Abstract
Premature ventricular complex (PVC) constitutes the most prevalent arrhythmia in pregnancy. Because of the potentially adverse maternal and fetal outcomes, managing symptomatic high-burden PVC in pregnancy is challenging; thus, selecting the optimal treatment is crucial. Conventionally, PVC has been managed with beta blockers. However, beta blockers may have negative consequences on the developing fetus. PVC ablation can be performed in patients without fluoroscopy using three-dimensional electroanatomical technology. We present a clinical case series of 6 high-burden pregnant patients who underwent single catheter PVC ablation with zero fluoroscopy during the second trimester of pregnancy. The right ventricular outflow tract was the site of origin of the PVC, which was effectively ablated. All patients were able to continue the pregnancy and delivered at full term. Managing pregnant patients with high-burden PVC is challenging as this population is underrepresented in clinical trials. This case series details the successful management of PVC in pregnancy.
Key words: cardiac electrophysiology, fetomaternal outcomes, premature ventricular complex ablation, zero fluoroscopy
Graphical Abstract
Physiological adaptations during pregnancy can aggravate maternal arrhythmias. The most prevalent arrhythmia during pregnancy is premature ventricular complex (PVC), which results from the physiological adaptation in pregnancy. In this unique demographic, treatment is always a challenge because PVC or antiarrhythmic medications may have negative effects on both the mother and the fetus. In a study by Chou et al,1 the incidence of placenta abruption was higher in the high PVC burden subgroup compared with the low PVC burden subgroup and control group; however, the causal relationship is unclear. Adverse fetal outcomes are linked to the use of drugs such as beta blockers and non-dihydropyridine calcium channel blocker.1 Performing catheter ablation during pregnancy exposes the mother and fetus to radiation. In this article, we report a case series of pregnant patients who underwent zero fluoroscopy PVC ablation.
Method of Using Zero Fluoroscopy PVC Ablation
Each patient's clinical information was reviewed and discussed during a multidisciplinary meeting between the cardiology and obstetric teams before zero fluoroscopy PVC ablation was planned. A detailed assessment was then conducted, including an electrocardiogram (ECG) and 24-hour Holter monitoring for the mother. Fetal assessment was also performed. Before embarking on this procedure, beta blockers were administered as the first line of treatment, and the patients were reassessed during second trimester for symptoms and PVC burden based on 12-lead ECG. Patients not responding to medical therapy were offered zero fluoroscopy PVC ablation. The 6 patients in our case series underwent zero fluoroscopy PVC ablation after failed medical therapy. Another important indication for zero fluoroscopy PVC ablation was that the suspected site of origin of PVC was the right ventricular outflow tract (RVOT) based on surface 12-lead ECG (Figure 1). All patients were reviewed by the obstetric team on the day of the procedure for the fetal assessment; however, there was no continuous fetal heart monitoring during the procedure. All patients underwent PVC ablation procedures during their second trimester of pregnancy using a similar protocol and workflow. The electrophysiology procedure was performed under conscious sedation using intravenous midazolam 2 mg and intravenous fentanyl 40 mg slow bolus during the procedure. This procedure involved a single irrigated ablation catheter for the RVOT electroanatomical mapping and radiofrequency ablation. The right femoral vein was cannulated using a single 8-F sheath. The single ablation catheter was introduced using an 8-F sheath, and the location of the catheter in the right atrium was identified based on the atrial signal on electrogram. Using three-dimensional (3D) electroanatomical mapping, anatomy of superior vena cava, inferior vena cava, right atrium, right ventricle, and RVOT was identified and created based on electrogram signal (Figure 2). By using the earliest signal relative to the QRS and/or the pace map morphology, more than 90% match determined the site of origin and ablation site.2
Figure 1.
Surface Electrocardiogram Showing Sinus Rhythm With Ventricular Bigeminy
Left bundle branch block morphology at V1, positive deflections at leads II, III, and AVF with transition at V4 suggestive of posteroseptal right ventricle outflow tract origin.
Figure 2.
3-Dimensional Electroanatomical Mapping Using Carto 3 System, Showing a Single Ablation Catheter at the Posteroseptal Right Ventricle Outflow Tract Origin
The radiofrequency ablation energy was titrated up from 25 to 35 W for 120 to 160 seconds for ablation.2 No anticoagulant was administered as our approach is from the venous system. During each ablation, a short run of ventricular tachycardia and/or immediate PVC termination and/or noninducible ventricular tachycardia was used to denote successful ablation.2,3 The patient was then monitored in the electrophysiology laboratory for 30 minutes post-procedure for any recurrence and discharged the following day.3 Additional detailed maternal and fetal assessment was performed by obstetric team before discharge. Follow-up of patients will be conducted in a combined clinic until delivery with symptom and ECG monitoring as well as fetal assessment. However, because our center has limited resources, 24-hour Holter monitoring was not performed. The primary end point in our case series was that the patient was able to deliver a term infant without using a beta-blocker.
