Accelerated idioventricular rhythm in newborns: a worrisome but benign entity with or without congenital heart disease.

Broad QRS rhythms (fast and slow) are worrisome findings in newborns. We present five cases with varied clinical presentations found to have broad QRS tachycardias, consistent with idioventricular rhythms. Each patient had an excellent prognosis because the tachycardias resolved, and eventually the patients were in sinus rhythm. None were symptomatic from their arrhythmia. It is important to establish the diagnosis when it occurs to differentiate this benign phenomenon from dangerous ventricular tachycardia.

Effect of palliative and corrective surgery on ventricular volumes in complete atrioventricular canal.

The effect of pulmonary artery banding (PAB) and intracardiac repair on ventricular volumes was studied in 35 patients with uncomplicated complete atrioventricular canal (CAVC). Right ventricular (RV) and left ventricular (LV) end-diastolic volumes (EDV), determined from biplane cineangiograms using Simpson's rule, were expressed as a percent of normal mean (% Nl) for body surface area; normal range (mean +/- 1SD) is equivalent to 75%-125% Nl. In preoperative studies (RV 26, LV 33), EDV averaged 149 +/- 51% and 184 +/- 50% Nl, respectively, P vs Nl less than 0.001 for both. In one of 26 patients, RV was very small (45% Nl), and one of 33 had a small LV (70% NI). In 13 patients studied post-PAB, RVEDV and LVEDV were lower than in the preoperative group (P less than 0.001) and averaged 114 +/- 40% and 126 +/- 52% Nl, respectively. In three of 13, RV was small (67% and 71% Nl) or very small (56% Nl). Three others had a small (71% and 67% Nl) or very small (56% Nl) LV. In serial pre- and post-PAB studies (RV 9, LV 11), EDV was increased or normal in all preoperatively. In seven of nine, RVEDV decreased, falling below normal range in three. In eight of 11, LVEDV decreased, falling below normal in three. Following repair, RV and LVEDV averaged 80 +/- 20% Nl and 126 +/- 23% Nl, respectively, in seven patients. Four of the seven had RVEDV below normal range. Two patients with a small ventricle had intracardiac repair and did well.(ABSTRACT TRUNCATED AT 250 WORDS)

Etiology of atrioventricular-conduction abnormalities following cardiac surgery.

Atrioventricular-nodal-conduction abnormalities following cardiac surgery have been attributed to the potassium ion in cardioplegic solutions. To clarify the etiology of these rhythm problems, 15 dogs were subjected to (I) 60 min 4 degrees C potassium cardioplegic arrest; (II) 30 min normothermic ischemic arrest; or (III) cardiac hypothermia without ischemia. In sinus rhythm and during atrial pacing, A-H and H-V intervals, Wenckebach cycle length (WCL), atrial- and AV-nodal refractory periods (ARP and NRP) were measured at 37 degrees C before and 30 min after arrest (groups I and II) and at various myocardial temperatures (group III). Following cardioplegic arrest and reperfusion, all AV-nodal-conduction properties were unchanged from preischemic values. In contrast, unprotected ischemia significantly prolonged AV-nodal-conduction time (P less than 0.01) and myocardial hypothermia resulted in prolonged WCL (P less than 0.01), prolonged functional NRP (P less than 0.05), in addition to delayed A-H interval (P less than 0.05). The data suggest that properties of AV-nodal conduction are preserved following potassium cardioplegic arrest, but impaired by ischemic injury or persistent local cardiac hypothermia.

Pathologic measurements in aortic atresia.

Detailed autopsy measurements were performed in 13 infants with hypoplastic left ventricle and aortic atresia. Emphasis was placed on the evaluation of changes in the right ventricle, since its function may be important in determining surgical survival. Other important aspects were the ascending aortic and transverse aortic arch diameter, the presence of left atrial obstruction, and the size of the left atrium. The development of improved 2DE and Doppler imaging will permit preoperative and sequential evaluation of these parameters. Measurements performed in this study may serve as a basis for selection of infants for palliative surgery; these procedures are being undertaken more frequently in this hitherto fatal lesion. The measurements may also serve as a basis for noninvasive serial studies of these infants postoperatively.

Efficacy of pulmonary artery banding in infants with complete atrioventricular canal.

