Postnatal Outcome in Patients With Fetal Tachycardia

Transcription

1 Pediatr Cardiol (2013) 34:81 87 DOI /s ORIGINAL ARTICLE Postnatal Outcome in Patients With Fetal Tachycardia Shreya Moodley Shubhayan Sanatani James E. Potts George G. S. Sandor Received: 31 January 2012 / Accepted: 9 May 2012 / Published online: 26 May 2012 Ó Springer Science+Business Media, LLC 2012 Abstract The diagnosis and management of prenatal tachyarrhythmias is well established; however, the postnatal course and outcomes are not. The purpose of our study was to review the natural history of patients with fetal tachycardia, determine the incidence of postnatal arrhythmias, and determine whether there are factors to predict which fetuses will develop postnatal arrhythmias. A retrospective chart review of patients with fetal tachyarrhythmias investigated at British Columbia Children s and Women s Hospitals between 1983 and 2010 was conducted. Sixty-nine mother fetus pairs were eligible for the study. Fifty-two had fetal supraventricular tachycardia, and 17 had fetal atrial flutter. Conversion to sinus rhythm occurred prenatally in 52 % of patients. Postnatal arrhythmia occurred in two thirds of patients, with 82 % of those cases occurring within the first 48 h of life. Hydrops fetalis, female sex, and lack of conversion to sinus rhythm was predictive of postnatal arrhythmia (P = 0.01, P = 0.01, and P = 0.001, respectively). Conversion to sinus rhythm prenatally did not predict postnatal arrhythmia. Median duration of treatment was 9 months. Two postnatal deaths of unknown etiology occurred. Two thirds of all patients with prenatal tachycardia will develop postnatal arrhythmia. Prenatal factors that predict postnatal arrhythmia include hydrops, sex, and whether or not conversion to sinus rhythm occurred prenatally. The majority of patients with postnatal arrhythmia present within 48 h of life, which has clinical implications for monitoring. S. Moodley S. Sanatani (&) J. E. Potts G. G. S. Sandor Division of Pediatric Cardiology, British Columbia Children s Hospital and The University of British Columbia, Vancouver, BC V6H 3V4, Canada ssanatani@cw.bc.ca Postnatal outcome is generally very good with most patients being weaned off medication in 6 12 months. Keywords Atrial flutter Natural history Prenatal and postnatal arrhythmias Supraventricular tachycardia Introduction Fetal heart rate is routinely monitored during pregnancy as an indicator of fetal well-being. Abnormalities of fetal heart rate are known to occur in 1 % of all pregnancies [3, 5, 27]. The majority of these arrhythmias are found to be benign, isolated extrasystoles; however, it has been reported that approximately 10 % of all referrals for fetal rhythm abnormalities are for sustained arrhythmias considered to be clinically significant [8] requiring intervention in the form of fetal or maternal medication or premature delivery [1, 11]. Sustained fetal tachyarrhythmia accounts for the majority of these abnormal rhythms with supraventricular tachycardia (SVT) occurring in % of cases [1, 18]. In the prenatal period, SVT can result in hydrops fetalis (hydrops) as well as fetal death [24]. In addition, therapeutic interventions for SVT are not benign and carry their own inherent risks to the fetus [2, 15, 16]. Therefore, SVT is an important cause of fetal morbidity and mortality [28]. Although the diagnosis and treatment of prenatal tachyarrhythmia is well established, the postnatal outcomes of this patient population are not well defined. The duration of postnatal monitoring, the need for testing, and the manner in which to counsel caregivers are not clear. In addition, at present we are not aware of any prenatal predictive factors for the postnatal recurrence of arrhythmia in a child with fetal tachycardia that would guide management and follow-up of these patients.

