Baseline characteristics and fetal or neonatal outcomes
6, 148 pregnant women who fulfilled the inclusion criteria were enrolled consecutively, of which 103 had symptomatic or asymptomatic PVCs. A total of 17 adverse events occurred in 103 pregnant women with PVCs, including 5 cases of respiratory distress syndrome, 5 preterm births and 7 small-for-gestational-age births. Finally, only 12 women with adverse events were counted, as multiple events occurred in some of them simultaneously. The remaining defined adverse events did not occur. The other 91 pregnant women with PVCs delivered safely without adverse events. A total of 177 fetal and neonatal adverse cases were counted in the cohort of 6,045 pregnant women without PVCs. The incidence of adverse events was significantly higher in PVC cases (11.65%) than in those without PVC (2.93%) (Fig. 1).
Cardiac rhythm of pregnant women with PVCs
The pregnant women with PVCs were divided into two groups on the basis of the presence or absence of adverse events. The baseline characteristics are listed in Table 1. The proportion of bigeminy PVCs was significantly higher in pregnant women with adverse fetal or neonatal outcomes (50% vs. 19.8%, p < 0.05), as was the median PVC burden, than in women without adverse events (9.02% vs. 2.30%, p < 0.01). The median documented PVC burden was 2.84% (1.02–6.10%). Eight pregnancies had a maximal PVC burden > 10%, and of these, 2 pregnancies had a PVC burden > 20%. Although the LVEF of the adverse outcome group was within the normal range, it remained slightly lower than that of the control group (64.16 ± 1.56% vs. 65.69 ± 2.54%, p < 0.05). There were no other significant differences in the remaining baseline data between the two groups.
Table 1
༎ Baseline characteristics of pregnant women with premature ventricular contractions
Characteristic
|
No adverse events
(n = 91)
|
Adverse events
(n = 12)
|
P value
|
Age, y
|
30.46 ± 4.62
|
32.67 ± 5.55
|
0.132
|
Previous abortion(%)
|
32(35.2)
|
5(41.7)
|
0.752
|
ECG
|
|
|
|
V-Bigeminy(%)
|
18(19.8)
|
6(50.0)
|
0.030
|
Multifocal PVC(%)
|
2(2.2)
|
2(16.7)
|
0.066
|
NSVT(%)
|
1(1.1)
|
0(0)
|
1.000
|
Origin
|
|
|
|
LV(%)
|
28(30.8)
|
5(41.7)
|
0.515
|
PVC burden(%)
|
2.30(0.88,4.85)
|
9.02(7.43,11.71)
|
0.000
|
LVEF
|
65.69 ± 2.54
|
64.16 ± 1.56
|
0.032
|
Childbirth type
|
|
|
|
Natural childbirth(%)
|
55(60.4)
|
5(41.7)
|
0.351
|
Data are expressed as mean ± SD, medians (25th–75th percentiles), or number (percentage). ECG, electrocardiogram; PVC, premature ventricular contraction; NSVT, non-sustained ventricular tachycardia; LV, left ventricular; LVEF, left ventricular ejection fraction |
12-Lead ECG showed normal sinus rhythm with premature ventricular complexes in the study. PVCs with an LBBB and inferior axis, most likely originating from RVOT, were found in 41.75% of pregnancies with PVCs. In contrast, PVCs with an RBBB and inferior axis, frequently associated with the left ventricular outflow tract (LVOT), accounted for approximately 11.65%, far less than PVCs associated with the RVOT. According to the special morphology of PVCs reported in the previous literature12–15, PVCs originating from the tricuspid annulus account for approximately 12.62% and 20.39% of PVCs originating from the papillary muscles or fascicle of the left ventricle, respectively. A total of 9.71% of PVC origins could not be determined from the ECG (Fig. 2).
Predictors of fetal and neonatal outcomes
The baseline characteristics of the study cohort suggested that the average burden of PVCs was related to adverse outcomes, so the burden of PVCs was further divided into low (< 33rd percentile), middle (33rd-67th percentile) and high groups (> 67th percentile) according to the percentile of the average PVC burden (Fig. 3). The incidence of adverse events was significantly higher in the high-burden PVC group than in the low and middle groups, indicating that the higher the PVC burden, the higher the likelihood of adverse events would be.
Univariable logistic regression analysis demonstrated that the LVEF, bigeminy and burden of PVCs were associated with adverse fetal or neonatal outcomes among pregnant women with PVCs; however, statistical significance was evident for PVC burden only in the multivariate logistic regression analysis (OR: 1.34, 95% CI (1.11–1.61), p < 0.05, Table 2).
Table 2
༎ Logistic regression analysis for adverse events in pregnant women with PVCs
|
Univariable analysis OR (95% CI)
|
Multivariable analysis OR (95% CI)
|
OR
|
95%CI
|
P value
|
OR
|
95%CI
|
P value
|
V-Bigeminy
|
4.06
|
(1.17,14.07)
|
0.027
|
|
|
|
PVC burden
|
1.35
|
(1.14,1.58)
|
0.000
|
1.34
|
(1.11,1.61)
|
0.002
|
LVEF
|
0.76
|
(0.58,1.00)
|
0.049
|
|
|
|
PVC, premature ventricular contraction; OR, odds ratio; CI, confidence interval; LVEF, left ventricular ejection fraction |