Total correction in infants less than 1 year old with complete atrioventricular (AV) canal carries a significant operative mortality. However, past reports suggest that the alternative palliative procedure, pulmonary artery banding (PAB), may be contraindicated in the presence of severe mitral insufficiency and/or a large left ventricular to right atrial shunt. Contrary to these previous reports, we report the results in 21 consecutive patients with congestive heart failure who underwent PAB at a mean age of 3.9 +/- 2.8 months and at a weight of 3.6 +/- 0.9 kg. (17/21 less than 6 months). Regardless of mitral valve competency, PAB was performed in conjunction with ligation of a patent ductus arteriosus (11 patients) and coarctation repair (two patients) with one death secondary to gastrointestinal bleeding (4.7% in-hospital mortality); one patient required early band readjustment because of hypoxemia. Repeat cardiac catheterization in 10 patients performed 4 to 41 months after PAB showed significant reduction in pulmonary hypertension and flow with no change in pulmonary vascular resistance. All infants were symptomatically improved after PAB and four have undergone successful total correction. Previous reports since 1977 indicate a significantly higher risk for total repair of complete A V canal before 1 year of age (36/147, 24%) than the risk for PAB in this series (p less than .05). Therefore, we believe that PAB is a rational alternative to total repair as the initial surgical treatment for symptomatic infants with complete A V canal, particularly when anatomic variants known to increase operative risk are recognized before cardiotomy.

Quantitative angiographic and morphologic aspects of aortic valve atresia.

Quantitative angiographic measurements were performed in 15 infants aged 1 to 35 days who had aortic valve atresia with intact ventricular septum and hypoplastic left ventricle. Thirteen infants had similar measurements performed at autopsy. The latter measurements were smaller than those found at angiography (because of shrinkage), but their relationship was predictable. Angiographic right ventricular (RV) volumes were 2 and 4 times normal in diastole and systole, respectively. The RV volume measured at autopsy was greater than 3 times normal. Mean RV ejection fraction was 0.40; it was below normal in 10 infants. Maximal right atrial volume was greater than 2 times normal, and mean left atrial maximal volume was two-thirds normal. The relation between circumferences of the aortic arch and ascending and descending aorta was similar at angiography and autopsy.

Prostaglandin E1 infusion in newborns with hypoplastic left ventricle and aortic atresia.

Prostaglandin E1 (PGE1) infusion was used in 7 infants with hypoplastic left ventricle and aortic atresia. Of 5 non-operated patients, 4 died shortly after the onset of PGE1 infusion and 1 survived for 30 hours. Of the infants who had surgery, 1 died during the operation and 1 survived for 38 days. In 6 infants, a transient metabolic and/or circulatory improvement could be demonstrated following PGE1 infusion. The lack of response of other infants may be related to the advanced deterioration of their clinical status at the time of study. In the light of recent surgical developments for infants with aortic atresia, support with PGE1 may nevertheless play an important role in their management if started early.

The conduction system in Pompe's disease.

We report our findings in the microscopic examination of the conduction system in four infants with glycogen storage disease, one of whom had adequate electrophysiologic studies. The electrophysiologic studies in the latter case showed P-A and A-H intervals at the lower limits of normal, but the H-V interval was just above the normal mean. This suggests that the rapid conduction was not localized in the anatomic counterpart of the H-V interval. The short P-R interval in the ECG may be related to the enlargement of cells, which may in turn be related to increased glycogen content. The relationship of glycogen per se to the speed of conduction is unknown. We found that the summit of the ventricular septum bulged, probably because of the generally increased cell size, and that the topography of the atrioventricular conducting system was different from normal. This is possibly related both to an increase in the cell sizes of the specialized conducting tissue itself and to deforming effects of this bulging summit of the ventricular septum. New microscopic details of the components of the conducting system are described in these cases.

Interrupted aortic arch operation in the first week of life: hemodynamic and angiographic evaluation one year later.

Operation for interrupted aortic arch (IAA) was successful in 2 infants during the first week of life. Both had postoperative hemodynamic and angiographic evaluation at one year of age. The first infant had a type A IAA, and prostaglandins were infused to prevent ductal closure prior to the insertion of a graft between the two ends of the interrupted aorta. The second infant had a palliative operation for type B IAA (pulmonary artery banding and graft from main pulmonary artery to descending aorta). These patients represent the ninth and tenth successful operations for IAA in this age group and are reported with long-term reevaluation.

Double outlet right ventricle with subvalvular aortic stenosis.

A case of double outlet right ventricle had progressive muscular subvalvular aortic stenosis unrelated to the ventricular septal defect. Ventricular systolic pressures were identical and higher than aortic, and the gradient was within the right ventricle. Selective angiocardiography showed a hypertrophied subaortic conus obstructing the right ventricular outlet. Serial haemodynamic and angiographic studies revealed progression of the subaortic stenosis which may have been related to an earlier pulmonary artery banding operation. Distal conal hypertrophy is postulated as the cause of the obstruction.

Correlation of angiographic and autopsy left ventricular dimensions in children.

