Image by BUPA

The Quick Summary

If you diagnosed or got diagnosed a prenatal, connatal or congenital AV-Block °III, an atrioventricular block, 3. grade or a congenital complete heart block without anything else out of the ordinary, you should immediately order a blood test of the mother to check Ro and La AK! In addition, Anti Phospholipid AK should be checked (Anti Cardiolipin).

If the heartbeat is below 60 bpm (beats per minute), you should also check for a pericardial_effusion, hydrops and (rare) endocardial fibroelastosis. With a positive medical evidence, or should there be anything else out of the ordinary the attending physician shall contact immediately the closest prenatal center with experience of heart disorders (Prenatal Cardiac Center). Depending on the exact diagnosis, an emergency referral to that Prenatal Cardiac Center (by ambulance if necessary) is likely! The child is in mortal danger, (further) fetal damage to organs or prenatal development can not be ruled out.

If the heartbeat is below 60 bpm but there is no other disorder, complication or other unusual diagnosis, the next Prenatal Cardiac Center should also be contacted immediately. An immediate referral into hospital is also necessary, though in this case, the attending physician may be instructed to medically stimulate the heartbeat before (by 5-10 bpm).

If the heartbeat remains above 60 bpm with none of the above mentioned complications, the chances are quite good to stop the negative development and, aside of a necessary pacemaker, the child may be completely healthy. No, it is not sure! Doctor or mother should also contact the next Prenatal Cardiac Center and request an appointment at earliest convenience! Earliest convenience means, the appointment does not have to be the same day! It is imperative to involve a Prenatal Cardiac Center, not every Prenatal Center and not every doctor appreciates sufficient experience!

More information about the further treatment follows. But first the diagnosis…

What is a prenatal AV-Block Type 3?

First of all, it is diagnosed (named) differently, sometimes as prenatal (pre-birth), sometimes congenital or connatal (both meaning “inborn”). Sometimes as an AV-Block 3rd Grade, sometimes associated with a bradycardia (slow heartbeat), sometimes as a complete or an atrioventricular block, sometimes simplified as a complete heart block or abbreviated as AVB or AVB3.

Whoever hears that diagnosis the first time, does not know anything about it and finds a lot of misleading or incorrect information on the web, most of it arousing panic. As we learned, many doctors have the same reaction, the diagnosis being so very very rare – only one out of 20,000 live births! With more than 660,000 births in Germany 2012 that would be 33 births/year in Germany, in Hanover at the medical university there are about 1-2 cases a year. With about 4 Mio. births in the U.S., it is just about 200 cases a year there.

Without wanting to belittle the diagnosis: If you are confronted with it, something very bad happened: Likely the CCS, the Cardiac Conduction System (CCS)1, responsible for the heart beat got irreparably damaged.

As bad as that diagnosis is and sounds, everything else can be managed! And if everything works out find, your child “just” gets a pacemaker, but in reality, that poses only little restrictions! Please keep reading!!
ExclamationMarkThe following information is not scientifically founded yet but are based on medical experiences, assessments and recommendations. As of the low number of cases, to our knowledge there are no reliable2 studies or results!
There are though studies with limited numbers of patients they are based on, which findings have lead to recommendations on how to handle the diagnosis, which is the base of what we write here. Some of the studies are found at the end of the page under Further Reading.

The likely reasons for a prenatal AV-Block Type 3

The diagnosis of a (complete) prenatal AV-Block Type 3 comes in three different manifestations, representing roughly about one third of the cases.

Variant 1 is in combination with a so-called congenital heart disorder, a born-in one, whereas in these cases, the entire heart and the organic development are also affected.

Variant 2 is called idiopathic, meaning there is no comprehensible reason.

Variant 3 is related to an auto-immune reaction with the mother. It is not a disorder, as an anti-immune reaction usually is “healthy”. Do they though turn against healthy body tissue they cause sickness and it’s called an anti-immune disorder.

