Electrophysiologic study and radiofrequency ablation in patients with intracardiac tumors and accessory pathways: is the tumor the pathway?

Effect of different dose regimens of everolimus in a series of neonates with giant cardiac rhabdomyomas

Everolimus is a mTOR inhibitor that has been increasingly used in high-risk cardiac rhabdomyomas in recent years. There are questions regarding the optimal dose and duration of therapy with everolimus for cardiac rhabdomyomas. The purpose of this study was to examine retrospectively the dosage-efficacy relationship in seven babies diagnosed with rhabdomyoma treated with different everolimus dose regimens retrospectively. Cardiac rhabdomyoma diagnosis was made in six of seven babies during the prenatal period. Indication of everolimus was an obstruction in six patients and supraventricular tachycardia which is resistant to antiarrhythmic drugs in the remaining one patient. The median age was 8 days (range; 2-105 days) at the time of starting everolimus. It was administered at a dose of 0.25 mg twice a day for two days a week in four patients; 0.1 mg/day in two and 0.4 mg/day in one patient. Serum everolimus level was kept between 5 and 15 ng/ml. All seven cases showed significant regression of cardiac rhabdomyoma within four weeks, and supraventricular tachycardia was controlled in two weeks after everolimus administration.This study demonstrates that everolimus was effective in accelerating regression of the cardiac rhabdomyoma. Dose with 2 × 0,25 mg/day, 2 days a week, seems appropriate. However, lower doses such as 0.1 mg/day are also effective. But dose adjustment should be made according to serum level monitoring.

Innovative Strategies for the Management of a Massive Neonatal Rhabdomyoma

Rhabdomyomas are histologically benign tumors known to be associated with tuberous sclerosis. The natural history predicts the majority of tumors to be asymptomatic and regress within the first year of life. We describe a neonate presenting on day 1 of life with cardiovascular collapse secondary to a massive rhabdomyoma. Surgical resection was excluded due to the extensive nature of the lesion and oral sirolimus, a mammalian target of rapamycin inhibitor, was commenced to promote tumor regression. The patient developed intractable arrhythmias requiring extracorporeal life support during therapy.

Fetal arrhythmias associated with cardiac rhabdomyomas

BACKGROUND

Primary heart tumors in fetuses are rare and mainly represent rhabdomyomas. The tumors have a variable expression and can be associated with arrhythmias, including both wide and narrow QRS tachycardia. Although multiple Doppler techniques exist to assess fetal heart rhythm, it can be difficult to record precise electrophysiological abnormalities in fetal life.

OBJECTIVE

Investigations defining precise electrophysiological diagnosis were performed by using fetal magnetocardiography (fMCG).

METHODS

In addition to routine fetal echocardiography, fMCG was used to investigate electrophysiological rhythm patterns in a series of 10 fetuses with cardiac rhabdomyomas.

RESULTS

The mean gestational age of the fetuses was 28.6 ± 4.7 weeks. The multiple rhabdomyomas were mainly located in the right and left ventricles as well as around the atrioventricular groove. Arrhythmias or conduction abnormalities were diagnosed in all 10 patients, although only 6 of them were referred due to that indication. Remarkably, 80% (8 of 10) had associated Wolff-Parkinson-White pre-excitation. In addition, we found prominent P waves in 4 fetuses.

CONCLUSION

In fetuses with rhabdomyomas, a disease where rhythm pathology is common, precise electrophysiological diagnosis can now be made by fMCG. fMCG is complimentary to echocardiography for rhythm assessment and can detect conduction abnormalities that are not possible to diagnose prenatally with M-mode or pulsed Doppler ultrasound. Risk factor assessment using fMCG can support pregnancy management and postnatal treatment and follow-up.

Incessant ventricular tachycardia due to multiple cardiac rhabdomyomas in an infant with Tuberous Sclerosis

We report a case of incessant ventricular tachycardia managed successfully with medications. The transthoracic echocardiogram showed multiple cardiac rhabdomyomas involving ventricular free wall and outflow tracts. Computerized tomography of brain showed multiple subependymal tubers confirming Tuberous Sclerosis. The follow up assessment showed sinus rhythm and regressing cardiac rhabdomyomas.

