Ventricular Systolic Time Intervals Research Articles

Agreement of Cardiac Output Estimates between Electrical Cardiometry and Transthoracic Echocardiography in Very Preterm Infants

Introduction: The aim was to evaluate the agreement between cardiac output estimates obtained by electrical cardiometry (EC) and transthoracic echocardiography (TTE) in very preterm infants. Methods: This is a single-center prospective observational study in infants born<32 weeks gestational age within 48 h of birth. Continuous EC was recorded and simultaneous TTE obtained on day 1 and day 2 of life. Blinded TTE measurements were performed within a 10 s timeframe using beat-to-beat EC data. The primary outcome was %error of left ventricular (LV) output in milliliters per kilogram per minute (cardiac index (CI)) obtained by TTE compared to LV-CI from EC. Secondary outcome parameters were bias, %bias, limits of agreement and include measures of right ventricular (RV) output and LV systolic time intervals. Results: Analysis was performed for 34 infants (median (IQR) gestational age 29 + 0 (24 + 5 to 30 + 6) weeks + days, birthweight 960 (748 to 1,490) grams) including 44 pairwise LV output measurements on 24 participants (22 on day 1 and day 2). The %error was 54% for LV-CI (EC: 214 (38) mL/kg/min vs. TTE: 163 (47) mL/kg/min). The %error was 78% for RV-CI (EC: 213 (37) mL/kg/min vs. TTE: 241 (77) mL/kg/min). While only LV-CI values affected LV-CI bias, signal quality, heart rate, and RV-CI values affected RV-CI bias. Conclusion: EC is not interchangeable with TTE to estimate indices of LV or RV output in very preterm infants within the first 48 h postnatally. EC may not measure LV output distinctly in very preterm infants with intra- and extracardiac shunts.

Contactless Measurement of Human Systolic Time Intervals Based on Doppler Cardiograms in Clinical Environment

As the most important organ of human body, heart has many measures and indicators to assess the cardiac function in clinic. Ventricular systolic time intervals (STIs) are of major relevance in providing crucial information regarding cardiovascular state. However, the existing measurement technologies are costly, complicated to operate, and also require contact sensors. Based on the human cardiovascular model and principle of Doppler cardiogram (DCG), the differential DCG (D-DCG) and quadratic D-DCG (QD-DCG) carry the aortic pressure (AP) information by which the STIs can be calculated. A 24-GHz digital dc-tuning Doppler radar sensor (DRS) has been implemented to detect the accurate DCGs. To assess the feasibility of contactless measurement of the STIs by DRS, clinical experiments and evaluations are carried out in the operation theater (OT). The preejection period (PEP) and the left ventricular ejection time (LVET) estimation results reached 95.23% and 93.12% accuracy, respectively, which indicates that the proposed method has great potential to be used for STIs estimation and could be convenient for patient home monitoring.

Echocardiographic assessment of intravenous administration of medetomidine and xylazine hydrochloride at different sedative doses inone-humped camel calves (Camelus dromedarious).

Echocardiography illustrates a convenient and noninvasive tool for measuring cardiac output (CO) changes after administration of sedative drugs, but it is unknown in camelids practice. The aim of present study was to investigate echocardiographic effects of intravenous (IV) injection of medetomidine and xylazine in camel calves. Twenty apparently healthy immature male one-humped camel calves (Camelus dromedarious) were divided into four groups (five animals in each treatment). Medetomidine and xylazine were injected into the left jugular vein at two different doses of 10.00 and 20.00 μg kg-1 and 0.20 and 0.40 mg kg-1, respectively. Effects on some selected echocardiographic parameters were recorded at different intervals, before drug administrations (baseline) and after 3, 60 and 120 min. Data were analyzed by repeated measure, ANOVA test, then relevance and significance were taken as p ≤ 0.05. Significant decrease in fractional shortening percentage (FS%), ejection fraction percentage (EF%), stroke volume (SV), heart rate (HR) and subsequent CO were noticeable 3 min after drug administration in medetomidine high dose (MH), medetomidine low dose (ML) and xylazine high dose (XH) groups (p ≤ 0.05), furthermore at this time significant decrease in left ventricular mass (LVmass) and left ventricular systolic time intervals were seen in these groups, however, in xylazine low dose (XL) group, the lowest level of most echocardiographic parameters were detectable after 60 min. High dose IV injection of medetomidine was associated with significant decrease in most echocardiographic parameters without echocardiographic arrhythmia. Although, ML and XH groups had the same effects on echocardiographic indices but the intensity and duration were less than MH group.

