Living morphogenetic studies show that each definitive ventricle is constructed from different primitive cardiac segments, and each has its specific anatomical features. These ventricular segments are the atrioventricular junction; the primitive inlet segment, part of the primary heart tube, which initially provides the inlets of each ventricle; the primitive outlet segment, which gives rise to both ventricular outlets; and the apical trabeculated regions of the right and left ventricles which grow from the primary heart tube, respectively. In this review, we describe regional pathology based on the relationship of these primitive ventricular components. We propose that the abnormal morphogenesis of one of these segments gives origin to regional ventricular pathology. For example, abnormal embryogenesis of the atrioventricular canal produces malformations of the atrioventricular junctions, such as double inlet ventricle, absence of one atrioventricular connection, and straddling and overriding atrioventricular valves. Similarly, abnormal morphogenesis of the primitive outlet segment gives rise to malformations of the subarterial region of each ventricle, along with the valves guarding these vessels. The principal anatomical features of these malformations of the ventricular inlets and outlets are described, and their possible morphogenesis is discussed. Due to the fact that the apical trabeculated region of each ventricle arises from a separate primitive segment, each ventricle can be identified according to the pattern of its apical trabeculations. This feature is crucial in the elucidation of complex congenital pathology, such as discordant atrioventricular connections.

Introduction: The frequent occurrence of prenatal hypertrophy of the muscular ventricular septum has been widely reported in fetuses of diabetic mothers. Objectives: This experimental study was carried out to test the hypothesis that the weight of the heart, the ratio of the cardiac weight to that of the body, the thickness of the muscular ventricular septum, and the myocytic profile within the ventricular septum are all increased in fetuses of diabetic rats in comparison to fetuses of normal rats. Methods: Diabetes was induced in 5 pregnant Wistar rats, bearing 30 fetuses, on the eighth day after conception, by intraperitoneal injection of 50mg/kg of streptozotocin. Five normal pregnant Wistar rats, bearing 20 fetuses, made up the control group. Morphometric data were obtained by a computer-assisted method applied to the measurements of the thickness of the ventricular septum, and myocytic nuclear area. Statistical analysis utilized Student's t-test and Kruskal-Wallis test. Results: The mean thickness of the septum was 675.56 μm (± 159) in the control fetuses, and 904.39 μm (± 262) in the fetuses carried by diabetic mothers (p < 0.001). The cardiac weight was 0.016 g (± 0.004) in the control group, and 0.023 g (± 0.005) in the group of diabetic fetuses (p < 0.001). The ratio of cardiac to body weight was 0.294% (± 0.079) in the control group, and 0.514% (± 0.073) in the diabetic group (p < 0.001). The myocytic nuclear area was 14.70 μm2 in the control group, and 21.43 μm2 in the diabetic group (p < 0.001). Conclusions: The presence of cellular and morphologic cardiac hypertrophy in fetuses of diabetic rats was demonstrated by the significant difference between the two groups for each analyzed feature.

Aims: Coronary arterial abnormalities, congenital and acquired, may co-exist with structural congenital malformations of the heart. This study analyses information obtained from coronary angiography in grown-up patients with congenital cardiac disease undergoing cardiac catheterisation. Methods and Results: We studied 448 patients, of whom 181 (40%) had selective coronary angiography. This was undertaken as a routine measure in 165 (37%), and because of clinical indications in 16 (4%). Aortic root angiography was carried out in 107 (24%). Coronary arterial abnormalities were demonstrated in one-third of those undergoing selective angiography, and in 69% of those with a clinical indication for angiography, compared with 30% who had a routine procedure. In those patients undergoing aortography alone, abnormalities were recognized in 17%, while the angiographic images were inconclusive in 24%. In the remaining 59%, no abnormality was apparent, but only the proximal coronary arteries could be seen clearly. In total, congenital abnormalities of the coronary arteries were found in 11% of the patients, acquired lesions were demonstrated in 5%, and surgically acquired lesions in 2%. Conclusion: Routine coronary angiography during catheterization of grown-up patients with congenital heart disease revealed a high incidence of abnormalities of the coronary arteries. Selective injection into the arteries had a higher sensitivity than aortography. Consideration should be given to performing routine coronary arteriography during invasive investigation of patients with congenital cardiac disease, as it provides useful and often unexpected information, which may be valuable for the interpretation of symptoms and the planning of subsequent surgery.

