Acute myocardial infarction in a city hospital. I. Clinical review of 264 cases

1. (1) A clinical evaluation of 264 proved cases of acute myocardial infarction in a city hospital during a one-year period is presented.

2. (2) Previous findings of a greater incidence of this disease in males, Hebrews, patients with a familial history of cardiovascular disease, previous evidence of coronary artery disease or diabetes mellitus are supported.

3. (3) A very low incidence of acute myocardial infarction in Negroes was observed.

4. (4) A greater number of older patients was noted in our series than in previous reports.

5. (5) Painless cardiac infarction was observed in 21 per cent of our patients.

6. (6) We observed a greater survival rate in patients who were hypertensive on admission or at some time during the hospital course than in normotensives or hypotensives.

7. (7) The grave prognosis of shock accompanying myocardial infarction is confirmed.

8. (8) Twenty-nine per cent of our patients had an elevated hemoglobin on admission, which elevation was transient.

9. (9) We observed three cases of cardiac rupture; these cases received no anticoagulants but were given ascorbic acid.

10. (10) A significantly greater survival rate was observed in patients who received vitamin C.

11. (11) The high mortality rate (47 per cent) was attributed to the age of the patients, more critically ill patients, lack of private nursing care, a city hospital ward population, and a high incidence of congestive heart failure, prolonged fever, and tachycardia.

     

Significance and treatment of nocturnal angina preceding myocardial infarction.

The presence of nocturnal angina and congestive heart failure within the month prior to admission was evaluated in the 174 patients with acute myocardial infarction. Heart size was evaluated radiographically at the time of admission. Twenty-three patients (13 per cent) experienced nocturnal angina. The incidence of nocturnal angina was significantly higher in those with anterior myocardial infarction (p less than 0.005) and subendocardial infarction (p less than 0.02) when compared with patients with inferior MI. Congestive heart failure was more common prior to admission in those with nocturnal angina (9/23) as opposed to those without (3/141) (p less than 0.001). Cardiomegaly was seen in 9/23 patients with nocturnal angina and 22/141 without (p less than 0.02). We conclude that the presence of nocturnal angina in those who develop MI increases the likelihood that the infarction will be either anterior or subendocardial rather than inferior. The association of nocturnal angina and congestive heart failure to anterior myocardial infarction is probably due to more severe and probably significant left coronary artery disease.     

Long-term propranolol therapy for angina pectoris

Sixty-three patients with stable, severe typical angina pectoris (New York Heart Association functional class III or IV) were treated with propranolol and studied prospectively with a follow-up period of 5 to 8 years to assess the rate of complications and long-term effectiveness after an initial control period. The patients' mean age was 56 years; the mean daily dose of propranolol was 255 mg. The average yearly mortality rate was 3.8 percent with a cumulative 5 year mortality rate of 19 percent. Patients whose reduction of angina with propranolol was less than 50 percent had a nearly four-fold greater mortality rate than those whose reduction was 50 percent or more (P < 0.01). Thirtytwo percent of patients per year were angina-free with propranolol and 84 percent per year had 50 percent or more reduction in anginal episodes. There was no evidence for tachyphylaxis. Heart failure developed in 25 percent of patients, two thirds of whom had either congestive heart failure with an acute infarction or a prior history of congestive heart failure. All patients whose initial cardiothoracic ratio was greater than 0.5 had heart failure during the first 3 years of propranolol therapy. Of 12 patients who had an acute infarction during therapy, 7 died, 6 with cardiogenic shock; in contrast, 8 of 9 patients who had congestive heart failure without acute infarction survived. Eight percent of patients had other significant side effects, including gastrointestinal symptoms (three patients), hallucinations (one) and postural hypotension (one). The occurrence of asthma in three patients was dose-related and did not require drug discontinuation.Propanolol is an effective form of long-term therapy for severe angina pectoris; it does not induce tachyphylaxis or increase the overall mortality rate, although it may increase the risk of cardiogenic shock in acute myocardial infarction. Previous history of congestive heart failure, a cardiothoracic ratio of more than 0.5 without overt heart failure and mild asthma are relative contraindications. A 50 percent or greater reduction in anginal pain with propranolol predicts a low mortality group.     

