Erik J. Meijboom

Dilated cardiomyopathy in isolated congenital complete atrioventricular block: early and long-term risk in children

OBJECTIVES We sought to identify the risk factors predicting the development of dilated cardiomyopathy (DCM) in patients with isolated congenital complete atrioventricular block (CCAVB). BACKGROUND Recently evidence has emerged that a subset of patients with CCAVB develop DCM. METHODS This was a retrospective study of 149 patients with CCAVB who had heart size and left ventricular (LV) function assessed by echocardiography and chest radiography over a follow-up period of 10 +/- 7 years. RESULTS Nine patients developed DCM at the age of 6.5 +/- 5 years. No definite cause could be identified. In these nine patients, CCAVB was diagnosed in eight at 23 +/- 2.3 weeks gestation and in one at birth. Maternal SSA/SSB antibodies were confirmed in seven of the nine patients. Pacemakers were implanted in eight patients in the first month and in one patient at five years of age. The initial left ventricular end-diastolic dimension (LVEDD) was in the 96th +/- 2.6 percentile and the cardiothoracic (CT) ratio was 64 +/- 3.8% in the nine patients who developed DCM, and differed significantly in patients with CCAVB (p < 0.005) who did not develop DCM. The LVEDD and CT ratio did not decrease in the patients with CCAVB and DCM, but decreased significantly in the patients with CCAVB without DCM (p < 0.001) once pacing was initiated. Two patients with DCM died within two months of diagnosis; one patient is neurologically compromised; two patients received a heart transplant; and four patients are listed for heart transplantation. CONCLUSIONS Isolated CCAVB is associated with a long-term risk for the development of DCM. Risk factors may be SSA/SSB antibodies, increased heart size at initial evaluation and the absence of pacemaker-associated improvement.

Amiodarone Therapy for Drug-Refractory Fetal Tachycardia

Background—Fetal tachycardia complicated by ventricular dysfunction and hydrops fetalis carries a significant risk of morbidity and mortality. Transplacental digoxin is effective therapy in a small percentage, but there is no consensus with regard to antiarrhythmic treatment if digoxin fails. This study evaluates the safety, efficacy, and outcome of amiodarone therapy for digoxin-refractory fetal tachycardia with heart failure. Methods and Results—Fetuses with incessant tachycardia and either hydrops fetalis (n=24) or ventricular dysfunction (n=2) for whom digoxin monotherapy and secondary antiarrhythmic agents (n=13) were not effective were treated transplacentally with a loading dose of oral amiodarone for 2 to 7 days, followed by daily maintenance therapy for <1 to 15 weeks. Digoxin therapy was continued throughout gestation. Newborns were studied by transesophageal pacing or ECG monitoring to determine the mechanism of tachycardia. Three fetuses were delivered urgently in tachycardia during amiodarone loading, and 3 required additional antiarrhythmic agents for sustained cardioversion. Amiodarone or amiodarone combinations converted 14 of 15 (93%) with reentrant supraventricular tachycardia, 2 of 2 with ventricular or junctional ectopic tachycardia, and 3 of 9 (33%) with atrial flutter. Amiodarone-related adverse effects were transient in 5 infants and 8 mothers. Mean gestational age at delivery was 37 weeks, with 100% survival. Conclusions—Orally administered amiodarone is safe and effective treatment for drug-refractory fetal tachycardia, specifically reentrant supraventricular tachycardia, junctional ectopic, or ventricular tachycardia, even when accompanied by hydrops fetalis or ventricular dysfunction.

Right ventricular dysfunction and pulmonary valve replacement after correction of tetralogy of fallot

