Letters to the Editor
629
Novel findings of fetal ectopic atrial tachycardia by cardiotocography A 32-year-old pregnant woman, gravida 2, para 0, was referred to our center at 35 weeks of gestation because of fetal arrhythmia. Cardiac morphological evaluation revealed a structurally normal heart without hydrops. Pulsed-wave Doppler recordings showed a basal ventricular rhythm of 240 bpm with short ventriculoatrial (VA) tachycardia, suggesting re-entry tachycardia (Figure 1). Fetal cardiotocography showed that the baseline heart rate accelerated gradually from 200 to over 240 bpm and decelerated gradually from 240 to 200 bpm (Figure 2). After transplacental administration of digoxin, the baseline fetal heart rate decreased generally but fetal tachyarrhythmia continued (Figure 2). Because of premature rupture of membranes prior to resolution of fetal tachyarrhythmia, we performed a Cesarean section at 36 weeks of gestation. The 2792-g male infant had an Apgar score at both 1 and 5 min of 8 and umbilical artery pH was 7.34. An electrocardiogram performed after birth and the subsequent reaction to a dose of adenosine triphosphate revealed the ectopic abnormal automaticity (Figure S1). Although intravenous administration of aprindine transiently terminated this ectopic atrial tachycardia (EAT), the EAT recurred immediately. Subsequently, the infant was intubated under sedation and the EAT terminated promptly (Figure S2). The neonate was extubated successfully, under digoxin, propranolol and low-dose aprindine to control heart rate. We found the clinical features of fetal EAT retrospectively by cardiotocography1 . Fetal EAT showed slow baseline changes as a ‘warm-up and cool-down’ phenomenon. Onset and termination are sudden in most cases of supraventricular tachycardia (SVT), whereas in EAT the shift of the pacemaker from the sinus node to the ectopic focus is more gradual2 – 5 . Thus, EAT shows a gradual rate of increase after the onset of tachycardia and a gradual rate of decrease before termination of tachycardia. Knudson et al.2 provided the first description of fetal heart tracings of EAT as short-term variability with acceleration during the tachyarrhythmia, but the present report is the first to indicate that fetal EAT shows a ‘warm-up and cool-down’ phenomenon in utero, similar to the features found postnatally. Echocardiography is the standard tool for diagnosis of fetal SVT3,4 . Measurements of atrioventricular (AV) and VA time intervals provide additional insight into the electrophysiological mechanisms involved. Atrioventricular re-entry tachycardia (AVRT) is the most common mechanism of fetal SVT and is associated with a short VA interval (VA/AV ratio < 1). EAT is another cause of SVT, accounting for approximately 5% of all cases, and is often associated with a long VA interval with a VA/AV ratio > 1. However, the diagnosis of fetal arrhythmia using echocardiography has limitations;
Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Figure 1 Two-dimensional ultrasound image of a segment of the ascending aorta (aAo), adjacent to the superior vena cava (SVC), draining into the right atrium at 35 weeks of gestation. Aortic ejection waves (V) were recorded below the zero velocity line. Antegrade flow in the SVC is above the line and small venous retrograde waves (A) caused by right atrial contraction are below the line. The characteristic pattern shows a basal ventricular rhythm of 240 bpm with short atrioventricular tachycardia (VA/AV ratio, 0.73).
pulsed-wave Doppler recordings of the present case of EAT showed a short VA tachycardia and led to an incorrect prenatal diagnosis of AVRT. We emphasize the importance of identifying the cause of SVT, because EAT is more refractory to pharmacological treatment than is AVRT, resulting in congestive cardiomyopathy5 . Although the diagnosis of fetal arrhythmia is based essentially on a Doppler approach with the evocative association of rhythm anomalies, we suggest that monitoring of fetal heart rate plays an important role in revealing the ‘warm-up and cool-down’ phenomenon, a criterion for the diagnosis of EAT which may help distinguish it from more common re-entry arrhythmias. T. Miyoshi*†, H. Sakaguchi‡, S. Katsuragi†, T. Ikeda§ and J. Yoshimatsu† †Departments of Perinatology and Gynecology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan; ‡Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan; §Department of Obstetrics and Gynecology, Mie University, Tsu, Mie, Japan *Correspondence. (e-mail: [email protected]) DOI: 10.1002/uog.14797
References 1. National Institute of Child Health and Human Development Research Planning Workshop. Electronic fetal heart rate monitoring: research guidelines for interpretation. Am J Obstet Gynecol 1997; 177: 1385–1390.
