Ask the Pediatric Cardiologist…

by Kathy on December 17, 2007 · 6 comments

in FET #1, Molly

I found this article on the American Heart Association’s website through a Google search for irregular fetal heart beats. The entire article is very interesting, but I especially found the part at the very end about “bradycardia” to be encouraging. Thank you for your comments, emails, phone calls and prayers. We continue to “prepare for the worst and hope for the best,” as Bob has said tonight.

Ask the Pediatric Cardiologist: Irregular Heart Rhythm

Question: My obstetrician detected an irregular heart rhythm during a regular visit today. I am 24 weeks pregnant and everything else has been fine. What is an irregular heartbeat and what does it mean for my unborn baby? Will this problem go away before my baby is born? Do I need to take medication?

Answer: An irregular heart rhythm is usually benign, but your obstetrician may refer you to a pediatric cardiologist for a fetal echocardiogram to better define the heart rhythm.

The normal fetal heart rate is between 120 and 160 beats per minute. The heartbeat is usually regular with only a little variation in the heart rate. Each heartbeat comes from the top part of the heart (atrium) beating first, followed immediately by the bottom part of the heart (ventricle). The bottom part of the heart is what causes blood to leave the heart and make a sound on the heart monitor.

The most common cause of an irregular heart rhythm is when the top part of the heart beats too early (premature atrial contraction, or PAC). Sometimes this premature beat is transmitted to the bottom part of the heart; other times the communication between the top and bottom part of the heart is interrupted after a premature beat.

An early beat that is transmitted or blocked will cause an irregularity in the heart’s rhythm. These premature atrial contractions are very common in the second half of pregnancy and usually don’t cause any problems. They may persist after the baby is born, but usually go away by one month of life. Medication isn’t necessary.

These premature beats can cause problems in a small percentage of cases if multiple consecutive premature beats occur. When this happens for a long enough period, it’s called tachycardia (fast heart rate). If the heart rate stays above 200 beats per minute for a long period of time (hours or days), it could damage the baby’s heart and other organs. If tachycardia occurs, your pediatric cardiologist and obstetrician will recommend medicine for you to take to help regulate your fetus’s heart rhythm. If there are any signs of damage to the fetal heart, it may be recommended that you be hospitalized while beginning the medicine. If you are put on medicine, it is likely the baby will need to take the same medicine after birth.

Most fetuses with tachycardia have a good prognosis if the heart is structurally normal. Some fetuses have a pattern of frequent blocked premature contractions resulting in a low heart rate (bradycardia). This does not usually cause any problems to the baby as long as the heart rate remains above 60–70. Some fetuses with premature atrial contractions can have bradycardia on one visit and develop tachycardia later on. An irregular heart rhythm is not usually worrisome in the fetus, but should be followed closely by your obstetrician.

{ 6 comments… read them below or add one }

1 Rachel Inbar December 18, 2007 at 3:58 am

I can’t imagine what you’re going through. I hope things will soon take a turn for the better, with a steady, normal heartbeat.

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2 Barb December 18, 2007 at 9:33 am

Came to you from Farah’s blog. Lots of well wishes for you!

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3 Katie December 18, 2007 at 10:53 am

Above 60 BPM!!! And yours is. Will be waiting with lots of prayers for Thursday’s ultrasound.

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4 Laura December 18, 2007 at 11:02 am

I will be raying extra hard for you guys. I love your OB, Where there is life, there is hope. So true Kathy. If anyone deserves a Christmas miracle, it is you, you are so wonderful, and I believe! Love you hon!

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5 Dreamer4agift December 18, 2007 at 11:55 am

Hi, I know you don’t know me, but I found your blog through FertilizeMe…

I’m sorry for the stress you’re having to endure, and I will keep you in my prayers.

I also thought it might help you to know that when my sister was preg. with her 2nd child, they found an irregular hb. Once he was born they realized he would have runs of svt (extremely fast heart rate) and a-fib (heart beats irregularly irregular). There were talks of surgeries and all that, but they put him on heart monitors and medications. He will be turning 2 yrs old in a couple of mths and while he still takes “maintenance” meds, he’s a healthy normal boy with no residual effects. So, there is hope where there is life. I saw it firsthand. Keep your head up and know we’re all sending positive thoughts your way.

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6 Searching December 18, 2007 at 3:24 pm

I can second the baby thing where they can have random heart things going on and meds work wonders. I don’t know anything about pre-born peanuts, but along with everyone else am trying to will that munchkin in there to get a little more excited and up that heart rate!

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