BACKGROUND Correction of tetralogy of Fallot often leads to pulmonary regurgitation, sometimes warranting pulmonary valve replacement, for which indications and timing to achieve optimal results are not yet clear. This retrospective study describes follow-up and reinterventions in our tetralogy of Fallot population. METHODS Review of all consecutive patients operated on for tetralogy of Fallot between 1977 and 2000 was conducted. Included are date and type of repair, Doppler echocardiography (two-dimensional echocardiography), electrocardiographs, reoperations, and physical condition. RESULTS Total repair was performed in 171 patients at a mean age 1.9 +/- 2.5 years, follow-up time counted 9.6 +/- 7.0 years. Right ventriculotomy was used in 92%, and transatrial ventricular septal defect closure was used in 8%; 74% received a transannular outflow patch. Twenty-year survival was 91%. Last follow-up electrocardiographs showed right bundle branch block in 67% and serious arrhythmias in 11%. Two-dimensional echocardiography demonstrated severe pulmonary insufficiency and dilated right ventricle in 31% and 38%, respectively, increasing with postrepair age (p < 0.001). Poor clinical condition (New York Heart Association class II+) and echocardiographic proof of right atrial dilatation (p = 0.012) and arrhythmias (p = 0.03) were significantly associated. Furthermore, the influence of residual hemodynamic lesions, such as a remaining ventricular septal defect or pulmonary stenosis, or right ventricular dilatation was important (p = 0.04). Reintervention was necessary in 32 patients (19%; 10-year freedom, 83%), including angioplasty for residual stenosis and pulmonary valve replacement. At a mean age of 9.2 years after correction, 14 patients received a homograft, and 2 patients received a heterograft. In 7 patients the right ventricle returned to normal dimensions and symptoms disappeared. The incidence of right ventricular dilatation was considerably higher (p = 0.020) in patients with a transannular patch; the transatrial approach showed the opposite (p = 0.03), and patients presented with lower QRS duration (p = 0.007), although no difference could be found between survival after both surgical techniques. Effects of early timing (correction < 6 months) on right ventricular dysfunction could not be established. CONCLUSIONS Severe right ventricular dilatation and pulmonary regurgitation secondary to outflow tract repair in tetralogy of Fallot are frequently occurring sequelae developing slowly over time. Indications for pulmonary valve replacement remain controversial because echocardiographic findings or arrhythmias are not always accompanied by deterioration of clinical condition. However, right atrial dilatation and additional hemodynamic lesions demand increased vigilance. Transatrial repair is associated with a favorable outcome.

Sotalol in the Treatment of Fetal Dysrhythmias

BACKGROUND Fetal tachycardia may cause hydrops fetalis and lead to fetal death. No unanimity of opinion exists regarding the optimum treatment. This study evaluates our experience with transplacental sotalol therapy to treat fetal tachycardias in terms of safety and efficacy. METHODS AND RESULTS The charts of 21 patients who were treated with sotalol for fetal tachycardia were reviewed. Ten fetuses had atrial flutter (AF), 10 had supraventricular tachycardia (SVT), and 1 had VT. Hydrops fetalis was present in 9 fetuses. Drug treatment was successful in establishing sinus rhythm in 8 of 10 fetuses with AF and in 6 of 10 fetuses with SVT. The mortality rate in this study was 19% (4 of 21 fetuses; 3 had SVT and 1 had AF); 3 deaths occurred just days after the initiation of sotalol therapy, and 1 occurred after a dosage increase. At birth, tachycardia was present in 6 infants. Two patients who converted to sinus rhythm in utero suffered from neurologic pathology postnatally. CONCLUSIONS Fetal tachycardia is a serious condition in which treatment should be initiated, especially in the presence of hydrops fetalis. The high success rate in fetuses with AF suggests that sotalol should be considered a drug of first choice to treat fetal AF. The low conversion rate and the fact that 3 of the 4 deaths in this study occurred in fetuses with SVT indicate that the risks of sotalol therapy outweigh the benefits in this group and that sotalol should, therefore, be limited in the treatment of fetal SVT.

