The haemodynamic effects of dobutamine were studied in I4 patients with chronic congestive cardiac failure. Heart rate, central venous, pulmonary arterial, pulmonary wedge, and aortic pressures, aortic dp/dt, cardiac output, cardiac index, stroke volume, and pulmonary and systemic vascular resistances were measured or derived. Dose-response curves were obtained by recording all measurements before and after intravenous infusion of dobutamine at rates of 2.5, 5, and IO ,ug/kg per min for periods of 30 minutes each. Significant increases in mean values were observedfor cardiac output from 3.7 to 6.4 1/min (82%), for stroke volume from 44 to 64 ml (39%), and aortic dp/dt from 692 to 1414 mmHg/s (92.0 to x88.i kPa/s) (76% (Fig. i).This investigation was developed to study the dose-related effects of dobutamine in a group of Received I5 November 1974. patients with chronic congestive heart failure. Haemodynamic and renal parameters were measured during the administration of graded increments of the drug. The present report describes initial clinical observations with the use of this new inotropic agent. Subjects and methodsFourteen patients (8 men and 6 women) whose ages ranged from 24 tO 74 years were investigated. All had cardiac failure secondary to myocardial, coronary, or valvular disease. Patients considered for this investigation received a complete verbal and written description of the procedure and of the potential effects of the drug to be administered. Consent was subsequently obtained in writing. The patients were allocated to 2 groups according to their functional class (New York Heart Association Classification) and cardiac index at the time of the study. Group A consists of 4 patients in functional class II, clinically 'compensated', and with a cardiac index more than 3 1 minl -m-2 on basal conditions. Group B consists of io patients in functional class III or IV, with clinical evidence of severe congestive failure, and with a cardiac index less than 3 1 min -m -2. Digitalis, when previously administered, was discontinued 24 to 48 hours preceding the study. Standard haemodynamic techniques and instrumentation were used. Catheters were placed in the superior vena cava and pulmonary artery via antecubital vein cut-down or femoral

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The electrocardiogram and vectoreardiogram are of great aid in differentiating atrial septal defect of the secundum type from the ostium-primum type. In the latter condition there is left axis deviation in the scalar electrocardiogram and superior orientation of the QRS vector in the sagittal and frontal planes. There are relatively few congenital lesions that lead to the same degree of axis deviation and superior orientation of the QRS vector.

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