defects. Two of the 3 patients survived
operation, were no longer cyanotic, gained height and
weight, enjoyed increased exercise tolerance and re-
mained free of fluid retention. The third patient
failed to survive because of the complications of
markedly increased pulmonary vascular resistance.
The Antihypertensive Properties of an Imidazoline
Compound (ST 1X), MICHAEL DAVIDO~, M.D.,
NIKOS KAKAVIATOS, M.D. and FRANK A. FINNERTY.
JR., M.D., F.A.c.c., Washington. D. C.
The antihypertensive properties of ST-155 [2-(2,6-
dichlorophenylamine)-2-imidazofine hydrochloride J
126 Abstracts
have been evaluated in 62 patients with severe hyper-
tension. Oral administration of 300 pg. to 32 patients
produced an average reduction in mean arterial pres-
surefroml81 Z!Z 14 to 128 i 19 mm. Hg (29 & 10%).
The average onset, peak and duration of action were
observed in one, two and six hours, respectively. At
the time of peak action there was a 35 +Z 12yc average
increase in cardiac output and 42 f 157, average
decrease in the total peripheral resis:ance (8 patients) ; the average urinary output and sodium and potassium
excretion were decreased by 84 & 32, 83 f 29
and 12 & 5%, respectively (6 patients). Inulin and
PAH clearances were decreased (5 to 10%) at the
end of the first hour and returned to control level
at the end of the second hour (6 patients). Thirty patients received ST 155 as the sole anti-
hypertensive medica ion for an average duration of
16 * 5 weeks. The average daily dose was 42 =I= 32
pg./kg. admisistered i.1 four dirided doses. The mean
arterial pressure fell from an average of 161 + 21 to
an average of 123 Z!X 19 mm. Hg (23 =t 12%) as com-
pared to an average of 143 •I= 14 mm. Hg (10 & 10%)
during prior therapy with thiazides plus reserpine
and alpha-methyldopa and/or guanethidine and/or
hydralazine. All patients gained weight (6 =t 4 lbs);
congestive heart failure developed in 3. Administra-
tion of thiazides promptly produced a further fall in
arterial pressure and weight loss and allowed reduc-
tion in dosage of ST 155.
ST 155 is a rapidly acting, potent and nontoxic
antihypertensive agent effective by mouth which,
when combined with thiazides, would seem to be a
valuable addition to the available antihypertensive
drugs.
Prevention of Lethal Cardiogenic Shock in Dogs
Tolerant to Endotoxin, RONALD H. DIETZMAN, M.D.,
SAM W. MOVSAS, M.D., JOHN A. FEEMSTER, M.D. and
RICHARD C. LILLEHEI, M.D., F.A.c.c., Minneapolis,
Minn.
Diffuse myocardial infarctions were produced in 53
control dogs by closed chest intracoronary artery microsphere embolization. Twenty-two dogs experi-
enced shock (42%), 17 ventricular fibrillation (32oj,),
and 14 did not go into shock (26%). The mean con- trol blood pressure (BP) in the shocked dogs was 138
mm. Hg, the mean cardiac output (CO) was 152 ml./kg./min., and the mean total peripheral resis-
tance (TPR) was 5,543 dynes sec. cm.-5. After
microsphere embolization, the BP fell co 58 mm. Hg
(-58oj,), CO to 43 ml./kg./min. (-72%), and TPR rose to 8,358 dynes sec. cm.? (i-151%). Within 60 minutes of embolization, the BP stabilized at 115 mm. Hg, CO at 81 ml./kg./min. and TPR at
8,358 dynes sec. cm.pa. Only 6 of the shocked dogs (27%) survived longer than 72 hours. Ten other dogs
were made tolerant to 2 mg./kg. of intravenous E.
coli endotoxin by graded injections over six weeks.
Endotoxin in this dosage increases sympathetic nerve
activity and catecholamine secretion. Microsphere
embolization in these tolerant dogs failed to produce
shock, even though infarction occurred and all 10
dogs (lOO’%j survived longer than 72 hours. The pre-
embolization BP in tolerant dogs was 155 mm. Hg,
CO 220 ml./kg./min., and TPR 3,320 dynes sec.
cm. ph. After microsphere embolization, the BP fell to
141 mm. Hg (-I’%), CO to 163 ml./kg./min.
(-26’%), and TPR rose to 4,169 dynes sec. cm.m5
(i-125’%). At 60 minutes postembolization, the BP
stabilized at 159 mm. Hg, CO at 152 ml./kg./min.
and TPR at 5,075 dynes sec. cm.?. These values for
BP and CO of tolerant dogs were significantly higher
than those of the control dogs (p = 0.0002), and the TPR significantly lower (p = 0.02). Thus endotoxin
tolerance appears to prevent cardiogenic shock in dogs
by reducing the peripheral vasoconstrictive response
associated with the infarction.
Transmission of Electrocardiograms from a Com-
munity Hospital for Remote Computer Analysis,
ROBERT J. DOBROW, M.D., ARNOLD FIELDMAN, M.D.,
W. PAGE C. CLASON, M.D., RALPH F. REINFRANK,
M.D. and CESAR A. CACERES, M.D., Hartford, Conn.
and Washington, D. C.
Recent advances in the automated measurement
and analysis of electrocardiograms, as developed by
the Instrumentation Field Station of the U. S. Public
Health Service, were suggested as a model and have
been successfully applied in Hartford Hospital. The
purpose of this project was to demonstrate the feasi-
bility of the system within the setting of a large com-
munity hospital. This has been accomplished by
establishing communications link by DATA-phone,
mail and teletype between Hartford Hospital and a
remote computer center in Washington, D. C. Addi-
tional objectives have been to: (1) evaluate the effects of phone transmission on the electrocardio-
gram; (2) evaluate the accuracy of computer diag-
noses and their usefulness in the interpretation of electrocardiograms in the community hospital; and
(3) introduce computer-assisted electrocardiographic diagnosis for emergency room patients.
Forty-three hundred electrocardiograms have been
transmitted by DATA-phone for remote computer
analysis; 300 were taken on emergency room patients;
4,000, on ambulatory patients in our clinics. Computer reports on clinic patients were mailed to the hospital; those on emergency room patients were teletyped.
THE AMERICAN JOURNAL OF CARDIOLOGY
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