Classic would be the rheumatoid arthritis or joint rheumatism. Here the antibodies attack the joint’s mucosa which results in arthritis (inflammation of the joint) and result then in destruction of cartilage and bones with damaged and stiff joints.

To my knowledge, this is generally the only confirmed cause, so this is what we can try to explain here.

AV-Block Type 3 + Sjörgren Syndrome

The cause for this AV-Block is likely a rheumatic reaction, a so-called Sjögren Syndrome of the mother, which can have happened long before the pregnancy. Very often, this disorder is not even noticed! As a result of this rheumatic reaction, the body has developed anti-bodies, so-called Ro and La AK, which then keep residing in the mother’s body.

These antibodies have been created by immune defense to counter a disease/disorder in the mother and as such are not generally hostile.

But now comes the pregnancy. Between pregnancy week 18 and 20, the antibodies, including these Ro and La AK penetrate through the placenta into the child’s body. In general a good idea, such giving the child the immunisation of the mother. In the case of Ro and La AK now there is a malfunction. These antibopdies “understand” the developing nerves at the child’s heart as rheumatic. In countering the (nonexisting) “rheumatic disorder” they unintentionally distroy the cardiac conduction system1! This happens first at the connection from the heart’s nerve node, the so-called AV-node to the hearts main chambers, which is why the diagnosis got this name. There are different manifestations, from a partial disorder to the complete destruction, being also named 3rd grade then (also written °III).

In many cases, this is fatal for the child. But then you would likely not read this. In other cases, the heart remains beating, thanks to secondary stimuli and nerves, but distinctly slowed. If there is a correlation between the mother’s heartbeat and that remaining one of the child, I have contradictory information about.

In the case I know (our own), the heartbeat collapsed to 62-63 beats per minute (bpm). Normal would be 110-160 bpm.

I have been asked to also mention the more rare case of a systemic lupus erythematosus (also called lupus or SLE). Sjögren Syndrome and SLE are two manifestations of a rheumatic anti-immune disorder with different symptoms, both should be identified by testing for Ro and LaAK antibodies.

The Diagnosis. What now?

baby-pacemakerImperative: Speed! As the antibodies are still active in the fetus, further damage is possible, more even likely. As such, quick response to the threat is important. Not to improve the situation but to avoid further damage and harm.

The diagnosis itself does not say anything, especially not about the further chances for survival of the child. Furthermore, this diagnosis is not sign for a mental “handicap” of the child whatsover!

Important is first and foremost to rule out further complications and such further damage.

Common complications are the above mentioned pericardial_effusionhydrops and endocardial fibroelastosis (the links open a new window). Whereas a small pericardial effusion is relatively “normal” and may be simply monitored. But specialized physicians of Prenatal Cardiac Centers can better evaluate that!

To avoid further damage of the fetus development of the cardiac conduction system1 is kind of difficult. As the diagnosis is so rare, there are no reliable studies2. But on earlier studies there, at the Hospital for Sick Children in Toronto (Canada) follows the therapeutic policy to apply mothers with a diagnosed fetal complete heart block with a frequency below 55 bpm (beats per minute) Dexamethason and a Betamimetica (to stimulate the β-receptors, the oppositve of β-blockers). This is opposed by the major AEPC-study, which did not find any improvement to the fetal survival rate for children treated with Cortisone. This study considers the time of diagnosis below 20 weeks, a heart frequency under 50 bpm, a hydrops and a reduced LV-funtion as especially unfavorable for the prognosis. On the other side, other authors (as also Prof. Dr. von Kaisenberg at the Hanover Medical University) recommend the therapy with steroids to avoid the hydrops.

(As any other treatment) Such a steroid-therapy has also its side-effects. Most notably is a change of the organic tissue in the fetal brain. But there is no medical evidence of any other negative side effects caused by that change in the organic tissue. But there is also no conclusive information that rules out such negative side-effects.

