Bradycardia (low heart rate) is a cardiology term. The heart beats slower than is normal for the respective age. Here you can read everything about the causes, acute triggers, therapies and home remedies for a low heart rate.
The heart of an adult at rest should beat 60 to 80 times per minute. In conjunction with an average blood pressure of 120/80 mmHg (millimeters of mercury) and a normal heart size – the heart should be as big as your own fist – the entire body is supplied with sufficient blood and the circulatory system is stable.
Certain chronic and acute diseases can disrupt the conduction of impulses in the heart and cause the heart to lose its rhythm ( arrhythmia ), increase its rate ( tachycardia ) or slow it down. The latter is called bradycardia (Greek βραδυκαρδία [bradykardía], literally meaning “slowness of heart”).
Article overview:
Causes of bradycardia
Bradycardia can be caused by a drug as an intended effect, but also as a side effect. Other possible causes are:
- Low Heart Rate in Athletes : Regular exercise can cause bradycardia, which is usually harmless.
- Malfunctions of a pacemaker : Similarly, a mechanical malfunction of a pacemaker can lead to a slow heartbeat.
- Hypothyroidism : Thyroid hormones regulate heart rate and circulating blood volume, among other things. A low heart rate can therefore be observed with an underactive thyroid gland.
It is also possible that the bradycardia is caused by a disease of the heart. This is also referred to as a cardiac arrhythmia, in which there is an error in the regulation of the heart rate.
Typical forms of bradycardia
The sinus node in the atrium of the right heart is the heart’s beat generator. This is where the electrical potentials form, which spread out in a controlled manner over the entire heart muscle, causing the heart to contract (contraction) and blood to be ejected. The sinus node usually emits 60 to 80 pulses per minute and can send up to 250 or more pulses of electricity through the heart within 60 seconds when under stress.
Sinus Bradycardia and Sick Sinus Syndrome:
In sick sinus syndrome, the sinus node is disturbed and the heart beats irregularly (absolute arrhythmia) or it fails completely. Then other areas of the heart take over the function of the clock generator (AV node or His bundle), which, however, can send an electric shock much less often, i.e. less than 60 times per minute.
Chronotropic Incompetence:
The cause is also in the sinus node. At rest, the heart beats almost normally. During exertion, however, the heart rate remains as low as the additional need for heartbeats cannot be compensated.
heart block:
In the case of heart block, the heart is not mechanically blocked, but rather the transmission of the electrical impulse. If the electric shock cannot spread to the atrium, this is called sinoatrial block (SA block). If the heartbeat from the atrium cannot stimulate the ventricles, this is referred to as atrioventricular block of varying severity (AV block 1st to 3rd degree).
atrial fibrillation:
If the heart were a car engine, the atrial fibrillation would be a series of misfires. A few of the ignitions come through and make the engine rev once, so the heart contracts and pumps once. However, most of the other sparks go nowhere and do not trigger a shock. As a result, the heart beats irregularly and slowly (absolute bradyarrhythmia).
Low pulse: symptoms
Most of the time, a low heart rate doesn’t cause any symptoms. In some cases, however, the pulse is so low that symptoms arise.
If the heart rate and thus the pulse decrease, this means that the heart contracts less frequently. With every heartbeat less, the blood circulates more slowly in the circulatory system. The body usually tries to compensate for this by increasing blood pressure. To do this, it narrows the vessels, through which less blood can flow. This results in an undersupply of all muscles and organs. Depending on how you get used to it, this can manifest itself in different ways:
- general or acute feeling of weakness
- exhaustion and tiredness
- visual disturbances
- dizziness
- nervous anxiety
- cold sweats
- shortness of breath
- clouding of consciousness up to fainting (unconsciousness)
How is bradycardia diagnosed?
In the case of circulatory problems, you can help with the correct diagnosis yourself. As soon as the acute symptoms appear, you should feel your pulse and use it to determine your heart rate. A sphygmomanometer can be used to determine not only blood pressure but also pulse.
The doctor will also listen to the heart sounds with the stethoscope (auscultation). In a detailed anamnesis interview, family risk factors, previous illnesses and current medication are clarified as influencing factors. A blood sample for examination in the laboratory is necessary to rule out metabolic diseases or an acute event such as a heart attack .
Exactly what is happening in the heart can only be determined indirectly from the outside. The most important examination methods for investigating bradycardia are an electrocardiogram ( ECG ), which shows a snapshot of the electrical conduction conditions in the heart. In addition, an EKG examination is carried out during exertion on the bike ( exercise EKG ), followed by a long-term EKG , which records heart activity over a period of 24 hours.
If there are still questions about the cause of the low pulse, other examination methods are suitable, such as the electrophysiological examination (EPU) of the heart, in which the ECG is not measured via the chest (transthoracic) but directly using puncture electrodes in the heart muscle. Before this minimally invasive procedure, other methods can be used to determine important information about heart activity. Other investigation methods are:
- Echocardiography (heart echo, UKG)
- Cardio Magnetic Resonance Imaging (Cardio MRI)
- Cardio computed tomography (cardio CT)
- cardiac catheter
Therapy for bradycardia: How to treat low heart rate
The treatment of bradycardia always depends on the cause. If the heartbeat is slowed down due to the side effect of a drug, it must be omitted or replaced. For example, beta-blockers can not only lower blood pressure, but also slow the heartbeat, resulting in a low heart rate. In order to continue to treat existing high blood pressure but to get the heart beating faster again, the doctor then prescribes another hypertensive drug, such as an ACE inhibitor or a diuretic.
If the heartbeat cannot be normalized with medication, a cardiac pacemaker can be used . This monitors the heart rhythm and either permanently takes on the function of the clock generator, for example if the sinus node has failed completely, or can – as is necessary in the case of chronotropic incompetence – become active if necessary by recognizing phases of physical stress and only then sending out its impulses. This mode of operation of a pacemaker, known as on-demand, generates a current pulse only when the heart needs it, otherwise the pacemaker remains inactive.
Living with a low heart rate: home remedies and tips
If the bradycardia is not based on a heart disease, those affected can only adapt their lifestyle to relieve the heart.
The general tips for a healthy lifestyle like
- diet rich in vitamins and fiber,
- weight reduction if necessary
- abstaining from alcohol and smoking,
- stress reduction and
- Movement,
also apply to bradycardia. When doing sport in your free time or physical exertion at work, you have to be careful so that your heart doesn’t overwork itself.
In a coronary sports group, under the medical supervision of specially trained trainers, the heart can only be kept fit with precisely defined loads. The trainer makes sure that the level of exertion of an exercise does not overtax the heart. Such a sports group is also recommended for people with pacemakers. For them, all activities of daily life, such as ordinary leisure sports, (house) work, travel and also sexuality, are still possible or only just possible again after the pacemaker has been inserted.
Home remedies for a low heart rate include various types of tea that are supposed to stimulate the circulation. These include liquorice tea, rosemary tea and lime blossom tea. Fresh ginger also has a positive effect on the heart and circulation.