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IN 1946 Vineberg1 reported that implantation of the internal mammary artery into the anterior wall of the left ventricular myocardium of dogs effected an anastomosis with the intramyocardial branches of the left coronary arterial system. The likelihood of such a connection could be enhanced through induction of local myocardial ischemia by simultaneous stenosis of the anterior descending coronary artery. This work was extended to a small group of human subjects2 but remained incompletely tested because selection of cases based on identification of site and degree of arterial disease was not possible, and subsequent evaluation of results was not feasible. The . . .

Insertion of one or two rigid perforated Tygon or polyethylene tubes throughout the entire length of the left ventricular myocardium was performed in twenty-three dogs. In eight of these, an additional shunt operation was simultaneously or previously performed in order to obtain cardiac hypertrophy. Twenty animals survived, and three died during the second postoperative month. Increase in cardiac output with exercise was well tolerated when one tube was inserted. Blood volumes after insertion of one or two tubes were unchanged. Electrocardiogram changes were similar to those observed in myocardial ischemia. Insertion of the tubes does not produce cardiac hypertrophy nor does it increase cardiac hypertrophy following shunt operations. A connective sheath of 1 to 2 cm. diameter was constantly formed around the tube. This sheath was larger in the areas of perforation and always projected into the lumen of the tube.

A difference in uptake and clearance of intravenously infused Rb 86 Cl between the endocardial and epicardial halves of the normally beating left ventricle of the dog has been shown. The higher endocardial clearance was due to the uptake of isotope directly from the left ventricular cavity rather than to increased forward coronary flow to the endocardium. When the ventricular source of isotope was eliminated, the uptake of Rb 86 by the endocardium was less than that by the epicardium, and was consistent with decreased forward coronary flow in the inner layers of the left ventricular myocardium under normal pressure-flow conditions.

This study presents a spectrum of injuries to the heart in 61 individuals from 2 months to 30 years of age who were in automobile accidents. Three patients are presented in detail. One patient died and had severe damage to the left ventricular myocardium. Another patient had severe damage to the tricuspid valve and survived after successful implantation of a Starr-Edwards valve. The third patient had a residual calcified plaque at the base of the left ventricle which was detected 30 years after a childhood automobile accident. Electrocardiographic changes compatible with myocardial injury were found in 29.5 per cent, and 19.6 per cent were found to have suspicious changes. Since the advent of open heart surgery, patients who sustain myocardial tears or rupture of cardiac septa are now potentially curable.

1. 1. A 6-year-old white girl with cyanotic congenital heart disease is described, in whom a congenital anomaly in origin and distribution of the coronary arterial blood supply led to a surgical catastrophe. A major branch of a single right coronary artery which was coursing over the anterior surface of the outflow tract of the right ventricle to supply the left ventricular myocardium was cut accidentally when a right ventriculotomy incision was made with the patient on cardiac bypass. 2. 2. Information concerning single coronary artery is reviewed briefly, with reference to its importance as a surgical hazard in patients undergoing open-heart surgery.

Electron microscopic analysis of left ventricular myocardium from rats made hypoxic for 2h, 10 and 30 days showed focal intracellular oedema as the only alteration in acute severe hypoxia (6% oxygen). No mitochondrial lesions were seen. In chronically hypoxic hearts (9% oxygen) the mitochondrial structure also remained normal. Morphometric analysis has showed a significant increase in capillary density and in the number of mitochondria. The mean diameter of the latter seems to be smaller in hypoxic than in control hearts.

Seven selective left ventricular angiocardiograms that permitted measurement of end-diastolic volume for 5 consecutive cardiac cycles were analyzed. Neither end-diastolic volume nor end-systolic volume changed significantly between the first and second cycles after ventricular opacification. A progressive increase in the major and minor ventricular semiaxes occurred beginning with the third opacified cycle. Correspondingly, the average end-diastolic volume and end-systolic volume increased by 6.9 ml and 3.4 ml, respectively, between the second and third cardiac cycles. Ventricular volumes progressively increased between the third and fifth cardiac cycles in each patient. These data suggest that sodium diatrizoate has a negative inotropic effect on left ventricular myocardium by the third cardiac cycle after injection. Physiologic information from cineangiocardiography should be derived from the first 2 cardiac cycles after opacification.

