Stanley Giannelli

The effects of intra-aortic counterpulsation on cardiac performance and metabolism in shock associated with acute myocardial infarction

The effect of intra-aortic counterpulsation (IACP, 22-94 hr) on hemodynamics and cardiac energetics was evaluated in 10 patients in shock after acute myocardial infarction. The data clearly indicate that IACP improves myocardial oxygenation, enhances peripheral perfusion, and probably improves myocardial contractility in the severely diseased heart. Before treatment, decreases in cardiac index (mean value, 1.22 liter/min per m(2)), systolic ejection rate (67 ml/sec), and time-tension index per minute (1280 mm Hg.sec/min) were observed. Systemic vascular resistance varied widely. Low coronary blood flow (68 ml/min per 100 g) was associated with increased myocardial oxygen extraction (79%), low coronary sinus oxygen tension (20 mm Hg), and abnormal myocardial lactate-pyruvate metabolism. During 4-6 hr of IACP, systolic pressure and left ventricular outflow resistance decreased by 18% and 24%, respectively, while cardiac index improved by 38%. Diastolic arterial pressure rose 98%. Increase in coronary blood flow from an average of 68 to 91 ml/100 g per min (P < 0.001) was significantly correlated with rise in mean arterial pressure (r = 0.685). This correlation was best expressed in a third-order curve, which intercepts the point of no flow at a mean aortic pressure of 30 mm Hg. The flow-pressure curve is relatively flat above 65-70 mm Hg, but becomes steeper as mean aortic pressure falls below this point. Myocardial oxygen consumption remained essentially unchanged during early IACP and tended to rise during the later stages. However, the relationship of cardiac work performed to oxygen availability was markedly improved. Myocardial lactate production of 6% shifted to 15% extraction (P < 0.001). After termination of IACP, hemodynamics and myocardial perfusion and metabolism remained improved in the four patients who could be reevaluated. Although the acute shock state was reversed in all patients, only one left the hospital. Extensive myocardial damage limits the long-term survival of such patients. Therefore early IACP seems desirable, when subtle evidence of pump failure after acute myocardial infarction occurs. Early use of IACP may prevent the development of severe coronary shock or may stabilize cardiac energetics in severe shock facilitating subsequent surgical intervention.

Hemodynamics, coronary blood flow, and myocardial metabolism in coronary shock; response to l-norepinephrine and isoproterenol

Hemodynamics and myocardial metabolism were evaluated in 18 patients in cardiogenic shock following acute myocardial infarction. The response to l-norepinephrine was studied in seven cases and the response to isoproterenol in four cases. Cardiac index (CI) was markedly reduced, averaging 1.35 liters/min per m(2). Mean arterial pressure ranged from 40 to 65 mm Hg while systemic vascular resistance varied widely, averaging 1575 dyne-sec-cm(-5). Coronary blood flow (CBF) was decreased in all but three patients (range 60-95, mean 71 ml/100 g per min). Myocardial oxygen consumption (MV(O2)) was normal or increased ranging from 5.96 to 11.37 ml/100 g per min. Myocardial oxygen extraction was above 70% and coronary sinus oxygen tension was below 22 mm Hg in most of the patients. The detection of the abnormal oxygen pattern in spite of sampling of mixed coronary venous blood indicates the severity of myocardial hypoxia. In 15 studies myocardial lactate production was demonstrated; in the remaining three lactate extraction was below 10%. Excess lactate was present in 12 patients. During l-norepinephrine infusion CI increased insignificantly. Increased arterial pressure was associated in all patients by increases in CBF, averaging 28% (P < 0.01). Myocardial metabolism improved. Increases in MV(O2) mainly paralled increases in CBF. Myocardial lactate production shifted to extraction in three patients and extraction improved in three. During isoproterenol infusion CI increased uniformly, averaging 61%. Mean arterial pressure remained unchanged but diastolic arterial pressure fell. CBF increased in three patients, secondary to decrease in CVR. Myocardial lactate metabolism deteriorated uniformly; lactate production increased or extraction shifted to production. In the acute state of coronary shock the primary therapeutic concern should be directed towards the myocardium and not towards peripheral circulation. Since forward and collateral flow through the severely diseased coronary bed depends mainly on perfusion pressure, l-norepinephrine appears to be superior to isoproterenol; phase-shift balloon pumping may be considered early when pharmacologic therapy is unsuccessful.

Systemic and Myocardial Hemodynamic Responses to Relatively Small Concentrations of Carboxyhemoglobin (COHB)

1992 National Health and Medical Research Council Act 1992 National Health and Medical Research Council June 1991 Passive smoking and the risk of heart attack or coronary death Annette J Dobson, Hilary M Alexander, Richard F Heller, Deborah M Lloyd Article published in: The Medical Journal of Australia, vol.154 A retrospective cohort study of smoking habits in Australia Jilda Hyndman, Michael Hobbs, Konrad Jamrozik, Richard Hockey, Richard Parsons Unit of Clinical Epidemiology, University of Western Australia

