Chapter 7 "finishing touches" Flashcards
what does hyperkalemia do to the EKG?
can cause ventricular fibrillation and death
- ALL of the leads will see a rise in T-waves (unlike myocardial infraction where only certain leads see a rise in T-waves).
- PR interval becomes prolonged (P-wave flattens then disappears)
- QRS becomes wider
- conduction blocks (high degree AV blocks develop)
what does HYPOkalemia do to the EKG?
- ST-segment depression
- flattening of the T-wave with prolongation of the QT interval
- Appearance of a U-wave (appears after the T-wave)
what does calcium levels effect on the EKG?
QT interval.
hypocalcemia prolongs it
hypercalcemia shortens it
Torsade de pointes (tachycardia) can occur in porlonged QT intervals.
what occurs during hypothermia?
- everything slows down; PR, QRS, QT intervals and segments become elongated, sinus bradycardia.
- J wave/osborn wave (ST elevation and then sudden plunge back to baseline) this will disappear if patient is rewarmed.
- arrhythmias may appear
- muscle tremor artifact do to shivering.
what does pericarditis cause?
ST-segment elevation and T-wave flattening or inversion.
the effects seem to be diffuse affecting multiple leads.
how do you define low voltage?
- the sum of the total QRS voltage in leads I, II, and III is less than 15mV
- QRS voltage in all precordial leads is less tan 10 mV.
low voltage can be caused by pericardial effusion which dampens the electrodes from reaching the heart.
what may be the result of excessive effusion into the pericardium?
electrical alternans; where the axis could change with each heart beat since now the heart can rotate within its sac.
what can myocarditis cause?
conduction blocks, branch blocks and hemiblocks.
how will atrial septal defect (ASD) show up on EKG?
low voltage and a small notch at the end of the QRS.
what will pulmonary disorders such as COPD show on EKG?
low voltage, right axis deviation, poor R wave progression.
