Association of fetal heart rate short term variability pattern during term labor with neonatal morbidity and small for gestational age status

OBJECTIVE

To assess the association of fetal heart rate short-term variability (STV) pattern during term labor with both neonatal composite morbidity (cord blood pH ≤ 7.10 and/or neonatal intensive care unit admission and/or Apgar score at 5 min <7) and small for gestational age (SGA) status.

STUDY DESIGN

Retrospective cohort in a single academic institution between January 2016 and December 2018. A total of 1896 women that delivered a singleton during labor in cephalic presentation after 37 weeks of gestation were included (948 women with SGA neonates and 948 women with appropriate weight for gestational age (AGA) neonates that were matched to women with SGA neonates based on maternal age, parity, induction of labor, gestational diabetes, gestational age at delivery and a history of one cesarean section using propensity score matching). STV was compared at labor onset (cervical dilation ≤ 4 cm), in the first stage of labor (cervical dilation = 6 cm) and in the second stage of labor (cervical dilation = 10 cm). A generalized linear mixed model was used to assess the association between SGA status, neonatal composite morbidity and STV.

RESULTS

After adjustment for maternal origin, term, gestational diabetes, labor length, SGA status was not associated with any change in STV during labor (mean adjusted STV: -0.20 ms, 95 %CI[-0.58-0.17], p = 0.284 at labor onset, 0.29 ms, 95 %CI[-0.1- 0.68], p = 0.155, in the first stage of labor and 0.36 ms, 95 %CI[-0.02-0.74], p = 0.065 in the second stage of labor). In case of neonatal composite morbidity mean adjusted STV was lower in the first stage of labor (mean adjusted STV: -1.29 ms, 95 %CI[-2.1 - -0.43], p = 0.003) and in the second stage of labor (mean adjusted STV: -1.15 ms, 95 %CI[-1.96 - -0.34], p = 0.005). The results were similar with the addition of delivery mode and meconium-stained amniotic fluid in the model or non-reassuring fetal heart rate and meconium-stained amniotic fluid.

CONCLUSIONS

This work suggests that STV decrease during term labor is associated with fetal well-being, independently of fetal weight. This suggests that further prospective studies should consider the evaluation of this parameter in the prediction of neonatal compromise.

Detection of Persistent Viruses by High-Throughput Sequencing in Tomato and Pepper from Panama: Phylogenetic and Evolutionary Studies

High-throughput sequencing from symptomatic tomato and pepper plants collected in Panama rendered the complete genome of the southern tomato virus (isolate STV_Panama) and bell pepper endornavirus (isolate BPEV_Panama), and almost-complete genomes of three other BPEV isolates. Tomato chlorosis virus, tomato mosaic virus, and impatiens necrotic spot virus were also detected. Analysis of the complete genome of STV and BPEV worldwide isolates revealed nucleotide diversities of 0.004246 and 0.070523, respectively. Bayesian phylogenetic analysis showed two main groups for each virus (I and II), and several subgroups for BPEV (IA, IB, IC, IIA and IIB). Isolate STV_Panama clustered with NC_12-03-08 from USA and Tom3-T from France (99.97% nucleotide identity) in Group I and BPEV_Panama was close to the Canadian isolate BPEV_Ontario (99.66% nucleotide identity) in Subgroup IB. No correlation was observed between geographic and genetic distances for both viruses. Panamanian BPEV isolates were divergent, belonging to Groups I and II (nucleotide identities > 87.33%). Evolutionary analysis showed purifying selection in all encoding regions of both viruses, being stronger in the overlapping region of both STV genes. Finally, recombination was detected in BPEV but not in STV. This is the first report of STV and BPEV in Panama.

Intrapartum PRSA: a new method to predict fetal acidosis?-a case-control study

PURPOSE

Phase-rectified signal averaging method (PRSA) represents an analysis method which applied on fetal cardiotocography (CTG) allows the quantification of the speed of fetal heart rate changes. By calculating the average deceleration capacity (ADC) an assessment of the fetal autonomic nervous system (ANS) is possible. The objective of this study was to test its ability to predict perinatal acidosis.

METHODS

A case-control study was performed at a University Hospital in Munich. All intrapartum CTG heart rate tracings saved during a 7-year period were considered for analysis. All neonates born with an umbilical arterial blood pH ≤ 7.10 were considered as cases. Controls were defined as healthy fetuses born with a pH ≥ 7.25. The main matching criteria were gestational age at delivery, parity, birth mode, and birth weight percentile. Exclusion criteria were a planned caesarean section, fetal malformations, and multiple pregnancies. ADC and STV were then calculated during the last 60, the last 45, and the last 30 min intervals prior to delivery.