Amounts of coronary arterial narrowing by atherosclerotic plaque at necropsy in patients with lower extremity amputation.

In 26 patients (mean age at death 68 +/- 9 years) who had undergone amputation (at mean age 63 +/- 12 years) of 1 or both lower extremities due to severe peripheral arterial atherosclerosis, the amounts of narrowing at necropsy in the 4 major (left main, left anterior descending, left circumflex, and right) epicardial coronary arteries were determined. During life, 15 of the 26 patients (58%) had symptoms of myocardial ischemia: angina pectoris alone in 1, acute myocardial infarction alone in 5, and angina and/or infarction plus congestive heart failure or sudden coronary death in 9. Twelve of the 26 patients (42%) died from consequences of myocardial ischemia: acute myocardial infarction in 5, sudden coronary death in 3, chronic congestive heart failure in 3, and shortly after coronary bypass surgery in 1. Grossly visible left ventricular necrosis or fibrosis, or both, was present in 21 patients (81%). Of the 26 patients, 24 (92%) had narrowing 76 to 100% in cross-sectional area of 1 or more major coronary arteries by atherosclerotic plaque. The mean number of coronary arteries per patient severely (> 75%) narrowed was 2.3 +/- 1.0/4.0. Of the 104 major coronary arteries in the 26 patients, 60 (58%) were narrowed > 75% in cross-sectional area by plaque. The 4 major coronary arteries in the 26 patients were divided into 5-mm segments and a histologic section, stained by the Movat method, was prepared from each segment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anti-angina therapy of coronary heart disease. Mono- or combination treatment]

Applying a metaanalysis, it was examined whether a combination of drugs is superior to monotherapy in the treatment of angina pectoris. The three classical groups of anti-anginal drugs, nitrates, calcium channel blockers and beta-receptor blockers were investigated. For data analysis, patients were divided in those suffering from "angina pectoris" and those suffering from "angina pectoris despite monotherapy." In patients with the inclusion criterium "angina pectoris" combination of drugs is not superior to monotherapy. This applies to the evaluation criteria "improvement of symptoms" and "reduction of ischemia". In patients with the inclusion criterium "angina pectoris despite monotherapy" however, there is a clear superiority of drug combination as compared to monotherapy. Again this applies to the evaluation criteria "improvement of symptoms" and "reduction in myocardial ischemia". With respect to antianginal efficacy all three possible combinations appear to be similar. If the evaluation criterium is "improvement of prognosis" no data are available with regard to drug combination. Furthermore no data are available on the prognostic effect of an anti-anginal therapy in patients with stable angina pectoris. A significant improvement of prognosis could be demonstrated for beta-receptor blocking agents without ISA in unstable angina, acute myocardial infarction, and in the postinfarction period. The effect of calcium channel blockers on prognosis depends on the substance class applied and on the presence or absence of signs of congestive heart failure. Monotherapy with nifedipine in instable angina and acute myocardial infarction fails to improve prognosis, and there even may be a tendency to adverse effects. In the absence of signs of congestive heart failure verapamil has been demonstrated to improve prognosis in the post infarction period. Likewise, improvement of prognosis by the administration of diltiazem in acute myocardial infarction only could be demonstrated in patients without signs of heart failure. In contrast, in patients with signs of congestive heart failure diltiazem increased the rate of reinfarction and mortality. For nitrates only in acute myocardial infarction a trend towards improved prognosis has been shown. Especially for nitrates the data on prognosis in coronary heart disease available so far are not convincing.     