To evaluate controlled pressure coronary artery perfusion fixation of hearts as a means of obtaining meaningful cardiac measurements at autopsy, left ventricular (LV) autopsy measurements were correlated with in vivo end-diastolic (D) and end-systolic (S) angiographic (angio) values from biplane cineangiograms in the same patients. Mitral (MV) and aortic valve (AV) circumferences, LV equatorial circumference (Circ), spatial inflow and outflow lengths, wall thickness (W) and LV volume (Vol) were measured in 34 children with congenital heart disease. All dimensions showed significant correlation of angiographic and autopsy data from which linear regression equations were derived. The r values obtained were: MV 0.74; AV 0.85; D Circ 0.83; S Circ 0.82; D inflow 0.92; S inflow 0.90; D and S outflow 0.96; W 0.78; D Vol 0.92; S Vol 0.86. Mean angio and autopsy values were not significantly different for AV, S inflow, and S Vol. Autopsy values were lower than all D angio values and MV (P less than 0.001 for all), and higher than angio W and S outflow (P less than 0.001 for both). The data show that changes of LV morphology with this fixation method are predictable, making estimation of in vivo values from autopsy measurements possible using the derived linear regression equations.

Right aortic arch, right patent ductus arteriosus, and mirror-image branching of the brachiocephalic vessels.

Two patients with a right aortic arch, right patent ductus arteriosus, and mirror-image branching of the brachiocephalic vessels are described. The clinical, angiographic, and surgical findings in these two cases are detailed, and a description of the embryologic basis for these anomalies is given.

Right and left ventricular volume characteristics in common atrioventricular canal.

Right (RV) and left (LV) ventricular volume characteristics were determined from biplane cineangiography in 29 patients with atrioventricular canal (AVC). The patients were classified into two groups: group I (N = 19), uncomplicated AVC; group II (N = 10), AVC associated with RV obstruction. In group I, LV end-diastolic volume (EDV) [177 +/- 9 (SEM)% of normal] and RVEDV (125 +/- 9%) both were greater than normal (P is less than 0.001 and less than 0.01, respectively). LV ejection fraction (EF) was decreased (0.59 +/- 0.02, P is less than 0.001) but RVEF was normal (0.58 +/- 0.03). LV stroke volume index (SVI) was increased (48 +/- 3 ml/m2, P is less than 0.005), and RVSVI was normal (34 +/- 3 ml/m2). One patient had a markedly small RVEDV (45%). In group II, LVEDV and RVEDV were not different from normal (119 +/- 11% and 97 +/- 15%, respectively). LVEF was depressed (0.52 +/- 0.04, P is less than 0.001) and RVEF was normal (0.55 +/- 0.05). LVSVI was normal (38 +/- 5 ml/m2) and RVSVI was slightly decreased (29 +/- 4 ml/m2, P is less than 0.025). Two patients had a markedly small RVEDV (31%, 55%). EDV correlated with the pulmonary-to-systemic flow ratio (LV, r = 0.71; RV, r = 0.68). The data show that in most patients with AVC, LV and RV are enlarged in the uncomplicated form but not in the form with RV obstruction. LV function is more compromised than RV in both groups. RV hypoplasia is rare but was documented in both uncomplicated forms and forms with RV obstruction.

A new prenatal cardiac diagnostic device for congenital heart disease.

A unique case of congenital heart disease and complete heart block diagnosed by fetal electrocardiogram (ECG) and phonocardiogram recorded initially at 32 weeks gestation is presented. The slow, regular fetal heart rate of approximately 50 beats/min with bizarre QRS and a diamond-shaped murmur beginning with the fetal QRS complex made a diagnosis of complete heart block (CHB) and associated congenital heart disease highly probable. Direct fetal electrocardiograms (FECG) recorded during labor and vaginal delivery at term confirmed the diagnosis of completel atrioventricular block. Cardiac catheterization at 1 day of age showed multiple congenital heart anomalies. The infant developed signs of congestive heart failure and transvenous pacemaker was successfully placed; however, he died at 9 days of age of sepsis and renal failure.

Bradycardia preceding apneic attacks in low-birthweight infants. The relationship and management.

Two premature infants had frequent episodes of prolonged apnea. The apneic spells were not due to the more commonly known causes of apnea in infancy, but were consistently preceded by severe bradycardia. Atropine or ephedrine produced favorable therapeutic results. Since severe bradycardia may be a cause of sudden death in infants, its recognition and treatment is important in the management of apneic infants.

The influence of age on cardiac refractory periods in man.

As age is a determinant of cardiac refractory periods, this communication describes changes of refractory periods in an age continuum of infants, children and adults, 7 months through 77 years. Seventy patients with evidence of normal A-V conduction on scalar electrocardiogram were included. The patients were divided into six age groups: less than 2 years, 3-5 years, 6-10 years, 11-15 years, 16-30 years, and greater than 30 years. Extrastimulus technique was used to determine refractory periods in sinus rhythm or at longest cycle length assuring atrial capture, then at shorter cycle lengths. Cycle lengths (CL) for each age group were divided into ranges: CL1, 1,000-600 msec; CL2, 599-460 msec; CL3, less than 459 msec. Refractory periods at the three CL's within each age group were determined. Full recovery times of the A-V node within groups of children were determined. Statistical significance of the data was found by analysis of variance. The younger group tended to have shorter values than the older groups (F less than 0.05-0.001).