Atrial automatic ectopic tachycardia due to an atrial tumor

[Prevention and treatment of cardiac arrhythmia in patients with congenital heart defects: surgical aspects]

Catheter ablation procedures have become established over the years due to their effectiveness and low invasiveness and have changed the indications for surgical treatment. The main field of activity of cardiac surgery remains the treatment of patients with congenital heart defects which show arrhythmia and necessitate surgical treatment. The combination of surgical ablative measures with a good view of the site using modern ablation instruments, atrial reduction by tissue resection and correction of the defect with the resulting volume relief, bring the best conditions for a curative treatment of arrhythmia. The same applies to the treatment of ventricular tachycardia resulting from old scars and residual defects. Special attention should be given to patients who received a Fontan conversion. This operation is a unique opportunity to relieve volume which in turn reduces the atrial size and at the same time to take ablative measures to restore sinus rhythm. The results are promising with low mortality and morbidity, high efficiency and finally a clear improvement of the functional status of patients. In appropriate cases minimally invasive surgical procedures can help where pharmacological and catheter ablation therapies remain ineffective.

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.

Surgical treatment of cardiac dysrhythmias in infants and children

A variety of cardiac rhythm disturbances that occur in infants and children may be refractory to medical or catheter ablation therapy, or both, and thus require surgical ablation. These dysrhythmias include Wolff-Parkinson-White syndrome, atrial automatic tachycardia, atrioventricular node reentry tachycardia, and ventricular tachycardia. The surgical technique originally used in adults may be equally well applied in infants and small children. In the interval from July 1, 1984, through December 31, 1993, a total of 130 infants and children (< or = 16 years old) underwent surgical treatment for various forms of dysrhythmias (96 with Wolff-Parkinson-White syndrome, 8 with atrioventricular node reentry, 11 with atrial automatic tachycardia, and 15 with ventricular tachycardia). The success rate for completely abolishing these arrhythmias has been 92% for the Wolff-Parkinson-White syndrome, 100% for atrioventricular node reentry, and 64% for atrial automatic tachycardia. In infants younger than 2 years, the success rate for the surgical treatment of ventricular tachycardia is 100%, but the long-term success in older children has been poor. One patient sustained a severe intraoperative neurologic event that resulted in her death (operative mortality, 0.7%). Ventricular function returned to normal in all patients in whom it was abnormal preoperatively. These data suggest that the surgical treatment of these dysrhythmias remains a viable alternative in those patients whose dysrhythmias are refractory to medical therapy, those in whom catheter ablation has been unsuccessful, or those in whom both situations apply.

Surgical management of dysrhythmias in infants and small children

Surgery for cardiac dysrhythmias is infrequently reported in infants and children as compared with adults. This report reviews 55 infants and small children (age, less than or equal to 5 years) operated on during the interval July 1, 1984 to December 31, 1991 for Wolff-Parkinson-White Syndrome (41), atrioventricular node reentry (two), atrial automatic tachycardia (two), and ventricular tachycardia (nine). Ages ranged from 3 weeks to 71 (mean, 29) months. Associated congenital heart defects were present in five (10%). Indications for surgery included failure of medical therapy, life-threatening dysrhythmias, and more recently, failure of catheter ablation. There were no hospital or late deaths. One patient sustained perioperative central nervous system injury. Surgery was successful in 52 of 55 (94.5%) (Wolff-Parkinson-White, 38/41 (93%); atrioventricular node reentry, 2/2 (100%); atrial automatic tachycardia, 3/3 (100%); ventricular tachycardia, 9/9 (100%). Ventricular function returned to normal in all 12 patients in whom it was abnormal before operation. Thus, surgical ablation is highly successful in the management of various forms of refractory or life-threatening dysrhythmias in infants and small children. Catheter ablation techniques require significant fluoroscopic time, are more difficult in infants, and as yet do not have adequate long-term follow-up. Accordingly, surgery may continue to play a role in this particular group of patients.

Noninvasive discrimination of right atrial ectopic tachycardia from sinus tachycardia in "dilated cardiomyopathy"

Right atrial ectopic tachycardia (RAET) with secondary cardiac dysfunction can be difficult to differentiate from primary dilated cardiomyopathy (CMP) with sinus tachycardia. In an attempt to separate RAET from CMP by noninvasive testing, routine surface electrocardiograms (EGGs), 24-hour ambulatory ECGs (Holter monitors), and echocardiograms of patients with RAET (n = 34) and CMP (n = 33) were reviewed. RAET atrial rates were significantly faster than CMP rates on the resting ECG and on Holter monitoring; 12 of 33 patients with RAET had resting ECG rates greater than 150% of predicted normal values for age but none of 32 patients with CMPs had resting ECG rates in this range. Mean P wave axis in the horizontal plane was more posterior in patients with RAET and was less than 0 degrees (negative in lead V2) in 8 of 29 patients with RAET but in 1 of 33 patients with CMP. Second-degree atrioventricular (AV) block was observed in 12 of 33 patients with RAET but in none of 33 with CMP. Shortening fraction less than 10% was found in 13 of 33 individuals with CMP but in only 1 of 27 with RAET. We conclude that noninvasive studies can help identify RAET among patients with poor functioning hearts and right atrial tachycardia.