The entire fetal echocardiogram volume for the study period was 11,704 (1,950/year) consisting of a total of 8368 pregnancies. The pre-COVID cohort had a total of 5,634 (1,878/year) fetal echocardiograms performed on 3843 patients and the peri-COVID cohort had a total of 6,070 (2,023/year) fetal echocardiograms performed on 4525 patients. There was an 8% increase in fetal echocardiogram volumes and 17% increase in total patient volumes between the two periods.
The REDCap search resulted in information on 45 total patients with the searched diagnostic codes: 17 with “SVT/ORT - Orthodromic reciprocating tachycardia”, 8 with “Atrial Flutter”, 2 with “Ventricular Tachycardia (VT)”, 6 with “Tachycardia-Other”, and 12 with “Third Degree or Complete Heart Block”.
The medical records of the 45 patients with fetal arrhythmia were examined to confirm type of arrhythmia diagnosis. Table 1 describes maternal demographic, pregnancy characteristics and information about fetal arrhythmia. After analysis of the medical record, the final division of diagnoses was 19 with supraventricular tachycardia (SVT), 8 with Atrial Flutter (AF), 1 with Ventricular Tachycardia (VT), 5 with another tachycardia diagnosis, and 12 with complete heart block (CHB). The most common other tachycardia diagnosis was non-sustained atrial tachycardia with documentation of tachycardia < 50% of the monitored time. Of those with documented fetal tachycardia, 15 (45%) were in the pre-COVID cohort and 18 (55%) were in the peri-COVID cohort. 4 tachycardia patients had no postnatal data available due to being lost to fetal follow up or pregnancy termination. Of patients with CHB, 4 (33.3%) were in the pre-COVID cohort and 8 (66.7%) were in the peri-COVID cohort. Four CHB patients had no postnatal data available due to being lost to fetal follow up or pregnancy termination. No patients with tachycardia or CHB had significant associated congenital heart disease which could be related to their underlying arrhythmia diagnosis. The single patient with VT was eventually diagnosed with long QT syndrome by fetal magnetocardiography and subsequently treated with Propranolol. There were no recognizable changes in the maternal age at presentation, percentages of female fetuses, estimated gestational age at delivery, or the prevalence of hydrops, pericardial effusion, or ventricular dysfunction at the time of diagnosis. The estimated gestational age at diagnosis for the entire patient group was notably lower in the peri-COVID cohort (median 25.8 weeks vs 30.7 weeks in pre-COVID cohort). The percentage of tachycardia patients requiring postnatal treatment with antiarrhythmic therapy increased from 53.8–62.5% as well. In the CHB patient group, the percentage of patients with documented antibody mediated heart block increased from 50% in the pre-COVID cohort to 87.5% in the peri-COVID cohort.
The fetal arrhythmia incidence at our institution is detailed in Table 2. The total incidence of significant fetal arrhythmia increased from 4.94 cases per 1000 pregnancies in the pre-COVID cohort to 5.75 cases per 1000 pregnancies in the per-COVID cohort. While AF and other non-sustained tachyarrhythmias show some decrease, SVT incidence increased from 1.82/1000 pregnancies to 2.65/1000 pregnancies, a 45% increase. CHB incidence also increased from 1.04/1000 pregnancies to 1.77/1000 pregnancies which is a 70% increase.