Clinical and diagnostic imaging findings in 37 rescued dogs with heartworm disease in Germany

Canine dirofilariasis is currently uncommon in Germany, but its prevalence appears to be increasing due to rehoming of dogs from endemic areas. As part of staging of the disease, this case series describes clinical, radiological and echocardiographic findings in 37 dogs tested positive for Dirofilaria immitis between October 2016 and January 2019. Clinical history revealed 12 (32 %) asymptomatic and 22 (59 %) symptomatic dogs, with most of the dogs showing exercise intolerance, coughing or breathlessness. Thoracic radiographs were performed in 34 dogs and showed parenchymal lesions in 14 (41 %) and bulging of the main pulmonary artery (MPA) in 8 (23,5 %). Enlarged peripheral pulmonary arteries were noted in 22 (65 %) dogs, mainly affecting caudal peripheral pulmonary arteries. In 12 (24 %) of dogs with echocardiographic findings, thoracic radiographs were unremarkable. Echocardiographic examination was performed to assess secondary pulmonary hypertension (PH), identification of worm burden and dilation of pulmonary arteries. RPAD was applied for grading of PH in 34 dogs. Normal values (RPAD > 35 %) were detected in 11 (32 %) dogs, mild PH (RPAD 28–35 %) in 12 (35 %), moderate PH (RPAD 23–27 %) in 5 (15 %), and severe PH (RPAD < 23 %) in 6 (18 %) dogs. Severe systolic PH was confirmed by pressure gradient of tricuspid regurgitation in two dogs. Pressure gradients of pulmonary insufficiency were suggestive of diastolic PH in 5 dogs and correlated with RPAD < 23 %. Right ventricular hypertrophy was observed in 6 dogs with severe PH, flattening of the interventricular septum in 5 dogs. Right ventricular systolic time intervals showed a short acceleration time (<80 ms) and AT/ET of <0.31 in all dogs with severe PH. MPA dilation, defined as the ratio of MPA to aorta (MPA/Ao) exceeding 1.0 was found in 16 (43 %) dogs. Right pulmonary artery (RPA) dilation, defined as the ratio of RPA to aorta (PRA/Ao) exceeding 0.5 was detected in 25 (68 %) dogs. Double, linear parallel objects (DL) suggestive for macrofilaria were found in 28 (76 %) dogs. Of these, 7 (19 %) had a high worm burden occupying RPA and MPA. Six months after the 3rd Melarsomine injection a follow up examination was performed in 21 dogs. Main findings included persistent dilation of RPA in 11 (52 %), as well as RPAD indicative of PH in 11 (52 %) dogs. This case series demonstrates that>70 % of dogs had at least one relevant finding suggestive of PH prior to starting adulticide treatment. Therefore, thoracic radiographs as well as a thorough echocardiographic examination are recommended in all dogs that test positive for D. immitis. Echocardiography should focus on presence and severity of PH, for which RPAD has been proven to be useful. A follow up examination after adulticide treatment should be performed, which provides comparative assessment of presence and severity of PH. Dogs with persistent moderate to severe PH may benefit from long-term monitoring and medical management.