Objective: Measurements of the variability in heart rate are increasingly used as markers of cardiac autonomic activity. We sought to establish the development this variability in healthy young infants while sleeping. Patients: We carried out polygraphic studies with electrocardiographic recording in 587 healthy infants aged from 5 to 26 weeks. Methods: We determined several variables over a period of 400 minutes sleeping: mean RR interval, 5 time-domain (SDNN, SDNNi, SDANNi, RMSSD, and pNN50) and 5 frequency-domain indexes (spectral power over 3 regions of interest, total power and low-to-high frequency ratio). Frequency-domain indexes were also assessed separately for the periods of quiet sleep and those of rapid eye movement sleep. Results: Our data showed a significant correlation between the indexes of heart rate variability and the mean RR interval, the breathing rate, and the corrected age of the infants. We also demonstrated the importance of the maturation of the sleeping patterns. Conclusion: These data in a large cohort of healthy infants confirm a progressive maturation of the autonomic nervous system during sleep, and may be used to examine the influence of physiological and pathophysiological factors on autonomic control during polygraphic studies.

Objective: To evaluate the origin of transient episodes of sinus bradycardia, atrial escape rhythm, and atrioventricular nodal escape rhythm in preterm infants. Material and methods: The study was observational, and was carried out in a third level neonatal intensive care unit. We studied 19 spontaneously breathing infants born healthy but prior to term, the examinations being carried out between the ages of 3 and 28 days. The mean gestational age was 29.2 ± 1.9 weeks, and the mean birth weight was 1154 ± 264 g. Transient episodes of bradycardia were defined as a decline in heart rate equal to or greater than 25% from baseline, lasting for at least 3 successive RR-intervals. To discriminate between different types of escape mechanisms, we used the P wave and the P axis of the electrocardiogram. Sinus bradycardia was diagnosed when the P axis was from +0 to +90 degrees; atrial escape rhythm when it was from +91 to +359 degrees, and atrioventricular nodal escape rhythm when the P wave was absent, hidden, or followed the QRS complex. Results: The mean P axis was +50 ± 11 degrees. We observed 60 transient episodes of bradycardia in 11 of the 19 infants. Of these, 34 (57%) were classified as sinus bradycardia, and 13 (22%) as atrial escapes. Atrioventricular nodal escapes developed during 6 episodes (10%), while 7 episodes (11%) could not be classified. Conclusions: Atrial excitation as evidenced by the P axis during sinus rhythm is similar in very preterm infants to that seen in children and adults. Escape rhythms with different origins occur during transient episodes of bradycardia in healthy preterm infants. In at least one third, the episodes are due to atrial or atrioventricul ar nodal escape.

Objective: Using a newly acquired archive of previously prepared material, we sought to re-examine the origin of the pulmonary vein in the human heart, aiming to determine whether it originates from the systemic venous sinus (“sinus venosus”), or appears as a new structure draining to the left atrium. In addition, we examined the temporal sequence of incorporation of the initially solitary pulmonary vein to the stage at which four venous orifices opened to the left atrium. Methods: We studied 26 normal human embryos, ranging from 3.8 mm to 112 mm crown-rump length, and representing the period from the 12th Carnegie stage to 15 weeks of gestation. Results: The pulmonary vein canalised as a solitary vessel within the mediastinal tissues so as to connect the intraparenchymal pulmonary venous networks to the heart, using the regressing dorsal mesocardium as its portal of cardiac entry. The vein was always distinct from the tributaries of the embryonic systemic venous sinus. The orifice of the solitary vein became committed to the left atrium by growth of the vestibular spine. During development, a marked disparity was seen between the temporal and morphological patterns of incorporation of the left-sided and right-sided veins into the left atrium. The pattern of the primary bifurcation was asymmetrical, a much longer tributary being formed on the left than on the right. Contact between the atrial wall and the venous tributary on the left initially produced a shelf, which became effaced with incorporation of the two left-sided veins into the atrium. Conclusions: The initial process of formation of the human pulmonary vein is very similar to that seen in animal models. The walls of the initially solitary vein in humans become incorporated by a morphologically asymmetric process so that four pulmonary veins eventually drain independently into the left atrium. Failure of incorporation on the left side may provide the substrate for congenital division of the left atrium.

Children with innocent murmurs are often referred to a paediatric cardiologist for diagnosis. The most common murmurs of early childhood are the so-called Still's murmurs, followed by ejection murmurs across the pulmonary or aortic vessels, and the venous hum. There also exists a high coincidence of murmurs with the presence of tendinous structures traversing the cavity of the left ventricle. In this report, we describe 6 patients who presented to our outpatient clinic with cardiac murmurs. None of them had abnormalities on the clinical examination, electrocardiographic, or echocardiographic investigation. They presented a similar murmur that was also audible over the back. On closer examination of the aorta with cross-sectional echocardiography, we discovered echogenic, tendinous structures crossing the lumen of the descending aorta or the aortic arch. Whilst we are not yet able to prove that the cords produced the innocent murmurs, the association is highly suggestive.