Ultrasound Obstet Gynecol 2015; 46: 627–632.
Letters to the Editor
630 (a) 240 bpm
160 bpm 110 bpm
3 min
(b) 240 bpm
160 bpm 110 bpm
3 min
Figure 2 (a) Fetal cardiotocography at 35 weeks of gestation in a fetus with arrhythmia, showing the baseline heart rate accelerating gradually from 200 to over 240 bpm and decelerating gradually from 240 to 200 bpm. (b) After transplacental administration of digoxin, the baseline heart rate decreased generally but tachyarrhythmia continued and the ‘warm-up and cool-down’ phenomenon persisted.
2. Knudson JM, Kleinman CS, Copel JA, Rosenfeld LE. Ectopic atrial tachycardia in utero. Obstet Gynecol 1994; 84: 686–689. 3. Steinfeld L, Rappaport HL, Rossbach HC, Martinez E. Diagnosis of fetal arrhythmias using echocardiographic and Doppler techniques. J Am Coll Cardiol 1986; 8: 1425–1433.
4. Matta MJ, Cuneo BF. Doppler echocardiography for managing fetal cardiac arrhythmia. Clin Obstet Gynecol 2010; 53: 899–914. 5. Wang JN, Wu JM, Tsai YC, Lin CS. Ectopic atrial tachycardia in children. J Formos Med Assoc 2000; 99: 766–770.
SUPPORTING INFORMATION ON THE INTERNET The following supporting information may be found in the online version of this article: Figure S1 Neonatal electrocardiogram showing the transient cessation of cardiac arrhythmia following adenosine administration, revealing the ectopic atrial tachycardia. Figure S2 Neonatal electrocardiogram of a fetus with cardiac arrhythmia showing the trend of a heart-rate warm-up, suggesting ectopic atrial tachycardia.
Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Ultrasound Obstet Gynecol 2015; 46: 627–632.
629
Novel findings of fetal ectopic atrial tachycardia by cardiotocography A 32-year-old pregnant woman, gravida 2, para 0, was referred to our center at 35 weeks of gestation because of fetal arrhythmia. Cardiac morphological evaluation revealed a structurally normal heart without hydrops. Pulsed-wave Doppler recordings showed a basal ventricular rhythm of 240 bpm with short ventriculoatrial (VA) tachycardia, suggesting re-entry tachycardia (Figure 1). Fetal cardiotocography showed that the baseline heart rate accelerated gradually from 200 to over 240 bpm and decelerated gradually from 240 to 200 bpm (Figure 2). After transplacental administration of digoxin, the baseline fetal heart rate decreased generally but fetal tachyarrhythmia continued (Figure 2). Because of premature rupture of membranes prior to resolution of fetal tachyarrhythmia, we performed a Cesarean section at 36 weeks of gestation. The 2792-g male infant had an Apgar score at both 1 and 5 min of 8 and umbilical artery pH was 7.34. An electrocardiogram performed after birth and the subsequent reaction to a dose of adenosine triphosphate revealed the ectopic abnormal automaticity (Figure S1). Although intravenous administration of aprindine transiently terminated this ectopic atrial tachycardia (EAT), the EAT recurred immediately. Subsequently, the infant was intubated under sedation and the EAT terminated promptly (Figure S2). The neonate was extubated successfully, under digoxin, propranolol and low-dose aprindine to control heart rate. We found the clinical features of fetal EAT retrospectively by cardiotocography1 . Fetal EAT showed slow baseline changes as a ‘warm-up and cool-down’ phenomenon. Onset and termination are sudden in most cases of supraventricular tachycardia (SVT), whereas in EAT the shift of the pacemaker from the sinus node to the ectopic focus is more gradual2 – 5 . Thus, EAT shows a gradual rate of increase after the onset of tachycardia and a gradual rate of decrease before termination of tachycardia. Knudson et al.2 provided the first description of fetal heart tracings of EAT as short-term variability with acceleration during the tachyarrhythmia, but the present report is the first to indicate that fetal EAT shows a ‘warm-up and cool-down’ phenomenon in utero, similar to the features found postnatally. Echocardiography is the standard tool for diagnosis of fetal SVT3,4 . Measurements of atrioventricular (AV) and VA time intervals provide additional insight into the electrophysiological mechanisms involved. Atrioventricular re-entry tachycardia (AVRT) is the most common mechanism of fetal SVT and is associated with a short VA interval (VA/AV ratio < 1). EAT is another cause of SVT, accounting for approximately 5% of all cases, and is often associated with a long VA interval with a VA/AV ratio > 1. However, the diagnosis of fetal arrhythmia using echocardiography has limitations;
Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Figure 1 Two-dimensional ultrasound image of a segment of the ascending aorta (aAo), adjacent to the superior vena cava (SVC), draining into the right atrium at 35 weeks of gestation. Aortic ejection waves (V) were recorded below the zero velocity line. Antegrade flow in the SVC is above the line and small venous retrograde waves (A) caused by right atrial contraction are below the line. The characteristic pattern shows a basal ventricular rhythm of 240 bpm with short atrioventricular tachycardia (VA/AV ratio, 0.73).
