Significance of Neonatal Heart Rate in the Delivery Room-A Review

BACKGROUND

Heart rate (HR) is considered the main vital sign in newborns during perinatal transition, with a threshold of 100 beats per minute (bpm), below which, intervention is recommended. However, recent changes in delivery room management, including delayed cord clamping, are likely to have influenced normal HR transition.

OBJECTIVE

To summarize the updated knowledge about the factors, including measurement methods, that influence HR in newborn infants immediately after birth. Additionally, this paper provides an overview of delivery room HR as a prognostic indicator in different subgroups of newborns.

METHODS

We searched PubMed, EMBASE, and Google Scholar with the terms infant, heart rate, delivery room, resuscitation, pulse oximetry, and electrocardiogram.

RESULTS

Seven studies that described HR values in newborn infants immediately after birth were included. Pulse oximetry-derived HR percentiles after immediate cord clamping may not be applicable to the current practice of delayed cord clamping and the increasing use of delivery room electrocardiograms. Mask ventilation may adversely affect HR, particularly in premature and non-asphyxiated infants. Prolonged bradycardia is a negative prognostic factor, especially if combined with hypoxemia in infants <32 weeks of gestation.

CONCLUSIONS

HR assessment in the delivery room remains important. However, the cardiopulmonary transition is affected by delayed cord clamping, gestational age, and underlying conditions.

P3433Growth differentiation factor 15 predicts subclinical left ventricular dysfunction: Data from the Akershus Cardiac Examination 1950 Study

Background

Growth differentiation factor 15 (GDF-15) is upregulated in response to both acute and chronic cardiac injury, and concentrations of GDF-15 are increased in acute myocardial infarction and acute heart failure. Associations between GDF-15, left ventricular structure and preclinical stages of left ventricular dysfunction in the general population remain unclear.

Methods

We measured GDF-15 in 1237 women and 1158 men participating in the prospective observational Akershus Cardiac Examination (ACE) 1950 Study, which included community dwellers aged 63–65 residing in Akershus county, Norway. All study participants were free from known coronary heart disease and underwent extensive cardiovascular phenotyping at baseline, including detailed echocardiography. Regression models were constructed on global longitudinal strain (GLS), left ventricular mass index (LVMI), and left ventricular ejection fraction (LVEF), and adjusted for demographics, established cardiovascular risk factors, hs-cTnT and NT-proBNP.

Results

Concentrations of GDF-15 were measurable in 98.1% of study participants, and were positively associated with male sex, age, BMI, current smoking, diabetes mellitus, as well as concentrations C-reactive protein, hs-cTnT and NT-proBNP. Higher education, alcohol consumption, eGFR and concentrations of total cholesterol were all associated with lower concentrations of GDF-15. Concentrations of lnGDF-15 were significantly associated with GLS (B −0.44 [95% CI −0.70 to −0.18]; Figure) and LVEF (B 0.72 [95% CI 0.14–1.29]), but not LVMI (Table).

Table 1. Associations between GDF-15 and indices of left ventricular structure and function. Model 1 Model 2 Model 3 B (95% CI)   GLS (n=2395) 0.17 (−0.07 to 0.42) −0.04 (−0.28 to 0.20) −0.44 (−0.70 to −0.18)   LVEF (n=2383) 0.01 (−0.52 to 0.54) 0.21 (−0.31 to 0.73) 0.72 (0.14 to 1.29)   LVMI (n=2371) 2.00 (0.32 to 3.68) −0.37 (−1.98 to 1.24) −0.42 (−2.16 to 1.33) OR (95% CI)   GLS (n=2395) 1.35 (0.98 to 1.87) 1.28 (0.92 to 1.78) 0.81 (0.56 to 1.17)   LVEF (n=2383) 1.04 (0.75 to 1.44) 0.88 (0.62 to 1.24) 0.73 (0.50 to 1.07)   LVMI (n=2371) 1.27 (0.91 to 1.76) 1.12 (0.79 to 1.57) 1.11 (0.75 to 1.64) Linear regression models constructed on continuous levels of GLS, LVMI and LVEF. Logistic regression models constructed on the upper sex specific deciles of GLS and LVMI, and on the lower sex specific decile of LVEF. GDF-15, hs-cTnT and NT-proBNP were all transformed by the natural logarithm. Model 1, unadjusted. Model 2, adjusted for sex, age and study site. Model 3, adjusted for sex, age, study site, BMI, eGFR, total and HDL cholesterol, CRP, higher education, hypertension, diabetes mellitus, statin use, current smoking, alcohol consumption, hs-cTnT and NT-proBNP.

