Abnormal Heart Rate Patterns Research Articles

Abnormal embryonic heart rate pattern in early pregnancy associated with Down's syndrome

The case history of a 35-year-old woman with a pregnancy following IVF treatment is presented. Transvaginal sonography revealed an abnormal pattern of the embryonic heart rate between 28 and 50 days following follicular aspiration. At term, a male infant with the characteristics of Down's syndrome was born. The diagnosis was confirmed by chromosome analysis. The implications of this observation are discussed.

Changes in antepartum heart rate patterns with progressive deterioration of the fetal condition

In this paper changes in antepartum fetal heart rate (FHR) patterns are described, that occur with progressive deterioration of the fetal condition. The data on the relationship between heart rate patterns and fetal blood gas and pH values are reviewed. A possible rank ordering is presented in which changes in FHR pattern, body movements and blood flow velocity wave form patterns occur with progressive deterioration of the fetal condition. It is concluded that in small-for-date fetuses changes in heart rate and movement patterns are rather late signs of impairment, coinciding with fetal hypoxaemia. In general, heart rate variation falls below the norm at the same time as decelerations occur; there are, however, large inter-fetal differences. In general, abnormal Doppler velocity wave form patterns precede the occurrence of heart rate decelerations. Their impact on the timing of delivery is, however, still uncertain. The advantages of a numerical analysis of FHR patterns include identification of fetuses with low FHR variation, precision of the actual fetal condition and (at early gestation) longitudinal follow-up of fetuses with abnormal heart rate patterns.

Antepartum heart rate patterns in small-for-gestational-age third-trimester fetuses: Correlations with blood gas values obtained at cordocentesis

Antepartum fetal heart rate records were made immediately before cordocentesis and blood gas analysis in 58 small- and 29 appropriate-for-gestational-age fetuses at 27 to 38 weeks' gestation. All appropriate-for-gestational-age fetuses had blood Pot and pH values within the normal ranges for gestation, and in 27 of 29 cases the heart rate pattern was reactive; in two it was nonreactive. Abnormal heart rate patterns were present in 15 of the 19 small-for-gestational-age fetuses that were found to be hypoxemic, acidemic, or both. The abnormalities included decreased baseline variation, absence of accelerations, presence of decelerations, and increased baseline heart rate. A repetitive decelerative pattern best identified the hypoxemic fetuses. Fetal P02 values in the lower normal range, present in many of the small-for-gestational-age fetuses, were in general associated with a reactive fetal heart rate pattern. (Am J Obstet Gynecolol 1990;162:698-703.)

Patient-recorded domiciliary fetal monitoring

Domiciliary fetal monitoring via a telephone link has been in clinical use at the Royal Free Hospital for 2 years, during which time 858 traces of 134 patients who were moderately at risk have been transmitted to the hospital. All recognized abnormal heart rate patterns were detected during the study period. In seven patients obstetric intervention took place on the basis of the domiciliary fetal monitoring recording and subsequent hospital monitoring. There were no intrauterine or neonatal deaths, and there was no overall increase in obstetric operative intervention. There appeared to be a significant reduction in the inconvenience suffered by the patient and her family, compared with conventional monitoring. Fetal heart recordings performed solely by the patient were of a high quality and reduced the demand on midwifery resources. To allow this only 3 hours of midwifery time daily was required and no additional demands on obstetric staff were made. It is anticipated that domiciliary fetal monitoring, performed by patients, will become an essential and established service throughout the United Kingdom (and probably Europe) as the principal means of monitoring fetal well-being.

Abnormal heart rate tracings and serum creatine phosphokinase in addicted neonates

Continuous cardiorespirographic (CRG) monitoring was done during the first five postnatal days in 12 infants of drug dependent mothers (IDDM) and 19 normal infants (control). Abnormal heart rate patterns in the IDDM included: (1) significantly ( p<0.01) higher baseline heart rate (129±15 vs. 118±8), beat-to-beat variability (4.4±2.4 vs. 2.6±1.6) and long-term variability (15.5±6.6 vs. 7.0±3.9), as compared to control and (2) frequent and spontaneous occurrences of large (40 beats per minute), brief rise and fall in heart rate giving a striking “wave-like” appearance to the tracing. These changes were more intense in the IDDM with moderate to severe, as compared to mild withdrawal. Treatment of the infant's withdrawal with drugs resulted in a clinical improvement, but the abnormal heart rate tracings persisted. Serum creatine phosphokinase (CPK) was also elevated (>450 IU/l) in the IDDM (mean±SE=984±299 IU/l) and 89% of the total CPK was the MM fraction. These infants exhibited tremors and hypertonicity.

The importance of antepartum cardiotocography.