Effect of Pulmonary Blood Flow upon Lung Mechanics

Airway pressure was continuously recorded in an isolated horizontally mounted canine heart-lung preparation during abrupt, stepwise 100-200 ml inflations to 20-25 cm water pressure, and subsequent deflations. With each change in volume there was a steep rise or fall in pressure, followed by stress relaxation to a static equilibrium airway pressure. Comparison was made between the nonperfused state and during perfusion with whole blood at 100 ml/kg dog wt per min, and left atrial pressure of 10 mm Hg. Pressure tracings were similar during deflation in the perfused and the nonperfused lung. During inflation, in the middle range of lung inflation volumes, the peak inflation and equilibrium airway pressures were greater in the nonperfused state; maximum difference of static pressures in nine preparations averaged 146% of perfused values and the average stress relaxation difference from eight of these was 276%. Lung distensibility was the same with packed red cells or plasma perfusates and was not changed by varying the perfusion rate up to 220 ml/kg per min. During cyclic ventilation, dynamic compliance was similarly greater in the perfused than in the nonperfused state in the middle range of inflation volumes. Static distention of the vascular bed produced similar results with progressive improvement in distensibility in mid-inflation range up to a hydrostatic pressure of 15 cm blood. These data suggest that the distended pulmonary vascular bed provides structural airway support which facilitates entry of gas into the terminal respiratory units at diminished pressure.

Carboxyhemoglobin and the Access to Oxygen

Carboxyhemoglobin (COHb) alters the oxyhemoglobin dissociation curve in such a manner that oxygen is released to the tissues with great difficulty and at a lower oxygen tension. The known effects on heart and brain of breathing .Sow concentrations of carbon monoxide are primarily related to this leftward shift and perhaps also to combination with myoglobin and certain iron-containing enzymes. Hemoglobin-oxygen equilibria in the presence of COHb resembles the equilibria of more primitive forms of hemoglobin and gives rise to the suggestion that this decrease in the access to oxygen is a form of counterevolution.

Use of the permanent transvenous pacemaker in 168 consecutive patients

Abstract One hundred and eighty-one implantations of permanent transvenous cardiac pacemakers have been performed in 168 patients at the St. Vincents Hospital, New York, N. Y., from April 1965, to March 1970. The chief indication for the implantations was complete heart block, although one-third of the patients were symptomatic from other bradyarrhythmias. Only ventricular triggered demand units have been used in the last two years. Cardiac output studies at varying rates indicated a rate of 60 beats per minute to be adequate in the group so studied, and all pacemakers are set at this rate. All patients have been relieved of symptoms. Complications have been minimal. The demand-type pacemaker has proved as reliable as the fixedrate unit, and appears preferable in all patients.

CAUSES OF ARTERIAL HYPOXEMIA IN PATIENTS WITH OBSTRUCTIVE PULMONARY EMPHYSEMA.

Abstract Arterial oxygen tension and alveolar ventilation were measured in eighteen patients with obstructive pulmonary emphysema. In ten of these patients the determinants of arterial hemoglobin saturation were analyzed by a technic combining the measurement of alveolar-arterial oxygen tension differences at two levels of inspired oxygen tension with the determination of the diffusing capacity of the lung for carbon monoxide. Arterial oxygen tension was lower than normal in all but two of the eighteen patients. It was concluded that hypoxemia in emphysema was due to a complex interplay of several factors, particularly alveolar ventilation, veno-arterial shunting and the distribution of alveolar ventilation and pulmonary capillary perfusion; diffusion limitations were not found to be a significant cause of hypoxemia in resting subjects with emphysema.

Use of the permanent subcutaneous transvenous pacemaker in Adams-Stokes syndrome

Abstract The technic and results of long term endocardial pacing with a subcutaneous power supply are discussed. Among 15 patients so treated during a 10 month period, 11 patients were discharged from the hospital with satisfactorily functioning transvenous units. One patient died suddenly one month after discharge. The other 10 have done well. Of the original group, 2 died suddenly in the hospital, and 2 had transthoracic epicardial pacemakers installed when transvenous units failed to function. The incidence of late failure of equipment has been small, and the ease and safety of installation under local anesthesia make it a satisfactory method for permanent pacemaking.

Pulmonic stenosis and associated atrial septal defects in older patients: Report of three cases, including one with calcific pulmonic stenosis

Abstract Three cases of pulmonic stenosis associated with atrial septal defects in older patients are reported. One 59 year old man presented the additional rare finding of a severely calcified pulmonic valve. He is probably the oldest patient reported to have calcific pulmonic stenosis diagnosed fluoroscopically, cineangiographically and surgically. The forms of atrial septal defects included a patent foramen ovale with functioning right to left shunt in a 44 year old woman with severe pulmonic stenosis who died five months after open heart surgery of complications from recurrent tracheal stricture. A second form included an atrial septal defect of the sinus venosus type, associated with partial anomalous pulmonary venous return, in a patient with moderate calcific pulmonic stenosis. A third type of interatrial communication is described in a 69 year old man with moderate pulmonic stenosis, systemic hypertension and an atrial septal defect, probably of the secundum type. Factors responsible for survival to an older age group, and for valve calcification, are discussed.

Cannulation of the Left Main Pulmonary Artery for Partial Left Heart Bypass

Abstract Cannulation of the left main pulmonary artery for partial left heart bypass is described. We have employed this method successfully in 5 patients who underwent resection of aneurysms of the descending thoracic aorta. A main advantage is that high and consistent rates of venous return are obtainable.