Abstract 18692: Evolution of Diastolic Parameters and Their Relationship to Heart Rate in the 7-15 Week Human Fetus

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Claudine M Bohun ◽  
Lisa Howley ◽  
Jesus Serrano Lomelin ◽  
Winnie Savard ◽  
Lindsay Mills ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Cycle ◽  
Fetal Heart ◽  
Left Ventricular ◽  
Time Interval ◽  
Ejection Time ◽  
Systolic Time ◽  
Ventricular Filling ◽  
Diastolic Time ◽  
Isovolumic Relaxation

Objectives: Fetal echo offers a unique opportunity to investigate cardiac function in humans from the 1st trimester. We sought to explore the evolution left ventricular (LV) diastolic parameters and their relationship to fetal heart rate (HR) from 7-15 weeks gestational age (GA). Methods: We prospectively performed fetal echo in 137 healthy pregnancies recruited from 7+0 to 15+0 (mean 11.5±2.1) weeks GA. From Doppler studies we measured LV isovolumic relaxation time (IRT), mitral valve (MV) inflow patterns,and duration, diastolic time (IRT+inflow duration), LV ejection time (ET) and systolic time interval (isovolumic contraction time+ET). All variables were compared to GA and HR and were assessed as a proportion of the cardiac cycle length (R-R). Data were analyzed by regression and correlation analyses. Results: Results: From 7+0-15+0 weeks, HR and GA showed a non-linear relationship (R2=0.55, p<0.001) with low HRs at 7-8 weeks, peaking between 8-9 weeks, then falling thereafter. Diastolic time linearly increased with GA (R2=0.65, p<0.001) and inversely correlated with HR (r=0.77, p<0.001). IRT showed a nonlinear inverse relationship with GA (R2= 0.70, p<0.001), but did not correlate with HR, and IRT/RR increased linearly with GA (R2=0.71, p<0.001). Both inflow duration and inflow duration/R-R linearly increased with GA (R2=0.81,p<0.001). Inflow duration inversely correlated with HR (r=-0.70) and with IRT (r=-0.71) and IRT/R-R (r=-0.83, p<0.001 for all 3). A uniphasic MV atrial systolic inflow signal was present in 20/21 fetuses at 7+1-9+0 weeks, whereas, biphasic MV inflow was seen in 45% at 9+1-10+0 , 76% at 10+1-11+0 , 95% at 11+1-13+0 and 100% after 13+1 weeks GA. Inflow duration was significantly longer (146.9±25.4 vs 85.2±12.6ms, p<0.001) and HR was lower (160±9 vs 170±10 bpm, p<0.001) in fetuses with a biphasic flow pattern. ET demonstrated a weak relationship with GA (R2=0.41) and no relationship with HR, IVRT,or IVRT/R-R, and the systolic time showed a nonlinear trend of decreasing with GA (R2=0.46). Conclusions: In the 7-15 week fetus, improvements in relaxation suggested by decreasing IRT, decreasing HR, and, to a lesser extent, decreasing systolic time likely contribute to increasing inflow duration and to early ventricular filling.

scholarly journals Systolic Time Interval (STI) in Hypothyroid Patients Receiving High Dose L-Thyroxine

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Nurul Aulia Zakaria ◽  
Hafizah Pasi ◽  
Mohammad Arif Shahar
Keyword(s):  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Lv Function ◽  
High Dose ◽  
Time Interval ◽  
Ejection Time ◽  
Systolic Time Interval ◽  
Systolic Time ◽  
Ventricular Ejection Time ◽  
Significant Increment

Introduction: Systolic Time Interval (STI) is a simple,noninvasive and precise technique to assess left ventricular (LV) function. It measures aortic Pre-Ejection Period (PEP) over Left Ventricular Ejection Time (LVET) from echocardiogram. Thyrotoxicosis will enhance LV function and cause reduction of STI.  This study was perform to measure the changes of STI after administration of high dose L-thyroxine and to determine the correlation between high dose L-thyroxine administration and STI. Materials and Method: A Total of 22 patients were screened. Those with cardiac diseases and high Framingham risk score were excluded. Nine patients were started on high dose L-thyroxine (7x their usual dose) once a week during the month of Ramadan.Thyroid hormones ( T3,T4,TSH)  and STI (PEP/LVET) were measured at baseline and within 24 hrs after high dose L-thyroxine ingestion. Results: All patients have normal thyroid hormones level and normal cardiac function at baseline. The median dose (mcg) of L-thyroxine was 600 (437.5,700) while the median level of fT4 (pmol/L) was 17.43(12.38,20.8). Despite the significant increment of fT4 after Lthyroxine ingestion [baseline 13.21(8.19,14.63) vs high dose 17.43(12.38,22.55) p; 0.011] there was no significant change in STI [baseline 0.3(0.2,0.4) vs high dose 0.28(0.26,0.45) p; 0.513]. There was no correlation found between the dose of Lthyroxine and STI (r=0.244 , p;0.526).  Conclusion: Administration of high dose Lthyroxine did not significantly alter STI despite significant increment of fT4 level unlike the naturally occurring thyrotoxicosis.Therefore ‘exogenous’ administration of high dose L-thyroxine is cardiac safe.

