Crisscross heart with dextrocardia and intact interventricular septum.

Crisscross heart is a rare congenital heart disease characterized by a twisted atrioventricular connection, as a result of rotation of the ventricular mass along its long axis. We report an asymptomatic 48-year-old woman referred to us for evaluation of a cardiac murmur. Further evaluation showed situs solitus, dextrocardia with normal atrioventricular and ventriculoarterial connection, and a crisscross relation of the atrioventricular valves. Unlike the usual case of crisscross heart, our patient had an intact ventricular septum.

A 48-year old woman was referred to us for evaluation of cardiac murmur. Her chest skiagram showed dextrocardia [Figure 1a] and the electrocardiogram revealed a normal P-wave axis, right upper QRS axis. The transthoracic echocardiogram showed situs solitus and dextrocardia. She also had severe infundibular pulmonary stenosis and a hypoplastic right ventricle with intact interventricular septum [Figure 1b and c]. The atrioventricular and ventriculoarterial relationships were concordant. The left atrioventricular valve was normal, crossed behind the right valve, and opened to the morphological left ventricle, on the right side. The right atrium was dilated and opened through a narrow tricuspid valve into the trabeculated morphological right ventricle on the left side [Figure 1d–f and Video 1]. Cardiac magnetic resonance imaging (MRI) confirmed crisscrossing of the atrioventricular valves [Figure 2a–g].

Figure 1

(a) Chest X-ray PA view showing dextrocardia. (b) Color Doppler echocardiogram in a tilted right parasternal short axis view: Turbulent jet across the right ventricular outflow tract (RVOT) (arrow). (c) Continuous wave Doppler showing a peak right ventricular outflow gradient of 105 mmHg (arrow). (d) Transthoracic echocardiogram – right parasternal long axis view: Showing left atrium (LA) connected to the left ventricle (LV) through the left atrioventricular valve. Superior right ventricle (RV) and inferior right atrium (RA) also shown. (e) Transthoracic echocardiogram – tilted right parasternal long axis view: Showing a dilated right atrium connected to the right ventricle through the right atrioventricular valve (arrow). (f) Transthoracic echocardiogram – right parasternal short axis view: Showing the superior right ventricle and inferior left ventricle with a horizontal interventricular septum (IVS) (arrow)

Figure 2

Cardiac magnetic resonance images showing crisscrossing of atrioventricular valves (a), (b) Right atrium connected to the right ventricle (arrow). (c) Left atrium connected to the left ventricle (arrow). (d) Right atrium connected to the right ventricle (arrow). Left ventricle and aorta (Ao) are also shown. (e) Dilated right atrium connected to the right ventricle (arrow) in a sagittal cut section. (f) Ascending aorta (AA) arising from the left ventricle in a sagittal cut section. (g) Pulmonary artery (PA) arising from the right ventricle in a sagittal cut section. The ascending aorta, aortic arch (AoA), and descending aorta (DA) are shown.

An angiocardiogram revealed that the dilated right atrium connected to the morphological hypoplastic right ventricle on the left side, which subsequently connected to a posterior pulmonary artery, thus confirming the crisscross atrioventricular relationship. The left ventricular angiogram showed an intact interventricular septum [Video 2].

In a crisscross heart with normal atrial arrangement and concordant atrioventricular connections, the morphological right ventricle is situated to the left of the morphological left ventricle, implying a clockwise rotation of ventricles around an apex to base axis, as seen from the apex. When the atrioventricular connections are discordant with the normal atrial arrangement, then the morphological right ventricle is typically found to the right of morphological left ventricle, suggesting a counter clockwise rotation around the long axis. This unusual twisting of the ventricular mass, places the right ventricular inlet anterior and superior to the left ventricular inlet. On account of this rotation, the two inlets are placed superior-inferior rather than parallel to each other; this feature accounts for the inability to image two atrioventricular valves in the same plane simultaneously. Thus, the direction of rotation is clockwise in a normal heart and in complete transposition of the great vessels, whereas, the rotation is counterclockwise in the corrected transposition of the great vessels.[1]

On review of the literature, only 150 cases of crisscross hearts have been reported. Nearly all the cases had associated ventricular septal defect, with only 50% having pulmonary stenosis. Previously, cases of crisscross heart with intact ventricular septum have been reported by Fontes et al. and Alday et al.[23] Our case is unusual in that the patient had dextrocardia and an intact interventricular septum.