Long-term Non-invasive Hemodynamic Evaluation of Left Endocardial Cardiac Resynchronization Therapy

Introduccion: La VAB es una cardiopatia congenita que puede asociarse a complicaciones aorticas y/o valvulares. Resulta importante identificar grupos de riesgo, para realizar un seguimiento mas estrecho e indicar la intervencion a tiempo. El siguiente trabajo busca analizar el impacto que tienen las caracteristicas clinicas y morfologicas valvulares en el desarrollo de disfuncion valvular aortica moderada/severa (significativa) y en la incidencia de eventos cardiovasculares mayores en adultos con VAB. Materiales y metodos: Se incluyeron pacientes consecutivos con diagnostico de VAB no sindromatica (2010-2019) en seguimiento en nuestra institucion. Se recabo informacion clinica y ecocardiografica de manera prospectiva. Se realizo analisis uni y multivariado para identificar caracteristicas clinicas y morfologicas predictoras de disfuncion valvular significativa y de eventos cardiovasculares mayores (muerte/cirugia/sindrome aortico). Una p menor 0,05 fue considerada significativa. Resultados: Se incluyeron 300 pacientes (44.3±15.3 anos, 71% hombres). La mayoria con VAB tipo I y presencia de rafe (79.6% y 77%, respectivamente). La edad media de diagnostico fue de 36.3 ±16.2 anos. Hubo 84 pacientes (31.2%) que presentaban disfuncion valvular aortica significativa al momento del inicio del estudio. Con un seguimiento a 4.9 ± 1.7 anos, 23 pacientes requirieron cirugia cardiaca (7.7%) y 3 fallecieron (1%). Al final del seguimiento 101 (33.6%) pacientes presentaban disfuncion valvular aortica significativa. La presencia de al menos 1 de los siguientes factores: prolapso valvular, calcificacion valvular aortica basal >1 y una edad > 50 anos se asocio a menor sobrevida libre de disfuncion valvular aortica significativa y de eventos mayores. Conclusiones: En nuestra cohorte, observamos una alta incidencia de eventos asociados a VAB. Dentro de las variables analizadas, la presencia de al menos 1 factor de riesgo se asocio a menor sobrevida libre de eventos mayores y disfuncion significativa a 4,9 anos.

Time to peak velocity in the main pulmonary artery as a marker of persistent pulmonary hypertension in neonates.

To assess right ventricular systolic time intervals, specifically, time to peak velocity (TPV) in the pulmonary artery as a marker of persistent pulmonary hypertension of the newborn (PPHTN). This was a retrospective case-control study of 30 infants with pulmonary hypertension requiring intensive care management. Cardiac ultrasounds were re-analysed, comparing TPV measurements to a group of 31 controls who had cardiac ultrasounds performed for incidental murmurs with structurally normal hearts. Time to peak velocity was significantly shorter in the PPHTN group compared to controls, 47 vs. 95ms, respectively. This was statistically significant with a P-value of <0.001. Time to peak velocity in the pulmonary artery is a useful marker of PPHTN in the first week of life. This measurement is especially useful if neither tricuspid regurgitation or a patent ductus are present for interrogation on ultrasound.

유산소 및 저항운동 후 고교생의 동맥경직도 및 좌심실 수축시간 변화

To investigate the effects of acute aerobic and resistance exercise on the arterial stiffness and the left ventricular systolic time interval(STI), high school students(16.4±.8 yrs, n=15) were tested at resting state, immediately after exercise, recovery 1hr, and 2hr. Experiments were performed in 3 conditions; control without any handling, aerobic exercise with track running at 80% HRR, and resistance exercise with maximal repetitions at 60% RM on bench press, arm curl, leg press and leg curl. Data were analyzed by repeated two-way ANOVA on time and exercise type. As results, ABPI, baPWV and AIx, that were arterial stiffness variables, were tend to decrease at immediately after aerobic and resistance exercise, but these variables were recovered and increased than the resting values during recovery 1hr and 2hr. The patterns of STI, LVET and PEP/LVET, that were left cardiac contractility variables, were similar with those of arterial stiffness variables during recovery periods after aerobic and resistance exercise. In conclusion, the arterial stiffness was decreased at immediately after aerobic and resistance exercise, but they were increased during recovery. These changes of arterial stiffness variables seemed to be independent with left cardiac contractility variables.