Systolic Time Interval Characteristics in Children with Duchenne's Progressive Muscular Dystrophy

PEDIATRICS ◽  
1982 ◽  
Vol 70 (6) ◽  
pp. 958-964
Author(s):  
Shyamal K. Sanyal ◽  
Ralph C. Tierney ◽  
P. Syamasundar Rao ◽  
Samuel E. Pitner ◽  
Stephen L. George ◽  
...  
Keyword(s):  
Heart Rate ◽  
Muscular Dystrophy ◽  
Normal Control ◽  
Left Ventricular ◽  
Time Interval ◽  
Systolic Time Interval ◽  
Control Subjects ◽  
Systolic Time ◽  
Ventricular Ejection Time ◽  
Duchenne's Muscular Dystrophy

Systolic time interval (STI) characteristics of 17 boys with Duchenne's muscular dystrophy (DMD) were compared with those of 80 normal boys who served as control subjects. The heart rate decreased linearly with age in normal control subjects (r = -.47, P &lt; .01). By contrast, heart rate was significantly higher in patients with DMD (P &lt;.001) and tended to increase further with age. Each STI variable for normal control subjects increased significantly with age (P ≤ .01); QII, left ventricular ejection time (LVET), and pre-ejection period (PEP), in addition, decreased with increasing heart rate (P ≤ .05). In dystrophic patients QII and LVET decreased with increasing heart rate (P &lt; .001) but were not influenced by age. None of the other STI values in dystrophic patients was significantly influenced by either age or heart rate. Mean QII, LVET, and QI were shorter and PEP, isometric contraction time (ICT), and PEP/LVET ratio were longer (P &lt; .001) for DMD patients than for normal control subjects. In 13/17 patients, QII and LVET were below the 95% confidence interval of the normal mean, whereas PEP, ICT, and PEP/LVET exceeded the upper limits of normal in 8, 9, and 11 patients, respectively. For dystrophic patients, the difference (Δ) between the observed values and those predicted from regression equations for normal control subjects was lower for QII, LVET, and QI (P &lt; .01) but higher for PEP (P &lt; .04), ICT, and PEP/LVET ratio (P &lt; .001). Δ QII and Δ LVET increased with age (P = .001 and .032, respectively). Duchenne's muscular dystrophy is thus documented to be associated with substantial alterations in STI characteristics that suggest a compromise of global left ventricular performance. Some of these abnormalities increase with age, probably reflecting the progressive cardiomyopathy characteristic of this disease.

Value of Systolic Time Intervals in the Diagnosis of Large Patent Ductus Arteriosus in Fluid-Restricted and Mechanically Ventilated Preterm Infants

PEDIATRICS ◽  
1984 ◽  
Vol 74 (6) ◽  
pp. 1069-1074
Author(s):  
François Heitz ◽  
Jean-Claude Fouron ◽  
Nicolaas H. van Doesburg ◽  
Harry Bard ◽  
François Teasdale ◽  
...  
Keyword(s):  
Patent Ductus Arteriosus ◽  
Right Ventricular ◽  
Ductus Arteriosus ◽  
Systolic Time Intervals ◽  
Left Ventricular ◽  
Ejection Time ◽  
Time Intervals ◽  
Systolic Time ◽  
Ventricular Ejection Time ◽  
Patent Ductus

