DEXTROCARDIA

From Big Medical Encyclopedia

DEXTROCARDIA (dextrocardia; lat. dexter right + Greek kardia heart) — anomaly of development (allotopia) which is characterized by an arrangement of the most part of heart in a thorax to the right from the centerline of a body. Distinguish uninsulated D. — at a full return arrangement of internals — situs viscerum inversus totalis (see Transpozition of bodies) and the isolated D. Izolirovannaya D. differs from uninsulated in normal position of a stomach, liver, spleen. Distinguish a form from the isolated D. with inversion of auricles and ventricles (synonym: mirror, true, uncomplicated.) and without inversion of cardial cavities (synonym: dextroversion, dekstrotorziya, dekstrorotation of heart, axial.). At mirror D. there are no deviations in the state of health usually, inborn heart diseases meet, unlike dextroversion, only a little more often than at a usual arrangement of heart. In the absence of the accompanying heart diseases both forms D. do not cause essential disturbances of a hemodynamics. Distinguish a dextrocardia from D., at a cut it mechanically moves to the right half of a thorax under the influence of extracardiac factors (a right-hand atelectasis or a pneumofibrosis, a left-side pleural exudate and t. II.).

Forms in the first weeks of pre-natal development. Its origins are unknown. The isolated D. meets seldom. According to Court and Schmidt (S. of Korth, J. Schmidt, 1955), only in 12 of 1000 cases of D. did not note the return arrangement of all internals.

At mirror D. venas cava are located at the left and bring blood to the right auricle which is also located at the left and several kpereda from the left auricle (designation of departments of heart the terms «right» and «left» at D. is conditional). The right ventricle with a coming from pulmonary trunk it is in front.

Fig. 1. The electrocardiogram at a dextrocardia: tooth of PI negative; PaVR — izoelektrichen; PaVL — negative; amplitude of teeth of R and S decreases from V1 to V6; TaVR — izoelektrichen; TaVL — negative. For a dextrocardia patognomonichno specular reflection of the normal ECG in assignments of I and aVL, change of ratios of amplitudes of teeth in assignments of II and III. On the right the electrocardiogram of the person at a normal arrangement of heart.

Pulmonary veins bring blood to the right lying left auricle, a cut is reported with the left ventricle located behind. The ascending department of an aorta which lies at the left and kzad from a pulmonary artery departs from a left ventricle. The cardiac impulse is defined from a breast to the right, cardiac sounds are more sonorous also to the right of a breast. On an ECG at mirror D. negative teeth of P in assignments of I and aVL, in assignment of aVR all teeth positive come to light, assignment of aVL reminds normal aVR, signs of the II assignment correspond to signs of normal III assignment and vice versa. In chest assignments the voltage of QRS increases from V1R to V6R and decreases from V1 to V6 (fig. 1).

Dextroversion of heart meets more often other forms D. Interposition of heart cameras and the main vessels at uncomplicated dextroversion normal, however in most cases dextroversion is combined with inborn heart diseases (defects or lack of partitions, a transposition of an aorta and a pulmonary trunk, a stenosis of a pulmonary trunk or an atresia of its valves etc.) and is frequent with malformations of a spleen (a lobular or multiple spleen, agenesias of a spleen).

The apical beat at dextroversion is found at the basis of a xiphoidal shoot on the right (if the top is not closed by a breast). The Auskultativny picture is defined by the accompanying defect. On an ECG in the I standard and in the left chest assignments the tooth of P positive, is noted increase in a voltage of the QRS complex from V6R to V1-2 with the subsequent decrease to V6.

Fig. 2. The roentgenogram of a thorax at a mirror dextrocardia. On the right above — the scheme of the roentgenogram with normally located heart (the arrow specified a gas bubble of a stomach).

In D.'s recognition radiodiagnosis has independent value. At mirror D. rentgenol. the research in a direct projection shows that heart is more located in the right half of a thorax and is turned around an anatomic axis on 180 °. At the same time the mirror image of cardial cavities and the main vessels (fig. 2) is defined. The top of heart is formed by a left ventricle and located on the right. The left auricle participates in formation of the right contour of heart and its top. The right auricle and a ventricle are projected to the left of a breast. The aortic arch passes not through left, and through the right bronchial tube. The descending aorta is located to the right of a backbone. The ascending aorta and a shadow of an upper vena cava are projected at the left, and the arch of a pulmonary trunk is visible on the right. Thus, at mirror D. the left border of heart is formed by two arches — the ascending aorta and the right auricle. The right border of heart consists of four arches — aortas, a pulmonary trunk, the left auricle and a left ventricle.

At reception of a baric suspension during roentgenoscopy in a direct projection the impression on the right contour of a gullet formed by an aortic arch is defined.

At a research in the right slanting situation rentgenol, the picture corresponds to the left slanting situation at a normal arrangement of heart, i.e. the back contour is formed by a left ventricle and an auricle, and front — the right cameras of heart.

Therefore for definition of extent of increase in ventricles of heart at D. the patient should be investigated in the right slanting or right side situation.

At a research in the left slanting situation the contour of heart corresponds to a contour at a projection of usually located heart in the right slanting situation. At the same time the contrasted gullet passes on a back contour of the left auricle located kranialny and partially comes for a contour of the right auricle located kaudalny.

If D. is not combined with heart diseases, then cameras of heart at rentgenol. a research are defined as not changed. At D.'s combination to other pathology of heart it is so deformed that usual X-ray inspection becomes insufficient for the diagnosis and the nature of pathology is specified with the help angiocardiography (see).

Rentgenol, a picture of dextroversion differs in the fact that the top of heart, edges, as well as at mirror D., is turned to the right, is formed by a right ventricle. Heart at the same time is turned around a longitudinal axis to the right. The left ventricle is located from a right ventricle to the left. Auricles and ventricles are located normally.

H. R. Paleev; And. X. Rabkin (rents.).

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