Electrocardiogram Flashcards
What is the first event you can see on the EKG?
Atrial activation (depolarization) which is resembled by the P wave.
What is the second event you can see on the EKG?
The onset of the QRS complex.
What does the T wave represent on the EKG?
ventricular repolarization, but still shows upward deflection.
What does the QRS complex represent?
It represents the impulse from the AV node through the ventricles = ventricular contraction = Systole
What does the S-T segment represent?
It is the interval when ventricles are contraction, it correlates w/ plateau phase of the myocyte AP.
How are abnormal sinus rhythms calculated?
by looking at the R-R interval.
What HR is considered to be Tachycardia?
anything >100 BPM
What HR is considered to be Bradycardia?
anything <60 BPM
Does HR increase more during inhalation or exhalation?
Inhalation
How is AV block identified?
By looking at the P-R interval.
What are causes of AV block?
- Ischemia of A-V bundle
- Compression or Inflammation of A-V bundle
- Extreme vagal stimulation.
What happens during a “dropped” beat?
The atria empty but the ventricles fail to contract.
What results if a ectopic pacemaker is present?
It results in a premature atrial or ventricular contraction.
What is characteristic of a premature atrial contraction?
a premature P wave is seen which indicates the ectopic foci near the AV node, also causes a compensatory pause which discharges SA node.
What happens when the AV node becomes a ectopic pacemaker?
It creates a premature ventricular contraction because its sending the signal to the ventricles without propagating through the atria. (you get a absence of P wave)