Non-invasive ultrasound-based assessment of ventricular–arterial interaction in vascular Ehlers–Danlos syndrome patients

The role of ventricular–arterial hemodynamic interaction in the occurrence of arterial dissection and rupture in vascular Ehlers–Danlos syndrome (vEDS) is unknown. We recently introduced an ultrasound-based method to extract, from common carotid artery (CCA) diameter waveforms, central arterial properties and left ventricular (LV) systolic time intervals. We obtained CCA diameters, compliance and distensibility coefficients, and LV isovolumic contraction and ejection periods (ICP and EP) of 19 vEDS patients (aged 27–65 yrs) and 19 age-matched healthy controls. CCA distension and compliance tended to be lower in vEDS subjects ( p = 0.062 and p = 0.073), especially in younger patients. ICP (−12 ms) and EP (−24 ms) were shorter ( p < 0.001), while heart rate was increased (+10 bpm; p < 0.001) in vEDS. The ICP/EP ratio and estimated isovolumic d P LV/d t indicated increased LV contractility in vEDS. In conclusion, vascular EDS patients tend to have a lower CCA compliance but a normal pulse pressure, most likely reflecting reduced physical fitness.

Normal left ventricular systolic time intervals assessed by pulsed wave Doppler echocardiography in the Turkmen horse of Iran.

The Turkmen horse is one of the oldest and purest breeds in the world. There is no information with regards to the normal echocardiographic parameters of this horse regarding to cardiac diseases. Pulsed-wave (PW) Doppler echocardiography was performed on 42 clinically normal 3- to 15-year-old racing Turkmen horses. There were 26 stallions and 16 mares. The left ventricular isovolumetric contraction time, pre-ejection period (PEP), and the left ventricular ejection time (LVET), were measured, and the values of the left ventricular total electromechanical systole (LVTES) and the PEP-to-LVET ratio were calculated. The most suitable window for the measurement of the aforementioned indices in PW Doppler echocardiography was the left parasternal window using the five-chamber apical view. The following values were acquired in PW Doppler echocardiography: PEP = 0.088 ± 0.018 s; LVET = 0.445 ± 0.031 s; LVTES = 0.533 ± 0.032 s; and PEP-to-LVET = 0.199 ± 0.046. These measurements can be used in the future as standard and reference values for the evaluation of cardiovascular disorders in the Turkmen horse.

Electromechanical Activation Time in the Prediction of Discharge Outcomes in Patients Hospitalized with Acute Heart Failure Syndrome

Left ventricular systolic time intervals, including pre-ejection period (PEP), ejection time (ET), and their ratio (PEP/ET), is determined by systolic and diastolic function and ventriculo-arterial coupling. We investigated the usefulness of the electromechanical activation time [(EMAT) PEP minus isovolumic contraction time] in the prediction of cardiac mortality or re-hospitalization for heart failure in patients with the acute heart failure syndrome (AHFS). A total of 45 patients (71.9±16.1 years old) hospitalized for AHFS were enrolled. Systolic time intervals and EMAT normalized by cardiac cycle length (%) were measured separately by separate automated acoustic devices. All parameters were assessed within 24 hours of admission, before discharge, and 2 weeks after discharge. During a mean follow-up of 242±156 days, 20 patients (44%) incurred adverse cardiovascular events including 18 re-hospitalizations for heart failure and 2 cardiovascular deaths. Using uni-variate Cox regression analysis, at admission %EMAT and %PEP, pre-discharge %EMAT, and post-discharge %EMAT significantly predicted post-discharge cardiovascular events with hazard ratios and 95% confidence intervals of 1.75 (1.13-2.70), 1.67 (1.02-2.70), 1.87 (1.10-3.17) and 2.50 (1.58-3.97) per 1-SD increment, respectively. The predictions remained significant after adjustment for age, sex, left ventricular ejection fraction, E/E´ by Doppler echocardiography, and serum N-terminal pro-brain natriuretic peptide. EMAT measured during the hospitalization course is useful in the prediction of cardiovascular outcomes in patients with AHFS independent of left ventricular ejection fraction, E/E´, and serum N-terminal pro-brain natriuretic peptide.