RESULTS

Of all stored birth CTG recordings, 227 cases met the inclusion criteria and were studied. ADC was significantly higher in fetuses born with acidemia (4.85 bpm ± 3.0) compared to controls (3.36 bpm ± 2.2). The area under ROC curve was 0.659 (95% CI 0.608-0.710) for ADC and 0.566 (0.512-0.620) for STV (p = 0.013).

CONCLUSIONS

This study confirms that the assessment of ADC using PRSA represents a good additional tool for the prediction of acute fetal acidosis during delivery.

Influence of gestational diabetes on fetal autonomic nervous system: a study using phase-rectified signal-averaging analysis

OBJECTIVES

Maternal gestational diabetes mellitus (GDM) is known to influence fetal physiology. Phase-rectified signal averaging (PRSA) is an innovative signal-processing technique that can be used to investigate fetal heart signals. The PRSA-calculated variables average acceleration capacity (AAC) and average deceleration capacity (ADC) are established indices of autonomic nervous system (ANS) function. The aim of this study was to evaluate the influence of GDM on the fetal cardiovascular and ANS function in human pregnancy using PRSA.

METHODS

This was a prospective clinical case-control study of 58 mothers with diagnosed GDM and 58 gestational-age matched healthy controls in the third trimester of pregnancy. Fetal cardiotocography (CTG) recordings were performed in all cases at entry to the study, and a follow-up recording was performed in 19 GDM cases close to delivery. The AAC and ADC indices were calculated by the PRSA method and fetal heart rate short-term variation (STV) by CTG software according to Dawes-Redman criteria.

RESULTS

Mean gestational age of both groups at study entry was 35.7 weeks. There was a significant difference in mean AAC (1.97 ± 0.33 bpm vs 2.42 ± 0.57 bpm; P < 0.001) and ADC (1.94 ± 0.32 bpm vs 2.28 ± 0.46 bpm; P < 0.001) between controls and fetuses of diabetic mothers. This difference could not be demonstrated using standard computerized fetal CTG analysis of STV (controls, 10.8 ± 3.0 ms vs GDM group, 11.3 ± 2.5 ms; P = 0.32). Longitudinal fetal heart rate measurements in a subgroup of women with diabetes were not significantly different from those at study entry.

CONCLUSIONS

Our findings show increased ANS activity in fetuses of diabetic mothers in late gestation. Analysis of human fetal cardiovascular and ANS function by PRSA may offer improved surveillance over conventional techniques linking GDM pregnancy to future cardiovascular dysfunction in the offspring. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Fast detection of Southern tomato virus by one-step transcription loop-mediated isothermal amplification (RT-LAMP)

Southern tomato virus (STV) is a double stranded RNA (dsRNA) virus belonging to genus Amalgavirus (family Amalgamaviridae) which has been detected in tomato plants showing stunting, fruit discoloration and size reduction. A one-step reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the detection of STV in total RNA or sap extracts (obtained just by grinding in buffer) from STV-infected tomato plants by using a set of three primers pairs which were designed to the sequence of the STV putative coat protein. Amplification products were visualized by gel electrophoresis or direct staining of DNA. The sensitivity of RT-LAMP was identical to that of the conventional RT-PCR and less affected by the presence of polymerase inhibitors. STV was detected by RT-LAMP in different tomato tissues, i.e. leaves, roots, fruits and seeds. Also the virus was successfully detected by RT-LAMP from sap extracts obtained from field tomato plants whereas conventional RT-PCR did not. Results of this work show that RT-LAMP is a specific, rapid and cheap procedure to detect STV and it could be implemented on field surveys and sanitation programs.

Phase-rectified signal averaging method to predict perinatal outcome in infants with very preterm fetal growth restriction- a secondary analysis of TRUFFLE-trial

BACKGROUND

Phase-rectified signal averaging, an innovative signal processing technique, can be used to investigate quasi-periodic oscillations in noisy, nonstationary signals that are obtained from fetal heart rate. Phase-rectified signal averaging is currently the best method to predict survival after myocardial infarction in adult cardiology. Application of this method to fetal medicine has established significantly better identification than with short-term variation by computerized cardiotocography of growth-restricted fetuses.