Atrial flutter in the perinatal age group: diagnosis, management and outcome

OBJECTIVES The aim of this retrospective study was to evaluate perinatal atrial flutter (AF) and the efficacy of maternally administered antiarrhythmic agents, postpartum management and outcome. BACKGROUND Perinatal AF is a potentially lethal arrhythmia, and management of this disorder is difficult and controversial. METHODS Forty-five patients with documented AF were studied retrospectively. RESULTS Atrial flutter was diagnosed prenatally in 44 fetuses and immediately postnatally in 1 neonate. Fetal hydrops was seen in 20 patients; 17 received maternal therapy, 2 were delivered and 1 was not treated because it had a severe nontreatable cardiac malformation. In the nonhydropic group of 24 patients, 18 were treated and the remaining 6 were delivered immediately. In the hydropic group, 10 received single-drug therapy (digoxin or sotalol) and 7 received multidrug therapy. In the nonhydropic group, 13 received a single drug (digoxin or sotalol) and 5 received multiple drugs. One patient with rapid 1:1 atrioventricular conduction (heart rate 480 beats/min) died in utero and another died due to a combination of severe hydrops because of the AF, sotalol medication, stenosis of the venous duct and hypoplastic placenta. Of the 43 live-born infants, 12 were in AF at birth. Electrical cardioversion was successful in eight of nine patients. No recurrences in AF have occurred beyond the neonatal period. Four patients with fetal flutter and hydrops showed significant neurological pathology immediately after birth. CONCLUSIONS Fetal AF is a serious and threatening rhythm disorder, particularly when it causes hydrops, it may be associated with fetal death or neurological damage. Treatment is required and primarily aimed at reaching an adequate ventricular rate and preferably conversion to sinus rhythm. Digoxin failed in prevention of recurrence at time of delivery in a quarter of our patients, whereas with sotalol no recurrence of AF has been reported, suggesting that class III agents may be the future therapy. Once fetuses with AF survive without neurological pathology, their future is good and prophylaxis beyond the neonatal period is unnecessary.

Treatment of fetal heart block with maternal steroid therapy: case report and review of the literature

The presence of maternal autoantibodies to SS‐A/Ro and/or SS‐B/La is associated with the development of fetal heart block. There are data suggesting that maternal treatment with steroids might reverse heart block. We report on a pregnancy in a mother with secondary Sjögren syndrome and systemic lupus erythematosus with presence of autoantibodies to SS‐A/Ro and SS‐B/La, which was complicated by the development of incomplete fetal heart block. Oral dexamethasone treatment could not prevent progression to complete heart block and was associated with a number of complications.

Fate of the aortic root after arterial switch operation

OBJECTIVE Concerns have been voiced about possible dilation and insufficiency of the neo-aortic valve after the arterial switch operation (ASO). AIMS To determine growth of the neo-aortic valve and the aortic anastomosis after ASO and the prevalence of insufficiency or stenosis. PATIENTS AND METHODS Since 1977, 144 consecutive patients (pts) underwent ASO for transposition of the great arteries (TGA). Median follow-up was 8.65 years (0.1--22.5 years). Simple TGA was present in 97 pts and 47 had TGA with ventricular septal defect (VSD). Detailed echocardiography included measurements of aortic diameter at four levels. The 608 measurements were compared with published normal values. RESULTS The mean aortic valve z-score was 1.5, without significant change with age (P=0.75). Under 4 months, mean valve z-score was 0.63+/-2.20, between 5 and 12 months 2.56+/-2.30 (P<0.0001). Gradual growth occurs thereafter. The aortic sinus follows an identical growth pattern. The aorta at the anastomosis, is initially smaller than normal (z-score -0.64). After 4 months the z-score is 0.83, followed by continued growth of 0.1 z-score per year. At the last visit, the aortic valve z-score was above 2 in 51 patients, between -2 and 2 in 72 and less than -2 in six patients, none of whom had a flow velocity above 2 m/s. z-score of patients with VSD remained above those without VSD (P<0.0001). Aortic insufficiency was grade 2/4 in three patients, grade 3/4 in one and grade 4/4 in one. No patient developed aortic stenosis. CONCLUSION After ASO the neo-aortic valve and sinus are larger than normal, representing the natural size difference in the prenatal situation and influence of associated cardiac malformations. In the first year of life, rapid dilatation of the new aorta is observed, followed by growth towards normalization of the valve and sinus size. Stenosis at the anastomosis was not observed. Aortic dilatation by itself is rarely associated with significant insufficiency.