2 82 Pediatr Cardiol (2013) 34:81 87 The purpose of this study was to determine the incidence and natural history of postnatal arrhythmias in patients diagnosed with sustained fetal tachycardia and to determine whether there are factors that can be used to predict which fetuses will go on to develop arrhythmias postnatally. Methods A retrospective chart review of patients with documented fetal tachyarrhythmia confirmed by fetal echocardiography during a 27 year period ( ) at British Columbia Children s and Women s Hospitals in Vancouver, Canada, was performed. Being the tertiary referral center for the Province, Children s Hospital would have followed-up virtually all cases in the province. A multidisciplinary service comprising the Division of Maternal Fetal Medicine, Pediatric Cardiology, and Medical Genetics was responsible for seeing pregnant women referred for fetal cardiac concerns. A database of these patients was prospectively maintained by the Division of Pediatric Cardiology. This database included both the indications for and findings of echocardiography for each patient. Once patients referred for fetal tachyarrhythmia were identified from this database, patient names, birth dates, and unit numbers were used to obtain further records of mother and patient through the Health Records Department at Children s Hospital. From these files, pertinent information regarding maternal health, fetal health, and postnatal health was recorded. In those cases where sufficient information was not available from existing records and where contact information was obtainable, patient families were contacted by way of letter, which was followed by a phone interview. Inclusion criteria was a diagnosis of fetal tachycardia which was defined as non sinus rhythm with a ventricular rate of[180 bpm that was sustained for[20 s in duration, documented, and confirmed by fetal echocardiography [28]. Tachyarrhythmias were defined by evaluating the chronologic relationship between atrial and ventricular contractions as well as assessing the ventricular atrial interval [12, 13]. Prenatal tachycardia was divided into SVT and atrial flutter (AF) during the earlier years of the period studied and further classified into short or long ventricular atrial interval SVT and AF in the more recent years of the period studied. Postnatal tachycardia was divided into SVT with short or long ventricular atrial interval and AF. SVT was defined by a 1:1 atrioventricular relationship. AF was defined as an atrial rate in excess of the ventricular rate, usually with atrial rates between 300 and 450 bpm and ventricular rates between 200 and 300 bpm [19]. Patients with ventricular tachycardia, premature atrial or ventricular contractions, and sinus tachycardia, as well as those lacking sufficient information through health records and/or the telephone questionnaire, were excluded from the study. During data collection, charts were reviewed for pertinent fetal information, including type of arrhythmia and associated features and complications, maternal history, and postnatal outcomes. This study received ethical approval from The University of British Columbia and Children s and Women s Health Centre Research Ethics Board. Statistical Analysis Frequency tables were generated for all categorical data. Chi-square test was used to test for group differences. Continuous variables were analyzed using a univariate procedure. The medians (ranges) are reported. Wilcoxon rank sum test was used to test for group differences. The level of significance was set at P \ All data were analyzed using SAS version software (SAS Institute, Cary, NC). Results Between 1983 and 2010, 10,000 fetal echocardiograms were performed on 8,000 patients. Two hundred fifteen of these scans were performed on 83 mothers for evaluation of fetal tachyarrhythmia. Therefore, 83 mother fetus pairs were identified as being eligible for the study through the Division of Pediatric Cardiology Fetal Echocardiography database. Fourteen cases were excluded because 4 charts were not available through health records, and there were insufficient data for 10 cases both through chart review and attempted telephone contact, thus leaving a total of 69 patient pairs for analysis. Prenatal Data Prenatal arrhythmia and associated features are listed in Table 1. The ventricular rate for SVT was 240 (range ) bpm. For AF, atrial to ventricular ratios were mostly 2:1 with a ventricular rate of 213 (range ) bpm. Hydrops, defined as fluid accumulation in two or more fetal compartments, occurred in 52 % of fetuses. Hydrops was diagnosed later in gestational age (GA) in those with AF versus those with SVT, although this difference did not reach statistical significance (32.5 vs. 29 weeks; v 2 = 1.975, P = 0.16). In the SVT group, 44 of 52 patients were treated medically, and 8 of 52 patients were not treated, with 3 patients being observed (1 achieved term with no complications and

