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Regional myocardial blood flow following coronary occlusion in unanesthetized normal and hypoxemic dogs
ABSTRACTS
PERMANENT CARDIAC PACEMAKER FOLLOW UP Michael Bilitch, MD, FACC; E. Betty Cassady, MA; John Lloyd, Ph.D.; University of Southern California, Los Angeles, California Patients with permanently implanted pacemakers require constant realistic follow up in order to recognize failures of the system. Random recovery of pacemakers from the community was used as a means of identifying pacemaker patient physicians; their patterns of patient follow up were then assessed. From 475 recovered pulse generators 172 persons were identified as patients' "pacemaker physicians". 104 of these physicians were interviewed and responses to a specific series of questions were tabulated and analyzed. Interviewees included internist-cardiologist 28.9% (30), internist 25% (26), thoracic surgeon 17.3% (18), general surgeon 7.7% (8), general practitioner 19.2% (20), other 1.9% (2). Evaluation of experience showed that 57.7% (60) followed l-8 patients, 19.2% (20) 9-24 patients, and 23.1% (24) 25-200 patients with pacemakers. Of the total group 37.5% (39/104) had a realistic follow up plan; 60% (18/30) of internist-cardiologists, 33.3% (6/18) of thoracic surgeons, and 23% (6/26) of internists had realistic plans. 62.5% (15/24) of physicians with the greatest experience used a magnet regularly while checking pacemaker function; although most pacemakers implanted today are demand type, only 5% (3/60) of physicians with the least experfence used the magnet. It is concluded that: 1) permanent pacemaker patients require more formal and stringent follow up than they receive at the present time, and 2) design characteristics of pacemaker systems should take the expertise of the physician-user into account.
REGIONAL MYOCARDIAL BLOOD FLOW FOLLOWING CORONARY OCCLUSION IN UNANESTHETIZED NORMAL AND HYPOXEMIC DOGS. Sanford P. Bishop, D.V.M., Ph.D. and Colin M. Bloor, M.D., FACC, University of California, San Diego, La Jolla, Ca. Regional distribution of coronary blood flow in the immediate post-infarction period was studied in chronically hypoxemic (Hpx) and normal unanesthetized dogs. Surgical transposition of the caudal vena cava to the left atrium was produced 18-30 months prior to coronary occlusion. Left ventricle weight to body weight was not significantly changed but ri ht ventricular weight to body weight was decreased 25% 9pc.05). Arterial O2 saturation was 70.0 f4.9(SD)%. A left atria1 tube and an inflatable cuff were placed around the left circumflex coronary artery in 5 Hpx and 3 normal dogs, and the left anterior descending coronary artery in 5 normal dogs. After recover (7-14d) 15 u tracer microspheres (TM) labeled with ax Sr, l'+lCe, or 51Cr were injected into the left atrium just prior to occlusion of the coronary cuff, 5 min and 24 h after occlusion. Gross infarct size in normal dogs was 17f7% of ventricular mass and 6f8% in Hpx dogs. The TM ratio of infarcted to non-infarcted tissue in the endocardial half of the myocardium durin control, 5 min and 24 h post-infarction was 0.97k0.23 9SD), 0.16t0.04, and 0.33t0.11 respectively in normal dogs, and 0.96t0.11, 0.56t0.32, and 0.81b0.41 in Hpx dogs. In the epicardial half of the myocardium the ratios were 0.89fO.04, 0.31*0.10, and 0.61* 0.17 in normal dogs and 1.07t0.33, 0.80t0.53, and 0.97t 0.34 in Hpx dogs. In both normal and Hpx dogs there was significant increase in blood flow to the infarcted area at 24 h compared to 5 min post-occlusion. With chronic Hpx there was greater blood flow to the infarcted tissue resulting in smaller infarct size than in normal dogs. These findings suggest that chronic hypoxia induces myocardial changes that are protective when infarction occurs.
THE PREQIJWCY AND PROGNOSIS OF VENTRICULAR ECTOPIC BEATS IN MIDDLE-AGED MEN Henry Blackburn, MD, FACC; Ancel Keys, Ph.D, FACC;Henry L. Taylor, Ph.D; R. Douglas Thorsen, BS; Jean L. Canner, MA; and Allen Il.Womelsdorf, BS, for the International Cooperative Study on Coronary Disease Epidemiology, Laboratory of Physiological Hygiene, School of Public Health and the Department of Medicine, School of Medicine, University of Minnesota, Minneapolis, Minnesota 55455 The frequency, associations and prognostic importance of ventricular ectopic beats (VEB) were studied in 2,451 U.S. railway men and 8,319 rural European men ages 40-59 and free of coronary disease (CHD) at entry. VEB frequency in routine resting and post-exercise electrocardiograms (ECG) increased with age, and was twice as great in "high risk" men of the upper 20% of a coronary risk score (computed from the primary risk factors) (PC.01). VEB were also concentrated in men having other ECG abnormalities. The crude risk ratio for 5-year deaths among men having 9 rest or post-exercise VEB was 1.9 compared to those with "0 VEB. The simple univariate regression of deaths according to frequency of VEB gave a significant slope (t - 3.l). and it remained significantly positive after adjustment for the presence of other ECG abnormalities and primary risk factore. However, poor prognosis for CHD and death, according to the frequency of VEB, was concentrated among men having highest risk score based on blood pressure, serum cholesterol and smoking habit. We conclude that VEB are possibly significant independent harbingers of future manifest CHD and sudden death but probably only in the presence of other ECG or clinical evidence of myocardial disease, or multiple and elevated CBD risk factors. Higher grade of VEB (pairs, runs, and early beats) were too rare in short term monitoring of the general population to analyze fruitfully.