Considerations for prenatal counselling of patients with cardiac rhabdomyomas based on their cardiac and neurologic outcomes

Cardiac rhabdomyomas are benign cardiac tumours with few cardiac complications, but with a known association to tuberous sclerosis that affects the neurologic outcome of the patients. We have analysed the long-term cardiac and neurological outcomes of patients with cardiac rhabdomyomas in order to allow comprehensive prenatal counselling, basing our findings on the records of all patients seen prenatally and postnatally with an echocardiographic diagnosis of cardiac rhabdomyoma encountered from August, 1982, to September, 2007. We analysed factors such as the number and the location of the tumours to establish their association with a diagnosis of tuberous sclerosis, predicting the cardiac and neurologic outcomes for the patients.Cardiac complications include arrhythmias, obstruction of the ventricular outflow tracts, and secondary cardiogenic shock. Arrhythmias were encountered most often during the neonatal period, with supraventricular tachycardia being the commonest rhythm disturbance identified. No specific dimension or location of the cardiac rhabdomyomas predicted the disturbances of rhythm.The importance of the diagnosis of tuberous sclerosis is exemplified by the neurodevelopmental complications, with four-fifths of the patients showing epilepsy, and two-thirds having delayed development. The presence of multiple cardiac tumours suggested a higher risk of being affected by tuberous sclerosis. The tumours generally regress after birth, and cardiac-related problems are rare after the perinatal period. Tuberous sclerosis and the associated neurodevelopmental complications dominate the clinical picture, and should form an important aspect of the prenatal counselling of parents.

Neonatal rhabdomyoma causing right ventricular inflow obstruction with duct-dependent pulmonary blood flow: Successful stenting of PDA

We describe an infant with the antenatal diagnosis of a large intracardiac rhabdomyoma causing tricuspid inflow obstruction. Postnatal cyanosis and arterial hypoxemia prompted commencement of intravenous prostaglandin E1 with immediate improvement in saturations. Clinical and genetic testing confirmed diagnosis of tuberous sclerosis. To secure ductal patency, two tandem coronary stents were implanted via an antegrade approach. Several episodes of long RP atrio-ventricular re-entrant tachycardia were observed. At 7(1/2) months of age, the tumor was no longer obstructive to tricuspid inflow, ductal flow was highly restrictive and there was no recurrence of supraventricular tachycardia.

Pediatric radiofrequency catheter ablation: results of initial 100 consecutive cases including congenital heart anomalies

Radiofrequency catheter ablation (RFCA) has recently become a management option for pediatric tachycardia. We reviewed the records of a total of 100 patients (aged 10 months to 19 yr) who had undergone RFCA, from March 2000 to June 2004. Types of arrhythmia (age, acute success rate) were as follows: atrioventricular reentrant tachycardia (AVRT, 9.0+/-3.7 yr, 66/67), atrioventricular nodal reentrant tachycardia (AVNRT, 13+/-2.5 yr, 16/16), ectopic atrial tachycardia (6.4+/-3.3 yr, 5/5), junctional ectopic tachycardia (10 month, 1/1), ventricular tachycardia (12+/-4.9 yr, 6/6), postsurgical intraatrial reentrant tachycardia (15.6+/-4.1 yr, 2/3), twin node tachycardia (4 yr, 0/1), and His bundle ablation (9 yr, 1/1). The age of AVNRT was older than that of AVRT (p=0.002). Associated cardiac disease was detected in 17 patients, including 6 univentricular patients, and 3 Ebstein's anomaly patients. RFCA for multiple accessory pathways required longer fluoroscopic times than did the single accessory pathway (53.9+/-4.8 vs. 36.2+/-24.1 min; p=0.03), and was associated with a higher recurrence rate (3/9 vs. 3/53; p=0.03). Regardless of the presence or absence of cardiac diseases, the overall acute success rate was 97% without major complications, the recurrence rate was 8.2%, and the final success rate was 97%. This experience confirmed the efficacy and safety of RFCA in the management of tachycardia in children.

