Letter to the Editor Fluttering waves in electrocardiograms recorded in neonatal intensive care unit Gabriele Bronzetti * , Angelita Canzi, Fernando Maria Picchio, Giuseppe Boriani Department of Pediatric Cardiology and Institute of Cardiology, University of Bologna, Policlinico S.Orsola-Malpighi, Bologna, Italy Received 13 August 2002; received in revised form 8 October 2002; accepted 15 January 2003 Keywords: Atrial fibrillation; Atrial flutter; Electrocardiographic artifact; Neonatal period 1. Case presentation The electrocardiogram shown in Fig. 1 was recorded in a newborn during his stay in neonatal intensive care unit. The pattern of fibrillating waves initially raised the suspicion of atrial flutter or of an organized atrial fibrillation. However, a more careful analysis of the tracing revealed some irregu- larities not typical of F waves. Indeed, atrial flutter waves in the newborn can have a frequency between 200 and 600 beats/min; however, atrial fibrillation is a very rare arrhyth- mia in newborns because a critical atrial mass is required to sustain this arrhythmia. As for the clinical setting, this newborn had previously experienced respiratory insufficien- cy due to a congenital left sided diaphragmatic hernia and at the time of electrocardiographic recording was under high frequency oscillatory ventilation [1]. This type of ventilation support (at frequencies ranging between 4 and 15 Hz) is clinically indicated in some conditions specific of the newborn age (i.e. congenital diaphragmatic hernia, persis- tent pulmonary hypertension of the newborn and pneumo- thorax). Few weeks later, after surgical correction of diaphragmatic hernia and recovery from respiratory insuffi- ciency, another electrocardiogram (shown in Fig. 2) was recorded in the same patient and sinus rhythm was clearly detectable. 2. Discussion Artifactual arrhythmias have been reported in adult patients in different settings [2–4]. The observation of artifactual arrhythmias is rare in newborns and their origin may be peculiar at this age. In this case, the high rate of the oscillations (500 – 600 beats/min) used for ventilating the newborn with diaphragmatic hernia, is the cause of electro- cardiographic pattern mimicking atrial flutter or organized atrial fibrillation. In this case other variations in the electrocardiogram occurred comparing recordings taken before and after correction of diaphragmatic hernia. The change in electro- cardiographic pattern between the first tracing, showing absence of R waves in the left precordial leads, and the second tracing, showing R/S ratio <1 in V1–V2 and extreme right QRS axis deviation, may be explained by the herniation of abdominal viscera present at the time of first recording, subsequently corrected by surgery. Moreover, the positive T wave in right precordial leads may be explained by right ventricular strain due to persistent pulmonary hypertension. In another newborn who underwent high frequency oscillatory ventilation (Fig. 3), the recognition of artifacts at the electrocardiogram was easier since some leads revealed the artifactual nature of the fluttering waves. Although these observations are not reported in lead- ing textbooks of pediatric arrhythmias and electrocardi- ography they are of clinical interest for daily clinical practice. In conclusion, the presence of mechanical high rate ventilation should be considered as a potential cause of artifactual atrial arrhythmias in electrocardiograms routinely recorded in neonatal intensive care units. High frequency oscillatory ventilation, used in some conditions specific of the newborn age, may be a cause of electrocardiographic artifacts mimicking atrial flutter/fibril- lation. This potential cause of artifactual atrial arrhythmias has to be considered in daily clinical practice. 0167-5273/$ - see front matter D 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/S0167-5273(03)00103-7 * Corresponding author. Tel.: +39-051-349-858; fax: +39-051-344-859. E-mail address: gabronz@hotmail.com (G. Bronzetti). www.elsevier.com/locate/ijcard International Journal of Cardiology 92 (2003) 299 – 301