As the experimental treatments have shown so far is that it largely reduces the danger of further damage, the survival factor of the children increased from 80% before testing the treatment to 95% after. And before, the survival chance of the child for the first year (weeks) after the birth (postnatal) was only 47%. Though without having hard facts, the following interpretation can be considered as likely:

“Despite missing prospective studies, fluoride corticoids are recommended for fetuses with incomplete AV-Block and Hydrops. If the AV-Block is completely established, regression has not, but advancing of the blockade from a second- to third-grade block have been reported.” (German Source). But also with a third-grade AV-Block there is an imminent danger of further damage by the antibodies! Therefore such therapy seems recommendable until the end of the pregnancy!

The treatment is about keeping the child as long as possible in the mother’s womb, as it will need a pacemaker right after birth. The earlier the child is delivered, the more difficult that operation and the more likely the chance something goes wrong. Without the treatment, a further damage of the tissue in the CCS1 is possible, having a negative impact on the survival chances again.

In short: Without treatment the damage can get worse, the danger of a heart failure increases, as well as of a hydrops or other complications. With the treatment, there will be a (medically possibly neutral) alteration of the brain tissue, but the survival chances increase (disputed).

Having the danger of further damaged reduced, it remains important to keep the baby’s heart beat above 60 beats per minute (bpm). Why?

Under 60 bpm, the chances for a hydrops or other complications increase exponentially. Therefore a value above 60 can justify an ambulatory treatment with a twice-weekly check by Doppler ultrasonic. One a week in the Prenatal Cardiac Center, once a week can be at your hometown, respectively the next doctor’s office having such a device. If that is not the treating gynecologist, the mother will likely want to see the own gynecologists bi-weekly.

In addition, with such a low heartbeat the danger of organic nourishment shortages (incl. the brain) increases. Above 60 bpm the development can proceed quite normal.

On the other side, as part of the suggested treatment, when the fetal heartbeat drops below 60 bpm, the mother should be hospitalized to receive a medical treatment to increase the heartbeat of mother and child (by about 5-10 bpm) and increase the monitoring checks. Should now a  pericardial effusion, hydrops and endocardial fibroelastosis develop, delivery (birth) becomes a necessity. The goal is to have this happen as late as possible.

The Birth

Image source: Indian Pacing Electrophysiology Journal

Before pregnancy week 28 the survival chances are considerably low.

From the 28th pregnancy week onward, the risk reduces at a daily rate, being a result of the fetal development in the womb.

From the 34th week the chances are good, the lung development has been finished. But as the child gains about 200-300 grams a week (7-10 oz) and grows, it sure is best if the birth can happen as close to the planned birth date as possible. According to our Prenatal Cardiac Doctor “after the 37th week”.

Delivery is done by C-section. Yes, I know, I did not mention that yet. But it makes sense, not to stress the weakened fetus further by the stresses of a normal birth. And right after birth the pacemaker shall be implanted. This too sure not being a happy thought, but a necessity.

If the heartbeat remains notably above 60 bpm the implantation of the pacemaker can be deferred to allow the child to recover from the birth stress. This also allows the child cardiologists to monitor and understand the child’s own capacity and check the child for further possible damage.

The two weeks following the birth and pacemaker implementation are critical, whereas the chance for survival is proportional to the “age” of the child.

If now everything turns out well, your child can grow up with a pacemaker, but otherwise mostly normal. If you feel so, you can contact one of the local self-help-groups.

Frequently Asked Questions

… and corrections

The answers reflect our understanding from discussions and talks with the physicians and doctors at the Hanover Medical University. In General, you should address these questions with the physician of your choice and possibly involve the doctors of the Prenatal Cardiac Center managing that individual case!