Cardiac index in ambulatory patients estimated by precordial dilution curves

1. 1. Four hundred and twenty-nine radiocardiograms were obtained in 240 ambulatory patients with and without heart disease by means of wide angle external counting over the precordium after the injection of radioactive iodinated human serum albumin into an antecubital vein. Cardiac index was calculated from the radiocardiogram and the blood volume. Only seven patients were encountered in whom a tracing adequate for calculation of cardiac index was not obtained.

2. 2. A mean cardiac index of 3.51 L. per minute per square meter surface area with a standard deviation of 0.97 was derived from forty-eight persons without known cardiac or vascular disease. Cardiac indices were slightly but significantly lower when derived from radiocardiograms taken twenty minutes after the initial tests. By contrast, cardiac indices did not differ significantly when calculated from tracings made weeks to months apart in patients with stable cardiovascular systems.

3. 3. A significant decrease in cardiac index was observed in patients with all types of heart disease who had congestive heart failure, whether overt or controlled.

4. 4. In the absence of congestive heart failure, mean cardiac index was increased in patients with borderline hypertension, normal in those with systolic hypertension, and frequently reduced in those with sustained diastolic hypertension, especially when evidence of myocardial involvement also was present.

5. 5. Cardiac index was usually normal in patients with coronary artery disease in the absence of congestive heart failure. Occasional reduction was seen in patients with old myocardial infarctions.

6. 6. A probably significant decrease of cardiac index as measured by the external counting technic was observed in patients with valvular heart disease without congestive heart failure. Also, cardiac index in congestive heart failure due to valvular heart disease was lower than that due to other types of heart disease. Valvular insufficiency apparently leads to erroneously low values of cardiac index estimated by the external counting technic.

7. 7. Classification of radiocardiograms according to qualitative features showed some correlation with cardiovascular status. Prominent fluctuations on the downslope were recognized most often in radiocardiograms of patients with valvular insufficiency. The appearance of the radiocardiogram maintained a constancy over considerable periods of time in the absence of marked change in cardiovascular status.

     

Excess triiodothyronine as a risk factor of coronary events

BACKGROUND: Abnormalities in cardiac function, eg, arrhythmias and congestive heart failure, often accompany thyrotoxicosis. A relationship between thyroid hormone excess and the cardiac complications of angina pectoris and myocardial infarction (MI) remains largely speculative. METHODS: The results of thyroid function studies on blood samples drawn from a total of 1049 patients (aged 40 years or older) immediately on emergency medical admission were related to frequencies of angina pectoris and myocardial infarction as determined according to current diagnostic algorithms. After 3 years, those patients who had initially presented with angina pectoris or acute MI were observed for subsequent coronary events; of these (n=185), 98% of the subjects (n=181) could be reevaluated. RESULTS: On hospital admission, the relative rate of angina pectoris and MI was markedly high (odds ratio, 2.6; 95% confidence interval, 1.3-5.2; P=.007) in patients with elevated serum free and total triiodothyronine (T(3)) levels. An initially elevated free T(3) level was a risk factor for subsequent coronary events during the 3-year follow-up (adjusted odds ratio, 4.8; 95% confidence interval, 1.3-17.4; P=.02). CONCLUSIONS: An elevation of serum free T(3) levels at hospital admission is associated with a 2.6-fold greater likelihood of the presence of a coronary event. Moreover, an initially elevated T(3) level is associated with a 3-fold higher risk of developing a subsequent coronary event during the next 3 years. Excess T(3) seemed to be a factor associated with the development and progression of acute myocardial ischemia.     

