Fig 19.1
EKG showing dissociated pattern for P waves and QRS pattern
Can you determine the site of block in the AV conduction system by looking at the EKG?
Does this patient require any urgent intervention?
What are the causes of this condition?
How will you decide whether this patient needs permanent pacemaker before proceeding to surgery or not?
If this patient has to go for urgent/emergent surgery, is there any preoperative preparation required?
What monitors will you use intraoperatively for this patient?
Answers
- 1.
This EKG shows atrial (P waves) and ventricular (QRS complexes) activity which are independent of each other, and there is no association between P waves and QRS complexes. That confirms that our patient has sinus rhythm with complete heart block (CHB).
- 2.
Ventricular rate can help determine the site of block in conduction system. Junctional rhythm tends to have a ventricular rate between 40 and 60 beats per minutes (bpm), while ventricular escape rhythm will have rates of 40 beats per minute or less, and they are often unstable, requiring immediate cardiology intervention [1]. In most cases, the atrial rate will be faster than the ventricular escape rate, and as a general rule, the more distal the level of block in AV conduction and His-Purkinje system, the slower the ventricular rate will be.
If EKG shows:
- (a)
Narrow QRS complex with junctional or AV nodal rhythm, then the AV block has occurred within the AV node or at the level of the bundle of His.
- (b)
Wide QRS complex with subjunctional escape rhythm, then the AV block is distal to the His conduction system.
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- (a)