Sure, it is a personal decision. But we oppose it usually, especially if there are no other sound reasons. Today, life with a pacemaker is almost uninhibited. Far too often these and other children with heart disfunctions or problems are being aborted, even where a single, postnatal operation could safely correct the “problem” permanently. Even where this is not the case, like here, you should give the child a chance. In the case of an AV-Block with Sjörgen-Syndrome you also have an increased risk for further pregnancy, seen question after next.
In the end, only the parents, ultimately only the mother can decide. But in any case, before such a decision you should definitely consult about this with the experts at your next Prenatal Cardiac Center and get a proper and complete briefing.

Cardiac Conduction System, are that nerves?

The physician correctly calls it Cardiac Conduction System (or CCS), being responsible for the heart beat. This are not “nerves” but modified muscle fiber, though they do have the same task for the amateur; they stimulate the heart to beat. They are differently constructed, which is why the antibodies attack here, but not the nerve cells and fibers. If the antibodies attack other muscles is not yet clear to me.

Critical Heartbeat 50 or 60 bpm

There are different opinions obviously about when the heartbeat becomes “critical”. In most medical literature, 50 bpm (beats per minute) is considered “critical”. At the Medial University of Hanover, Prof. Dr. von Kaisenberg specified “critical” as 60 bpm. So I allow myself the following interpretation. Critical-critical is 50 bpm, but from 60 bpm we come into a critical range that may make an increased monitoring (hospitalization) recommendable.

Further Reading

Our Prenatal Cardiac Center at the Medical University of Hanover has referred us initially to a Canadian Study: The Benefits of Transplacental Treatment of Isolated Congenital Complete Heart Block Associated with Maternal Anti-Ro ⁄ SSA Antibodies: A Review, published (as linked) in the Wiley Online Library.

For the page, we also used a German study, of which we extracted the paragraphs related to our topic here.

If you learn about other publications you believe noteworthy, please let us know!

In-Uterus heart pacemaker implantation

There are clinics implanting the pacemaker in uterus (in the womb). This should be the absolute exception for severe emergencies. If the child is grown enough to get a pacemaker, the managing of an early-born is usually far less risky. So this is really only reasonable in very extreme exceptions. We urge you to get a second medical assessment from a different clinic.

I had the Sjörgren Syndrome, can I get a baby at all?

The different question was if another pregnancy would be possible at all after a pregnancy that came up with an AV-Block.
Even if you had the Sjörgen Syndrome, another pregnancy is possible. But!
There is the risk of a nerv damaging for the unborn child as explained above. To minimize that risk best possible, a cortisone treatment shall begin before the pregnancy already and must be maintained on throughout the complete pregnancy. With a Cortisone treatment for more than six months the side effects are usually no longer completely reversible (that they cease completely), that refers to mother and child! The gynecologist should sure be completely informed and make sure of a frequent check with Doppler-ultrasonic.
If you do not do that Cortisone treatment, you have a very high likeliness of an AV-block °III (complete, irreversible damage of the nerves).
With the treatment, you have a good chance for a healthy child (though no safety, but that’s non-existing anyway).

Studies – why do you call them unreliable?

We refer to several studies in Further Reading. As we were made to understand, you call a study “reliable” when several thousand patients took part. As a “major study” the AEPC was named with 175 cases: Eliason H et al. Circulation 2011; 124:1919-26 which we did not find online to link here. This is far from any “major study” and our attending professor did not want to use “reliable”, instead calling it “highly probable”.


In Wikipedia there are some pages with short information about the prenatal (congenital) AV-block. The short publication leaves more questions than it provides answers, but I will try (happily with your help) to collect and consolidate answers to be publish here (and maybe also extend Wikipedia).

Errors, Amendments

The information on this website has been compiled best to individual knowledge and understanding. The page does not imply to be complete or to contain all the information available. Other possibilities to treat this diagnosis are conceivable. Should you believe the page to show additional information or opinions or if you find real errors, please contact me or leave a comment!

Remark: I have somewhere taken up “Type 3”. It was emphasized to me that this is medically incorrect. Having found that definition also on the Internet, I kept the keyword in the Meta-tags of this page.


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