05b: Arrhythmia Flashcards
In EKG, PR-interval starts at (X) and ends at (Y).
X = beginning of P wave Y = beginning of QRS
In EKG, PR-segment starts at (X) and ends at (Y).
X = end of P wave Y = beginning of QRS
Normal range of PR interval.
3-5 small boxes (0.12-0.2s)
Normal range of QRS.
Less than 2.5 small boxes (under 0.1s)
A sinus arrhythmia is present if shortest and longest (X) interval/segment varies by more than (Y) sec.
X = P-P interval Y = 0.16s (4 small boxes)
EKG: The normal P wave contour is replaced by high frequency, undulating, and often saw tooth appearing waves. Which condition is this?
Atrial flutter
In atrial flutter, the cause of the oscillating waves on EKG is considered to result from (X).
X = a reentrant rhythm
(X) atria, that be a consequence of stenotic AV valves, would be more likely to develop a reentrant rhythm. Why?
X = Dilated;
The longer it takes for the wave of depolarization to spread, the more likely the tissue initiating the excitation can be excited again (out of refractory period)
It has been observed that an abnormal impulse reaching nodal tissue during its refractory period tends to (increase/decrease) the refractory state.
Increase (prolong) - safety mechanism
Atrial fibrillation is similar to (X) condition, but the (higher/lower) amplitude waves have (lower/higher) frequency and lack the (Y) seen in (X).
X = atrial flutter
Lower;
Higher;
Y = regularity
Explain why atrial flutter and A-fib (do/don’t) seriously hamper cardiac output at rest.
Don’t;
Most ventricular filling is passive, so the lack of productive atrial contraction doesn’t impact CO at rest
List some conditions under which atrial flutter/fib would especially impact CO.
- Exercise (passive fill time of ventricles reduced)
2. AV valve stenosis (high flow resistance)
PACs (premature atrial contractions) are common and can be caused by:
alcohol, caffeine, stress or lack of sleep
Where would you expect to see the (X) wave in spontaneous, premature junctional excitation that originates in the AV node and spreading to ventricles first?
X = P
After QRS (atria excited after ventricles)
First-degree (X) block is identified by:
X = AV
a lengthening of the PR interval
Second-degree (X) block is identified by:
X = AV
the failure of some but not all P-waves to be conducted into the ventricle
Third-degree (X) block is identified by:
X = AV
complete dissociation of electrical activity in the atria and ventricles (SA an AV nodes fire at their own rhythms)
In (X) degree heart block, the (SA/AV) node fires at significantly lower frequency than (SA/AV) node.
X = third;
AV;
SA
Mobitz type 1 or Wenckebach (X) degree block displays which phenomenon?
X = second
PR intervals increase with each subsequent impulse until one beat (QRS) “dropped” (P not conducted); then rhythm reset and cycle repeats
Mobitz type 2 (X) degree block differs from Mobitz type 1 in that:`Which is more common?
X = second
P wave is dropped but is not preceded by complexes with progressively prolonged PR intervals
Type 1 more common
EKG: A constant, prolonged QRS, period of ventricular depolarization, can be explained by (X).
X = of conduction in one of the bundle branches
In EKG, you see two random odd-shaped QRS complexes, not preceded by P wave. It’s likely that these were triggered spontaneously from a(n) (X) in the (atria/ventricles).
X = irritable focus
Ventricles
In EKG, you see two random odd-shaped QRS complexes, not preceded by P wave. If the contours of the two waves are different, it is likely that there were (X) number of (Y) that led to depolarizations travelling along (same/different) routes.
X = at least 2
Y = irritable foci (in ventricles)
Different
Ventricular (X) presages sudden cardiac death
X = fibrillation