Mortality, mode of death and risk indicators for death during 5 years after coronary artery bypass grafting among patients with and without a history of diabetes mellitus

OBJECTIVE: To describe mortality, mode of death, risk indicators for death and symptoms of angina pectoris among survivors during 5 years after coronary artery bypass grafting (CABG) among patients with and without a history of diabetes mellitus. METHODS: All patients in western Sweden who underwent CABG without concomitant valve surgery and who had no previous CABG between June 1988 and June 1991 were entered prospectively in this study. After 5 years, information on deaths that had occurred was obtained for the analysis. RESULTS: In all, 1998 patients were included in the analysis; 242 (12%) had a history of diabetes. Among the non-diabetic patients, 5-year mortality was 12.5%; the corresponding relative risk for diabetic patients was 2.1 (95% confidence interval 1.6 to 2.9). A history of diabetes was an independent risk indicator of death; there was no significant interaction between any other risk indicator and diabetes. Independent risk indicators for death among diabetic patients were: current smoking, renal dysfunction and left ventricular ejection fraction < 0.40. Compared with non-diabetic patients, those with diabetes more frequently died in hospital, died a cardiac death, or had death associated with the development of acute myocardial infarction and with symptoms of congestive heart failure. Among survivors, diabetic patients tended to have more angina pectoris 5 years after CABG than did those without diabetes. CONCLUSION: During a period of 5 years after CABG, diabetic patients had a mortality twice that of non-diabetic patients. The increased risk included death in hospital, cardiac death and death associated with development of acute myocardial infarction and with symptoms of congestive heart failure.     

The complement system in ischemic heart disease

The mechanisms by which tissue injury after acute myocardial infarction (AMI) occurs has not been fully elucidated. Recent evidence in experimental models has suggested involvement of the complement system in microvascular and macrovascular injury subsequent to AMI. With respect to angina pectoris, whether or not the complement system is activated is not clear. The present study assessed the role of complement as a mediator of myocardial inflammation by quantifying products of complement activation, including C3d, C4d, Bb, and SC5b-9 complexes, in 31 patients with AMI, 17 patients with unstable angina pectoris, 19 patients with stable angina pectoris, and 20 normal volunteers. The plasma C3d levels increased in patients with AMI and in those with unstable angina pectoris (p less than 0.01). The plasma levels of C4d, Bb, and SC5b-9 increased only in patients with AMI (p less than 0.01). The plasma SC5b-9 level was related to peak creatine phosphokinase (r = 0.71) and inversely related to the ejection fraction (r = -0.71). The plasma SC5b-9 level of patients with congestive heart failure was higher than that of patients without congestive heart failure in AMI. These results show that activation of complement system occurs after AMI and show an association of myocardial damage with complement activation. With respect to angina pectoris, the complement system is mildly activated in patients with unstable angina pectoris; however, the cardiac function of patients with unstable angina pectoris is not damaged. The complement system of patients with stable angina pectoris is not activated.     

The incidence and clinical significance of ECG-VCG changes of myocardial infarction following aortocoronary saphenous vein bypass surgery

The electrocardiogram and vectorcardiogram were analyzed in 35 consecutive patients before and after undergoing elective aortocoronary saphenous vein bypass grafting for angina pectoris. Typical changes of perioperative myocardial infarction were seen in 40 per cent (ECG) and 46 per cent (VCG). Changes of ST segments and T wave could not be correlated with QRS changes of infarction. Surgery with or without infarction resulted in a loss in R wave voltage in anterior and lateral precordial leads (V₄, V₅, and V₆) as well as in a symmetric shrinkage of the vector loop in the transverse and frontal planes.Comparing one year follow-up results of those with versus those without perioperative VCG changes of infarction showed that late death, clinical evidence of myocardial damage, and reinfarction were more frequent in the infarction group. However, no difference in N.Y.H.A. functional classification, congestive heart failure alone, or persistence of angina pectoris could be demonstrated between the two groups. The ECG and VCG changes of perioperative infarction are common with this operation and helped to predict late morbidity and death.     

