Friday, 14 November 2014

Pathological ECG findings | ARRHYTHMIA


ARRHYTHMIA


Cardiac dysarhythmia (also known as arrhythmia or irregular heartbeat) is any of a group of conditions in which the electrical activity of the heart is irregular or is faster or slower than normal.

The heartbeat may be too fast (over 100 beats per minute) or too slow (less than 60 beats per minute), and may be regular or irregular.

Above is the ECG for "sinus arrhythmia".


Classification of arrhythmia :

1) Atrial
-Premature Atrial Contractions (PACs)
-Wandering Atrial Pacemaker
-Multifocal atrial tachycardia
-Atrial flutter
-Atrial fibrillation (Afib)

2) Junctional arrhythmias
-Supraventricular tachycardia (SVT)
-AV nodal reentrant tachycardia is the most common cause of -
Paroxysmal Supra-ventricular Tachycardia (PSVT)
-Junctional rhythm
-Junctional tachycardia
-Premature junctional contraction

3) Ventricular
-Premature ventricular contractions (PVCs), sometimes called
ventricular extra beats (VEBs)
-Premature ventricular beats occurring after every normal beat are
termed "ventricular bigeminy"
-PVCs that occur at intervals of 2 normal beats to 1 PVC are
termed "PVCs in trigeminy"
-Accelerated idioventricular rhythm
-Monomorphic Ventricular tachycardia
-Polymorphic ventricular tachycardia
-Ventricular fibrillation

4) Heart blocks
i. First degree heart block, which manifests as PR prolongation
ii. Second degree heart block
-Type 1 Second degree heart block, also known as Mobitz I or Wenckebach
-Type 2 Second degree heart block, also known as Mobitz II
iii. Third degree heart block, also known as complete heart block.



Abnormalities of normal sinus, it can be :

i. "sinus tachycardia" 
✔ ️ Rate >100.
✔ ️ Causes: Anaemia, anxiety, exercise, pain, high T°, sepsis, hypovolaemia, heart failure, pulmonary embolism, pregnancy, thyrotoxicosis, beri beri, CO2 retention, autonomic neuropathy, sympathomimetics.

ii. "sinus bradycardia" 
✔ ️ Rate <60.
✔ ️ Causes: Physical fitness, vasovagal attacks, sick sinus syndrome, acute MI (esp. inferior), drugs
(beta- blockers, digoxin, amiodarone, verapam- il), hypothyroidism, hypothermia, high intracranial pressure, cholestasis.

But in "sinus arrhythmia",
✔ ️ it is disturbances of cardiac rhythm or arrhythmias are:
• Common
• Often benign (but may reflect underlying heart disease)
• Often intermittent, causing diagnostic difficulty
• Occasionally severe, causing cardiac compromise.

✔ ️ causes are :
1) Cardiac: MI, coronary artery disease, LV aneurysm, mitral valve disease, cardiomyopathy, pericarditis, myocarditis, aberrant conduction pathways.

2) Non- cardiac: Caffeine, smoking, alcohol, pneumonia, drugs (Bete2-agonists, digoxin, L-dopa, tricyclics, doxorubicin), metabolic imbalance (K+, Ca2+,Mg2+, hypoxia, hypercapnia, metabolic acidosis, thyroid disease), and phaeochromocytoma.




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