Table 1
Descriptive statistics of fetal arrhythmia cohorts. Values are mean +/- SD, n (%), or median (IQR)
| Overall (n = 45) | pre-COVID (n = 19) | peri-COVID (n = 26) |
Maternal age, y | 31.9 +/- 5.4 | 31.0 +/- 5.4 | 32.5 +/- 5.4 |
Maternal race | | | |
White | 24 (53.3) | 8 (42.1) | 16 (61.5) |
Black or African-American | 11 (24.5) | 5 (26.3) | 6 (23.1) |
American Indian or Alaskan Indian | 0 (0.0) | 0 (0.0) | 0 (0.0) |
Asian | 5 (11.1) | 2 (10.5) | 3 (11.5) |
Native Hawaiian or other Pacific Islander | 0 (0.0) | 0 (0.0) | 0 (0.0) |
Other | 4 (8.9) | 4 (21.1) | 0 (0.0) |
Unknown | 1 (2.2) | 0 (0.0) | 1 (3.9) |
Female, fetus | 25 (55.6) | 11 (57.9) | 14 (53.8) |
Type of fetal arrhythmia | | | |
SVT | 19 (42.2) | 7 (36.8) | 12 (46.1) |
AF | 8 (17.8) | 5 (26.3) | 3 (11.5) |
VT | 1 (2.2) | 0 (0.0) | 1 (3.8) |
Other tachycardia | 5 (11.1) | 3 (15.8) | 2 (7.7) |
CHB | 12 (26.7) | 4 (21.1) | 8 (30.9) |
EGA at diagnosis, wk | 28.1 (23.0-32.6) | 30.7 (23.9–34.7) | 25.8 (23.0-31.5) |
EGA at delivery, wk | 37.9 (36.3–39.0) | 38.0 (35.9–39.1) | 37.4 (36.4–39.0) |
Hydrops | 10 (22.2) | 5 (26.3) | 5 (19.2) |
Pericardial Effusion | 17 (37.8) | 8 (42.1) | 9 (34.6) |
Ventricular Dysfunction | 12 (26.7) | 5 (26.3) | 7 (26.9) |
Fetal tachycardia cohort | 33 (73.3) | 15 (78.9) | 18 (69.2) |
Maximum fetal heart rate (beats/min) | 235.7 +/- 46.1 | 239.0 +/- 36.2 | 233.5 +/- 52.8 |
Duration of fetal tachycardia, d | 7.0 (2.0–13.0) | 4.0 (2.0–7.0) | 9.5 (4.8–17.3) |
Transplacental digoxin | 17 (51.5) | 8 (53.3) | 9 (50.0) |
Fetal Intramuscular digoxin | 3 (9.1) | 0 (0.0) | 3 (16.7) |
Transplacental amiodarone | 2 (6.1) | 0 (0.0) | 2 (11.1) |
Transplacental Flecainide | 12 (36.3) | 4 (26.7) | 8 (44.4) |
Transplacental Sotolol/Propanolol | 5 (15.2) | 2 (13.3) | 3 (16.7) |
Duration of transplacental therapy, d | 39.0 (24.0-88.3) | 33.0 (18.0-60.3) | 61.0 (33.3–97.3) |
Postnatal treatment required* | 19 (65.5) | 7 (53.8) | 10 (62.5) |
Fetal CHB cohort | 12 (26.7) | 4 (21.1) | 8 (30.8) |
Ventricular rate at diagnosis (beats/min) | 57.0 +/- 9.3 | 62.8 +/- 12.3 | 54.1 +/= 6.5 |
Minimum fetal ventricular rate (beats/min) | 49.5 +/- 11.2 | 36.2 +/- 11.4 | 52.8 +/- 10.6 |
Transplacental steroids | 9 (75.0) | 2 (50.0) | 7 (87.5) |
Antibody-mediated | 9 (75.0) | 2 (50.0) | 7 (87.5) |
Antibody diagnosis after CHB diagnosis | 10 (83.3) | 4 (100) | 6 (75.0) |
Postnatal treatment required** | 7 (87.5) | 2 (100) | 5 (83.3) |
AF = atrial flutter, SVT = supraventricular tachycardia, VT = ventricular tachycardia, CHB = complete heart block, EGA = estimated gestational age
*4 tachycardia patients with no postnatal data
**4 CHB patients with no postnatal data
Table 2
Arrhythmia incidence divided by pre-COVID and peri-COVID time periods. Values are cases per 1000 pregnancies.
Diagnosis | pre-COVID (n = 19) | peri-COVID (n = 26) |
SVT | 1.82 | 2.65 |
AF | 1.3 | 0.66 |
VT | 0 | 0.22 |
CHB | 1.04 | 1.77 |
Other | 0.78 | 0.44 |
Total | 4.94 | 5.75 |
PAC = premature atrial contraction, SVT = supraventricular tachycardia, AF = atrial flutter, VT = ventricular tachycardia, CHB = complete heart block |