Burchell, Howard B.

Thirty-three cases of corrected transposition of the great vessels are analyzed: 31 of corrected transposition in situs solitus, and two of corrected transposition in situs inversus. In 18 of these 33 cases, of which 64% were males, diagnosis was confirmed by necropsy or operation. There was no history of congenital heart disease in the families of any of these patients. The person whose sole anomaly is corrected transposition has no hemodynamic basis for symptoms. Symptoms are the result of associated lesions, the most common of which are anomalies of the left atrioventricular valve usually causing incompetence, ventricular septal defects, pulmonary valvular stenosis, and advanced disturbances of atrioventricular conduction. Physical findings in corrected transposition depend upon these associated defects. Noncardiac associated anomalies are rare. Anteroposterior thoracic roentgenograms may suggest the diagnosis, particularly when a narrow waist is present at the base of the heart, accompanied by the absence of a pulmonary-artery "knob" and the presence of an enlarged left atrium. Electrocardiographic features that should suggest corrected transposition are atrioventricular block (particularly 2:1 or complete heart block), abnormal P waves, absent or low R voltage in aVR, an initial Q wave in leads 3, aVR, aVF and V1, absence of a Q wave in lead V6, upright T waves across the precordium in children, and a clockwise spatial loop in the frontal plane. Cardiac catheterization may be diagnostic in this malformation when careful documentation is made of the location of the atrioventricular valves and their relation to the semilunar valves, together with the position of the great vessels in the anteroposterior and lateral views. Alteration of hemodynamics is secondary to associated malformations. Inability to enter the pulmonary artery during catheterization should arouse suspicion, and in these cases, particularly, angiocardiography can be diagnostic. The decision as to whether the most frequently associated malformations exist as isolated entities, or whether they are present in combination with corrected transposition, appears to be the main differential problem–together with the differentiation of corrected transposition with associated cyanosis from complete (that is, uncorrected) transposition. Surgical treatment of corrected transposition has been difficult because of complete atrioventricular block before or after operation, residual incompetence when deformed left atrioventricular valves were present, and the mirror-image arrangement for the coronary arteries. The most common cause of death was cardiac failure, often with a terminal bout of pulmonary edema. The average age at death in this series was about 14 years, with a median age at death of about 4 years. A review of the literature again emphasizes the association of corrected transposition with some degree of atrioventricular block evidenced on the electrocardiogram. The most frequently reported associated cardiac lesions were ventricular septal defect, pulmonary stenosis or atresia, patent ductus arteriosus, and dextrocardia. The incidence of anomalies of the left atrioventricular valve in these reported cases has probably been underestimated.

A total of 696 patients with atrial septal defect (ASD) of either the secundum (90.5%) or the sinus venosus (9.5%) type were operated on at the Mayo Clinic from 1954 through 1965. Pulmonary hypertension (PHT, defined as pulmonary artery systolic pressure of 60 mm Hg or greater) or chronic congestive cardiac failure (CCF) (or both) was associated with 80% of the hospital deaths. For the years 1958 through 1965 (531 cases), the hospital mortality for these three groups was 10% (three of 30), 14% (one of seven), and 18% (two of 11), respectively; only two (0.4%) of the remaining 483 patients died, and both were more than 45 years old (among a total of 93 patients more than 45 years old). There have been no operative deaths among those less than 45 years of age and without PHT or CCF (390 cases) in the years 1958 through 1965. No operative deaths occurred in the years 1963 through 1965. Of 16 patients 60 years or older (1954 through 1965), one has died. A 6- to 12-year follow-up was possible on 397 patients operated on from 1954 through 1960. In the absence of PHT or CCF, 330 survived operation. Among the 53 patients more than 45 years old, four died later (not definitely related to closure of ASD), three were not well, 32 were in excellent health, and 14 were lost to follow-up in 1966. Among the 277 patients less than 45 years old, 10 died later (all but one probably unrelated to closure of ASD), three were unwell, 186 were in excellent health, and 78 were lost to follow-up in 1966. Forty-two patients with PHT survived operation in the period from 1954 through 1960. Ten had pulmonary resistance of more than 640 dynes sec cm -5 ; four of these were well, two had died (with PHT), two had severe PHT, one was in CCF, and one was moderately disabled. Thirty-two had pulmonary resistances of 640 dynes sec cm -5 or less; three of these had died (unrelated to closure of ASD), five were moderately disabled, 16 were in excellent health, and eight were lost to follow-up in 1966. Eighteen patients with CCF survived operation in the period from 1954 through 1960. All had had grade IV disability (New York Heart Association classification). There were three late deaths (one due to severe pulmonary vascular disease and two unrelated to closure of ASD), one patient had grade IV disability, five had grades I to II disability, eight were in excellent health, and one was lost to follow-up in 1966. Paroxysmal arrhythmia occurred in 75 of 397 patients (19%) operated on from 1954 through 1960. In 53 patients it was present preoperatively and persisted postoperatively in 15 of them (28%); in an additional 22 it appeared for the first time after closure of the ASD.

The status of 58 patients, 3 to 57 years of age, with ventricular septal defect and a marked increase in pulmonary vascular resistance (pulmonary obstructive disease) was determined 5 years or longer after diagnostic catheterization. Forty-six (80%) were alive 5 years after that study. The probability of living 5 years was 95% for patients aged 10 through 19 years and 56% for those 20 years of age or older. The dissimilarity of actuarial curves between these two groups is consistent with the hypothesis that pulmonary vascular obstructive disease develops under age 20. Calculated pulmonary resistance increased with age of patient on admission to the study, suggesting its progressive nature. Hemoptysis was rare under age 20, and its presence over this age indicated a poor prognosis. The most common causes of death were "sudden" or "unknown." Most surviving patients were gainfully employed or attending school without severe symptoms.

A patient with an atrial septal defect, paroxysmal tachycardia, and the Wolff-Parkinson-White syndrome (type B) had epicardial exploration to determine the nature of the excitation anomaly. Right bundle-branch block in association with the WPW syndrome (type B) was evidenced by the late activation (0.12 sec) of the epicardium over the outflow tract of the right ventricle. Early activation of the base of the right ventricle (near the atrioventricular groove at the right border of the heart) was interpreted as indicating an actively conducting atrioventricular muscle bridge (bundle of Kent) in this region. During paroxysms of tachycardia, the ventricular area excited much later than when sinus mechanism was present, and the adjacent right atrium was excited in sequence. This sequence supported the concept of a circus movement, that is, movement from atrium to ventricle via atrioventricular bundle (His) and ventricle to atrium via a muscle bridge (Kent). Injection of procaine into the base of the right ventricle abolished the pre-excitation of the ventricle.