Figure 1

Conclusion

Concentrations of GDF-15 are inversely associated with GLS, a highly sensitive index of subclinical myocardial dysfunction. In healthy subjects free from known cardiovascular disease, GDF-15 appears protective and promotes beneficial cardiac function.

Correction: Nerdrum Aagaard et al. Significance of Neonatal Heart Rate in the Delivery Room-A Review. Children, 10, 1551

In the original publication [...].

Prediction of incident atrial fibrillation with GDF-15 and echocardiographic left atrial volumes: data from the Akershus cardiac examination 1950 study

Background

Left atrial structural remodeling is associated with the risk of incident atrial fibrillation, but there is uncertainty as to what echocardiographic left atrial indices that best predict incident atrial fibrillation. GDF-15 is a marker of oxidative stress and inflammation that is closely associated with the risk of stroke, bleeding and mortality in patients with atrial fibrillation. There is, however, limited data regarding its relation with left atrial remodeling and incident atrial fibrillation in the general population.

Purpose

To investigate the association between GDF-15 and left atrial volumes, and their prognostic properties for incident atrial fibrillation in a general population cohort.

Methods

The Akershus Cardiac Examination 1950 Study is a population-based cohort of individuals born in 1950. Comprehensive baseline examinations were performed for 3706 study participants in 2012–2015. Left atrial maximum and minimum volumes were measured, indexed to body surface area yielding LAVimax and LAVimin. Left atrial emptying fraction (LAEF) was calculated as ((LAVimax - LAVimin)/LAVimax)x100%. Individuals with known atrial fibrillation at baseline (n=166) were excluded, leaving 3540 included in this analysis. National health registries provided clinical outcome data regarding atrial fibrillation and death from any cause. Incident atrial fibrillation cases were validated by health records. Atrial flutter was included in the outcome definition. The CHARGE-AF risk score for atrial fibrillation was quantified. Prediction of incident atrial fibrillation was assessed by Cox proportional hazards regression models and visualised by Kaplan-Meier plots.

Results

Mean age at baseline was 63.9±0.7 years and 1763 (49.8%) were female. GDF-15 correlated weakly with LAVimax (r=−0.07, p&lt;0.001) and LAVimin (r=−0.05 p=0.007), but not with LAEF (r=−0.01, p=0.61). During a median follow-up of 6.4 years, incident atrial fibrillation occurred in 135 (3.8%) individuals. Subjects who developed atrial fibrillation had larger LAVimax (30.1±8.3 vs. 26.2±6.9 mL/m2; p&lt;0.001), larger LAVimin (17.1±7.1 vs. 14.1±4.7 mL/m2; p&lt;0.001), and lower LAEF (44.3±10.7 vs. 46.3±9.0%; p=0.019). Concentrations of GDF-15 were not significantly different in those who experienced atrial fibrillation (median 850 [670–1107] vs. 790 [630–1020] ng/L; p=0.06). Left atrial volumes and LAEF, but not GDF-15, were associated with incident atrial fibrillation (Table 1 and Figure 1).

Conclusions

In this population-based cohort study, LAVimax, LAVimin, and LAEF predicted incident atrial fibrillation independently of the CHARGE-AF risk score. GDF-15 was not significantly associated with left atrial structural remodeling or with increased risk of incident atrial fibrillation.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Vestre Viken HF, Hospital TrustAkershus University Hospital

P1270 Systolic blood pressure at age 40 is associated with left atrial volumes at age 64

Funding Acknowledgements

Vestre Viken Hospital Trust

Background

Left atrial (LA) enlargement is associated with elevated blood pressure (BP) and with cardiovascular morbidity and mortality. In the assessment of LA size, echocardiographic guidelines recommend the use of LA end-systolic volume (LAVmax). LA end-diastolic volume (LAVmin) and LA emptying fraction (LAEF) may add valuable information in risk assessment. The knowledge of early adulthood BP and its association to LA volumes and LAEF later in life is limited.

Purpose

To explore the association between systolic BP at age 40 and LA volumes and LAEF at age 64.

Methods

We linked data from subjects who had participated in both a nationwide cardiovascular screening survey (1990-1991) at the age of 40, and the Akershus Cardiac Examination (ACE) 1950 Study (2012-2015) at the age of 64 (n = 2,597). In the ACE 1950 Study, LAVmax and LAVmin were measured with echocardiography according to the summation of discs method. LAEF was calculated as (LAVmax-LAVmin/LAVmax)x100%. The association between systolic BP at age 40 and LA volumes and LAEF at age 64 was assessed in univariate and multivariate linear regression analyses.

