Intermittent fetal bradycardia induced by midpregnancy fetal ultrasonographic study.

Fetal bradycardias were observed during fetal ultrasonographic and echocardiographic studies performed in the second trimester of pregnancy. The episodes of bradycardia were brief and recovery was usually rapid. Ultrasound transducer pressure applied to the maternal abdomen during the study provoked the phenomenon. Vagal discharge resulting from an increase in intrauterine pressure appeared to be the causative mechanism.

Asynchronous atrioventricular valve opening as it relates to right to left interatrial shunting in the normal newborn.

The opening of the tricuspid valve and the onset of right ventricular filling precede the opening of the mitral valve and the onset of flow in the normal adult. Sixty-five studies of atrioventricular flow with range-gated pulsed Doppler echocardiography, performed on 32 normal neonates, consistently demonstrated the reverse sequence. Further investigation showed that at the time of mitral valve opening, while the tricuspid valve was still closed, the valve of the foramen ovale began to bow posteriorly into the left atrium and remained posteriorly bowed for most of diastole. The magnitude of posterior bowing varied among the neonates but, concomitant with the more prominent grades of posterior bowing, right to left shunting across the foramen ovale was demonstrated on color flow mapping. Ultrasound studies in the normal fetus also revealed earlier opening of the mitral valve, bowing of the valve of the foramen ovale into the left atrium and right to left shunting across the foramen ovale. These findings indicate that in the normal immature heart isovolumic ventricular relaxation is completed earlier on the left than on the right side and that left ventricular compliance appears to be greater than right ventricular compliance. The relation of left and right ventricular compliance in the adult is different from that in the normal immature heart. Whereas systemic and pulmonary vascular resistance and pressure levels change rapidly in the newborn period, ventricular compliance matures over a longer period of time. As a result of the differential maturity, for a variable period of time in the normal neonate, a left to right ductal shunt coexists with a right to left atrial shunt.

Diagnosis of fetal arrhythmias using echocardiographic and Doppler techniques.

Fetal echocardiography is the most practical method for diagnosing prenatal arrhythmias. Because some prenatal tachyarrhythmias have been shown to respond to antiarrhythmic drugs, correctly diagnosing fetal arrhythmias has assumed new importance. With the aid of two-dimensional echocardiographic imaging, an M-mode cursor can be aligned to record atrial and ventricular wall motion--either independently or simultaneously. A consistent feature in the fetus is prominent atrial wall contractions that can be readily recorded on the M-mode tracing. By matching atrial and ventricular wall contractions with assumed P waves and QRS complexes, the fetal electrocardiogram can be reconstructed. In 57 fetuses studied, recurrent atrial and ventricular ectopic beats were the most common prenatal arrhythmias. However, atrial flutter, ventricular tachycardia, atrial and ventricular bigeminy and atrial and ventricular bradyarrhythmias have been correctly identified and in some instances appropriately treated. Marked fetal bradycardia in the midtrimester of pregnancy is shown for the first time to be caused by transducer pressure on the maternal abdominal wall.

Transplancental cardioversion of intrauterine supraventricular tachycardia with digitalis.

Intrauterine congestive heart-failure caused by a supraventricular tachyarrhythmia was diagnosed in a fetus at 29-30 weeks' gestation. Major congenital malformations were excluded by sonography, amniocentesis, and fetal abdominal paracentesis, and those of the heart by intrauterine fetal echocardiography. The mother was given digoxin and the fetal tachycardia converted to sinus rhythm.

Evaluating indirect blood pressure measurement techniques: a comparison of three systems in infants and children.

The systemic arterial blood pressures obtained in infants and children utilizing three indirect measuring devices--Arteriosonde 1010. Infrasonde 3000, Pedisphyg system--were compared to each other and to intra-arterial pressure measured directly. The results indicate that Arteriosonde performs considerably better than Infrasonde; nevertheless, the Arteriosonde values are often only approximations of true systole and diastole. The Pedisphyg system yields accurate, reproducible values for systole; however, the system is not designed to determine diastolic blood pressure.

Sphygmomanometry in the pediatric patient.

The indirect measurement of blood pressure in the pediatric population is often difficult or impossible to perform and when values are obtained, they are often unreliable or inaccurate. An accurate measurement of arterial systolic pressure in the upper extremity is obtainable with a properly designed and sized occluding cuff and an ultrasonic device to detect the first Korotoff sound. For the detection of the first Korotkoff sound ultrasonic Doppler devices are superior to the stethoscope. When wider occluding cuffs than usual are applied to the upper extremity, the error of measurement is minimized. A method for accurately measuring end diastolic pressure has yet to be described despite assertions to the contrary.

[Advances in sphygmomanometry (author's transl)]. / Fortschritte in der Sphygmomanometrie.

Problems of the accuracy and reliability of Riva-Rocci's non-invasive method of measuring blood pressure always arise when the cuff does not fit well, i.e. with a very conical upper limb, adiposity or in neonates or patients in shock. From thorough clinical investigations it appeared that the cuff used for blood pressure measurements in adults and the few models for neonates and children are too inaccurate. The cuff must enclose the limb completely and have a minimum ratio of breadth to length of 1 : 3. An integral inflatable cuff unit has been developed and clinically tested in our laboratory during the last two years. It consists of a heat-sealed polyolefine film.

Left ventricle to aorta valved conduit for relief of diffuse left ventricular outflow tract obstruction.

Operative relief of congenital tunnel subaortic stenosis by means of local incision or excision, or both, has generally been unsatisfactory. The use of a valve-bearing conduit between the left ventricular apex and thoracic aorta offers a predictable means of bypassing the left ventricular outflow obstruction. The procedure was used in a 17 year old girl with an excellent hemodynamic result. The history of operative management with diverting plantation of valved conduits in this position have not been defined, but use of these prostheses appears advisable in severe subvalvular, valvular and supravalvular obstructions that are not readily amenable to predictable and safe surgical palliation. The operation may prove useful in selected cases of idiopathic hypertrophic obstructive cardiomyopathy.

Late systolic murmur of rheumatic mitral insufficiency.

Of 184 patients with acute rheumatic fever and associated mitral insufficiency encountered during a 15 year period, 34 manifested a mid-late systolic murmur or a nonejection click, or both, during the course of follow-up. The mid-late systolic murmur later disappeared in four patients whose condition is now considered normal. In one of the four, systolic prolapse of the mitral valve was demonstrated on an angiocardiogram obtained when the systolic murmur was present. Since disappearance of the murmur there has been no evidence of systolic prolapse on meticulous echocardiographic study of the mitral valve. In another child with angiographically demonstrated systolic prolapse of the mitral valve the systolic murmur has also disappeared, but systolic prolapse is still evident on echocardiographic study. None of the 34 patients with a mid-late systolic murmur manifested the T wave abnormalities commonly associated with the familial variety of mitral valve prolapse.