Prenatal echocardiographic differential diagnosis of fetal cardiac tumors

OBJECTIVES

To present data on echocardiographic findings of fetal cardiac tumors and discuss their differential diagnoses.

METHODS

We retrospectively reviewed 14 cases of fetal echogenic cardiac mass diagnosed between 1990 and 2003; 12 were confirmed to be cardiac tumors and two were false-positive diagnoses. The echocardiographic characteristics examined included number, size, location and associated complications.

RESULTS

Eight fetuses had a single tumor and four fetuses had multiple tumors. The left ventricle was most often affected. Parents of eight fetuses opted for termination of pregnancy, one fetus died in utero and three affected fetuses survived. Histopathological examination revealed cardiac rhabdomyoma in six fetuses, fibroma in two, teratoma in two, lipoma in one and hemangioma in one. The pitfalls associated with prenatal echocardiographic diagnosis of cardiac tumors include: they may be too small to be visualized, intracardiac echogenic foci may mimic tumors, and echogenicity resulting from extracardiac structures or neoplasms near the heart may falsely appear as tumors.

CONCLUSION

Fetal cardiac tumors can be detected by echocardiography. However, differential diagnosis is important as this will affect prognosis and subsequent management.

Cardiac rhabdomyoma in an adult patient presenting with ventricular arrhythmia

Cardiac rhabdomyomas are extremely uncommon in the adult patient. We describe a previously healthy man who presented with ventricular arrhythmias resulting from a right ventricular, cardiac rhabdomyoma. Echocardiography, CT scanning, and MRI are recognized as useful diagnostic modalities for intracardiac lesions. Cardiac catheterization in our patient demonstrated the presence of a tumor blush. This has not previously been reported with cardiac rhabdomyomas. Although lesions may spontaneously regress, surgery is often necessary and frequently resolves the underlying arrhythmia.

Pre-excitation syndrome secondary to cardiac rhabdomyomas in tuberous sclerosis

Rhabdomyomas are not uncommon in infants with tuberous sclerosis. We describe a neonate who presented with hydrops fetalis arising from a tachyarrhythmia during fetal life related to rhabdomyomas. After reversion of the arrhythmia, pre-excitation was noted on an interval electrocardiogram. Following regression of the tumours, the delta wave disappeared with no further arrhythmias noted.

Primary pediatric cardiac tumors: a 17 year experience

We reviewed 22 cases of primary pediatric cardiac tumors followed at our institution from January 1981 through November 1997, analyzing them by subtype, age and manner of presentation, location, associated findings, interventions, and clinical course. Rhabdomyomas were the most common (11), followed by intrapericardial teratomas (2), myxomas (1), fibromas (1), hemangiomas (1), mesotheliomas (1), and rhabdomyosarcomas (1), with 4 undetermined tumors. The majority (77%) of tumors were diagnosed before the age of one year, including six prenatally. The most common presentations were murmurs (5), arrhythmias (5), and abnormal screening fetal ultrasound examinations (4). Tumors were located most frequently in the right ventricle (13) and left ventricle (7), with multiple tumors being present in 10 cases. Eight patients (36%) had associated arrhythmias or conduction abnormalities, and of the 11 patients with rhabdomyomas, tuberous sclerosis was diagnosed in 8. Eight patients underwent cardiac catheterization, including two for electrophysiologic study with radiofrequency ablation, and seven patients had complete or partial tumor resection. The follow-up period ranged from 2 months to 15 years, and there were 3 tumor-related deaths. Therefore, despite the benign histology of most primary pediatric cardiac tumors, there may be significant associated morbidity and occasional mortality. As echocardiographic techniques such as fetal ultrasonography have continued to improve, however, these cardiac tumors have increasingly been detected early before significant symptoms develop.