Hemodynamic status in repaired tetralogy of Fallot assessed by Doppler echocardiography and cardiac catheterization. Comparisons with healthy subjects and elucidation of factors associated with cardiorespiratory function.

Thirty-four patients were studied after corrective surgery for tetralogy of Fallot (mean follow-up 10 years) and compared with healthy matched controls. All underwent Doppler echocardiography, spirometry and treadmill exercise test. Post-operative cardiac catheterization had been performed on 26 (76%) of the patients and showed poor hemodynamic results in four (15%). Significant correlations of pressure gradients obtained from catheterization and estimated by Doppler echocardiography were right ventricular to right atrial (r = 0.77), pulmonary outflow (r = 0.75), pure valvular pulmonary outflow (r = 0.94) and diastolic pulmonary pressure gradients (r = 0.53). Pulmonary outflow gradients and right ventricular to right atrial pressure gradients estimated from tricuspid regurgitation jets were significantly increased in the patients. Diastolic pulmonary artery pressure, vital capacity and ventilatory anaerobic threshold were independent factors of maximal oxygen consumption. It is suggested that Doppler-derived diastolic pulmonary artery pressure, lung function studies and exercise testing with assessment of the ventilatory anaerobic threshold should be included in follow-up after repair of Fallot's tetralogy.

Respiratory gas exchange during treadmill exercise testing: reproducibility and comparison of different exercise protocols.

Ten subjects performed 4 maximal exercise tests to evaluate reproducibility and effects of treadmill inclination on submaximal and maximal oxygen consumption. They performed a standard Bruce protocol twice, and 1 protocol with progressive speed increase with constant, or without, inclination. At maximal exercise there was no significant difference between the protocols in oxygen consumption, respiratory gas exchange ratio, minute ventilation, plasma lactate, serum potassium or heart rate. Exercise time and treadmill distance were shorter than Bruce protocol with inclination, and considerably prolonged without. Reproducibility for Bruce protocol was good for group comparison of oxygen consumption throughout exercise. The individual variations for oxygen consumption were small at maximal exercise, but were considerable at rest and at the lowest exercise steps, this was slightly improved by analysing longer sampling time. Thus, measurement of oxygen consumption is reliable for group analysis, but interpretation must be careful in individuals unless maximal exercise is obtained. Treadmill inclination may be adjusted according to individual preferences.

Influence of low osmolality contrast media on electrophysiology and hemodynamics in coronary angiography: differences between an ionic (ioxaglate) and a nonionic (iohexol) agent.

It has recently been suggested that the addition of sodium to low osmolality contrast media may reduce the incidence of ventricular fibrillation and conduction disturbances during coronary angiography. In a randomized, double blind study of 30 patients undergoing coronary angiography we therefore examined the electrophysiological and hemodynamic effects of the two low osmolality contrast media-ioxaglate (with sodium) and iohexol (without sodium). Standard ECG, aortic blood pressure, and His bundle electrocardiogram were recorded. The contrast media were well tolerated and no serious arrhythmias were observed. Both induced a transient decrement in systolic blood pressure and reduction in heart rate 10 s following contrast injection (all P less than 0.01). Ioxaglate prolonged the QT interval at 10 s (P less than 0.01) and also when analysed for the whole observation period (120 s) (P less than 0.05), whereas iohexol did not cause any significant changes in the QT-interval. The AH-interval was prolonged by ioxaglate at 10 s (P less than 0.01), but not altered by iohexol. Thus, other factors than osmolality and sodium content might contribute to QT prolongation, since only the contrast agents with sodium (ioxaglate) induced QT prolongation in this study.

Hemodynamic and electrocardiographic consequences of high- and low-osmolality contrast agents for left ventricular angiography.

The cardiovascular effects of two nonionic contrast agents with low osmolality (iohexol and metrizamide) were compared with one standard ionic, high-osmolality contrast agent (metrizoate) used for left ventricular (LV) angiography in patients with coronary heart disease. Metrizoate induced a marked elevation of LV end-diastolic pressure and LV systolic pressure and an increase in cardiac output after a delay of a few minutes. All these changes were significantly less severe with iohexol and metrizamide. Hypotension occurring 30 sec after LV angiography was observed only with use of metrizoate. All agents increased heart rate, but the increase after metrizoate was significantly more pronounced and prolonged. The PQ and QT interval was prolonged only by metrizoate. The subjective symptoms were significantly more marked with metrizoate than with the two other agents. Thus the new nonionic contrast agent iohexol and metrizamide produced markedly less hemodynamic and electrocardiographic disturbance than the ionic agent metrizoate.

Improved cardiac performance by salbutamol, a selective beta 2-agonist, in chronic cor pulmonale.

The effects of salbutamol, a relative specific beta 2-agonist, on hemodynamics and arterial blood oxygenation, were studied in 12 patients with chronic cor pulmonale. The studies were done during heart catheterization at rest (n = 12) and during arm bicycle exercise (n = 7) before and during salbutamol infusion of 0.2 microgram/kg/min. At rest, salbutamol significantly increased cardiac index on average by 31%, stroke volume index by 11%, and heart rate by 12 beats/min. Mean pulmonary artery pressure was not changed by salbutamol, whereas a small reduction in mean arterial pressure was observed. The vascular resistance was reduced by 15% in pulmonary and 24% in systemic circulation. Similar hemodynamic changes by salbutamol were observed during exercise. Arterial oxygen tension and saturation were not changed by salbutamol, but a significant rise in mixed venous oxygen saturation and oxygen delivery were observed both at rest and during exercise. Thus, salbutamol infusion improves the cardiac performance in patients with chronic cor pulmonale through a chronotropic effect combined with vasodilation in both the systemic and pulmonary circulation and thereby increased stroke volume. No deleterious effects on arterial blood oxygenation by salbutamol infusion were observed.

Transient visual disturbance during cardiac catheterization with angiography.

The occurrence of visual disturbances following cardiac catheterization with angiographies was studied in a prospective study of 2,006 consecutive adult patients. The overall incidence of visual disturbances was 1.0% and of complete blindness 0.2%. Women had higher incidence than men (2.0 versus 0.6%, p less than 0.01) and patients with a history of angina pectoris with normal coronary arteries had higher incidence than those with coronary artery stenosis (3.7 versus 0.8%, p less than 0.02). Thirteen of twenty patients also had signs of mental confusion. An abnormal electroencephalogram was found in 8 of 13 patients studied. Other neurological findings were observed in one patient only. All patients had complete recovery within 24 hours. Thus, the incidence of visual disturbances is found to be higher than earlier reported, but the visual loss is transient with a benign course.

Cardiomyopathy induced by anthracycline-derivates.

Two cases of anthracycline-induced congestive heart failure are described. Serial assessment of cardiac function during treatment showed early deterioration of the systolic time intervals of the left ventricle (LSTI) before congestive cardiomyopathy could be demonstrated by echocardiography. We recommend that the cardiac function should be assessed regularly during anthracycline therapy by systolic time intervals and echocardiography to reveal early signs of cardiotoxic effect and that anthracycline therapy should be stopped when LSTI is 0.45 or when it has increased more than 50% compared to pretreatment values.