1. 1. After occlusion of the anterior descending coronary artery, perfusion of oxygenated or nonoxygenated Tyrode solution at a rate of 2 ml. per minute into the center of the cyanotic region of the anterior surface of the left ventricle, the boundary zone between cyanotic and noncyanotic regions, or the noncyanotic neighboring myocardium resulted in a further decrease in the arterial pressures and cardiac output (CO), an increase in the left ventricular end-diastolic pressure (LVEDP) and venous pressure, and an increase in the extrasystoles. Perfusion of the cyanotic apical region increased the arterial pressures and CO to below preocclusive levels and decreased the LVEDP and extrasystoles. 2. 2. After occlusion of the circumflex coronary artery, perfusion of oxygenated or nonoxygenated Tyrode solution at a rate of 2 ml. per minute into the center of the cyanotic region of the posterior left ventricular myocardium, the boundary zone between the cyanotic and noncyanotic areas, or the noncyanotic neighboring myocardium resulted in a further decrease in the arterial pressure and CO, and an increase in the LVEDP, venous pressures, and extrasystoles. Perfusion of the cyanotic apical region increased the arterial pressures and CO to below preocclusive levels and decreased the LVEDP and extrasystoles.

Effects of seven levels of chronic physical activity on the metabolic and morphologic characteristics of left ventricular myocardium of adult male albino rats were investigated.

Isopropylarterenol is the most effective drug for treatment of acute syncopal attacks of Adams-Stokes disease and prevention of recurrent attacks. When syncope does not resolve quickly, closed-chest cardiac massage can be applied effectively whether the arrhythmia is due to ventricular arrest or fibrillation, affording time to determine the mechanism and organize appropriate therapy.Permanent electric pacemaking is now feasible, either with a portable pacemaker connected to an electrode catheter in contact with the endocardium of the right ventricle or with a subcutaneously implanted pacemaker connected to electrodes placed in the left ventricular myocardium.

The left ventricular myocardium of 48 approximately normal human hearts had an average creatine content of 194 mg. per 100 grams of tissue, this value being based upon an arbitrary water content of 80 per cent. There were neither sex nor age differences in this creatine content. A few cases included in the normal group, but having creatine contents differing widely from the mean, are listed separately with diagnoses given in detail. Analyses of 17 decompensated hearts showed a significantly lower average creatine content than normal. Scar tissue was not a significant factor in producing this low value. Fifteen abnormal, but not decompensated, hearts had an average creatine content significantly lower than normal, but higher than the values for the decompensated hearts. These are listed separately, with their diagnoses given in detail. Septicemia per se had no effect upon the creatine content of the left ventricle. An effect of hypertrophy per se on the creatine content of the heart was not definitely established. These findings suggest that the “reserve” of the heart closely parallels its creatine content.

The authors present the case histories of two patients who underwent otherwise successful replacement of the mitral valve by a Starr-Edwards ball-valve prosthesis, but died because of cardiac arrhythmia several weeks after the operation. Necropsy revealed that the steel cage of the prosthesis caused scarring and necrosis of the interventricular septum in one patient and pressed deeply into the mural myocardium in the other. The recommendation is made to use the low profile “meniscus”-type valvular prosthesis instead of the Starr-Edwards ball-valve to prevent the possibility of the cage irritating the ventricular myocardium.

Electric and mechanical properties of right and left ventricular muscle of hyperthyroid rats have been studied in vitro. Excitability was not modified but refractory period was lengthened in left ventricular muscle. Developed tension was significantly reduced in both ventricles, the greater reduction being on the right. The results suggest direct and disproportionate effects of thyroid hormone on right and left ventricular myocardium.

