Arrhythmia vs Dysrhythmia
Both arrhythmia and dysrhythmia mean the same. Arrhythmia means no regular rhythm and dysrhythmia means abnormal rhythm. Disturbances of cardiac rhythm or arrhythmias are common in people, often benign, and often intermittent. However, they can be severe sometimes leading to cardiac compromise. This article will take a closer look at arrhythmia, highlighting different types of arrhythmia (such as cardiac arrhythmia, sinus arrhythmia, ventricular arrhythmia), symptoms and diagnosis of arrhythmias, and also the course of treatment they require.
Causes of arrhythmia: Common causes of cardiac arrhythmia (cardiac dysrhythmias) are myocardial infarction (heart attacks), coronary artery disease, left ventricular aneurysm (abnormal dilatation), mitral valve disease, cardiomyopathy (heart muscle abnormalities), myocarditis, pericarditis, and abnormal conduction pathways of the heart. Common non-cardiac causes of arrhythmia are caffeine, smoking, alcohol, pneumonia, drugs (such as digoxin, beta blockers, L dopa, and tricyclic), and metabolic imbalances (potassium, calcium, magnesium, high carbon dioxide level, thyroid diseases).
Arrhythmia symptoms: Patients with arrhythmia are present with chest pain, palpitations, fainting attacks, low blood pressure and collection of fluid in lungs. Some arrhythmias are asymptomatic and incidental. Palpitations may be regular, irregular, fast, or slow. The durations of arrhythmias symptoms vary according to the cause. Drug history, family history of heart diseases, and past medical history are very important in the investigation.
Diagnosis of arrhythmias needs full blood count, blood urea, and electrolytes, blood glucose, serum calcium, magnesium, thyroid stimulating hormone, and electrocardiogram. Electrocardiogram may show ischemic changes, atrial fibrillation, short PR interval (Wolf-Parkinson-White syndrome), long QT interval (metabolic), and U waves (low potassium). Echocardiogram may also show signs of structural heart diseases. Further investigation may include exercise ECG, cardiac catheterization and electrophysiological studies.
Treatment for arrhythmias varies according to the type of arrhythmia. If the ECG is normal during palpitation, the patient needs no intervention.
Bradycardia arrhythmia is defined as heart rate slower than 50 beats per minute. If the patient is asymptomatic and the rate is above 40 bpm, he needs no intervention. Causative drugs and medical conditions (such as hypothyroidism) should be corrected. Atropine, isoprenalin, and pacing are known treatment methods.
Sick sinus syndrome is due to abnormal electrical activity of SA node. Symptomatic patients need pacing.
Supraventricular tachycardia arrhythmia features absent P waves, narrow QRS complex, and a heart rate above 100bpm. Carotid massage, verapamil, adenosine, amiodarone, and DC shock may be used to treat SVT. Atrial fibrillation and flutter may be incidental findings. Atrial fibrillation features irregular QRS complexes and absent P wave. Atrial flutter rate is usually around 300 bmp, but ventricular rate is about 150 bpm. Digoxin can control ventricular rate. Verapamil, beta blockers, and amiodarone are effective alternatives. DC shock is needed if cardiac function is compromised.
Ventricular tachycardia arrhythmia features broad QRS complexes in ECG. Ventricular tachycardia is a shockable rhythm. Amiodarone and DC shock can be used to treat VT.
As a final measure, a permanent pacemaker may be used to override arrhythmias. Automatic implanted defibrillators which restart cardiac electrical activity in case of cardiac arrest save lives.