 Any atrial area may originate an impulse.  Rhythms have upright P waves preceding each QRS complex.  Not as well-rounded  Heart rates usually from 60 to 100 beats/min

 Atrial flutter  Atria contract too fast for ventricles to match  Resemble a saw tooth  F waves get blocked by AV node, creating several F waves before each QRS complex

 Atrial flutter (cont’d)  Caused by hypertension, coronary artery disease, and cardiomyopathy.  frequently degenerates into atrial fibrillation.  Symptoms include shortness of breath, chest pains, lightheadedness or dizziness, nausea and, in some patients, nervousness and feelings of impending doom.  Treatment is usually medication or electrical cardioversion.

 Atrial fibrillation  Atria fibrillate or quiver  Random depolarization from atria cells depolarizing independently Adapted from Arrhythmia Recognition: The Art of Interpretation, courtesy of Tomas B. Garcia, MD.

 Atrial fibrillation (cont’d)  Irregularly irregular appearance  Usually signs of serious heart problem  Tendency to cause clots  Prehospital treatment is rare.

 Supraventricular tachycardia (SVT)  Tachycardic rhythm from pacemaker  Regular rhythm, rate exceeding 150 beats/min  QRS complexes: 40 to 120 ms.  May have cannon “A” waves Adapted from Arrhythmia Recognition: The Art of Interpretation, courtesy of Tomas B. Garcia, MD.

 Supraventricular tachycardia (cont’d)  Called paroxysmal SVT (PSVT) because of tendency to begin and end abruptly  Caused by re-entry and automaticity  May greatly reduce CO

 Premature atrial complex  A particular complex within another rhythm  Upright P wave precedes each QRS complex Adapted from Arrhythmia Recognition: The Art of Interpretation, courtesy of Tomas B. Garcia, MD.

 Premature atrial complex (cont’d)  Non-conducted PAC: P wave occurs early on the ECG and is not followed by a QRS complex.  PACs occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a premature heartbeat.  Can result from drugs or organic heart disease  Not treated in prehospital setting

 Wandering atrial pacemaker  is an atrial arrhythmia that occurs when the natural cardiac pacemaker site shifts between the sinoatrial node (SA node), the atria, and/or the atrioventricular node (AV node).  Upright P wave precedes each QRS (at least 3 shapes of P waves within a strip)

 Wandering atrial pacemaker (cont’d)  Most common with significant lung disease

 Multifocal atrial tachycardia (MAT)  Pacemaker moves within various atrial areas  Rate of more than 100 beats/min  Upright P wave preceding each QRS complex P waves vary.

 Multifocal atrial tachycardia (cont’d)  PR interval: 120 to 200 ms  Most common with significant lung disease, but it can occur after acute MI, hypokalemia, and hypomagnesemia  Therapies for SVT generally ineffective

 The P-waves and P–R intervals are variable due to a phenomenon called wandering atrial pacemaker (WAP).  Then, if the heart rate exceeds 100 beats per minute, the phenomenon is called multifocal atrial tachycardia.