ESTIMATED RIGHT VENTRICULAR SYSTOLIC TIME INTERVALS FOR THE ASSESSMENT OF RIGHT VENTRICULAR FUNCTION IN ACUTE RESPIRATORY DISTRESS SYNDROME

Right ventricular (RV) systolic time intervals (STIs) have been shown to accurately reflect RV function in patients with acute respiratory distress syndrome (ARDS). The measurement of RVSTIs requires phonocardiography to define the time of RV end systole. If RV end-systolic pressure (RVESP) can be derived from peak pulmonary artery (PA) systolic pressure, then the time of RV end systole, and hence, RVSTIs can be deduced without phonocardiography. We tested this possibility. In 34 patients with ARDS, RVESP was determined on the PAP curve at RV end systole, which was defined by phonocardiography. The ratios of RVESP/peak PA systolic pressure were obtained in each patient, the mean of which was 0.90 +/- 0.006. With an application of this value, the estimated RVSTIs were determined in other groups of patients. Right ventricular end-systolic pressure was estimated from the peak PA systolic pressure by multiplying 0.9. Then the point of RV end systole was determined on the electrocardiographic tracing that coincided with the point of RVESP on the PAP curve by simultaneous display of electrocardiograph and PAP curve. Total electromechanical systole was measured from the onset of the QRS complex to the point of RV end systole on the electrocardiograph. The onset of RV ejection was defined by PAP curve. The validity of this estimated RVSTIs was tested by comparing with the measured RVSTIs. By Bland-Altman analysis, the mean difference in RVSTIs between the two methods was 0.007, and bias was 0.0036, suggesting close agreement. The estimated RVSTIs can be used to accurately assess RV function.

Cardiovascular impact of dobutamine in neonates with myocardial dysfunction

Objective To study effects of dobutamine on cardiac functional parameters, cerebral, mesenteric and renal blood flow in preterm neonates with myocardial dysfunction. Study design Prospective evaluation of Doppler sonographically measured left ventricular systolic time intervals, stroke volume (SV), cardiac output (CO), and blood flow parameters of anterior cerebral artery (ACA), superior mesenteric artery (SMA) and renal arteries (RA), before, after 20 min and 8–10 h of dobutamine treatment in 20 neonates (gestational age 29.6 ± 4.4 weeks, birth weight 1450 ± 609 g and postnatal age 2 ± 2.1 days). Dobutamine was given in a mean dosage of 9.1 ± 1.1 μg/kg. Results After 20 min SV increased from 1.71 ± 0.5 ml to 2.12 + 0.57 ml/kg, CO from 223 ± 76 to 290 ml/kg/min. A shortening of left ventricular pre ejection period from 86 ± 12 to 66 ± 13 ms and of the ratio of pre-ejection period/ejection time from 0.52 ± 0.12 to 0.40 ± 0.11 were observed. Blood flow velocities of ACA increased after 8–10 h: peak systolic flow velocity (PSV) from 19.0 ± 6 to 29.6 ± 7.1 ms, end diastolic velocity (EDV) from 2.9 ± 2.6 to 12.7 ± 11.3 ms. PSV of SMA increased from 32.5 ± 4.7 to 49.7 ± 7.8 ms after 8–10 h, EDV from 8.9 ± 8 ms to 20.6 ± 6.1 ms. PSV of RA increased from 18.2 ± 6.1 ms to 39.9 ± 4.8 ms, EDV from 2.2 ± 1.2 to 8.2 ± 2.1 ms after 8–10 h. The pulsatility indices decreased significantly after 8–10 h: ACA from 2.3 ± 0.6 to 1.4 ± 0.5, SMA from 1.7 to 1.2 and RA from 2.57 to 1.57. Conclusion Dobutamine improves the cardiac functional parameters already after 20 min and has an influence on the blood flow parameters of ACA, SMA and RA 8–10 h after administration in neonates with myocardial dysfunction.