LEFT VENTRICULOGRAPHY IN PATIENTS WITH THE ANGINAL SYNDROME AND NORMAL CORONARY ARTERIOGRAMS William E. Boden, BS; Harold Smulyan, MD; James Potts, MD; Lewis W. Johnson, MD; Anis I. Obeid, MD; Robert H. Eich, MD, SUNY Upstate Medical Center, Syracuse, New York Left ventriculography, heretofore, has not been subjected to detailed investigation in patients with the angina1 syndrome (AS) and normal coronary arteriograms. The left ventriculograms, obtained in the right anterior oblique (RAO) projectian, of 45 patients (24 females, 21 males), mean age 47.1 years, were analyzed utilizing the oneplane cineangiographic measurement of left ventricular volume. Tracings of end-systole and end-diastole were made from the cineangiograms in the P&J projection. The ejection fraction (EF) was computed from the ratio of left ventricular systolic to diastolic volume, In addition, the percent change for both longitudinal axis (IA) and transverse axis (TA) that occurred during ventricular systole was analyzed. The EF for the 24 females in the study group ranged from 0.647 to 0.915 (mean 0.818), and for the 21 males The mean percent
ranged change
from 0.658 to 0.895 (mean 0.788). in the LA and TA which was ob-
served during ventricular systole was 31.2% and 51.6% in the female sub-group, and 26.3% and 49.7% in the male sub-group, respectively. The high values for EF (mean 0.803, SD 0.0627, SE 0.0133, SEE 0.0002, (P(.OOl), compared to reported normals, suggest that hyperdynamic ventricular contraction (HVC) may be a contributing factor to the pain typical of AS in patients without angiographically demonstrable atherosclerotic lesions of the coronary arteries. In conclusion, HVC. as suggested by markedly increased EF and high degree of LA and TA shortening, could produce a state of increased myocardial oxygen consumption resulting in ischemic heart pain, and might explain the salutary effect of beta-adrenergic blockade and nitrites in some of these patients.
January 1974
The American Journal of CARDIOLOGY
Volume 33
127
PERMANENT CARDIAC PACEMAKER FOLLOW UP Michael Bilitch, MD, FACC; E. Betty Cassady, MA; John Lloyd, Ph.D.; University of Southern California, Los Angeles, California Patients with permanently implanted pacemakers require constant realistic follow up in order to recognize failures of the system. Random recovery of pacemakers from the community was used as a means of identifying pacemaker patient physicians; their patterns of patient follow up were then assessed. From 475 recovered pulse generators 172 persons were identified as patients' "pacemaker physicians". 104 of these physicians were interviewed and responses to a specific series of questions were tabulated and analyzed. Interviewees included internist-cardiologist 28.9% (30), internist 25% (26), thoracic surgeon 17.3% (18), general surgeon 7.7% (8), general practitioner 19.2% (20), other 1.9% (2). Evaluation of experience showed that 57.7% (60) followed l-8 patients, 19.2% (20) 9-24 patients, and 23.1% (24) 25-200 patients with pacemakers. Of the total group 37.5% (39/104) had a realistic follow up plan; 60% (18/30) of internist-cardiologists, 33.3% (6/18) of thoracic surgeons, and 23% (6/26) of internists had realistic plans. 62.5% (15/24) of physicians with the greatest experience used a magnet regularly while checking pacemaker function; although most pacemakers implanted today are demand type, only 5% (3/60) of physicians with the least experfence used the magnet. It is concluded that: 1) permanent pacemaker patients require more formal and stringent follow up than they receive at the present time, and 2) design characteristics of pacemaker systems should take the expertise of the physician-user into account.