Air Travel and Adults With Cyanotic Congenital Heart Disease

BACKGROUND Concern has been expressed that a reduction of partial oxygen pressure during flight in commercial aircraft may induce dangerous hypoxemia in patients with cyanotic congenital heart disease. METHODS AND RESULTS To evaluate the validity of this concern, the transcutaneous SaO2 was measured in 12 adults with this type of heart disease and 27 control subjects during simulated commercial flights of 1.5 and 7 hours in a hypobaric chamber. Ten of those patients and 6 control subjects also were evaluated during two actual flights of approximately 2.5 hours in a DC-10 and an A-310, respectively. During the prolonged simulated and actual flights, the capillary blood pH, gases, and lactic acid were analyzed in the patients and during one of the actual flights also in the control subjects. During the simulated flights the SaO2 was at all times lower in the patients than in the control subjects. However, the maximal mean actual percentage decrease, as compared with sea level values, did not exceed 8.8% in either patients or control subjects. During the actual flights, this maximal decrease in the patients was 6%. In-flight reduction of the capillary PO2 was considerable in the control subjects but not in the patients. It is our hypothesis that the lack of a significant decrease of the PO2 in the patients might possibly be due to a high concentration of 2.3 diphosphoglycerate in the red cells. The flights had no influence on the capillary blood pH, PCO2, bicarbonate, or lactic acid levels in either patients or control subjects. CONCLUSIONS Atmospheric pressure changes during commercial air travel do not appear to be detrimental to patients with cyanotic congenital heart disease.

Treatment of fetal tachycardia with sotalol: transplacental pharmacokinetics and pharmacodynamics

OBJECTIVES The aim of this study was to investigate the pharmacokinetics and pharmacodynamics of sotalol in the treatment of fetal tachycardia. BACKGROUND Maternally administered, intrauterine therapy of fetal tachycardia is dependent on the transplacental passage of the antiarrhythmic agent. METHODS In a prospective study of patients treated for fetal tachycardia with sotalol, concentrations of sotalol were determined in maternal and umbilical blood and in amniotic fluid, and the relationship between these concentrations and the occurrence of conversion to sinus rhythm was investigated. RESULTS Eighteen fetal patients were studied, nine with atrial flutter and nine with supraventricular tachycardia. Fourteen were treated with sotalol; 13 converted to sinus rhythm, of whom 2 relapsed. There was one intrauterine death. Four patients were treated with sotalol and digoxin, of whom two were treated successfully. Mean birth weight was 3,266 g. The daily maternal sotalol dose was linearly related to the maternal plasma concentration. The mean fetal/maternal sotalol plasma concentration was 1.1 (range 0.67 to 2.87, SD 0.63), and the mean amniotic fluid/fetal blood ratio of sotalol was 3.2 (range 1.28 to 5.8, SD 1.4). The effectiveness of sotalol therapy could not be extrapolated from maternal blood levels. CONCLUSIONS Sotalol is a potent antiarrhythmic agent in the treatment of fetal tachycardia. The placental transfer is excellent. Sotalol accumulates in amniotic fluid but not in the fetus itself. Therefore it seems that renal excretion in the fetus is efficient and greater than the oral absorption by fetal swallowing. The maternal blood level is not a reliable predictor of the chances of success of therapy. Sotalol is not associated with fetal growth restriction.

Drug Treatment of Fetal Tachycardias

The pharmacological treatment of fetal tachycardia (FT) has been described in various publications. We present a study reviewing the necessity for treatment of FT, the regimens of drugs used in the last two decades and their mode of administration.The absence of reliable predictors of fetal hydrops (FH) has led most centers to initiate treatment as soon as the diagnosis of FT has been established, although a small minority advocate nonintervention. As the primary form of pharmacological intervention, oral maternal transplacental therapy is generally preferred.Digoxin is the most common drug used to treat FT; however, effectiveness remains a point of discussion. After digoxin, sotalol seems to be the most promising agent, specifically in atrial flutter and nonhydropic supraventricular tachycardia (SVT). Flecainide is a very effective drug in the treatment of fetal SVT, although concerns about possible pro-arrhythmic effects have limited its use. Amiodarone has been described favorably, but is frequently excluded due to its poor tolerability. Verapamil is contraindicated as it may increase mortality. Conclusions on other less frequently used drugs cannot be drawn.In severely hydropic fetuses and/or therapy-resistant FT, direct fetal therapy is sometimes initiated. To minimize the number of invasive procedures, fetal intramuscular or intraperitoneal injections that provide a more sustained release are preferred.Based on these data we propose a drug protocol of sotalol 160mg twice daily orally, increased to a maximum of 480mg daily. Whenever sinus rhythm is not achieved, the addition of digoxin 0.25mg three times daily is recommended, increased to a maximum of 0.5mg three times daily. Only in SVT complicated by FH, either maternal digoxin 1 to 2mg IV in 24 hours, and subsequently 0.5 to 1 mg/day IV, or flecainide 200 to 400 mg/day orally is proposed. Initiating direct fetal therapy may follow failure of transplacental therapy.