307 Disturbed Cardiac Functional Parameters and Blood Flow Parameters of Peripheral Arteries in Premature Sga Neonates

Top of pageAbstract Problem: Small for gestational age preterm neonates (SGA) are at higher risk for early postnatal morbidity and cardiovascular and metabolic diseases in later childhood. The aim of the prospective study was to determine the cardiac adaptation and the organ blood flow in growth retarded neonates after intrauterine hemodynamic disturbances in comparison to appropriate for gestational age preterm infants (AGA). Patients and methods: 25 AGA neonates (29.1 ± 1.4 wks, 1420 ± 243 g) and 25 small for gestational age neonates (30.1 ± 1.2 wks, 985 ± 167 g) were examined during the first five days. By Doppler sonographic measurements the cardiac left ventricular systolic time intervals, peak systolic velocities, end diastolic velocities and pulsatility indices of anterior cerebral artery (ACA), superior mesenteric artery (SMA) and renal artery (RA) were investigated. Results: Significantly increased left ventricular pre ejection period was observed in SGA neonates. Systolic peak velocities and end diastolic velocities of ACA, SMA and RA were significantly decreased in SGA neonates in relationship to AGA neonates. The pulsatility indices were significantly increased in SGA neonates during the first five days. Conclusions: Disturbed left ventricular time intervals were observed as a sign of myocardial dysfunction in SGA neonates. In relationship to the diminished myocardial contractility there were demonstrated pathologically diminished blood flow parameters of peripheral vessels and an increased pulsatility caused by a vasoconstriction in the regional vascular bed. For that reason it seems possible, that the disturbed intrauterine perfusion persists into the postnatal life and could cause later cardiac and metabolic problems.

Cardiovascular findings in very low birthweight schoolchildren with and without bronchopulmonary dysplasia

Background With the introduction of new therapies in peri- and neonatology, the clinical picture of bronchopulmonary dysplasia (BPD) seems to alter. The consequences of this “new BPD” are of interest. Aim To evaluate cardiovascular findings during the surfactant era in very low birthweight (VLBW, birth weight <1500 g) schoolchildren with and without BPD. Methods At 7–8 years of age, 34 VLBW children with BPD born in one hospital underwent blood pressure (BP) measurement, electrocardiography (ECG), two-dimensional Doppler and M-mode echocardiography, flow-volume spirometry and whole-body plethysmography. The age- and sex-matched control groups comprised 34 VLBW children without BPD (no-BPD group) and 34 term children (term group). Results The mean(SD) diastolic BP was significantly higher in the no-BPD than in the BPD group (65(9) vs. 59(8) mm Hg, p<0.05). No clinically significant tricuspid regurgitations were found. The groups did not differ with respect to right ventricular systolic time intervals corrected for heart rate. The results of all M-mode measurements were within normal range. Compared to term controls, the BPD cases had lower mean(SD) forced expiratory flow in 1 s (90(14)% vs. 99(11)% of ref., p<0.05) and more often high ratio of residual volume to total lung capacity (15(52%) vs. 4(13%), p<0.01). No clinically significant correlations were found between current lung function and echocardiographic findings. Conclusion In the surfactant era, school-aged VLBW survivors with and without BPD do not seem to evince indirect signs of elevated pulmonary pressure. The increased pulmonary vascular resistance associated with BPD appears to resolve with time more rapidly than abnormalities in respiratory function.