老年急性初发心肌梗死前有无心绞痛对心功能及预后的影响

目的观察老年急性心肌梗死前有无心绞痛对心功能及预后的影响。方法76例老年初发急性心肌梗死患者按急性心肌梗死发病前有无心绞痛发作分为两组,有心绞痛发作组42例,无心绞痛发作组34例,观察其心律失常、梗死后心绞痛、心功能和病死率。结果心肌梗死前有心绞痛发作组的心原性休克和心力衰竭的发生率及病死率均低于心肌梗死前无心绞痛发作组(分别为33.3%vs58.8%,2.4%vs23.5%),两组间差异有显著性,P<0.05;超声心动图检查发现LVEF和E/A有心绞痛发作组高于无心绞痛发作组(分别为0.52±0.056vs0.45±0.03,0.86±0.29vs0.54±0.35),两组间差异有显著性,P<0.05。结论心肌梗死前有心绞痛对老年初发急性心肌梗死患者的心功能有保护作用,可改善患者的近期预后。     

Plasma norepinephrine as an indicator of sympathetic neural activity in clinical cardiology

This review summarizes the available medical literature about plasma norepinephrine, which has been used as an indicator of sympathetic neural activity in clinical cardiology. Plasma norepinephrine levels are elevated in myocardial infarction and congestive heart failure, and the norepinephrine concentration varies with severity of disease. Patients with ischemic heart disease at rest show essentially normal plasma norepinephrine, but no studies have assessed norepinephrine levels during spontaneously occurring typical angina pectoris. Plasma norepinephrine also is increased during hypertension occurring after coronary bypass surgery or repair of aortic coarctation. Propranolol increases plasma norepinephrine, and acute withdrawal of propranolol does not. Sodium restriction increases plasma norepinephrine in healthy persons, but no information is available about its effect on patients with congestive heart failure.

Insufficient data are available to make strong inferences about sympathetic activity in cardiomyopathy, essential hypertension or pulmonary hypertension, and little or no information is available about plasma norepinephrine in ventricular fibrillation without myocardial infarction, the mitral valve prolapse syndrome, digoxin effect, syndromes associated with prolonged electrocardiographic Q-T interval and the hyperkinetic heart syndrome.     

Clinical predictors of angina following myocardial infarction.

To determine if angina following myocardial infarction could be predicted before hospital discharge we prospectively evaluated 219 consecutive patients admitted to the coronary care unit with acute myocardial infarction. Of the 166 who survived to one year, angina was present before infarction in 53 per cent and after infarction in 61 per cent. Angina did not recur postinfarction in 26 per cent of the patients who had angina before infarction. However, in 47 per cent of those without previous angina it developed postinfarction. Although postinfarction angina correlated with the presence of angina before infarction (p < 0.0005), it did not correlate significantly with age, sex, site of infarction, Killip class on admission nor the presence of a previous infarction.To improve our ability to predict angina after infarction we performed exercise tests to 5 metabolic equivalents (METS), or 70 per cent of age-predicted maximal heart rate, before hospital discharge on all patients less than 70 years old who were without chest pain within four days or without overt heart failure. Of the 105 patients exercised, 31 (86 per cent) of the 36 with positive tests had angina during the subsequent year compared to only 25 (36 per cent) of the 69 with negative tests (p < 0.001). Postinfarction angina occurred in 96 per cent (23 of 24) of the patients who had both angina before infarction and a positive test, but in only 26 per cent (10 of 39) of the patients with neither finding (p < 0.001).We conclude that the presence of angina prior to infarction and a positive limited exercise test performed before hospital discharge are predictive of angina following infarction. Myocardial infarction abolishes angina in a quarter of the patients, but angina develops postinfarction in nearly half of the patients who did not have angina previously.     

Coronary artery disease in patients dying from cardiogenic shock or congestive heart failure in the setting of acute myocardial infarction.