M-mode echocardiographic features suggesting a patent ductus arteriosus are based on two groups of indirect criteria: dilation of the left cardiac cavities and changes of systolic time intervals. The reliability of the first group of criteria has been questioned in fluidlimited, mechanically ventilated preterm infants. The sensitivity of the systolic time intervals in the same circumstances is investigated. Twenty-three patients with a large patent ductus arteriosus were selected. Review of their echocardiograms shows that the sensitivity of the various criteria (expressed as percentage of positivity) was as follows: inversion of the ratio of left ventricular preejection period to right ventricular preejection period, 91.3%; left ventricular preejection period to left ventricular ejection time over right ventricular preejection period to right ventricular ejection time &lt; 1, 83%; left atrium dilation, 74%; shortening of left ventricular preejection period, 70%; dilation of left ventricular internal dimensions in diastole, 65%; increase in left atrium/aorta, 52%; and decrease of left ventricular preejection period to left ventricular ejection time, 48%. Three criteria involving time intervals (left ventricular preejection period to right ventricular preejection period, left ventricular preejection period, and left ventricular preejection period to left ventricular ejection time) had 100% specificity. The lowest specificity was found with criteria involving the left atrium (left atrial to aortic root ratio 75% and left atrium 63%). It is concluded that study of systolic time intervals is a reliable means of detecting preterm infants with hemodynamically significant left-to-right shunt through a patent ductus arteriosus even if the infants are mechanically ventilated and fluid restricted.

Influence of heart rate on left ventricular isovolumic relaxation time: a Doppler study in healthy newborns

2004 ◽  
Vol 17 (4) ◽  
pp. 330-331 ◽  
Author(s):  
Antonio De Merulis ◽  
Giulio Calcagni ◽  
Paolo Versacci ◽  
Renato Lucchini ◽  
Flavia Ventriglia ◽  
...  
Keyword(s):  
Heart Rate ◽  
Relaxation Time ◽  
Left Ventricular ◽  
Isovolumic Relaxation Time ◽  
Doppler Study ◽  
Isovolumic Relaxation

scholarly journals Atrioventricular Conduction Time in Fetuses Assessed by Doppler Echocardiography

2011 ◽  
pp. 611-616 ◽  
Author(s):  
V. TOMEK ◽  
J. JANOUŠEK ◽  
O. REICH ◽  
J. GILÍK ◽  
R. A. GEBAUER ◽  
...  
Keyword(s):  
Heart Rate ◽  
Reference Values ◽  
Gestational Age ◽  
Doppler Echocardiography ◽  
Fetal Heart ◽  
Atrioventricular Conduction ◽  
Time Interval ◽  
Conduction Time ◽  
Time Intervals ◽  
Normal Limits

We performed measurement of mechanical atrioventricular conduction time intervals in human fetuses assessed by Doppler echocardiography and provided reference values. We found that atrioventricular conduction time interval was prolonged with gestational age and decreased with increasing fetal heart rate. No correlation between gestational age and heart rate was found. Using normal limits established by this study, mechanical atrioventricular interval >135 ms in the 20th week and/or >145 ms in the 26th week of gestation could be suspected of having the first-degree AV block. We compared reference values with fetuses of mothers with anti-SSA Ro/SSB La autoantibodies, being in risk of isolated congenital heart block development. One of 21 fetuses of mothers with positive autoantibodies was affected by prolonged atrioventricular interval according to the established limits, with sinus rhythm after the birth.

Utility of M-Mode Echocardiography for Early Identification of Infants with Persistent Pulmonary Hypertension of the Newborn

PEDIATRICS ◽  
1981 ◽  
Vol 68 (4) ◽  
pp. 515-525 ◽  
Author(s):  
Lilliam M. Valdes-Cruz ◽  
Golde C. Dudell ◽  
Angelo Ferrara ◽  
Barbara J. Nickles
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Disease ◽  
Early Identification ◽  
Clinical Deterioration ◽  
Persistent Pulmonary Hypertension ◽  
Time Interval ◽  
Ejection Time ◽  
Systolic Time Interval ◽  
Systolic Time ◽  
Ventricular Ejection Time

The clinical syndrome of persistent pulmonary hypertension of the newborn (PPHN) still carries high mortality in spite of improved neonatal care. The purpose of this prospective study was to assess the utility of M-mode echocardiography for the early identification of infants with PPHN prior to clinical deterioration. Echocardiograms of 51 infants who needed fractional inspiratory oxygen (FIO2) ≥0.25 to maintain adequate Pao2 within 36 hours of life were compared to those of 115 healthy full-term and preterm newborns. Of the 51 infants, ten had elevated systolic time interval ratios of both ventricles simultaneously (ventricular pre-ejection period to ventricular ejection time [RPEP/RVET ≤0.50, LPEP/LVET ≤0.38J]). All of these newbrns had PPHN that was manifest clinically by 11 to 30 hours of age. The echocardiographic findings preceded clinical deterioration by at least one to five hours in all cases. The other 41 infants had clinical courses consistent with uncomplicated pulmonary disease. These data indicate that systolic time interval ratios, although not accurate measures of pulmonary arterial pressure and/or pulmonary vascular resistance, permit early identification of infants with PPHN and separation from others with uncomplicated pulmonary disease.

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