The significance of antepartum cardiotocography was examined on patients at the University of Cologne in the years 1982 and 1983. We analyzed 13,310 cardiotocograms of 1,463 women and correlated their pregnancies and deliveries with the status of their newborns. There were only 66 suspect/prepathologic fetal heart rate recordings in 50 patients. All these patients had severe complications during their pregnancies. Impending prematurity, toxemia, first and second trimester bleeding as well as placental insufficiency and polyhydramnios were the leading complications. The analysis of the cardiotocograms using Hammacher's criteria demonstrated that the CTG characteristics "floating line" and "oscillation type" together accounted for the largest proportion (43.9%) to the total score and thus constituted the most important parameters. Fetuses with abnormal CTGs had a birthweight of less than 1500 grams in 30% of the cases. This group also had poorer Apgar scores and umbilical artery pH values than neonates with normal antepartum cardiotocograms. After excluding non-viable malformations the perinatal mortality was 80 per 1000, i.e. it was nine times higher for newborns with abnormal antepartum heart rate patterns. The study demonstrated that abnormal antepartum CTGs in non-selected patients are rare and are always associated with severe complications of pregnancy. Thus, the method is not suitable as a general screening method but should be used for specific indications in high risk pregnancies and for the evaluation of any tocolytic treatment. The recognition of abnormal CTG characteristics requires technically adequate recording and accurate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities of ambulatory 24-hour heart rate in diabetes mellitus.

Twenty-one normal subjects and 64 diabetics with varying severity of autonomic damage underwent 24-h ambulatory EKG monitoring. No diabetics had the "sick sinus syndrome," and the frequency of arrhythmias was no higher than in the normal subjects. The diabetics had higher mean hourly heart rates, and with increasing autonomic damage there was reduction in diurnal heart rate variation. The mean waking and sleeping heart rates were higher in the diabetics. The maximum heart rates were not significantly different, but the minimum heart rates were significantly higher in the diabetics. These previously unrecognized abnormal 24-h heart rate patterns provide further evidence of damage to the heart rate-controlling mechanisms in diabetes mellitus.

Antepartum sinusoidal and decelerative heart rate patterns in Rh disease

A review was made of the data on 42 cases of Rh disease that resulted in the birth of a liver infant after 33 weeks' gestation. On 12 occasions, antepartum monitoring of fetal heart rate (FHR) showed a sinusoidal and/or decelerative heart rate pattern. All 12 infants were anemic at birth; only one was born acidotic. One infant died neonatally. Monitoring of FHR identified the severely affected infant more reliably than did the Liley classification. Within the same Liley group, infants with an abnormal heart rate tracing had lower values of hemoglobin at birth than did infants with a normal tracing. The conclusion is that a decelerative heart rate pattern is just as indicative of an infant severely affected with Rh disease as is the sinusoidal pattern. Once the abnormal heart rate pattern is identified, early delivery nearly always results in an infant who survives.

High-resolution determination of the R-R interval

A preprocessor is described that determines the time interval between successive R waves of the electrocardiogram with an error of less than 0.2 ms. It accomplishes this by sepearting in hardware the function of determining the approximate location of the R wave from the function of localizing with great accuracy the peak of the wave form. With this device it is possible to detect abnormal heart rate patterns characterized by exceedingly small beat-to-beat variability. The approach may be useful for other bioelectric signals.

Paracervical block with low doses of chloroprocaine. Fetal and maternal effects.

Results of 261 paracervical blocks done with a dose of 12 ml of 1% chloroprocaine hydrochloride solution containing 1:200,000 epinephrine were recorded. The blocks were followed by abnormal heart rate patterns for 3 to 15 minutes in six of 104 (5.8%) of the fetuses. Excellent pain relief was obtained with 142 of 172 blocks or 83%. One fetus died owing to multiple congenital anomalies. Paracervical blocks performed as described are completely safe for the mother and do not affect Apgar scores. Potential fetal risks are acceptable when considered in light of the ease of administration and the amount of pain relief obtained.

Maternal hypoxaemia after pethidine.

SummaryTranscutaneous oxygen tension (tcPO2) was monitored in 28 women during labour, using a method which correlates closely with arterial oxygen tension. Most women increased their ventilation during uterine contractions and decreased it when the uterus relaxed. The tcPO2 record, therefore, showed a wave form synchronous with the uterine pressure curve.In four out of nine women given 50 mg. of pethidine and in 13 out of 19 given 100 mg. of pethidine with 1.25 mg. of levallorphan (Dolantin S), the fall in tcPO2 became greater immediately following the administration of the drug. The tcPO2 fell to about 30 mm. Hg in four women. Abnormal heart rate patterns were recorded from eight fetuses.

Fetal heart rate and acid-base status in the assessment of fetal hypoxia

This study is aimed at assessing the usefulness and correlation between measurement of fetal blood acid-base status and continuous fetal heart rate monitoring as indicators of fetal hypoxia during labor. One hundred and twenty-nine labors were studied, the majority having some obstetric condition which could increase the possibility of fetal hypoxia. When scalp blood pH was < 7.20, the baby was likely to be born with a low Apgar score (mean, 3.6). Of 23 fetuses with acidosis, 2 were stillborn and one died neonatally. In the presence of clinical evidence of fetal distress measurement of fetal blood acid-base status improved prognostic accuracy threefold. The importance of fetal heart rate changes during contractions was confirmed. Two abnormal heart rate patterns were distinguished, these being associated with low Apgar scores. A correlation was also found between abnormal fetal heart rate patterns and the presence of fetal acidosis. All other heart rate patterns were associated with high mean Apgar scores. Both fetal heart rate monitoring and fetal blood acid-base measurement are valuable in assessing fetal condition and are complementary to each other.