ABSTRACTS

EXERCISE VERSUS BYPASS SURGERY FOR CORONARY ARTERY DISEASE. Ronald H. Selvester, MD; Harry Rice, MD; John 0. Wagner, MD and Miguel E. Sanmarco, MD. A study to compare the rehabilitation benefit of exercise training with revascularization surgery for patients with ischemic heart disease was undertaken in 1969. Patients under sixty years with stable angina were studied by bicycle ergometry, high gain ECG and VCG, coronary angiography and ventriculography. Group A - 63 patients with cardiac functioning capable of undertaking a vig- orous exercise program, and Group B - 31 patients whose ventricular function was poor, because of large areas of local dysfunction. In both groups there were an equal number treated medically and surgically. All operated patients, usually at about six weeks post-operation were placed on an exercise program. The results can be sunnnarized as follows: 1. The New York Association functional and therapeutic classification showed a statistically significant improvement over the 24 month time interval for the Group A patients, but no change for patients in Group B. 2. Ihe limiting exer- cise load on bicycle ergometry showed significant improve- ment over the interval for Group A but no change for the patients in Group B. There was no significant improvement in these two parameters for patients having surgery with exercise over those with exercise only. 3. In Group A there was a significantly high mortality in the surgical group. This difference was due to the surgical mortality (8%). 4. The incidence of new infarctions and late deaths in the two year follow-up is the same following surgery (8%) as for patients not going to surgery (8%). 5. In Group B the two year operative and late mortality was 40%. In the medically treated group 38%

HOME-MONITORING OF HIGH-RISK CORONARY PATIENTS Herbert J. Semler, MD, FACC, Lee E. Kuhn, Laurel D. Smith,

St. Vincent Hospital and University of Oregon Medical School, Portland, Oregon

The key to lowering pre-hospita I mortality from acute coronary

disease is early detection and prompt treatment of arrhythmias.

The present study evaluated a long-term telemetry system for rapid

recognition of arrhythmias in coronary-prone individua Is. Ninety “high-risk”coronary patients were instructed in the use

of a portable telemetric sensor. The patient simply presses the

sensor against the chest, and transmits ECG signals via telephone

to a receiver in the coronary care unit (CCU). Two-way voice

communication permits the CCU nurse to advise the patient to

either come to the hospital, contact his physician or take

appropriate medication. The light-weight, battery-operated

sensor is carried like CI camera and requires no paste-on electrodes,

electrolyte, skin preparation or limb lead connections.

Usual transmission time was less than one minute and was

satisfactory in 87 of the 90 patients. One patient with unexplained

syncope suddenly fainted at home, and while unconscious, his

wife applied the sensor. The tmnsmitted ECG disclosed complete

A-V block, and he was immediately brought to the hospital for

pacemaker implantation. Correlation of the telemetered tracing

with the standard ECG was good in 84 patients. Four hod negative

P waves suggesting either A-V junctional or ectopic atria1 rhythm.

In two, atria1 fibrillation with aberrancy could not be

distinguished from ventricular tachycordia. The ambulatory patient can transmit his ECG at any time from

any phone, at home or during daily activities, so that he is in

immediate contact with the CCU. This reduces patient decision

time, enables early recognition of arrhythmias, and initiates

pre-hospito I coronary care.

CHANGES IN INFARCT SIZE FOLLOWING ADMINISTRATION

OF PROPRANOLOL IN THE CONSCIOUS DOG

William E. Shell, MD; Burton E. Sobel, MD, FACC, UCSD,

La Jolla, California.

To determine whether propranolol alters the extent of ischemic in-

iury after coronary occlusion in the conscious dog we compared

infarct size predicted from serum CPK changes prior to propranolol

administration (ISP) to infarct size determined directly from myo-

cardial CPK analysis (ISM) 24 hours after coronary occlusion. As

we have shown previously, infarct size predicted from best fit log

normal curves derived from the five initial hourly serum CPK

determinations in this model correlates closely with ISM (r = .96,

n = 12) in the absence of interventions. Accordingly, coronary

occlusion was produced in 1 I conscious dogs; left atrial pressure

(LAP) was monitored with an exteriorized catheter; serum CPK was

determined hourly; propronolol (2 mg/kg i.v.) was administered

beginning 5 hours ofter occlusion to maintain heart rate less than

85/minute; dogs were killed 24 hours after occlusion and ISP was

compared to ISM. In all animals, mean LAP did not rise above

12 mmHg either before or after propranolol administration. In 2

addition01 dogs with coronary occlusion propranolol was given in

low dose (0.5 mg/kg) such that heart rate was not changed. In

these two animals ISP did not deviate from ISM. In seven dogs

propronolol (2 mg/kg) decreased infarct size considerably [average

ISM/ISP = .54 f .I 1 (S .E.)l . The other 4 dogs exhibited no net

reduction of infarct size despite early transient favomble trends in

serum CPK values. Thus, propranolol administration in conscious

dogs with coronary occlusion results in early protection of jeopar-

dized myocardium; however, late escape may result despite con-

tinued administration of the drug.

PREDICTION OF INFARCT SIZE FROM SERUM CPK CHANGES

EARLY AFTER MYOCARDIAL INFARCTION

William E. Shell, MD; Burton E. Sobel, MD, FACC, UCSD,

La Jolla, California.

Infarct size appears to be an important determinant of prognosis

after acute myocordial infarction (AMI). Accordingly, a new

method was used to predict infarct size before evolution of myo-

cardial necrosis was complete and thus at a time when salvage of

jeopardized myocardium might still be attainable by appropriate

therapeutic interventions. Analysis of serial serum CPK changes

in 30 patients with AMI without complications indicated that val-

ues conformed to a consistent pattern and fit a log normal function.

To predict infarct size serum CPK values during the first 7 hours

after initial enzyme elevation were used to obtain the best fit log

normal curve for each patient (non-linear least squares method).

Actual infarct size, determined by analysis of all serum CPK val-

ues (from onset of elevation through return to baseline) correlated

cbsely with predicted infarct size [(predicted) = .99 x (actual) +

2.4, r = .93, variance = i 7%, n = 301. The mean difference

between predicted and actual infarct size was 0.99 CPK-gram-

equivalents. In 8 patients with electrocardiographic evidence of

extension of infarction and associated chest pain, subsequent serum

CPK values exceeded 95% confidence limits of predicted values

within 4 hours. In 4 patients treated by reduction of afterload,

myocordiol salvage was reflected by subsequent CPK values which

were significantly lower than those predicted. Thus, curve fitting techniques applied to serial serum CPK changes within 7 hours

after onset of initial CPK elevation permit: 1) accurate prediction

of infarct size, and 2)detection and quantification of either exterr

sion of infarction or myocardial salvage following therapeutic

interventions.

January 1973 The American Journal of CARDIOLOGY Volume 31 157