Fetal Tachycardia: identifying at early stages
- Tachycardia fetus: identification of the early stages of treatment
fetal tachycardia - is an abnormal increase in fetal heart rate, and is defined as a heart rate above the 160-180 beats per minute.As a rule, tachycardia fetal heart rate is 170-220 beats per minute (with tachyarrhythmia observed more frequent cuts).
first case of fetal tachycardia S. Hyman recorded in 1930.Today, the estimated prevalence is at around 0.4-1 pregnancies.In most cases, the hearth of abnormal electrical pulses are atrium.Tachycardia fetus can range from a simple sinus tachycardia Sinus tachycardia: a violation of the heart to a variety of tachyarrhythmias.Fetal tachycardia can be caused by many diseases, both mother and child: the mother - hyperthyroidism Hyperthyroidism: increased secretion of thyroid hormone and taking certain medications;fetus - fetal infection, fetal hypoxia, anemia, fetal chromosomal abnormalities (Patau Syndrome or trisomy 13 (chromosomal human disease that is characterized by the presence of an extra chromosome in the cells 13) and Turner syndrome).
- ultrasound fetal echocardiography
Doppler study in M-mode is best suited for the analysis of the fetus.It is desirable that the sampling line crossing the walls of the atria and ventricles that allow for the simultaneous assessment of the reduction of both ventricles and atria.When fetal ultrasound Doppler technique is used to detect motion, mainly red blood cells (RBCs).So it is revealed blood flow in the heart and other vascular lesions.
Ultrasound can also show the defects and complications of the fetus, for example, signs of fetal hydrops.
Treatment and prognosis
In most cases, long-term prognosis when diagnosed sinus tachycardia fetus is generally favorable, abnormal heart rate stabilized during the first year of life.For the treatment (if necessary) is carried out transplacental administration of antiarrhythmic drugs.
- reciprocating tachycardia Supraventricular fetus
most common type of fetal tachycardia is a supraventricular reciprocating tachycardia.Scientists have shown that the transient atrioventricular connection is normal in the early stages of fetal development, but noted that the preservation of these bonds in late pregnancy may contribute to the development of reciprocating tachycardia.The presence of fetal arrhythmia Extrasystole - heart rhythm disorder atrial (which is observed in 1-2% of pregnancies) may lead to the development of supraventricular (supraventricular) tachycardia, which usually occurs at 24-32 weeks of gestation.If supraventricular tachycardia proceeds to sinus rhythm, heart rate should return to normal for gestational age (in the absence of drug therapy).When combined with fetal tachycardia, bradycardia, it may be suspected long QT interval syndrome or the presence of inflammatory conditions.In this case, the choice of antiarrhythmic drugs may be hampered because of the need to avoid drugs that lengthen the interval QT.In general, the best indicator of tachycardia - it occasionally or permanently changing the atrioventricular or ventricular-atrial conduction, identified by echocardiography.If during an episode of tachycardia, there are obstacles atrioventricular or ventricular-atrial conduction, supraventricular tachycardia reciprocal rule and consider other forms of tachycardia.
- Atrial flutter
Atrial flutter is observed in approximately 30% of cases of fetal tachyarrhythmia.Most fetuses diagnosed with prenatal atrial flutter, there is an additional atrioventricular connection, which can lead to the development of atrioventricular reciprocating supraventricular tachycardia in utero or postnatally.Atrial rhythm in atrial flutter, usually less than 400 beats per minute, and usually is regular and combined variable atrioventricular block.Atrial rhythm with other forms of atrial tachycardia or is irregular (chaotic atrial tachycardia) or kept at 180-240 beats per minute (ectopic atrial tachycardia).
Other forms of fetal tachycardia
Atrial ectopic tachycardia Tachycardia - the body to the limit? - one of the primary forms of atrial tachycardia.Ectopic foci can be localized in any parts of the atria, but more often detected in the eye or the side wall of the right atrium, in the confluence of the pulmonary veins.Atrial ectopic tachycardia is caused by the presence of auto focus or trigger activities outside the site.In this state, the atrioventricular node passively activated.Atrioventricular node as passive when the chaotic atrial tachycardia, uzloy ectopic tachycardia and ventricular tachycardia.The nodal and ventricular tachycardia is rare, but increasingly found in utero.