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Address reprint requests and correspondence: Dr Norman C. Wang, UPMC Presbyterian, 200 Lothrop Street, South Tower, 3rd Floor, Room E352.9, Pittsburgh, PA 15213.
Affiliations
Division of Cardiology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
A literature search of maternal atrioventricular nodal re-entrant tachycardia (AVNRT) during pregnancy that was proven by electrophysiology study, including the case report from this article, yielded 24 patients.
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Maternal AVNRT during pregnancy is associated with good maternal and fetal outcomes.
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Zero-fluoroscopy catheter ablation using electroanatomic mapping systems is a curative therapeutic option that may be considered during pregnancy in patients with high-risk features.
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Medication failure and heart rates of 170 beats/min or greater during AVNRT may be important considerations for referral to centers with cardio-obstetrics teams and zero-fluoroscopy catheter ablation capability.
Introduction
Atrioventricular nodal re-entrant tachycardia (AVNRT) is a common supraventricular tachycardia (SVT) in women of child-bearing ages. For most situations, experts suggest first-line treatment with atrioventricular (AV) nodal blocking agents.
Risk stratification to optimize management requires insight into a comprehensive spectrum of clinical presentations. This is the first detailed description of a woman with maternal AVNRT during pregnancy who was managed with a β-blocker until delivery and treated with catheter ablation in the postpartum period. A literature review on maternal AVNRT during pregnancy was performed.
Case report
In June 2021, a 33-year-old woman of Black race, G3 P1011, and in the 22nd week of pregnancy presented to the emergency department with palpitations, shortness of breath, and lightheadedness. She had a history of right-sided aortic arch, asthma, and Cesarean section. Her smartwatch detected heart rates over 160 beats/min. The initial electrocardiogram (ECG) demonstrated SVT at 126 beats/min with pseudo-R′ waves in lead V1, and the subsequent ECG, obtained after spontaneous conversion, demonstrated sinus rhythm without pre-excitation (Figure 1). An echocardiogram was normal. She was evaluated by the obstetrics and gynecology service, then discharged home with metoprolol tartrate 12.5 mg twice daily.
Figure 1Twelve-lead electrocardiograms. A: Supraventricular tachycardia at 126 beats/min. B: Normal sinus rhythm at 82 beats/min.
Although it was her first diagnosis of SVT, she had lesser palpitations for the past 5 years. She did not have palpitations or SVT during the pregnancy of her first child, which was 8 years prior.
In July 2021, she went to the emergency department with similar symptoms. It resolved by the time she arrived. She was instructed to change to metoprolol succinate 25 mg daily, but she declined. She felt “weird” and “exhausted” on metoprolol tartrate but did not want to change.
In September 2021, she had palpitations and her smartwatch recorded SVT with rates between 130 beats/min and 170 beats/min. Metoprolol and Valsalva maneuver were unsuccessful in terminating her arrhythmia. She went to bed and it resolved by morning. One day later, at a gestational age of 32 weeks and 5 days, she was evaluated for catheter ablation in the cardiac electrophysiology office. She favored curative treatment as soon as possible. In discussion with her obstetrics team, it was decided to wait until after delivery. Elective Cesarean section was scheduled.
In October 2021, at a gestational age of 38 weeks and 0 days, she presented to the emergency department with contractions and was admitted for labor. Given the failed trial of labor after Cesarean section with arrest of dilation at 6 cm, she underwent successful low transverse Cesarean section. A healthy female of 3400 g was delivered with Apgar scores of 8 at 1 minute and 9 at 5 minutes.
In November 2021, 32 days after delivery, she underwent electrophysiology study. Three sheaths were inserted into the right femoral vein. The CARTO 3 electroanatomic mapping system was used with a 4-mm-tip NAVISTAR nonirrigated radiofrequency ablation catheter (Biosense Webster, Irvine, CA) to create reconstructions of the right atrium and coronary sinus. Diagnostic catheters were placed in the His bundle region and coronary sinus. An obstruction within the coronary sinus body, presumably a valve, directed the catheter into a branch.
During programmed atrial and ventricular stimulation with single extrastimulus, there were no jumps, echoes, or sustained arrhythmias induced. Pacing from the proximal coronary sinus electrode repeatedly induced SVT with cycle lengths varying between 360 ms and 500 ms. There was a septal ventriculoatrial time of <70 ms, an A-H-A response to atrial overdrive pacing, and a V-A-V response to ventricular overdrive pacing (Figure 2). These observations supported a diagnosis of typical AVNRT.
Figure 2Diagnostic maneuvers with the mapping, or ablation, catheter (MAP) in the right ventricle. A: Atrial overdrive pacing from the proximal coronary sinus (CS 9,10) at a cycle length of 400 ms resulted in an A-H-A, or a pseudo-A-H-H-A, response. B: Ventricular overdrive pacing at a cycle length of 480 ms resulted in a V-A-V response. Recording speed = 100 mm/s. TCL = tachycardia cycle length.
Radiofrequency energy was delivered at the usual slow AV nodal pathway region, or the right inferoparaseptal AV junction segment (Figure 3), in temperature-controlled mode with a target temperature of 55°C at powers of 30 to 50 W for up to 60 seconds per lesion. Junctional beats were elicited during ablation. After ablation, typical AVNRT could no longer be induced in the baseline state, on intravenous (IV) isoproterenol 1 μg/min, and on isoproterenol washout. The procedure time was 183 minutes. Zero fluoroscopy was used. Metoprolol was stopped on discharge.