Study of systolic time interval in patients with essential hypertension by echocardiography

P-33 Key Words: Echocardiography, Essential Hypertension, Systolic Time Interval

Systolic time intervals assessed by 2‐D echocardiography and spectral Doppler in the horse

ABSTRACTIn the present study, the ‘acoustic windows’ for the measurement of the left ventricular systolic time intervals is studied by means of 2‐D echocardiography and cardiac Doppler ultrasonography, and the normal values in the horse (n = 112) are determined. The left ventricular isovolumetric contraction time, the pre‐ejection period (PEP), as well as the left ventricular ejection time (LVET) have been measured, and the values of the left ventricular total electromechanical systole (LVTES) and the PEP‐to‐LVET ratio have been calculated. It has been established that the most suitable window for the measurement of the aforementioned indices in 2‐D echocardiography is the right parasternal window in a view in short axis at the level of the cardiac base to measure the aortogram. In Doppler ultrasonography, the preferred window is the left parasternal using the five chambers apical view. The following values have been acquired: PEP = 0.071 ± 0.01 s; LVET = 0.532 ± 0.097 s; LVTES = 0.6 ± 0.1 s and PEP‐to‐LVET = 0.138 ± 0.025 measured by 2‐D echocardiography and PEP = 0.068 ± 0.009 s; LVET = 0.527 ± 0.076 s; LVTES = 0.598 ± 0.098 s and PEP‐to‐LVET = 0.131 ± 0.01 measured by Doppler ultrasonography.

Historical Perspectives

When pharmacologic closure of patent ductus arteriosus (PDA) in the preterm infant using indomethacin was introduced in 1976, there was a paucity of knowledge about the factors controlling the caliber of the ductus arteriosus both before and after birth. Additionally, mortality and morbidity of prematurity (associated with what was then usually referred to as hyaline membrane disease) was remarkably high in the early 1970s. As early as the 1950s, some neonatologists recognized PDA as a complication of what later became designated as “respiratory distress syndrome” (RDS), although it was not until the advent of intermittent mandatory ventilation (IMV) and continuous positive airway pressure (CPAP) that the concept gained prominence. Patency of the ductus appeared to be a major complication, especially in the smallest of preterm babies (at that time, < 1,350 g]) and usually carried a terminal prognosis. The advent of IMV and CPAP kept these small babies alive for a sufficient period of time for the patent ductus to become recognized progressively as a distinct clinical entity and an important early complication of preterm birth. Observant neonatologists noted that babies who had RDS often improved up to a point, beyond which they worsened. The usual story was that the baby experienced ventilatory failure, was treated with mechanical ventilation, and began to improve, with lower inspired oxygen requirements. After a few days, when discussions ensued about taking the baby off the ventilator, the infant’s improvement would cease. The radiographic picture changed from a clearing of the initial ground glass appearance coupled with a relatively small heart to an enlarging heart and the pulmonary edema of congestive heart failure due to a left-to-right shunt across the PDA. Beginning in the mid-1960s, aggressive surgeons advocated operative closure of the PDA in these small preterm infants, but multiple centers consistently reported unacceptably high …

A Study of Potential Toxic Effects After Repeated 10-Week Administration of a New Iron Chelator – Salicylaldehyde Isonicotinoyl Hydrazone (SIH) to Rabbits

Salicylaldehyde Isonicotinoyl Hydrazone (SIH)--a Pyridoxal Isonicotinoyl Hydrazone (PIH) analogue--is an effective iron chelator with antioxidant and antimalarial effects, as documented in numerous in vitro studies. However, no toxicological data obtained from in vivo studies have been made available yet. In this study, the potential toxic effects of repeated administration of SIH (50 mg/kg, once weekly, 10 weeks, i.p.), partially dissolved in a 10% Cremophor solution, on various biochemical, haematological, and cardiovascular parameters and on morphology of selected tissues were investigated in rabbits. The obtained values were compared with data from the control (saline, 1 ml/kg, i.v.) and the Cremophor (10% Cremophor solution, 2 ml/kg, i.p.) groups. In this study, SIH did not induced marked signs of toxicity: No premature deaths occurred, the body weight increase was comparable with the control and Cremophor groups. Only few and mild changes in some biochemical and haematological parameters could be determined, most of them were noticed also in the control or Cremophor groups. The morphological changes in the kidney were mild and did not manifest in the biochemical examination. The cardiac function was also not affected markedly--the values of left ventricular ejection fraction and systolic time interval did not differ from the values of control group. Only an increased left ventricular contractility (dP/dtmax) was noticed in the SIH group at the end of the experiment as compared to the controls (13,354+/-1191 vs. 9339+/-647 mmHg/s, resp.). These results seem to be promising from the standpoint of possible clinical use of SIH.