3 Pediatr Cardiol (2013) 34: Table 1 Patient demographics a a Data are reported as numbers (percentage) or mean ± SD Demographics SVT (n = 52) AF (n = 17) Male sex (%) 31 (60) 8 (47) Ventricular rate (bpm) 240 ( ) 2:1 block 218 bpm 3:1 block 250 bpm 5:1 block 100 bpm GA at diagnosis (weeks) 31 (16 38) 34 (27 38) Hydrops (%) 29 (56) 6 (35) GA at hydrops (weeks) 29 (17 38) 32.5 (27 36) Maternal age (years) 30 (19 43) 28 (22 38) Family history of arrhythmia (%) 3 (6) 0 Previous pregnancy with arrhythmia 3 (alive) 0 2 spontaneously converted to sinus rhythm), 4 patients being delivered because they were near term, and 1 patient being delivered for hydrops. In the AF group, 15 of 17 patients were treated medically, and 2 of 17 were not treated because they were delivered at term on the day of fetal arrhythmia diagnosis. Medication use for both the SVT and AF groups is shown in Fig. 1. This included one patient with SVT who was being investigated for hyperthyroidism and received digoxin, flecainide, and propothiouracil. Information regarding conversion to sinus rhythm is known for 62 of 69 patients. Conversion to normal sinus rhythm occurred in 32 patients (46 %). In the SVT group, 27 converted, 20 did not convert, and 5 are unknown. Three converted spontaneously. Fifteen of those who did not convert received treatment, whereas 5 of those who did not convert were never treated. In the AF group, 5 converted to sinus rhythm, 10 did not convert, and 2 are unknown. Of the 10 fetuses who did not convert, 8 did so despite treatment, and 2 were never treated. Elective delivery only occurred in cases in which prenatal treatment failed, the patient was hydropic with anticipated failure of medical therapy, or the fetus was of advanced GA. There were 51 live births and 1 intrauterine death in the group with fetal SVT; 19 went into spontaneous labour; 11 were delivered for hydrops; 15 were delivered for arrhythmia either having failed therapy or despite success with therapy having caused sufficient concern to prompt delivery; 2 were delivered for fetal distress; 1 was delivered for intrauterine death; and 4 were delivered for unknown reasons. The intrauterine death in this group occurred at 22 weeks GA 2 weeks after diagnosis of arrhythmia and hydrops in a fetus treated with digoxin and flecainide. In the fetal AF group, there were 16 live births and 1 intrauterine death. Nine were delivered due to arrhythmia either having failed therapy or despite success with therapy having caused sufficient concern to prompt delivery; 3 were delivered for hydrops; 2 went into spontaneous labour; 1 was delivered for fetal distress; 1 was delivered for pre-eclampsia; and 1 died in utero. The intrauterine death in this group occurred in a fetus diagnosed with arrhythmia and hydrops at 29 weeks GA. Death occurred at 30 weeks GA from persistence of arrhythmia despite the use of digoxin, sotalol, and labetalol. GA at delivery was similar for the SVT and AF groups (36 vs. 37 weeks; v 2 = 0.172, P = 0.68) with delivery more likely to be premature in those patients with hydrops compared with those without hydrops (34 vs weeks; v 2 = , P \ ). Fetal management and outcomes are listed in Table 2. Postnatal Data Fig. 1 Medication use for treatment of prenatal SVT and AF Postnatal data were available for 66 of 69 patients; there were 2 intrauterine deaths and 1 patient with no follow-up information. Forty-four patients (67 %) developed postnatal arrhythmia: 34 of those with fetal SVT and 10 of those with fetal AF (see Table 3). In the 32 patients who converted to sinus rhythm prenatally, 14 (44 %) were found to have postnatal arrhythmia. In the 28 patients who did not convert to sinus rhythm prenatally, 26 (93 %) went on to

4 84 Pediatr Cardiol (2013) 34:81 87 Table 2 Prenatal management and outcomes a a Data are reported as number (percentage) or median (range) Management and outcomes SVT (n = 52) AF (n = 17) Medication (%) 44 (85) 15 (88) Medication route 43 maternal 15 maternal 1 maternal? direct GA at delivery (weeks) All 36 (22 41) 37 (30 39) With hydrops 35 (22 40) 34 (30 36) Without hydrops 37 (32 41) 37.5 (35 39) Birth weight (g) 2,950 (520 4,480) 2,960 (1,828 4,365) Live births (%) 51 (98) 16 (94) Postnatal death (%) 2 (4) 0 Table 3 Postnatal management a Postnatal management SVT (n = 51) AF (n = 16) Postnatal arrhythmia (%) 34 (67) 10 (63) Postnatal arrhythmias 33 (65) 10 (63) no. treated (%) No postnatal arrhythmias no. treated (%) 0 1 (6) a One patient from each cohort died in utero and were excluded from this analysis. The number (%) is reported have postnatal arrhythmia. In 4 patients with postnatal arrhythmia, and in 2 patients without postnatal arrhythmia, it was unknown whether or not conversion occurred. In those who had fetal SVT, postnatal arrhythmia types included 28 with atrioventricular re-entry tachycardia [3 of whom had evidence of pre-excitation on their electrocardiograms (ECG)], 2 with atrial ectopic tachycardia, 3 with permanent junctional reciprocating tachycardia, and 1 was unknown. In those who had fetal AF, postnatal arrhythmia types included 5 cases of AF, 4 cases of atrioventricular reentry tachycardia (1 of whom was found to have preexcitation on ECG), 1 case of atrial ectopic tachycardia, and 1 case was unknown. Information regarding the timing of onset of postnatal arrhythmia was available in 34 of 44 patients. In the fetal SVT group, postnatal arrhythmia occurred within the first h of life in 21 patients, within 1 month for 5 patients, and at age 14 years in 1 patient. In the AF group, arrhythmias in 7 patients began within the first 48 hours of life. Thus, 28 of 34 patients (82 %) had recurrence of arrhythmia within the first 48 h of life. Postnatal treatment in the fetal