Patient 1
A 30-year-old primigravida presented with symptoms of frequent palpitations occurring 2 to 3 times per week and aggravated by physical activity. Clinical examination was unremarkable. The ECG demonstrated sinus rhythm with left bundle branch PVC morphology at V1; positive deflections at leads II, III, and AVF; and transition at V4 (Figure 1). Echocardiography demonstrated a structurally normal heart. However, 24-hour Holter monitoring revealed a high-burden PVC (25%). The patient was diagnosed with posteroseptal RVOT PVC. Because she was very symptomatic, she subsequently underwent zero fluoroscopy PVC ablation over the posteroseptal RVOT during the 24th week of pregnancy. Post-procedure, the patient was asymptomatic with ECG showing sinus rhythm. She was able to continue her pregnancy until term, and the infant was born via spontaneous vaginal delivery at 40 weeks.
Patient 2
A 30-year-old woman, at, 23 weeks gestation in her second pregnancy, presented with recurrent palpitations that had been occurring since early pregnancy. She was diagnosed with PVC in early pregnancy and was given oral propranolol, but her symptoms persisted despite the medication. Clinical examination was unremarkable. ECG revealed sinus rhythm with left bundle branch PVC morphology at V1; positive deflections at leads II, III, and AVF; and transition at V4. The 24-hour Holter monitoring demonstrated a PVC burden of 23%, and zero fluoroscopy PVC ablation was offered. Echocardiography showed a structurally normal heart. She underwent zero fluoroscopy PVC ablation at 23 weeks of pregnancy, and radiofrequency ablation was performed at the subpulmonic posterolateral RVOT. Post-procedure, her symptoms improved, and ECG revealed sinus rhythm.
Patient 3
A 35-year-old woman at 18 weeks of gestation presented with reduced effort tolerance that she had been experiencing since early pregnancy. She had underlying high-burden RVOT PVC, for which she had previously refused intervention. NYHA functional class I-II was assigned. Her clinical examination was unremarkable. ECG revealed sinus rhythm with frequent PVC; echocardiography revealed a left ventricular ejection fraction (LVEF) of 60% with no other abnormalities. She underwent zero fluoroscopy PVC ablation at the subvalvular posteroseptal RVOT region. Afterward, her symptoms improved remarkably. The pregnancy was carried until term, and the infant was delivered via normal vaginal delivery at 39 weeks.
Patient 4
A 34-year-old woman with underlying high-burden PVC was initially planned for PVC ablation, but she was found to be 10 weeks pregnant. She was otherwise asymptomatic, and the clinical examination was unremarkable. ECG showed sinus rhythm with frequent PVC. Echocardiography showed an LVEF of 20% to 25% with global hypokinesia and a dilated left ventricular chamber. Owing to the impaired LVEF, PVC ablation was advised despite the patient being asymptomatic and without assessing the PVC burden on 24-hour Holter monitoring. Zero fluoroscopy PVC ablation was performed over the anteroseptal RVOT, and the PVC was successfully terminated. On follow-up, LVEF improved to 55%, and she delivered a term infant at 39 weeks via normal vaginal delivery.
Patient 5
A 21-year-old primigravida at 23 weeks of pregnancy presented with palpitations, which she began experiencing since the beginning of the second trimester. The patient experienced shortness of breath; NYHA functional class II was assigned. Clinical examination was unremarkable. ECG demonstrated a sinus rhythm with frequent PVC. Echocardiography showed an LVEF of 60% with no other abnormalities. She underwent zero fluoroscopy PVC ablation at the posteroseptal subvalvular RVOT. The remainder of her pregnancy was unremarkable, and she delivered a term infant at 40 weeks via normal vaginal delivery.
Patient 6
A 27-year-old woman in her second pregnancy presented with recurrent presyncope at the beginning of the second trimester. Presyncope was associated with palpitations and worsened on exertion. ECG demonstrated a sinus rhythm with frequent PVC. She underwent zero fluoroscopy PVC ablation over the anteroseptal RVOT. She delivered her infant at 38 weeks via elective cesarean section owing to a previous scar.