Dopplersonographic findings in neonates with significant persistent ductus arteriosus

The aim of the study was the description and review of a diagnostic management for treatment of patent ductus arteriosus in preterm neonates. Indomethacin, widely used to effect nonoperative closure of patent ductus arteriosus, has been implicated in vasoactive side effects and requires an accurate diagnosis. Firstly, the hemodynamic significance of the ductus arteriosus was assessed by clinical signs, such as tachycardia, disturbed microcirculation and a high difference of central and peripheral temperature. The patent ductus arteriosus was confirmed by echocardiography. The left ventricular systolic time intervals and the cerebral perfusion were obtained by pulsed doppler recordings. 48 preterm infants below 1500 g were investigated within the first 12 hours of life and during the first week. In 32 preterm neonates (67 %) a patent ductus arteriosus without hemodynamic significance and in 9 neonates a patent ductus arteriosus with hemodynamic changes was detected. In 9 neonates there were no signs of patent ductus arteriosus. Neonates with typical clinical signs of patent ductus arteriosus exhibited significantly diminished preejection time, prolonged ejection time and a decreased quotient of preejection and ejection time. We found pathologically changed parameters of anterior cerebral artery in neonates with clinical signs of patent ductus arteriosus. To judge the efficiency of the diagnostic management the groups of neonates were compared concerning the evidence of complications. Neonates with ductus arteriosus but without therapy did not reveal more pulmonary problems as well as intracerebral hemorrhages, renal or intestinal disturbances than the group of neonates with treated ductus arteriosus. Summarizing, we suggest that the described criteria are to be taken into account before treatment of ductus arteriosus in preterm neonates. In this way a wide clinical and echocardiographical investigation will be performed in risk neonates and a useless therapy can be avoided.

Cerebral blood flow velocity wave form as an indicator of neonatal left ventricular heart function

Objective: To investigate the relationship between cerebral blood flow velocity wave form (CBFV-WF) parameters and myocardial contractility indices in healthy and sick preterm and term newborns. Methods: Total group of 82 babies was divided into four subgroups: prematures with gestational age <34 weeks with ( n=20) and without ( n=14) respiratory distress syndrome (RDS) and infants with gestational age of >33 weeks with ( n=18) and without ( n=30) asphyxia. On day 1, 2, 3, 6 and 14, the acceleration time, Q(ECG)-peak(flow) time and preejection period of CBFV-WF (internal carotid artery) were measured through the anterior fontanel by Doppler ultrasonography. Simultaneously cardiac output, fractional shortening, systolic time intervals and their ratio were determined echocardiographically. Results: RDS-babies had higher cardiac output and better myocardial performance then non-RDS-babies. Asphyxiated babies had lower cardiac output as compared to healthy babies, improving over time. Correlations were found between CBFV-WF parameters and several myocardial function indicators, but preejection period of cerebral blood flow velocity correlated closest with the same period measured echocardiographically ( r=0.67, P<0.0001). Multiple linear regression revealed no influence of gestational age or clinical condition on this relationship. Assessment of agreement indicated that only substantial changes in myocardial performance could be monitored using preejection period of CBFV. Conclusion: Although a relationship was detected between the preejection period of CBFV and left ventricular systolic time interval (used as indicator of changes in left ventricular function), only rather large changes in left ventricular performance can be reliably detected using the preejection period of CBFV.