The application of the resistance-wire strain gauge arch by BONIFACE et al. to the beating heart in situ has recently conducted to allow the direct measurements of the mechanical function of the heart, and several models of apparatus for this purpose have been devised. The use of a semiconductor as the transducing element makes the strain gauge arch smaller and more efficient in transduce than the use of the wire strain gauge. The present report describes the structures and the performances of some models of the new instruments which have been designed using semiconductor strain gauge elements. This report also provides the discussion on the propriety of this method manifesting the accurate myocardial contractility of the left ventricle through the detailed analysis of myocardial tension curves recorded with the new strain gauge arch. Methods 1) Mechanical properties of the strain gauge arch. The strain gauge arches, which were used in this investigation, were transducers capable of translating the forces acting on their attachments into proportional changes in the bridge output voltage. The body of the transducer was made of a kind of spring-steel in the form like an arch as a whole, consisting of a beem between two legs with two attachments. The distance between two legs was 15 mm (in Model L-3) or 10mm (in Model L-6), and the whole weight was less than 1g. The modified arch (Model VL-5), which could be adjusted the distance between two legs by means of a micro-screw, was also developed. As strain gauge elements, four pieces of n type Ge [111] were cemented on both sides of the upper parts of the legs. A "four active full-bridged circuit" which was constituted by the semiconductor elements was supplied with 3V in DC. There was a linear relation between the force necessary to displace the attachments and the increase of the distance between the attachments, and even a force of 250g wt. could move the attachments less than 5 per cent of length of the beem. There was also linear relation between the force acting attachments and the bridge output voltage and 210mV of output voltage was obtained by 250g wt of force in Model L-3. The frequency response of the strain gauge arch was found to be uniform through 350cps.

Extrasystoles were observed in normal dogs against the background of reflex bradycardia caused by the intravenous administration of adrenalin. Three – four months after the creation of experimental aortic stenosis attacks of left ventricular paroxysmal tachycardia appeared in the same animals after the administration of the same dose of adrenalin. Three factors play an important role in the appearance of these attacks: 1) vagal inhibition of the automatism of the sinoatrial node; 2) direct action of adrenalin, increasing the myocardial excitability; 3) stimulating effects of cardiosclerotic foci on definite areas of the left ventricular myocardium.

In spite of several investigations (1, 3, 4, 5) on whole heart and on ventricular strip, it is yet impossible to assess with certainty whether the intensity of mechanical systole is more dependent upon initial volume (or fiber length) or on telediastolic level of intraventricular pressure (or passive tension).

A microscopic wavy appearance of myofibers as an expression of early myocardial damage was studied in random sections of both the right and left ventricles in 207 consecutive autopsies. Waviness of myofibers was consistently associated with fuchsinorrhagia, indicating chemical alterations in the wavy fibers. Both waviness and fuchsinorrhagia appeared to precede the necrosis of myofibers. These changes were transient and were absent in frankly infarcted myocardium. Severe and extensive waviness was present in the left ventricle in recent myocardial infarction and in both ventricles in pulmonary emphysema. Waviness and fuchsinorrhagia were observed more frequently in the right than in the left ventricular myocardium except with recent infarction. It is considered that covert recent myocardial damage, particularly of the right ventricle, may precipitate death in many non-cardiac diseases.

A simple drill-biopsy technique was developed. It was applied to sampling rabbit skeletal muscle and the beating left ventricular myocardium of the dog. No significant impairment of cardiac performance was evident after serial sampling. Statistical studies for labile and non-labile compounds demonstrated a satisfactory reproduceability of the technique. Comparisons were made for CP and ATP with the quick-freeze tongs method. The technique appears valid for the study of the progress or deterioration over the course of time of a living organ suffering from an acute or chronic evolutive condition.

The study of energetics of the left ventricular myocardium, normally based on its oxygen consumption and mechanical work performance, can be extended by determining its heat production as well. By considering all forms of energy input and output of the left ventricle, calculations were made of left ventricular net heat production under a variety of hemodynamic conditions. One of the mechanisms for removal of the heat produced is provided by the coronary blood, which is warmed in transit through the myocardium. Direct measurements of the rate of heat removal by the coronary circulation were made from coronary flow rate and veno-arterial temperature gradient. The fraction of left ventricular net heat production which is removed by the coronary perfusion is proportional to coronary flow rate. The fraction at a given flow rate is sufficiently reproducible to permit estimation of total heat produced from the portion measured in the coronary circulation. Certain of the theoretical applications of heat data may require more accuracy than appears feasible by this method. Which of the applications discussed will prove practical remains to be determined. Submitted on February 13, 1961