Discussion
This case series describes 6 pregnant patients with high-burden PVC who underwent zero fluoroscopy with single-catheter PVC ablation. Tables 1 and 2 illustrate patient characteristics and outcome, respectively. Various physiological adaptations in pregnancy induce alterations in hemodynamic status, adrenergic response, and levels of catecholamines and neurohormones. These alterations may also aggravate maternal arrhythmias in pregnant women. PVC is the most common arrhythmia that occurs during pregnancy, but it is not as benign as previously thought, especially among patients with high-burden PVC. Notably, high-burden PVC (≥10%) has been associated with a higher risk of placental abruption, though the causal relationship is unknown.1 In view of this potential risk, a pregnant patient with a high-burden PVC is referred to both cardiologists and obstetricians in our center for further assessment. Before the procedure, the patient is reevaluated extensively before embarking on the procedure. The decision to undergo this procedure is made after a discussion during a multidisciplinary meeting with the patient and her partner.
Table 1.
Demographic Data of Patients Who Underwent Zero-Fluoroscopy Ablation
| Patient 1 | Patient 2 | Patient 3 | Patient 4 | Patient 5 | Patient 6 | |
|---|---|---|---|---|---|---|
| Age, y | 30 | 30 | 35 | 34 | 21 | 27 |
| Main symptom | Palpitation | Palpitation | Dyspnea | Asymptomatic | Palpitation | Presyncope |
| Medication | Verapamil | Propranolol | Bisoprolol | Bisoprolol | Bisoprolol | Bisoprolol |
| PVC morphology description | Left bundle branch PVC morphology at V1, positive at lead II, III, AVF, with transition at V4 | Left bundle branch PVC morphology at V1, positive at lead II, III, AVF with transition V4 | Left bundle branch PVC morphology at V1, positive at lead II, III, AVF with transition V4-V5 | Left bundle branch PVC morphology at V1, positive at lead II, III, AVF with transition V3-V4 | Left bundle branch PVC morphology at V1, positive at lead II, III, AVF, with transition at V4 | Left bundle branch PVC morphology at V1, positive at lead II, III, AVF, with transition at V4 |
| LVEF, % | 55 | 60 | 60 | 25 | 60 | 74 |
| PVC burden per 24 h, % | 25 | 23 | 23 | 42 | NA | 32 |
| Gestational age during procedure, wk | 24 | 23 | 21 | 17 | 23 | 24 |
LVEF = left ventricular ejection fraction; NA = not available; PVC = premature ventricular contraction.
Table 2.
Procedure Description and Outcome for Patients Who Underwent Zero Fluoroscopy PVC Ablation
| Patient 1 | Patient 2 | Patient 3 | Patient 4 | Patient 5 | Patient 6 | |
|---|---|---|---|---|---|---|
| 3D electroanatomical mapping and ablation equipment | Carto 3 with SmartTouch ablation catheter | Carto 3 with SmartTouch ablation catheter | Carto 3 with SmartTouch ablation catheter | Ensite with TactiCath ablation catheter | Carto 3 with SmartTouch ablation catheter | Carto 3 with SmartTouch ablation catheter |
| Site of origin | Posteroseptal RVOT | Posterolateral RVOT | Posteroseptal RVOT | Anteroseptal RVOT | Posteroseptal RVOT | Anteroseptal RVOT |
| Procedure outcome | Success | Success | Success | Success | Success | Success |
| ECG post-procedure | Sinus rhythm | Sinus rhythm | Sinus rhythm | Sinus rhythm | Sinus rhythm | Sinus rhythm |
| Fetal outcome | Delivered term via normal delivery at 40 wk | Currently in last trimester | Delivered term via normal delivery at 39 wk | Delivered term via normal delivery at 39 wk | Delivered term via normal delivery at 39 wk | Elective cesarean section owing to previous scar at 38 wk |
3D = 3-dimensional; ECG = electrocardiogram; PVC = premature ventricular complex; RVOT = right ventricular outflow tract.
Additionally, the use of antiarrhythmic drugs in pregnancy carries a risk of fetal exposure and teratogenicity as these medications may cross the placenta.1 Currently, beta blockers or nondihydropyridine calcium channel blockers are the first-line treatment for symptomatic PVC with structurally normal cardiac function. However, the use of this medication is limited to patients with severe symptoms. Although beta blockers are generally considered relatively safe, they pose an increased risk of growth restriction, preterm birth, neonatal morbidity, and mortality.4 One significant limitation is that pregnant patients usually have lower blood pressure than normal owing to vasodilation caused by the hormone relaxin, which further limits use of this medication.5 By performing a zero fluoroscopy PVC ablation in these mothers, we were able to stop their medication and eliminate the risk related to beta blockers.
