1. Atrial Ectopy Atrial tachycardia Arial flutter Atrial fibrillation ARRHYTHMIAS OF THE ATRIA AND ATRIOVENTRICULAR NODE 2. ATRIAL ECTOPIC BEATS Premature atrial beats Atrial ectopics are impulse firing from somewhere in the atria earlier in the cardiac cycle prior to the next anticipated sinus beat. Hence the QRS complex in ectopic beat will appear closer to the previous complex compared to the normal time interval. Image: www.aiyisheng.org 3. ATRIAL ECTOPIC BEATS Premature atrial beats QRS rate: usually normal, though dependent upon underlying rhythm and frequency of atrial ectopic beat QRS rhythm: slightly irregular owing to the presence of atrial ectopic beats. QRS width: usually normal width and constant morphology; the prematurity of the ectopic beat may result in the impulse being conducted to the ventricles with bundle branch block- QRS morphology will then differ. P waves associated with atrial ectopic beats will be of different morphology from sinus P waves and may be superimposed on the preceding T waves Each P wave is followed by QRS but PR interval may be marginally longer than in sinus rhythm Image: www.aiyisheng.org 4. ATRIAL TACHYCARDIA QRS rate: usually 150-200/min QRS rhythm: regular QRS width: normal width and morphology P waves: rate between 150 and 250/min, may not be visible, may be merged into preceding T waves. If visible different morphology from sinus P waves. As P waves are not clearly distinguishable PR interval cannot be determined. If there is AV node conduction block, P waves may not be conducted to the ventricles Image: www.ekginterpretation.tripod.com 5. ATRIAL Flutter Usually arises in the right atrium and is often associated with diseases of the right side of the heart. Atrial flutter is characterised by zigzagging Baseline which produces typical sawtooth (F) flutter waves. QRS rate: dependant on the degree of AV block; usually 150/min QRS rhythm: regular or irregular (dependant on AV block) QRS width: normal width and constant morphology P waves: sawtooth flutter waves present, usually 300/min. Usually there is AV node conduction block present Image: www.pixgood.com 6. ATRIAL FIBRILLATION Atrial fibrillation is characterised by rapid re-entrant impulses that result in incomplete contractions and ineffective emptying of the atria. As the atria is not emptying properly blood can pool in the chamber causing thrombus formation which may result in a stroke. QRS rate: may be slow, normal or rapid QRS rhythm: totally irregular (regular if 3rd degree AV block is present) QRS width: normal width and constant morphology P waves: not present, irregular baseline owing to fibrillation waves. Treatment Drug therapy includes digoxin and amiodarone Synchronised electrical cardioversion Radiofrequency ablation Anti-thrombotic therapy to prevent stroke Image: www.ecgmedical.com 7. Reference Jevon, P 2009, Essential clinical skills for nurses: ECGs for Nurses, Chapter 5, 2nd edn.,Wiley-Blackwell.