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Adrenaline in local anesthetic solutions is thought to be the causative factor of acute exacerbations of preexisting cardiac diseases during dental anesthesia. This assumption presupposes the systemic effectiveness of adrenaline when coinjected with a local anesthetic drug. To test the above assumption, cardiovascular effects (PS, PD, dP/dTmax LVEP, CO, HR, EGG) and arterial drug concentrations were measured before and after injection of 1.0 ml/kg b.w. of a 0.9% NaCl, 1:300,000/1:100,000 adrenaline-HCl or 2% lidocaine-HCl alone and in combination into the mucobuccal fold of adrenalectomized rats. The transient increase in the cardiovascular parameters by adrenaline was abolished by lidocaine coinjection. The cardiodepressant effect of plain lidocaine was only reversed by the higher adrenaline dose, which however induced a small fall in PD, R and PM. Lidocaine increased the bioavailability of adrenaline from the intraoral depot. Inhibition of COMT activity by lidocaine may contribute to this effect. These findings demonstrate no cardiac response to adrenaline, up to 1:100,000 in a 2% lidocaine solution. In agreement with clinical findings the 1:100,000 adrenaline containing solution can be safely used in compromised cardiovascular patients. However, an interaction between a vasoactive comedication and lidocaine/adrenaline on the vascular system has to be taken into consideration.

The aortic origin of one pulmonary artery, also called hemitruncus arteriosus, is a rare congenital anomaly with poor prognosis. In this report the case of an asymptomatic 18-year-old man with a systolic precordial murmur and the electrocardiographic finding of biventricular hypertrophy is described. The diagnosis of hemitruncus was confirmed by cardiac catheterization. Echocardiography showed biventricular hypertrophy and moderate enlargement of the right atrium and ventricle. In contrast to reports in children, the diagnosis could not be verified by transthoracic echocardiography because of the lack of a satisfactory acoustic window. On the other hand, the aortic origin of the right pulmonary artery and the continuation of the main pulmonary artery as left pulmonary artery were visualized by transesophageal echocardiography. However, the shunt-volume could not be determined by means of the velocity-time-integral and the diameter of the right pulmonary artery because of the turbulent blood-flow in its proximal part.

Inadvertent intravascular injection of a local anaesthetic is the main cause of incidents during local dental anaesthesia. The composition of the local anaesthetic solution determines the clinical symptoms in dependence on the patient's pathophysiological condition and a possible drug therapy. Since an intravascular injection cannot be excluded with certainty slow injection of the anaesthetic solution and the knowledge of its composition are prerequisites.

Echocardiographic imaging (two-dimensional and M-mode technique) with extrathoracal transducer positioning is, in addition to other echocardiographic methods (transesophageal scanning, contrast-enhanced echocardiography, Doppler ultrasound), an important diagnostic tool for determining the morphology, function, and hemodynamics of the heart and the large vessels. It is a safe diagnostic procedure and is, therefore, an important basis for further cardiac evaluation by invasive techniques. Echocardiography in general is not only of high diagnostic value for the noninvasive evaluation of cardiac disorders, but it is also often the basis for an adequate therapeutic procedure, as well as for evaluation of clinical follow-up, prognosis, and exercise performance of the cardiac patient.

1. In anesthetized cats 2,4,7-triamino-6-phenyl-pteridine (triamterene) (5 mg/kg i.v.) causes a short-lasting increase in blood pressure, a decrease in heart rate, whereas the contractility (see article) remains unchanged. N-Amidino-3,5-diamino-6-chloropyrazinecarboxamide (amiloride) (5 mg/kg i.v.) causes a fall of blood pressure, an increase in heart rate, and an increase in contractility. 2. In cats the i.v. toxicity of digoxin is diminished by pretreatment with triamterene or amiloride; the arrhythmias and the cardiac arrest are significantly delayed in the course of an infusion of digoxin. In guinea-pigs a pretreatment with triamterene only delays the arrhythmias but not the lethal effect of digoxin or g-strophanthin. 3. In the isolated atria of the guinea-pig triamterene and amiloride (5 mug or 50 mug/ml) lowers the rate of contraction and prolongs the functional refractory period. The force of contraction is increased by triamterene and diminished by amiloride.