The symptoms of palpitation, dyspnea, and presyncope are known to have a poor correlation with documented arrhythmia in nonpregnant patients. This is even more evident during pregnancy, in which pregnancy-related symptoms often overlap. Given the potential risk of continued pregnancy with high burden PVC and medication adverse effects on the fetus, we chose to perform zero fluoroscopy PVC ablation in these highly selected mothers.
The mechanism of PVC involves early ventricular activation that spreads in all directions. This can happen due to automaticity, triggered activity, or microreentry.6 Currently, there are no established guidelines or consensus on the usage of catheter ablation for PVC ablation in pregnancy. Given that there were no available recommendations and with our understanding regarding the single catheter ablation technique, we decided to embark on this procedure.
In our case series, all the PVCs originated from the RVOT based on the surface ECG. It is characterized by with a left bundle branch block, which exhibits negative QRS morphology in V1, as seen in all our patients.
In pregnancy, however, physiological adaptations occur in the cardiovascular system to accommodate higher metabolic demand. One study showed that average pulmonary artery dilation in pregnancy was 2 mm, especially in the second and third trimesters, possibly involving the RVOT.7 Thus, the site of origin of PVC based on ECG may differ between pregnant and nonpregnant patients. It also explained the increase of PVC burden in pregnancy.
Catheter ablation has limited indications in pregnant patients because of concern of x-ray exposure during the electrophysiology procedure. In radiation exposure, there are 2 main biological effects: the deterministic effect (a tissue reaction) and the stochastic effect (carcinogenicity).8 Radiation exposure at high-dose exposure of more than 500 mGy negatively affects growth and development, including intellectual development. Regarding the stochastic effect, a dose exposure of more than 100 mGy increases the risk of cancer for both the mother and the fetus.8 Generally, electrophysiology studies use an average effective dose of 3.2 mSv for diagnostic procedures and 15.2 mSv for ablation, which increases the risk of radiation exposure to the fetus.8 However, zero fluoroscopy electrophysiology procedures can be performed with the help of 3D electroanatomical mapping to help to eliminate these risks.
Performing zero fluoroscopy PVC ablation in pregnancy enabled these patients to continue their pregnancy until term without any adverse complications affecting the mother and fetus development. A recent systematic review comparing catheter ablation and antiarrhythmic drug therapy revealed a lower rate of adverse events in catheter ablation (0%-5.6% vs 9.5%-21%).9 Despite this systematic review involving nonpregnant patients, the low adverse effects with catheter ablation is adequate to justify performing catheter ablation in pregnant mothers, who are always excluded in clinical trials. In addition, our case series takes into account the potential negative effects of beta blockers on the fetus.
Zero fluoroscopy radiofrequency ablation has been shown to be effective in pregnant patients. Chen et al9 reported using zero fluoroscopy catheter ablation in patients with severe drug-resistant arrhythmia using 3D-electroanatomical mapping. In this case series, 1 patient had drug-resistant and poorly controlled high-burden PVC, and another patient experienced recalcitrant supraventricular tachycardia. Mladoniczky et al10 also reported 13 pregnant patients who underwent zero fluoroscopy, which in their study population constituted patients who had severe arrhythmia-related symptoms or drug-refractory symptoms. In these case series, zero fluoroscopy catheter ablation had been performed in patients with atrial tachycardia, atrioventricular reentry tachycardia, atrioventricular nodal reentry tachycardia, and sustained monomorphic ventricular tachycardia. Our case series differed in our population, single catheter approach, and curative aim.
Conclusions
Cardiovascular adaptations in pregnancy are well recognized and important in fetal development. However, approximately 1.68% of pregnant women with structurally normal hearts develop high-burden PVC owing to these adaptations, which is associated with 11.65% of adverse events to both the mother and the fetus. In our case series, zero fluoroscopy PVC ablation in pregnancy was shown to be safe for both the mother and the fetus. PVC ablation during pregnancy also will help the woman to endure the pregnancy without beta blocker usage, which potentially can affect the fetus.
Funding Support and Author Disclosures
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Take-Home Messages
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To perform risk stratification of PVC management in pregnant patients.
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To identify the potential effect of PVC on pregnancy outcomes.
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To demonstrate the zero fluoroscopy PVC ablation procedure in pregnant patients.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
References
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