pulsed-wave Doppler recordings of the present case of EAT showed a short VA tachycardia and led to an incorrect prenatal diagnosis of AVRT. We emphasize the importance of identifying the cause of SVT, because EAT is more refractory to pharmacological treatment than is AVRT, resulting in congestive cardiomyopathy5 . Although the diagnosis of fetal arrhythmia is based essentially on a Doppler approach with the evocative association of rhythm anomalies, we suggest that monitoring of fetal heart rate plays an important role in revealing the ‘warm-up and cool-down’ phenomenon, a criterion for the diagnosis of EAT which may help distinguish it from more common re-entry arrhythmias. T. Miyoshi*†, H. Sakaguchi‡, S. Katsuragi†, T. Ikeda§ and J. Yoshimatsu† †Departments of Perinatology and Gynecology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan; ‡Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan; §Department of Obstetrics and Gynecology, Mie University, Tsu, Mie, Japan *Correspondence. (e-mail: [email protected]) DOI: 10.1002/uog.14797
References 1. National Institute of Child Health and Human Development Research Planning Workshop. Electronic fetal heart rate monitoring: research guidelines for interpretation. Am J Obstet Gynecol 1997; 177: 1385–1390.
Ultrasound Obstet Gynecol 2015; 46: 627–632.
Letters to the Editor
630 (a) 240 bpm
160 bpm 110 bpm
3 min
(b) 240 bpm
160 bpm 110 bpm
3 min
Figure 2 (a) Fetal cardiotocography at 35 weeks of gestation in a fetus with arrhythmia, showing the baseline heart rate accelerating gradually from 200 to over 240 bpm and decelerating gradually from 240 to 200 bpm. (b) After transplacental administration of digoxin, the baseline heart rate decreased generally but tachyarrhythmia continued and the ‘warm-up and cool-down’ phenomenon persisted.
2. Knudson JM, Kleinman CS, Copel JA, Rosenfeld LE. Ectopic atrial tachycardia in utero. Obstet Gynecol 1994; 84: 686–689. 3. Steinfeld L, Rappaport HL, Rossbach HC, Martinez E. Diagnosis of fetal arrhythmias using echocardiographic and Doppler techniques. J Am Coll Cardiol 1986; 8: 1425–1433.
4. Matta MJ, Cuneo BF. Doppler echocardiography for managing fetal cardiac arrhythmia. Clin Obstet Gynecol 2010; 53: 899–914. 5. Wang JN, Wu JM, Tsai YC, Lin CS. Ectopic atrial tachycardia in children. J Formos Med Assoc 2000; 99: 766–770.
SUPPORTING INFORMATION ON THE INTERNET The following supporting information may be found in the online version of this article: Figure S1 Neonatal electrocardiogram showing the transient cessation of cardiac arrhythmia following adenosine administration, revealing the ectopic atrial tachycardia. Figure S2 Neonatal electrocardiogram of a fetus with cardiac arrhythmia showing the trend of a heart-rate warm-up, suggesting ectopic atrial tachycardia.
Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Ultrasound Obstet Gynecol 2015; 46: 627–632.