Summary Several groups of dogs were submitted to hemorrhagic hypotension, prolonged for 135 and 180 minutes, followed in some of the dogs by reinfusion of the blood withdrawn. Epinephrine (EP) and norepinephrine (NEP) were determined according to the method of von Euler and Lishajko, using trichloroacetic acid extracts of the right and left ventricular myocardium. Hemorrhagic hypotension affects inversely the catecholamine content of the heart, lowering the NEP concentration and increasing that of EP. The effect on NEP is more marked in the left ventricular myocardium than in the right, and it seems to be dependent on the duration of the hypotensive period. Reinfusion of the extravasted blood following the hypotensive period seems to correct partially the aforementioned disturbances with diminishing efficacy as the hypotensive period is prolonged. The lower content of NEP in the left ventricular myocardium corresponds to an abnormal electrocardiographic pattern. No correlation could be found between abnormalities in the electrocardiogram and the ventricular levels of EP.

The purpose of this study was to get information concerning the supply of oxygen to the canine heart under steady-state conditions and concerning the dynamic behavior of the myocardial Po2 with sudden temporary changes of oxygen supply. Microelectrodes of trie size generally used for Po2 measurements in other organs proved to be too fragile for insertion into the beating heart. Therefore we had to employ electrodes with a tip diameter above 40/u.

The relations between end-diastolic ( D ) and end-systolic (S) cavitary volumes ( V c ), wall volumes ( V 10 ), and cavitary dimensions have been studied in the canine and human left ventricle. However, the models selected for left ventricular myocardium do not represent the real heart adequately for a fiber-by-fiber analysis of fiber orientation and sarcomere length during successive states of the ejection cycle. In this study, the endocardial and epicardial surfaces were postulated to be a nested set of truncated ellipsoidal shells of revolution where wall volumes were preserved from D to S. Shell dimensions on the semiminor and semimajor axes, R and Z , respectively, were related to V c and V w by two representations: confocal and nonconfocal. If the focal length C = ) 1/2 and C is the same for each shell, then the shells are confocal, otherwise they are nonconfocal. From measured V c , V w , and epicardial Z in D , shell dimensions were calculated for states D and S, using both confocal and nonconfocal representations, and compared with the measured dimensions. When no empirical corrections were made, the calculated endocardial R in S underestimated the measured R in S by 12%; moreover, the calculated epicardial R in S overestimated the measured R in S by 4%. Endocardial and epicardial C measured 3.73 ± 0.33 (SE) cm and 3.79 ±0.34 cm, respectively, in D and 3.77±0.11 cm and 3.71 ±0.10 cm, respectively, in S.

1. 1. It is possible to visualize the left ventricular myocardium of the intact, living patient, without discomfort or danger to the patient, by photoscanning after the administration of cesium-131. 2. 2. The normal left ventricular myocardium appears as a full, even density, with a smooth contour. Myocardial infarcts appear as “cold” areas of decreased uptake. 3. 3. In 6 patients with unequivocal fresh myocardial infarcts, the scans were positive in 5 and doubtful in 1. In 2 patients who probably had suffered recent myocardial infarctions, the scan was positive in 1 and negative in 1. In 2 patients who had heart disease but who had probably not had recent myocardial infarctions, the scan was negative in 1 and doubtful in 1. The scan was negative in each of 3 patients with normal hearts.

Coronary and systemic hemodynamics were compared in 15 normal men and 15 normal women. Systemic hemodynamics were very similar. The women had 26.5 per cent greater coronary flow and 19.6 per cent more oxygen consumption/100 Gm. of left ventricular myocardium. Their calculated coronary vascular resistance was 35 per cent less. Significant negative correlations between coronary flow and calculated heart weight, and between cardiac oxygen consumption and calculated heart weight, as well as between coronary flow and hematocrit probably explain the differences in part. Whether hormonal or anatomic differences are also significant is not known.