SVT group consisted of oral medication and in the AF group included oral medication as well as one transesophageal overdrive pacing and one cardioversion. The duration of postnatal treatment was known in 32 patients. Medical treatment lasted for 9 months (range 1 month to 18 years). Two patients with treatment lasting [5 years were eventually ablated. Two patients had recurrence while on treatment (1 with atrioventricular reentry tachycardia and 1 with atrial ectopic tachycardia). One patient with previous atrioventricular reentry tachycardia had a recurrence at age 15 years. The outcome of patients in the SVT group was 1 intrauterine death, 49 alive, and 2 postnatal deaths. One postnatal death occurred due to presumed sudden infant death syndrome at 3.5 months of age in a term infant who converted to sinus rhythm prenatally and who had no documented recurrence of arrhythmia postnatally as well as 1 postnatal death at 5 months of age of unknown causes. In the AF group, there was 1 intrauterine death, 15 alive, and 1 unknown. Echocardiograms were performed in 40 patients postnatally, with 8 patients having no postnatal echocardiogram; there was no information available for the remainder. Findings included one patient with an atrioventricular septal defect, one patient with mild coarctation, two patients with ventricular septal defects, three patients with cardiac hypertrophy, and eight patients with abnormal function, including one patient with dilated cardiomyopathy. Structural abnormalities, such as ventricular septal defects, were thought to be congenital anomalies, whereas changes such as ventricular hypertrophy and cardiomyopathy were likely secondary to arrhythmia. Follow-up of patients was not standardized; however, in general, patients with postnatal arrhythmia were followedup by pediatric cardiology for 6 months to 1 year after successful discontinuation of medication or successful ablation. All other patients were followed-up by pediatricians in the community with instructions for referral for symptoms suspicious for arrhythmia. Analysis of factors predictive of postnatal arrhythmia showed that patients with fetal SVT who developed hydrops were more likely to go on to have postnatal arrhythmia than those with fetal SVT who did not have hydrops (v 2 = 6.615; P = 0.01), and GA at the time of diagnosis of hydrops was not a significant predictor. Female sex was predictive of postnatal arrhythmia (v 2 = 6.563; P = 0.01). Lack of conversion to normal

5 Pediatr Cardiol (2013) 34: sinus rhythm during the fetal period was associated with a higher incidence of postnatal arrhythmia (v 2 = ; P = 0.001). because one should not be reassured by prenatal conversion and should continue to monitor for postnatal recurrence in this population as well. Discussion There are limited data regarding the postnatal outcome of patients diagnosed with fetal tachyarrhythmias. Our study focused on the postnatal course and management of these patients, as well as the prenatal factors which may influence this course, with the hopes of gaining a better understanding of the natural history of fetal tachyarrhythmias. Prenatal Arrhythmia After M-mode and Doppler studies were performed in our fetal patient population, 75 % of cases were classified as SVT and 25 % of cases as AF, which is similar to other studies [11, 19, 22]. As previously described in the literature, AF occurred at a later GA than SVT in our patient cohort [18]. This later occurrence of AF explains the appearance of hydrops at a later GA in this group. In both fetal SVT and AF, digoxin remained the most common medication choice, reflecting that, similar to other centers, digoxin was accepted as first-line therapy for many years at our hospital [1, 6, 14, 20]. Digoxin was used alone in two cases of fetal AF and four cases of fetal SVT patients with hydrops. The literature now shows that in hydropic patients, digoxin as monotherapy has low efficacy due to poor placental transfer of medication, thus favouring the use of other medications, such as sotalol or flecainide, as first-line therapy in fetuses with hydrops [10, 21, 22]. An era effect was seen with the selection of medical therapy. Although digoxin continued to be a popular choice throughout the study period, verapamil and amiodarone were used as additional agents in the 1980s, sotalol was introduced as an alternative medication in the 1990s, and both sotalol and flecainide were used in the 2000s, in some cases as first-line agents. There appear to be few prenatal factors that are helpful in predicting which fetuses will develop postnatal arrhythmia and which will not. The presence of hydrops, in addition to being associated with a poor prognosis, was predictive of postnatal arrhythmia, possibly reflecting a more persistent arrhythmia. Female newborns were more likely than their male counterparts to develop postnatal arrhythmia. Lack of conversion to normal sinus rhythm did predict development of postnatal arrhythmia; however, conversion to normal sinus rhythm was not as helpful in predicting the absence of postnatal arrhythmia because 44 % of those who converted prenatally went on to develop arrhythmia after birth. This is of clinical importance Postnatal Arrhythmia In our study cohort, in both those with fetal SVT and fetal AF, two thirds went on to have an arrhythmia after