Arrhythmias
Tachy brady syndrome
Tachy brady syndrome is a heart rhythm problem in which the heart rate increases and then decreases spontaneously, without any external influence. Instead of settling at a pace that matches what you are doing, the heart swings between periods of a slow rate and sudden bursts of a fast one. It is closely linked to sinus node disease, and it occurs mostly alongside atrial fibrillation.
What tachy brady syndrome is
The name simply describes the two halves of the pattern. Tachycardia is the fast phase, bradycardia is the slow phase, and in tachy brady syndrome the two alternate spontaneously in the same person, without any external influence.
Normally the heart reacts to its surrounding environment, and the heart rate will only increase or decrease if required by the level of activity. Exercise would increase the heart rate, and sleeping would decrease the heart rate. In tachy brady syndrome that link between what you are doing and how fast your heart beats is lost, so the rate changes on its own.
The condition is normally diagnosed as a period of bradycardia, meaning a low heart rate, with alternating spontaneous paroxysmal supra-ventricular beats. Those are short and unpredictable runs of fast beats that originate above the ventricles, the lower chambers of the heart.
- Tachycardia describes the fast phase, when the heart rate rises
- Bradycardia describes the slow phase, when the heart rate falls
- In tachy brady syndrome the two alternate, rather than one or the other occurring alone
What happens in the heart
The heart is not simply a pump made of muscle. It also has a carefully organised electrical system that controls the timing of each beat. Signals begin in a small area called the sinus node, which acts as the heart's natural pacemaker, and travel through specialised pathways so that the chambers contract in a coordinated sequence.
Tachy brady syndrome occurs because of the conduction of abnormal automated impulses through the atrial tissue. The atria are the upper chambers of the heart, and they receive blood into the heart before it is pumped by the ventricles to either the lungs or the rest of the body.
The condition occurs mostly with atrial fibrillation, the rhythm problem in which the atria fire chaotic electrical impulses and the muscle quivers instead of beating properly. It also sits closely alongside sinus node disease, also known as sick sinus syndrome, where the sinus node is not functioning properly. Sometimes the node will send impulses, and sometimes it may not fire an impulse at all or the impulses may be out of sync.
At least 50% of patients with sick sinus syndrome develop this alternating slow and fast rhythm, so the two are often assessed together rather than treated as entirely separate problems.
Symptoms you may notice
Tachy brady syndrome combines two patterns, so the symptoms below are the ones reported with sinus node disease, with atrial rhythm problems and with a slow heart rate.
During the slow phase, a slow heart rhythm can reduce the amount of blood reaching the brain and other organs, which is why tiredness, light-headedness and fainting can occur. During the fast phase, people are often more aware of the heartbeat itself. Some people notice very little, and symptoms vary widely from one person to another.
- Palpitations, which people describe as a racing, fluttering or pounding sensation in the chest
- Shortness of breath
- Dizziness or light-headedness
- Persistent fatigue
- Fainting episodes
How tachy brady syndrome is diagnosed
The diagnosis of heart rhythm issues is usually done through an ECG, or a Holter monitor, which is a prolonged ECG recording, to get an understanding of the heart rhythm.
Because tachy brady syndrome is defined by the alternation between slow and fast, a recording that covers a longer period will often show more than a single tracing taken in clinic, which may catch only one phase or land in a settled spell. Monitoring is therefore usually arranged over long enough to record both the bradycardia and the bursts of fast supra-ventricular beats, and the relationship between them.
An echocardiogram may also be used to assess the structure of the heart, since rhythm problems can sit alongside other cardiac conditions. Once a plan is in place, regular ECGs will be conducted to ensure that treatments are successful and effective.
What any individual needs is decided at consultation. Dr Jogiya will go through your symptoms and your history before deciding which recordings are worth arranging.
How tachy brady syndrome is treated
Treatments for tachy brady syndrome will relate to the more serious problem, so the first question is whether the slow phases or the fast phases are causing the greater difficulty. That is judged on the monitoring findings and on how far the symptoms affect day to day life.
A lower heart rate will require a pacemaker to increase and regulate the impulses being delivered to the atria. A pacemaker is a small device implanted beneath the skin of the chest and connected to the heart by one or more thin wires called leads. It monitors the rhythm continuously and delivers a gentle electrical impulse when the heart beats too slowly, and it stays inactive while your own rhythm is doing its job.
Where sinus node disease is the underlying picture, the common treatment is a single chamber pacemaker in the atrium, which regulates the impulses being sent from the atria to the ventricles. Sometimes a dual chamber pacemaker might be implanted to further regulate and manage the heart rhythm in both the atria and the ventricles.
