Sustained ventricular tachycardia associated with influenza syndrome in a young girl--a case report

Influenza associated cardiac arrhythmia- a systematic review

BACKGROUND

Influenza infection is rarely associated with cardiac conduction disorder. Cardiac arrhythmias due to such an infection have a full spectrum with ventricular arrythmias being the most common.

METHODS

In our systematic review from PubMed, OVID Medline and EMBASE we have identified 23 articles describing arrythmias associated with different influenza infection. Most of them were case reports where ventricular arrhythmias were the most common.

RESULTS

Complete heart block after influenza infection is usually temporary and a permanent pacemaker is rarely needed. There are reports of Influenza associated with arrhythmias in adults, neonates, and even fetuses in pregnant woman. Different mechanisms were described in literatures by which influenza causes arrhythmias such as interleukin 6 & tumor necrosis factor-alpha mediated inflammatory response, sympathetic overactivation, focal myocarditis and cleavage of angiotensin converting enzyme 2 protein which is cardioprotective.

CONCLUSIONS

ACE 2 binder influenza viruses have more prone to be associated with cardiac conduction disorder. Oseltamivir for influenza infection is also associated with bradycardia and can shorten or lengthen QT segment. Influenza vaccination has found to be protective from cardiac arrhythmia.

Catheter ablation for right ventricular outflow tract ventricular tachycardia induced by fever in a 7-year-old girl

We report a 7-year old girl with ventricular tachycardia exacerbated by fever. She experienced her first symptom of palpitations during an influenza infection, and electrocardiogram showed wide QRS tachycardia of a left bundle branch block inferior axis pattern. We performed an electrophysiological study (EPS) for diagnosis, but the wide QRS tachycardia could not be induced. The wide QRS tachycardia recurred during upper respiratory tract infection with fever and ceased with lidocaine administration. Wide QRS tachycardia is characteristic of ventricular tachycardia (VT) exacerbated by fever. VT was not able to be induced at a normal temperature on EPS; however, when her temperature exceeded 38 degrees C, VT was easily induced and was accompanied by decreased blood pressure. Radiofrequency catheter ablation was performed in the right ventricular outflow tract (RVOT) just under the pulmonic valve, with a fractionated potential 29 ms before onset of V1 QRS. VT was terminated approximately 4 s after RF application, and then VT could not be induced with or without high fever. This is the first report of successful ablation treatment in RVOT VT exacerbated by fever in a young child.

Case report: fatal ventricular tachycardia exacerbated by fever in a child

Primary ventricular tachycardia (VT) is rare in children. We report a child with VT exacerbated by fever which was ultimately fatal. His first episode occurred at 5 months old and recurred with fever, occasionally causing syncope. Episodes were difficult to control with antiarrhythmic agents during fever but remitted with antipyretics. He was admitted to hospital 23 times because of VT and died suddenly with fever when he was 17 years old. At autopsy, severe fatty replacement of the bundle of His and interstitial fibrosis of the sinus node was found.

Safety and utility of endomyocardial biopsy in infants, children and adolescents: a review of 66 procedures in 53 patients

The benefits and risks of endomyocardial biopsy in infants, children and adolescents were determined by reviewing the indications for and complications and results of 66 procedures in 53 patients aged 2 months to 20 years. One patient had a pneumothorax, and three had a right ventricular perforation. Ventricular tachycardia developed in four patients; it was treated with lidocaine in three and was self-limited in one. The procedure was unsuccessful in two patients. Among 25 patients with a prebiopsy diagnosis of idiopathic dilated cardiomyopathy, microscopic features were consistent with cardiomyopathy in 24 (96%) and were normal in 1. Of nine patients with clinically suspected myocarditis, only two (22%) had microscopic evidence of inflammation, and seven had chronic nonspecific features suggestive of dilated cardiomyopathy. Of eight patients with unexplained arrhythmias, six (75%) had microscopic findings compatible with dilated cardiomyopathy and two had myocarditis. Biopsy tissue samples from seven patients with nondilated forms of cardiomyopathy (four hypertrophic, three restrictive) were consistent with the clinical diagnosis in six and were inadequate in one. Cardiac biopsies were also performed in four patients with other disorders. Among the 51 patients with adequate biopsy specimens, microscopic features were considered diagnostic in 5, confirmatory in 44 and not helpful in 2 with normal tissue. The results indicate that endomyocardial biopsy is safe in infants, children and adolescents. It is useful for the evaluation of cardiomyopathy and specific secondary forms of myocardial disease. There seems to be little correlation, however, between clinical and tissue diagnoses of myocarditis.