Results

Systolic BP at age 40 was associated with LAVmax and LAVmin but not with LAEF at age 64. In our multivariate model, a 10 mm Hg higher systolic BP at age 40 was associated with a 0.9 ml greater LA end-systolic volume and a 0.5 ml greater LA end-diastolic volume at age 64.

Conclusion

Early adulthood systolic BP is associated with LA volumes 24 years later in life.

Table. Association of systolic blood pressure at age 40 to left atrial (LA) volumes and LAEF at age 64 Univariate Multivariate* Dependent variable B (95% CI) p-value B (95% CI) p-value LAVmax (ml) 2.4 (2.0, 2.9) &lt;0.001 0.9 (0.4, 1.4) 0.001 LAVmin (ml) 1.5 (1.1, 1.8) &lt;0.001 0.5 (0.1, 0.9) 0.015 LAEF (%) -0.01 (-0.3, 0.3) 0.938 0.2 (-0.2, 0.5) 0.294 *Adjusted for gender, body mass index, smoking, resting heart rate and antihypertensive treatment, all assessed at age 40. B (95% CI), regression coefficient for systolic blood pressure (per 10 mm Hg) with 95% confidence interval; LAVmax, LA end-systolic volume; LAVmin LA end-diastolic volume; LAEF, LA emptying fraction

103 Normal values and gender differences of left atrial volumes

Funding Acknowledgements

Vestre Viken Hospital Trust

Background

Left atrial (LA) enlargement is associated with cardiovascular morbidity and mortality. Echocardiographic guidelines recommend body surface area (BSA) indexed LA end-systolic volume (LAVimax) in the assessment of LA size with an upper normal limit of 34 ml/m² for both genders and all age groups. LA end-diastolic volume (LAVimin) and LA emptying fraction (LAEF) may add valuable information in risk assessment, but there are limited data on normal values.

Purpose

To add knowledge and explore gender differences of LA volumetric measures.

Methods

In The Akershus Cardiac Examination 1950 Study, all inhabitants of Akershus County, Norway, born in 1950 were invited. In 3,489 individuals LAVmax and LAVmin were measured with echocardiography according to the summation of discs method and indexed to BSA. LAEF was calculated. A healthy group was defined by excluding those with heart failure, atrial fibrillation, coronary artery disease, stroke, hypertension, diabetes, chronic obstructive pulmonary disease, body mass index &gt; 30kg/m², eGFR &lt; 60 ml/min/1.73 m², left ventricular ejection fraction &lt; 50%, E/e’&gt;14 and E/A &gt; 2.0. Data are presented as mean ± standard deviation (SD) and a normal range of mean ± 2SD. T-tests were used for comparisons.

Results

In 840 healthy individuals, aged 63.8 ± 0.6 years, mean LAVimax was 25.6 ± 6.3 ml/m² and the normal range was 13.0-38.2 ml/m². Men had significantly larger volumes than women.

Conclusion

We present LA volumes and LAEF in a large cohort from the general population at age 64. The upper normal limit of LAVimax in 840 healthy individuals was 38 ml/m². Men had larger LA volumes than women, contrary to most previous studies. Thus, 13% of the healthy men in our cohort would be defined with an enlarged atrium with the current cut-off value at 34 ml/m².

Table. Left atrial (LA) volumes and LAEF Total (mean ± SD) Total (2SD range) Male (mean ± SD) Female (mean ± SD) P-value (male vs. female) All participants (n = 3489) LAVimax (ml/m&sup2;) 26.8 ± 7.6 11.6-42.0 27.9 ± 8.1 25.6 ± 6.8 &lt;0.001 LAVimin (ml/m&sup2;) 14.7 ± 5.8 3.1-26.3 15.5 ± 6.5 13.9 ± 4.9 &lt;0.001 LAEF (%) 45.6 ± 9.7 26.2-65.0 45.3 ± 10.2 45.9 ± 9.2 0.07 Healthy group (n = 840) LAVimax (ml/m&sup2;) 25.6 ± 6.3 13.0-38.2 26.6 ± 6.7 24.9 ± 5.8 &lt;0.001 LAVimin (ml/m&sup2;) 13.7 ± 4.3 5.1-22.3 14.1 ± 4.6 13.3 ± 3.9 0.008 LAEF (%) 46.8 ± 8.8 29.2-64.4 47.0 ± 9.1 46.5 ± 8.4 0.37 LAVimax, LA end-systolic volume, body surface area (BSA)-indexed; LAVimin, LA end-diastolic volume, BSA-indexed; LAEF, LA emptying fraction; SD, standard deviation