Infection with varicella zoster virus, leading to chicken pox in susceptible hosts, is usually a benign self-limiting disease conferring immunity in those affected. Cardiac complications are rare, but when present may lead to severe morbidity or mortality.

We have recently encountered three children, all of whom developed significant cardiac complications secondary to infection with varicella. Myocarditis has long been associated with such infection. The pathological mechanism is presumed similar to other cardiotropic viruses, where both direct cytopathic and secondary auto-immune effects contribute to myocardial cellular destruction and ventricular dysfunction. Complications include arrhythmias and progression to dilated cardiomyopathy.

Pericarditis, and secondary pericardial effusion, related to infection with the virus is most commonly associated with secondary bacterial infiltration. Both cardiac tamponade and chronic pericardial constriction may result.

Endocarditis complicating varicella has only been described in the last fifteen years, and is associated with the emergence of virulent strains of both streptococcus and staphylococcus, the two organisms most commonly associated with endocarditis. The exact mechanism by which varicella causes secondary bacterial endocarditis remains unclear.

Whilst cardiac complications of infection with the varicella zoster virus are rare, the resulting complications are potentially life threatening. Evidence of varicella-induced carditis must be aggressively pursued in any child with signs of acute cardiac decompensation in whom chicken pox is confirmed or suspected.

An 8-year-old girl, without any previous medical history, presented with a first short syncope. Physical examination was unremarkable. Transthoracic echocardiography revealed a thin-walled, echo-free cystic structure adjacent to the posterior wall of the left ventricle, and compressing it moderately. Other echocardiographic findings were normal. Both computed tomography and magnetic resonance imaging suggested a simple pericardial cyst, but during surgery we found an epicardial cyst with partial involvement of the circumflex branch of the left coronary artery. Cardiopulmonary bypass was necessary for successful resection of the cyst, leaving behind only the small area in continuity with the coronary artery.

A young woman with surgically treated tetralogy of Fallot with pulmonary atresia, with multiple aorto-pulmonary collateral arteries, developed an arteriovenous fistula subsequent to transvenous insertion of an automatic implantable defibrillator via the left subclavian vein. The fistula extended between this vein and a systemic-to-pulmonary collateral artery arising from the subclavian artery. Unilateral peau d'orange, and painful congestion of the left arm and breast, ensued. These were cured by coil embolization of a fistula-related aneurysm.

We report our experience of aortic valvar replacement subsequent to the arterial switch procedure, incorporating the Lecompte maneuver, in patients with complete transposition. The anterior wall of the neoaorta was incised in continuity with the posterior wall of the pulmonary trunk. The aortic root was reconstructed with or without augmentation using a patch after the operative procedures to the aortic valve. With this approach, the neoaortic root could readily be exposed without extensive dissection, and valvar replacement was safely achieved. These patients experienced no postoperative complications.

Cardiac rhabdomyoma represents the commonest primary cardiac tumour. Its natural history is generally favourable, with resolution in the majority of cases. Surgical resection has been described for intractable arrhythmia, severe obstruction of the inflow or outflow tracts sufficient to compromise cardiac output, and systemic embolization. We describe an alternative palliative strategy, which was associated with regression of the tumour.

A newborn infant with tetralogy of Fallot and absent pulmonary valve was successfully corrected in two stages. Absent pulmonary valve syndrome presenting in early infancy manifests severe respiratory symptoms that still make challenging both management and surgical treatment. This is ascribed to tracheobronchial compression by the extremely dilated pulmonary arteries, and to the resultant pulmonary obstructive lesions. We report herein the first findings of 99m Technegas ventilation lung scanning in an infant with the syndrome to assess the pulmonary obstructive lesions.

We describe a neonate with DiGeorge syndrome undergoing diagnosis and successful repair of interrupted right aortic arch and origin of the left pulmonary artery from the aorta. We discuss a link between this lesion and persistence of a left fifth arch.

We report a case of 2:1 atrioventricular block associated with acquired long QT syndrome. A newborn presented to our neonatal intensive care unit with intermittent bradycardia due to 2:1 atrioventricular block. Initial evaluation showed QT prolongation and significant electrolytic abnormalities. After correction of the electrolytic imbalance, the QT interval normalized and atrioventricular block resolved. Compared to congenital long QT syndrome with 2:1 atrioventricular block, acquired long QT syndrome with comparable atrioventricular block has a benign prognosis, provided treatment is initiated quickly.