OBJECTIVE

The aim of this study was to determine the longitudinal progression of phase-rectified signal averaging indices in severely growth-restricted human fetuses and the prognostic accuracy of the technique in relation to perinatal and neurologic outcome.

STUDY DESIGN

Raw data from cardiotocography monitoring of 279 human fetuses were obtained from 8 centers that took part in the multicenter European "TRUFFLE" trial on optimal timing of delivery in fetal growth restriction. Average acceleration and deceleration capacities were calculated by phase-rectified signal averaging to establish progression from 5 days to 1 day before delivery and were compared with short-term variation progression. The receiver operating characteristic curves of average acceleration and deceleration capacities and short-term variation were calculated and compared between techniques for short- and intermediate-term outcome.

RESULTS

Average acceleration and deceleration capacities and short-term variation showed a progressive decrease in their diagnostic indices of fetal health from the first examination 5 days before delivery to 1 day before delivery. However, this decrease was significant 3 days before delivery for average acceleration and deceleration capacities, but 2 days before delivery for short-term variation. Compared with analysis of changes in short-term variation, analysis of (delta) average acceleration and deceleration capacities better predicted values of Apgar scores <7 and antenatal death (area under the curve for prediction of antenatal death: delta average acceleration capacity, 0.62 [confidence interval, 0.19-1.0]; delta short-term variation, 0.54 [confidence interval, 0.13-0.97]; P=.006; area under the curve for prediction Apgar <7: average deceleration capacity <24 hours before delivery, 0.64 [confidence interval, 0.52-0.76]; short-term variation <24 hours before delivery, 0.53 [confidence interval, 0.40-0.65]; P=.015). Neither phase-rectified signal averaging indices nor short-term variation showed predictive power for developmental disability at 2 years of age (Bayley developmental quotient, <95 or <85).

CONCLUSION

The phase-rectified signal averaging method seems to be at least as good as short-term variation to monitor progressive deterioration of severely growth-restricted fetuses. Our findings suggest that for short-term outcomes such as Apgar score, phase-rectified signal averaging indices could be an even better test than short-term variation. Overall, our findings confirm the possible value of prospective trials based on phase-rectified signal averaging indices of autonomic nervous system of severely growth-restricted fetuses.

Vernakalant is devoid of proarrhythmic effects in the complete AV block dog model

The anesthetized chronic AV-blocked dog (cAVB) and methoxamine-sensitized rabbit model are widely used to determine pro-arrhythmic properties of drugs. In general, both models show similar results. However, conflicting data have also been reported; K201 and AZD1305 induced Torsade de Pointes (TdP) exclusively in cAVB dogs. Vernakalant, an antiarrhythmic drug that blocks several ion channels has been approved only in Europe. Its propensity to induce repolarization-dependent TdP arrhythmias has been evaluated solely in the methoxamine-sensitized rabbits. We therefore assessed the proarrhythmic potential of vernakalant in the cAVB dog model. Vernakalant was evaluated in 10 mongrel dogs (sinus rhythm (SR) 2mg/kg; chronic AV block (cAVB) 2+3mg/kg). The same dogs were challenged with dofetilide (25 μg/kg) to evaluate TdP inducibility. During the serial experiments the animals were paced from the right ventricular apex (60 beats/min). Short-term variability of repolarization (STV) was quantified for proarrhythmic risk. In SR (n=8) vernakalant prolonged QT (265 ± 11 to 311 ± 18 ms P<0.01(**)) but not PQ or QRS. In cAVB (n=8), 2mg/kg vernakalant prolonged QT (391 ± 43 to 519 ± 73 ms(**)) and QRS (103 ± 24 to 108 ± 23 ms(**)). After a 30 min lag-time, 3mg/kg vernakalant (n=4) increased QT to a lesser extent (413 ± 34 to 454 ± 27 ms(**)) while maintaining QRS prolongation (114 ± 18 to 122 ± 20 ms(**)). Neither dose increased STV or caused arrhythmias. Dofetilide prolonged QT (398 ± 51 to 615 ± 71 ms(**)), increased STV (1.0 ± 0.4 to 2.2 ± 1.0 ms P<0.05(⁎)) and induced TdP arrhythmias in 6/8(⁎) cAVB dogs. Vernakalant did not induce arrhythmias in the cAVB dog model. Higher dosages (3mg/kg) did not prolong repolarization further whereas negative inotropic effects were starting to become apparent precluding further increases in dose.