REGIONAL MYOCARDIAL BLOOD FLOW FOLLOWING CORONARY OCCLUSION IN UNANESTHETIZED NORMAL AND HYPOXEMIC DOGS. Sanford P. Bishop, D.V.M., Ph.D. and Colin M. Bloor, M.D., FACC, University of California, San Diego, La Jolla, Ca. Regional distribution of coronary blood flow in the immediate post-infarction period was studied in chronically hypoxemic (Hpx) and normal unanesthetized dogs. Surgical transposition of the caudal vena cava to the left atrium was produced 18-30 months prior to coronary occlusion. Left ventricle weight to body weight was not significantly changed but ri ht ventricular weight to body weight was decreased 25% 9pc.05). Arterial O2 saturation was 70.0 f4.9(SD)%. A left atria1 tube and an inflatable cuff were placed around the left circumflex coronary artery in 5 Hpx and 3 normal dogs, and the left anterior descending coronary artery in 5 normal dogs. After recover (7-14d) 15 u tracer microspheres (TM) labeled with ax Sr, l'+lCe, or 51Cr were injected into the left atrium just prior to occlusion of the coronary cuff, 5 min and 24 h after occlusion. Gross infarct size in normal dogs was 17f7% of ventricular mass and 6f8% in Hpx dogs. The TM ratio of infarcted to non-infarcted tissue in the endocardial half of the myocardium durin control, 5 min and 24 h post-infarction was 0.97k0.23 9SD), 0.16t0.04, and 0.33t0.11 respectively in normal dogs, and 0.96t0.11, 0.56t0.32, and 0.81b0.41 in Hpx dogs. In the epicardial half of the myocardium the ratios were 0.89fO.04, 0.31*0.10, and 0.61* 0.17 in normal dogs and 1.07t0.33, 0.80t0.53, and 0.97t 0.34 in Hpx dogs. In both normal and Hpx dogs there was significant increase in blood flow to the infarcted area at 24 h compared to 5 min post-occlusion. With chronic Hpx there was greater blood flow to the infarcted tissue resulting in smaller infarct size than in normal dogs. These findings suggest that chronic hypoxia induces myocardial changes that are protective when infarction occurs.
THE PREQIJWCY AND PROGNOSIS OF VENTRICULAR ECTOPIC BEATS IN MIDDLE-AGED MEN Henry Blackburn, MD, FACC; Ancel Keys, Ph.D, FACC;Henry L. Taylor, Ph.D; R. Douglas Thorsen, BS; Jean L. Canner, MA; and Allen Il.Womelsdorf, BS, for the International Cooperative Study on Coronary Disease Epidemiology, Laboratory of Physiological Hygiene, School of Public Health and the Department of Medicine, School of Medicine, University of Minnesota, Minneapolis, Minnesota 55455 The frequency, associations and prognostic importance of ventricular ectopic beats (VEB) were studied in 2,451 U.S. railway men and 8,319 rural European men ages 40-59 and free of coronary disease (CHD) at entry. VEB frequency in routine resting and post-exercise electrocardiograms (ECG) increased with age, and was twice as great in "high risk" men of the upper 20% of a coronary risk score (computed from the primary risk factors) (PC.01). VEB were also concentrated in men having other ECG abnormalities. The crude risk ratio for 5-year deaths among men having 9 rest or post-exercise VEB was 1.9 compared to those with "0 VEB. The simple univariate regression of deaths according to frequency of VEB gave a significant slope (t - 3.l). and it remained significantly positive after adjustment for the presence of other ECG abnormalities and primary risk factore. However, poor prognosis for CHD and death, according to the frequency of VEB, was concentrated among men having highest risk score based on blood pressure, serum cholesterol and smoking habit. We conclude that VEB are possibly significant independent harbingers of future manifest CHD and sudden death but probably only in the presence of other ECG or clinical evidence of myocardial disease, or multiple and elevated CBD risk factors. Higher grade of VEB (pairs, runs, and early beats) were too rare in short term monitoring of the general population to analyze fruitfully.
LEFT VENTRICULOGRAPHY IN PATIENTS WITH THE ANGINAL SYNDROME AND NORMAL CORONARY ARTERIOGRAMS William E. Boden, BS; Harold Smulyan, MD; James Potts, MD; Lewis W. Johnson, MD; Anis I. Obeid, MD; Robert H. Eich, MD, SUNY Upstate Medical Center, Syracuse, New York Left ventriculography, heretofore, has not been subjected to detailed investigation in patients with the angina1 syndrome (AS) and normal coronary arteriograms. The left ventriculograms, obtained in the right anterior oblique (RAO) projectian, of 45 patients (24 females, 21 males), mean age 47.1 years, were analyzed utilizing the oneplane cineangiographic measurement of left ventricular volume. Tracings of end-systole and end-diastole were made from the cineangiograms in the P&J projection. The ejection fraction (EF) was computed from the ratio of left ventricular systolic to diastolic volume, In addition, the percent change for both longitudinal axis (IA) and transverse axis (TA) that occurred during ventricular systole was analyzed. The EF for the 24 females in the study group ranged from 0.647 to 0.915 (mean 0.818), and for the 21 males The mean percent
ranged change
from 0.658 to 0.895 (mean 0.788). in the LA and TA which was ob-
served during ventricular systole was 31.2% and 51.6% in the female sub-group, and 26.3% and 49.7% in the male sub-group, respectively. The high values for EF (mean 0.803, SD 0.0627, SE 0.0133, SEE 0.0002, (P(.OOl), compared to reported normals, suggest that hyperdynamic ventricular contraction (HVC) may be a contributing factor to the pain typical of AS in patients without angiographically demonstrable atherosclerotic lesions of the coronary arteries. In conclusion, HVC. as suggested by markedly increased EF and high degree of LA and TA shortening, could produce a state of increased myocardial oxygen consumption resulting in ischemic heart pain, and might explain the salutary effect of beta-adrenergic blockade and nitrites in some of these patients.
January 1974
The American Journal of CARDIOLOGY
Volume 33
127