Pathological findings in the heart and particularly in the coronary arteries are reported from 70 patients dying from pump failure after acute myocardial infarction. Fifty of the patients had died in cardiogenic shock, the remainder from refractory congestive heart failure. Three-vessel disease (greater than or equal to 75% occlusion) was present in 68 per cent of the group with cardiogenic shock but in only 35 per cent of those with fatal congestive heart failure (P less than 0-02). In both groups there was an almost equal incidence (84% for cardiogenic shock and 80% for congestive heart failure) of severe disease (greater than or equal to 75% occlusion) over a long segment of the left anterior descending artery. However, there were differences between the two groups regarding the involvement of the other coronary arteries. Whereas patients with cardiogenic shock generally showed severe disease over a long segment in all coronary arteries, in 60 per cent of those with congestive heart failure there was only local severe narrowing of the right coronary artery with little or no narrowing of the peripheral part. Similarly, 60 per cent of those with congestive heart failure had less than 75 per cent narrowing in the left circumflex artery. These anatomical findings may be of relevance with regard to desirability of acute coronary bypass surgery in patients with pump failure after acute myocardial infarction.     

Exercise testing soon after myocardial infarction.

Forty-six men under age 70, without clinical congestive heart failure or unstable angina pectoris, performed treadmill tests 3, 5, 7, 9 and 11 weeks after myocardial infarction. Patients were more frequently able to perform moderate exertion (2 mph, 14% grade) at 7 and 11 weeks than at 3 weeks following infarction. Ischemic ST-segment depression, usually unaccompained by angina pectoris, occurred in 45% of patients and was associated with a significantly increased incidence of subsequent coronary events. The presence of exercise-induced ventricular ectopic activity provided little independent prognostic information. No serious complications occurred in 210 tests. Exercise testing soon after myocardial infarction provides objective information concerning the capacity to resume physical activity, including return to work. Two tests, at 3-5 weeks and at 7-11 weeks, appear to provide most of the information contined in five tests performed during this time.     

Gamma-glutamyl transpeptidase activity in ischemic heart disease]

The blood plasma gamma-glutamyltranspeptidase (GGTP) activity was studied in 133 patients with macrofocal myocardial infarction, in 40 patients with microfocal myocardial infarction, in 30 patients with angina pectoris, and in 75 patients with cardiosclerosis and congestive cardiac failure. The activity of the enzyme increased in most patients with macrofocal myocardial infarction and in less than half of those with microfocal myocardial infarction beginning with the 3rd or 4th day, reached maximum by the 6th to 8th day of the disease, and then returned to normal levels in various lengths of time. In all patients with angina pectoris and acute left-ventricular failure the activity of the enzyme remained normal. It may be assumed from the results of the study that determination of GGTP activity in dynamics may be mainly employed in the diagnosis of macrofocal myocardial infarction, particularly after the first days of the disease. The enzyme test is hardly suitable for differential diagnosis between microfocal myocardial infarction and angina pectoris.     

Coronary occlusion in industry: A study of eighty-four cases with reference to subsequent employability

Eighty-four patients who had ninety-seven myocardial infarctions before Jan. 1, 1944, were studied, of whom 75 per cent were manual laborers. The period of study ended April 20, 1944.The average period of observation was 11.7 months.Fifty-six patients (66.6 per cent of the total, and 73.7 per cent of those surviving four weeks) returned to work after myocardial infarction.Thirty patients (43 per cent of the survivors and 35 per cent of all observed) returned to work and were still working at the conclusion of the period of study.Of these, nineteen returned to the same type of work they were doing before infarction occurred.Eleven of them returned to lighter work.Neither angina pectoris nor slight congestive failure nor mild degrees of both prevented twenty patients from returning to gainful employment.Only twenty (23.8 per cent) of our patients made a complete symptomatic recovery.The probability that manual laborers may be able to resume their former employment after mhocardial infarction appears to be no less than for sedentary workers.Twenty-six patients (31 per cent of all observed) returned to gainful employment, but did not continue. Of the twenty-one who were disabled by arteriosclerotic heart disease, the average time worked after myocardial infarction was thirteen months.Twenty patients who survived the initial critical period failed to return to work, eighteen because of heart disease.Eighteen patients (32 per cent of those returning to work) were able to work more than one year after recovery from acute myocardial infarction.     

