3 lead

Question 1

SVT

Answer 1

Supraventricular tachycardia is an ominous rhythm with rates often between 170-230 per minute. The telltale sign of supraventricular tachycardia is the narrow QRS which defines its supraventricular origin (AV node) and its regular, rapid pattern. This rhythm is most likely not sinus tachycardia due to its very fast rate . For those who are at rest, narrow QRS tachycardias over 150 / minute are most often supraventricular tachycardia.

Question 2

AF

Answer 2

Atrial fibrillation is a chaotic rhythm with recognizable QRS complexes. The chaotic rhythm pattern and the absence of P waves are the hallmarks of this dysrhythmia.The chaotic baseline - known as fibrillatory waves - is quickly seen. Note: 1) atrial kick is lost here; and 2) the risk of thrombus formation is particularly significant after 48 hours.

Question 3

1st degree AV block

Answer 3

First degree AV block results from a prolonged transmission of the electrical impulse through the AV junction (AV node and the Bundle of His). The significant finding of this rhythm is a prolonged PR interval of more than .20 seconds. The underlying rhythm should be identified and named prior to claiming a first degree AV block. For example, this rhythm is a normal sinus rhythm WITH a first degree AV block.

Question 4

Second degree AV block Type I (Wenckebach or Mobitz Type I)

Answer 4

Second degree AV block Type I (Wenckebach or Mobitz Type I) results from a cyclical and progressive conduction delay through the AV junction. The ECG presents with a cyclical lengthening of the PR interval followed by a dropped QRS - a P wave not partnered with a QRS. The QRS complexes yield an irregular rhythm. Second degree AV block Type I may be caused by enhanced vagal tone, myocardial ischemia or the effects of drugs such as calcium-channel blockers, digitalis and beta-blockers.

Question 5

Second Degree AV Block Type II

Answer 5

Second Degree AV Block Type II is typically caused by an intermittent block (interrupted supraventricular impulse) below the AV node. One or more QRS complexes are dropped with PR intervals that do not change (fixed PR interval). This irregular rhythm requires close monitoring: 1) low cardiac output is likely when multiple dropped QRS complexes occur; and 2) this rhythm can progress to complete heart block (third degree AVB).

Question 6

third degree AV block

Answer 6

Third degree AV block (complete heart block) is often an ominous rhythm requiring close monitoring for hemodynamic compromise, progression to ventricular standstill or asystole and other lethal dysrhythmias. Significant characteristics of this rhythm are: 1) lonely P waves - P wave without an accompanied QRS complex; and 2) chaotic PR intervals. A narrow QRS denotes a higher junctional block while a wide QRS points more towards a sub-nodal block high in the bundle branches

Question 7

VT

Answer 7

Ventricular tachycardia (VT) often results in hemodynamic compromise (due to minimal ventricular filling time and the absence of atrial kick). What makes this rhythm more ominous is its tendency to transition into ventricular fibrillation. Causes of VT include myocardial ischemia, a PVC landing on a T wave (R-on-T ), cardiac drug toxicity and electrolyte imbalance. Non-sustained VT (a group of 3 or more PVCs) is a run of VT

Question 8

VF

Answer 8

Ventricular fibrillation (VFib) is a chaotic rhythm originating in the ventricles, resulting in no cardiac output. Coarse VFib is noted when the amplitude (height) of the rhythm is equal to or more than 3 mm. Fine VFib is less than 3 mm in height and signifies less electrical energy within the myocardium - less opportunity for a successful defibrillation.