HEART ARRHYTHMIA
A brief overview
Arrhythmia
Symptoms can include
Palpitations
Dizziness
Breathlessness
Feeling tired
Losing consciousness
Arrhythmia can arise from different or both mechanisms.
- Disorder of electrical pulse generation
- Disorder of electrical impulse conduction
Examples of problems with electrical pulse generation
Sinus arrest
Sinus node fails to produce electrical impulses, resulting in slow heart beat.
Artrial Fibrillation
Extra impulse generated cause a fast and irregular heart rhythm.
Examples of problems with electrical pulse conduction
AV block
Where there is a delay in the impulse being conducted through the AV node.
Types of Arrhythmias
Bradycardia: heart rate is slower than 60 b.p.m
Tachycardia: heart rate faster than 100 b.p.m
Tachycardia
Tachycardia are more symptomatic when heart beats is fast and sustained.
They are subdivided into supra ventricular(atrium) or the ventricular which tends to arise from the ventricles.
Supra Ventricular Tachycardia (SVT)
SVT's can start from the atrium or atrioventricular junction and are generally down to the electrical impulses failing to control the heart rhythm. The heart beats tend to speed up then rapidly slow down. Can be seen when exercising.
Symptoms
- Heart suddenly beats faster, (usually lasts for a few minutes, but can sometimes last for several hours)
- Can happen several times a day or once a year – it varies
- Can be triggered by tiredness, caffeine, alcohol or drugs – but often there's no obvious trigger
- Can happen at any age, but often starts for the first time in children and young adults – many people have their first symptoms between 25 and 40
- May get no other symptoms, but sometimes people also:
- have chest pain
- feel weak, breathless or lightheaded
- Tired
- Feeling nauseous
Diagnosis is by electrocardiogram (ECG)
Treatment
Mild attack: the valsalva manoeuvre – take a deep breath, shut your mouth tight, hold your nose tightly and blow out as hard as you can
the cold water technique – fill a bowl with cold water and put some ice in it, hold your breath and put your face in the water for a few seconds.
Longer attacks: Treated in hospital with medication, cardioversion or
catheter ablation – a treatment where thin tubes are placed through a vein or artery into your heart to correct the problem with the electrical system; this permanently cures the problem in most patients.
Arterial Fibrillation (AF)
People with AF have an increased chance of developing stroke.
Atrial fibrillation can be defined in various ways, depending on the degree to which it affects you.
- paroxysmal atrial fibrillation – episodes come and go, and usually stop within 48 hours without any treatment
- persistent atrial fibrillation – each episode lasts for longer than 7 days (or less when it's treated)
- long-standing persistent atrial fibrillation – where you have had continuous atrial fibrillation for a year or longer
- permanent atrial fibrillation – where atrial fibrillation is present all the time
Symptoms
Irregular heart beat
tiredness
breathlessness
dizziness
possibly chest pain
Diagnosis of AF is confirmed by ECG
Treatment
The main aim of treatment is to relieve the symptoms & to reduce the chance of a stroke.
Anticoagulants such as warfarin are prescribed along with mediation to control the heart rate as first line treatment. e.g bisoprolol or atenolol, or a calcium channel blocker, such as verapamil or diltiazem.
Digoxin or Amiodarone may be added to help control the heart rate further.
If symptoms are persistent than the heart rhythm is looked to be controlled by the use of flecainide beta-blockers, particularly sotalol or amiodarone
If medication is unsuccessful the patient will be offered Catheter Abaltion.
Bradycardia
Non medicated slow heart beat can be caused by a block of the electrical signal in the heart from either the Sinoatrial (SA) or the Atroventricular (AV) node. These blockages can result in either a first, second or third degree block.
Symptoms
Fatigue
Lightheadness
Dizziness
Fainting (syncope)
Third degree block symptoms may also include
Chest pain, breathlessness, confusion Heart flutters
Causes of Heart Block
Congenital heart block. (From birth)
Acquired heart block and can be caused by other heart conditions, such as a heart attack
other diseases, such as Lyme disease
having heart surgery
Treatment
Heart block normally only needs to be treated if it's causing symptoms.
The heart is stabilised using a method called transcutaneous pacing (TCP), where pads are attached to the chest and electrical pulses are delivered through them to help restore heart rate to normal.
Once a heartbeat has been stabilised, a permanent pacemaker may be fitted.