Five mongrel dogs were given 0.08 mg/kg of tritiated digoxin over a 24-hour period. Left ventricular myocardium was excised and subsequently fixed, dehydrated, and embedded in Epon 812 epoxy resin. Tissue was sectioned and coated with a monolayer of photographic nuclear emulsion and exposed for varying time intervals up to three months. After development these autoradiographs were viewed with the electron microscope. It was found that of the total number of nuclear tracks counted, 75% were found to overlie the sarcomere of the myofibril, 27% to overlie the mitochondria, and 8% to overlie other structures. Of those tracks associated with the sarcomere, 72% were found to overlie the A band. Evaluation of the data obtained and the techniques used are presented.

A technique for constricting the pulmonary artery of the rabbit is described. The procedure causes right ventricular hypertrophy in the study of which the left ventricular myocardium may be used as a control. Assay systems for the measurement of cytoplasmic aminoacyl-tRNA synthetase and transferring enzyme activity have been applied to the right and left ventricular myocardium in rabbits undergoing constriction of the pulmonary artery or a sham operation. In the absence of constriction of the pulmonary artery aminoacyl-tRNA synthetase and transferring enzyme activities are lower in the right ventricle than in the left. The induction of right ventricular hypertrophy had no significant effect on the level of either enzyme activity.

In left ventricular myocardium of 9 hypertrophic (artificial aortic insufficiency) and 12 normal rabbit hearts, ribonucleic and desoxyribonucleic acids were determined. In hypertrophy DNA-P was significantly reduced, where-as RNA-P was higher than in normal myocardium. The RNA-P/DNA-P ratio was 2·9 in normal as compared to 4·0 in hypertrophic heart muscle.

Experimental reinvestigation of the mechanism and spread of ventricular activation by Prinzmetal and his co-workers 1 has stimulated interest in the clinical correlation between subendocardial infarction and its electrocardiographic manifestations. In this regard, cases of particular importance are those in which the infarction is widespread circumferentially, but limited to the inner half or less of the left ventricular myocardium. Because of conflicting statements in the recent literature concerning the presence or absence of QRS alterations with this specific type of infarction, we were encouraged to review our autopsied cases of extensive subendocardial infarction that had had recent electrocardiograms. Seventeen such cases were available for study. From the case material available at the Rhode Island Hospital during the decade 1950-1960, we excluded those cases of subendocardial infarction combined with transmural extensions or those having significant conduction disturbances prior to the onset of the infarction. Thus, two cases with previous left and

Numerous investigators have conducted a variety of studies directed toward revascularization of the heart. Of the procedures attempted, most fall into one or more of the following groups: (1) the introduction of an irritant in the pericardium; (2) the grafting of other organs or tissues to the surface of the heart; (3) the anastomosis of a systemic artery to the coronary sinus, and (4) the implantation of a systemic artery into the left ventricular myocardium. The last mentioned of these procedures was introduced by Vineberg and associates, and they have reported encouraging results both in the experimental animal and in man. 7,8 Their experimental findings have been confirmed by some, 2 whereas others have obtained different results. 3,5,6,8 In all of the work yet reported on arterial implants into the myocardium the implants have been placed into the left ventricle. In this communication the studies concern similar arterial implants into

The fatal acute cardiac failure which sometimes intervenes during the course of exfoliative dermatitis due to arsphenamine is seldom anticipated clinically, and the microscopic appearance of the myocardium post mortem is even less expected. The cases of such myocardial changes following the onset of arsphenamine dermatitis comprise part of the general group of instances of a condition designated as acute interstitial, isolated or Fiedler's myocarditis. The more than 40 recorded cases making up this general group have in common the apparently spontaneous occurrence of progressive myocardial failure and diffuse interstitial inflammation involving a thickened left ventricular myocardium, according to postmortem observations. Fiedler in 1899 called attention to this peculiar nonspecific interstitial myocarditis, accounts of which first reached the American literature in 1929, with a review by Scott and Saphir. 1 They collected 30 cases and added 2 of their own but did not include Fiedler's cases because of their relative