Figure 3Electroanatomic maps of the right atrium and coronary sinus (orange). Color points indicate His bundle recordings (yellow), the tricuspid annulus (teal), and ablation lesions associated with junctional beats (green). A: Left anterior oblique projection. B: Right anterior oblique projection.
She had no recurrence of symptoms or SVT at her follow-up office visit that was 10 months after ablation. Her infant continued to be healthy.
Literature review
A primary search of PubMed without limitation for publication year was conducted on November 1, 2022, to identify articles on maternal AVNRT during pregnancy that was confirmed by electrophysiology study. MeSH (Medical Subject Headings) terms “pregnancy” and “supraventricular tachycardia” were used. English language and human species filters were imposed. A secondary search consisted of manual reviews of references and Google Scholar citations of relevant articles from the primary search.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
reported on 38 women that included 13 (34%) women with onset of SVT during pregnancy, 11 (29%) women with pre-existing SVT that was exacerbated by pregnancy, and others with no change in SVT symptoms through pregnancy. Of the 38 women, 8 were diagnosed with AVNRT by electrophysiology studies performed in the nongravid state. Additional details, including medications and SVT heart rates, were not described.
observed a pause in fetal heart rhythm on cardiotocography in a 30-year-old pregnant woman with a gestational age of 26 weeks and 3 days who received 6 mg of IV adenosine for SVT at 184 beats/min. Subsequently, she was discharged without additional medication. She had SVT recurrence at 38 weeks of gestation and was again successfully treated with IV adenosine, after which she immediately went into spontaneous labor. Four months after uncomplicated Cesarean section, she underwent successful catheter ablation for AVNRT.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
described a patient who presented in the 24th week of pregnancy with palpitations and lightheadedness for over 40 minutes and had a heart rate of 200 beats/min. She went into ventricular fibrillation before an ECG could be obtained. Twelve months after delivery, she underwent successful ablation for AVNRT as part of a cardiac arrest investigation. The authors theorized that AVNRT degenerated into ventricular fibrillation due to aortocaval compression when she was placed in the supine position. She received a subcutaneous implantable cardioverter-defibrillator and did not undergo electrophysiology study during pregnancy due to radiation concerns for the fetus.
In 9 remaining articles of the literature review that reported 13 patient experiences, catheter ablation was performed during pregnancy.
For all 24 patients in the review, catheter ablation was 100% successful and there were no reported procedural complications. There were 2 cases of atypical AVNRT.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
The remaining, when specified, were typical AVNRT. There were no cases of incessant AVNRT. When reported, radiofrequency energy was used in all articles except one, in which cryoenergy was used.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
all patients with detailed information had good outcomes, and there were no reports of tachycardia-induced cardiomyopathy, cardiogenic shock, maternal death, or fetal loss.
Discussion
This is the first detailed description of a woman with maternal AVNRT during pregnancy who tolerated metoprolol tartrate through almost half her pregnancy, delivered a healthy infant, and underwent successful catheter ablation shortly thereafter. Her episodes of AVNRT had relatively modest heart rates and spontaneously terminated without IV medications. The literature review is the first summary of the worldwide experience on proven maternal AVNRT during pregnancy. Common characteristics of patients who underwent catheter ablation during pregnancy included medication failure and heart rates of 170 beats/min or greater.
Patients in the literature review had generally good outcomes. This contrasts with maternal focal atrial tachycardia during pregnancy.
Optimal management strategies may differ by suspected arrhythmia mechanisms. More data are needed to create risk stratification pathways for referral to specialized centers with cardio-obstetrics teams and zero-fluoroscopy catheter ablation capability.
β-blockers are commonly suggested AV nodal blocking agents, with metoprolol and propranolol preferred.
2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.
Nevertheless, it remains questionable if β-blockers, or other antiarrhythmic drugs, are effective in pregnant patients, given changes in sympathetic nervous system activity.
2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.
Since 2015, all reports of catheter ablation during pregnancy for AVNRT have used electroanatomic mapping systems to achieve zero fluoroscopy. Accordingly, catheter ablation with efforts to minimize fluoroscopy has a class IIb recommendation in the 2015 American SVT guideline, whereas zero-fluoroscopy catheter ablation has a class IIa recommendation in the 2020 European SVT guideline.
2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.
Heart rates of 170 beats/min or greater during paroxysmal SVT in nonpregnant patients have been associated with potentially disabling symptoms, specifically dizziness and syncope.
Other potentially important features include symptom severity, number of episodes, duration of episodes, IV medication requirement for arrhythmia termination, adverse clinical consequences, underlying structural heart disease, fetal viability status, and patient preference.
Conclusion
Maternal paroxysmal AVNRT during pregnancy is associated with good outcomes. Medication failure and heart rates during sustained AVNRT of 170 beats/min or greater may identify women who should be referred to centers with cardio-obstetrics teams and zero-fluoroscopy catheter ablation capability.
Acknowledgments
The author thanks Mark Vines, BS, of Biosense Webster for creation of the electroanatomic maps.
Funding Sources
The article publishing charge for open access was supported by UPMC Heart and Vascular Institute seed account FBS25 14919.
Disclosures
The author declared no conflicts of interest.
Authorship
The author attests he meets the current ICMJE criteria for authorship.
Patient Consent
Written informed consent was obtained from the patient.
Ethics Statement
The case report presented in the manuscript adhered to the CARE (CAse REport) guidelines.
Unusual presentation of supraventricular tachycardia degenerating into ventricular fibrillation during pregnancy: aortocaval compression the probable culprit.
2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.
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