In fourteen patients referred for preoperative evaluation of heart disease we compared the transthoracic electrical impedance method to the direct Fick (four patients) and dye dilution methods (ten patients) for estimation of cardiac output. On statistical analysis of paired differences we found no reliable agreement between the absolute impedance values and the reference methods. The reproducibility was, however, acceptable, and the coefficient of variation for impedance cardiac output was 7.8%, and for impedance stroke volume 7.6%. Our conclusion is that in patients with advanced heart disease cardiac output cannot be determined with accuracy with the impedance cardiographic method. In clinical practice this must be considered so important, that we hesitate to use the method for monitoring cardiac output in critically ill patients even if the reproducibility for individual changes is acceptable.

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SUMMARYThe cardiovascular reaction induced by amyl nitrite was studied in a main group of 11 patients with pronounced and isolated aortic insufficiency, and in an additional and more heterogeneous group of seven patients with moderate aortic insufficiency combined with other lesions, by measuring left ventricular end-diastolic pressure, systemic and peripheral arterial pressures, cardiac output, peripheral blood flow, and venous tone.Total peripheral resistance decreased, but local vascular resistance differed significantly between the upper and the lower extremities. In most cases arterial dilatation in the forearm (mainly muscle) was found. Simultaneously, there was uniform vasoconstriction in the calf (mainly muscle) which was interpreted to be secondary (baroreceptor reflex). This regional difference in circulatory reaction was also manifested in a pronounced change of the contour of the brachial arterial pulse, while the femoral arterial pulse was practically unchanged. The hand blood flow (skin) decreased while the foot blood flow did not change significantly.A marked fall in systemic arterial pressure and in left ventricular end-diastolic pressure was clearly demonstrated, and secondarily there was a rise in heart rate as well as a pronounced venoconstriction in both the upper and lower extremities, also interpreted to be secondary (a baroreceptor reflex). There was good correlation between maximal increase in heart rate and maximal increase in venous tone and also between the augmentation in heart rate and cardiac output. An A complete hemodynamic study was obtained in all patients by means of a routine cardiac catheterization including right heart catheterization, transseptal left heart catheterization, and angiocardiography. Approximately 1 hour before the catheterization was started in the morning, the patients, who were fasting, were given a small dose of a barbiturate (amobarbital, 0.1 g). The patients were studied in the supine position throughout the whole procedure. A polyethylene catheter (PE 160) 75 cm long was introduced percutaneously via the brachial artery to the arch of the aorta. Right heart catheterization was performed in the usual manner via an exposed superficial cubital vein, followed by transseptal left heart catheterization. The transseptal catheter, a radiopaque Teflon catheter, was introduced into the right femoral vein by the percutaneous technic of Seldinger.14 For the interatrial septal puncture we used the modified instrument of Bevegard's group.15 The tip of the right heart catheter was placed in the pulmonary artery, and the transseptal catheter was in the left ventricle. Pressure measurements were made with pressure transducers EMT 34 or 35 and electromanometer EMT 31.* The pressure curves and ECG were recorded on a direct-writing sixchannel ECG apparatus (Mingograf 81*).Owing to the short duration of the effects of amyl nitrite, the dye-dilution method was used for determination of cardiac output: 5 mg of indocyanine green (Cardio-Green) was injected into the pulmonary ...

A total of 154 episodes of infective endocarditis (IE) in 149 patients were studied retrospectively with special regard to the major aetiological groups and the surgical evaluation. There were 136 episodes of native valve endocarditis (NVE) (88%) and 18 episodes of prosthetic valve endocarditis (PVE) (12%). Three major groups of NVE crystallized: Streptococcus viridans in 37 (27%), Staphylococcus aureus in 39 (29%) and culture negative IE in 28 (21%) episodes. In these groups surgery during the active phase was required in 41, 28 and 18%, respectively. At the operation myocardial abscess was found in as many as 7/15 cases with S. viridans, but in only in 3/11 cases with S. aureus and 1/5 cases with culture negative IE. The mean duration of preoperative antibiotic treatment was 34 d. This long period of unsuccessful pharmacotherapy, preceded by a mean of 47 d from start of symptoms to admission to hospital, has probably resulted in the high frequency of myocardial abscess in S. viridans NVE. Surgical evaluation should be considered when fever persists beyond 10 d of adequate treatment, even in the absence of clinically apparent complications. Among the PVE episodes, 11/18 were managed with pharmacological treatment alone. Uncomplicated PVE may thus often be successfully treated with antibiotics alone.

The acute hemodynamic response to captopril (8 patients) and enalapril (8 patients) was evaluated in congestive heart failure patients in NYHA functional class III. All patients had a history of congestive heart failure for more than six months. The results show marked interindividual variations but average values for cardiac output increase and decrease in filling pressures agree with findings in the literature. 6 patients in the captopril group and five in the enalapril group were started on maintenance therapy. One patient in the captopril group deteriorated and underwent a successful heart transplantation and one patient in the enalapril group returned with arrhytmias and hypertension (probably not drug-related) after 48 h of therapy. Our data indicate that activation of the renin-angiotensin system through excessive administration of loop-diuretics is associated with a risk of hypovolemia and thus drug-induced hypotension that deserves special attention when considering converting enzyme inhibitor therapy in congestive heart failure.