birth, which is slightly higher than that described in previous studies [26]. In the group with fetal SVT, the predominant arrhythmia type was atrioventricular re-entry tachycardia. This is described in the literature as the most common mechanism for fetal and neonatal SVT due to the structural and functional changes of the heart that accompany the transition from fetal life to the first year of postnatal life [7, 9, 21]. These changes, including the disappearance of accessory atrioventricular connections [23] during the physiologic process of atrioventricular junction isolation, may explain the common occurrence of fetal SVT and the lower incidence of neonatal SVT [4, 7, 25]. In the AF group, the predominant postnatal arrhythmia type remained AF, followed by atrioventricular re-entry and atrial ectopic tachycardia. Although permanent junctional reciprocating tachycardia has been described as a rare arrhythmia in the neonate, three cases were identified in our cohort. Similar to other studies, these patients were difficult to manage on conventional medical therapy. In 82 % of patients, postnatal arrhythmia occurred within the first 48 h of life. This finding has implications for postnatal monitoring and recommendations provided to parents regarding the assessment and monitoring of their child s heart rate on discharge. Treatment was given to 43 newborns. The mainstay of treatment was digoxin, followed by sotalol, flecainide, and propranolol used alone or in combination for a median treatment duration of 9 months, which is the usual duration of treatment for neonatal SVT. In our patient cohort, the majority of SVT patients discontinued medication at 6 12 months. By 6 months, there was resolution of arrhythmia in the atrial ectopic tachycardia group. There was no resolution of arrhythmia in the permanent junctional reciprocating tachycardia group. These patients were referred for radiofrequency ablation. These results are similar to the natural history described in other studies [6, 17]. Seven patients received treatment for several years, either due to recurrence when medication was weaned off or due to refractory arrhythmia occurring while the patient awaited ablation. The natural history of AF beginning in the prenatal period is a favourable postnatal outcome with no recurrence after establishment of sinus rhythm, regardless of whether or not postnatal treatment was given [9]. In the AF group, all patients received treatment and had no recurrence of arrhythmia.

6 86 Pediatr Cardiol (2013) 34:81 87 Outcomes Both prenatal and postnatal outcomes for those with fetal tachyarrhythmia are generally good, as previously described in the literature [17]. In our cohort, the majority of patients achieved live birth with there being only two intrauterine deaths (one in the SVT group and one in the AF group). However, a significant number in both cohorts were delivered prematurely, which has its own associated morbidity and therefore may be considered an important outcome in this population. Hydrops is considered to be an important prognostic factor in fetal tachycardia [21]. Patients with hydrops were more likely to be delivered prematurely. In addition, the two intrauterine deaths in our series occurred in patients with hydrops, highlighting the difference in morbidity and mortality between hydropic and nonhydropic fetuses previously described in other studies [3, 6, 14]. There were also two postnatal deaths in the series, which may or may not have been associated with arrhythmia. Limitations This was a retrospective chart review over a long time period. Pertinent information was not always available or recorded in the patient charts, resulting in an incomplete data set. In addition, being a tertiary referral centre, some patients were initially seen during the prenatal period and then lost to follow-up, likely delivering at peripheral, primary care centres with loss of postnatal data. Telephone interviews, although helpful in providing supplementary information, are subject to recall bias, which may lead to inaccuracies. However, our sample size is large enough to provide useful information. Because a specific protocol was not followed at our center, treatment choice was often staff-dependent based on experience or the medical evidence available at the time. It is, therefore, difficult to deduce the reasoning behind decision-making for specific management plans. Conclusion Two thirds of all patients with prenatal SVT and AF will go on to develop postnatal arrhythmia. Prenatal factors that may predict postnatal arrhythmia include hydrops, female sex, and lack of conversion to normal sinus rhythm during the prenatal period. Conversion to sinus rhythm in response to treatment in utero is not reassuring because almost half of this group will still go on to develop postnatal arrhythmia. The majority of patients will present with postnatal arrhythmia within the first 48 h of life. The clinical implications of these findings are that patients should be monitored in hospital for rhythm disturbance within the first 48 h and then discharged home with instructions on monitoring heart rate for the first 1 or 2 months of life. Treatment of postnatal arrhythmia is successful and results in good outcomes in this patient population. References 1. 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