Prognostic value of a persistently positive technetium-99m stannous pyrophosphate myocardial scintigram after myocardial infarction.

Technetium-99m stannous pyrophosphate myocardial scintigrams were obtained in 138 clinically stable patients 32.7 +/- 47.3 weeks (range 6 to 260) after acute myocardial infarction. Of the 138 patients, 74 (54 percent) had a persistently positive scintigram. Patients with such a scintigram were more likely to have severe angina pectoris, compensated congestive heart failure, anterior location of acute myocardial infarction, Q waves and S-T segment elevation in the electrocardiograms, cardiomegaly, left ventricular dyssynergy (dyskinesia or global dyssynergy), and an ejection fraction of less than 50 percent. During a follow-up period of 11.6 +/- 6.9 months after scintigraphy, 42 percent of the patients with a persistently positive scintigram had either a cardiac death, a nonfatal myocardial infarction, unstable angina pectoris or decompensated congestive heart failure compared with 13 percent of the patients with a negative scintigram (P less than 0.001). Of the 14 patients with cardiac death, 13 (93 percent) had a persistently positive scintigram. A persistently positive scintigram not only was the best single predictor of cardiac death and combined end points, but also added significantly to the predictive ability of the other clinical variables, including age, location of acute myocardial infarct, clinical status, electrocardiographic findings, and chest X-ray findings. It is concluded that technetium-99m stannous pyrophosphate myocardial scintigraphy has prognostic value in patients after acute myocardial infarction.     

Coronary collateral circulation: clinical significance and influence on survival in patients with coronary artery occlusion

In a consecutive series of 96 patients with coronary artery occlusion, 67 had good and 29 had no or poor collateral circulation. Patients with good collaterals had the severest degree of coronary artery disease. Good collaterals are associated with a higher incidence of angina pectoris and normal electrocardiogram and with lower incidence of Q-waves, positive exercise tests, heart failure, previous myocardial infarction, and dyskinesia at ventriculography. Survival rates after 10 years were (1) 51.5% with good and 34.5% with poor collaterals (p less than 0.1), (2) 59.4% with angina pectoris and good collaterals and 41.2% with angina pectoris and poor collaterals (p less than 0.05), (3) 64.8% without and 24.4% with heart failure and good collaterals (p less than 0.001), and (4) 58.3% without and 16.1% with heart failure and poor collaterals (p less than 0.01). Good collaterals protect the myocardium by prevention of acute myocardial infarction and heart failure and thus improve survival.     

Effect of restriction of venous return on the hemodynamics of normal persons and patients with congestive heart failure

1. 1. Restriction of venous return by occlusion of the inferior vena cava (inflation of a balloon catheter above the renal veins) was carried out 25 times in 23 patients. The procedure was safe and undetected by the subject.

2. 2. Complete inferior vena cava occlusion produced similar changes in control circulatory pressures, cardiac output and ventricular stroke work in normal subjects and in patients with elevated ventricular filling pressures. On the average, right venticular filling pressure fell to 41 per cent of control, mean pulmonary arterial pressure to 68 per cent, left ventricular filling pressure to 64 per cent, systemic arterial pressure to 88 per cent, cardiac index to 69 per cent, right ventricular stroke work index to 50 per cent and left ventricular stroke work index was decreased 70 per cent. No significant change in oxygen consumption or pulse rate occurred.

3. 3. Partial occlusion of the inferior vena cava increased venous pressure caudal to the balloon with little alteration in intracardiac pressures and slight but significant declines in cardiac output and ventricular stroke work in both patients with normal and elevated ventricular filling pressures.

4. 4. In no subjects, either with partial or complete occlusion of the inferior vena cava was there a rise in stroke work, and hence evidence for a descending limb of a Starling curve was not obtained. Since patients with severe congestive heart failure were not included in this study, the conclusion can be applied only to mild and moderate cases of heart failure under resting conditions.