Fast heart rates can be treated with medication. Sometimes a specialised pacemaker or an internal defibrillator may be implanted to regulate the heart rhythm and control fast heart rates.
Where atrial fibrillation is present as well, it is treated in its own right. That begins with medication to control the heart rate and regulate heart function, and patients diagnosed with atrial fibrillation may often also be commenced on blood thinning medication to prevent the risks of stroke or other blood clot formations in the heart.
No two cases are the same, and the choice between these options is made with the consultant on the basis of your own recordings and cardiac history rather than from a page like this one.
- A pacemaker to lift and steady the rate during the slow phases
- Medication to control the fast phases
- A specialised pacemaker or an internal defibrillator in some cases
- Treatment of any atrial fibrillation in its own right, which can include blood thinning medication
- Ongoing ECG review to check that treatment is working
When to seek help
Call 999 immediately if you have chest pain, if you collapse or lose consciousness, or if someone with you collapses, becomes unresponsive or stops breathing. Do not wait to see whether the episode settles.
Outside an emergency, arrange a review if you are noticing palpitations, unexplained dizziness, breathlessness or a level of tiredness that is new for you, if you have fainted without a clear explanation, and particularly if these things come and go rather than staying constant. Intermittent symptoms are the pattern that longer term monitoring is designed to catch.
If you already have a diagnosis of atrial fibrillation or sinus node disease and your symptoms change, it is worth mentioning, because tachy brady syndrome commonly occurs alongside both. Dr Jogiya is an expert in the treatment and management of abnormal heart rhythms, and can advise on the monitoring and treatment that suit your situation.
This page is general information about tachy brady syndrome and is not individual medical advice.
Where the figures on this page come from
Every figure above is quoted from one of these. This page is general information, not individual medical advice.
More in arrhythmias
Related conditions he treats.
- Atrial fibrillationAtrial fibrillation, commonly known as AF, is a condition where the atria, or upper chambers of the heart, fire chaotic electrical impulses. This leads the muscle to quiver, or fibrillate, instead of beat, so the heartbeat becomes irregular and is often faster than normal. It is one of the most common heart rhythm issues and around 1.7 million people in the UK have been diagnosed with it.
- Atrial flutterAtrial flutter is a heart rhythm problem that affects the upper chambers of the heart, known as the atria. Instead of beating at a normal pace, the atria beat rapidly, but in a regular and organised pattern rather than a chaotic one. Because the chambers do not have enough time to fill properly, blood is not pumped efficiently from the top chambers to the bottom chambers, which is what leads to shortness of breath.
- Atrial tachycardiaAtrial tachycardia is a fast heart rhythm that starts in the atria, the two upper chambers of the heart. An electrical signal emerges from another section of the atria and causes a rapid repeating beat, which means the atria beat very fast. It is one form of supraventricular tachycardia, or SVT, and short bouts of it can be common.
- Bundle branch blockBundle branch block describes a block in the part of the heart's conduction system known as the bundle branches. These branches carry the electrical impulse from the AV node down to each ventricle, and when one of them is blocked the signal reaches one side of the heart before the other, so the two ventricles no longer contract in step. It is a pattern picked up on an ECG, and mostly it is something monitored rather than actively treated.
- First degree heart blockFirst degree heart block is common, and it can affect anyone at any age. It describes a delay in the electrical signal as it travels from the upper chambers of the heart to the lower chambers, rather than a true blockage. Every signal still gets through, which is why many people notice nothing at all and why the condition is usually diagnosed when testing is being done for something else.
- Second degree heart blockSecond degree heart block is a fault in the heart's electrical wiring, not a blockage in an artery. Some of the electrical signals travelling from the upper chambers of the heart fail to reach the lower chambers, so a heartbeat is occasionally missed. There are two types, known as Mobitz I and Mobitz II, and they are treated very differently.
- Sick sinus syndromeSick sinus syndrome, also called sinus node disease, is a condition where the sinus node, the small area of tissue that acts as the heart's own natural pacemaker, is not functioning properly. Sometimes the node will send an impulse as it should, and sometimes it may not fire an impulse at all, or the impulses may be out of sync. Some patients notice symptoms such as palpitations and shortness of breath, and because the node is unreliable rather than permanently stopped, those symptoms often come and go.
- Supraventricular tachycardiaSupraventricular tachycardia, usually shortened to SVT, is a fast heart rhythm that starts above the ventricles, in the upper part of the heart. Symptoms vary widely from one person to another, so some people are very aware of an episode while others barely notice one. Short bouts of SVT can be common, and can usually be treated very easily.