EKG- Final Thoughts

Question 1

Potassium plays a large role in ______ during the cardiac cycle

Answer 1

the depolarization and repolarization of the cardiac tissue

Question 2

Hyperkalemia (elevated serum potassium) produces a progressive evolution
of changes in the EKG tracing that can eventually culminate in _____

Answer 2

Ventricular
Fibrillation and death

Question 3

How are peaked T waves different with hyperkalemia than they are with infarction?

Answer 3

With increased K+, T waves across
the entire 12-lead begin to peak.
○ Diffusely peaked T waves, as opposed to
anatomically specific as seen with infarction

Question 4

What happens to the PR interval with increased K+?

Answer 4

As K+ concentration increases, the PR interval prolongs,
and the P wave gradually flattens and then disappears.

Question 5

Hyperkalemia effect on QRS

Answer 5

Ultimately, the QRS widens until it merges with the T wave, forming a classic Sine Wave pattern.
○ This can deteriorate into V-Fib

Question 6

Three EKG changes can be seen with hypokalemia, in no particular order:

Answer 6

○ ST-segment depression
○ Flattening of the T wave with
prolongation of the QT interval
○ Appearance of a U wave
■ The term U wave is given to a wave
that appears after the T wave, and
before the P wave

Question 7

A U wave generally has the same axis as the T wave and is often best seen in which leads?

Answer 7

the anterior precordial leads

Question 8

T/F U waves are diagnostic of hypokalemia

Answer 8

F - It’s also important to understand that while U waves are the most characteristic
feature of hypokalemia, they are not in and of themselves diagnostic.

Question 9

Rarely, severe hypokalemia can cause ____

Answer 9

ST-segment elevation

Question 10

Alterations in the serum calcium concentration primarily affects the _____ on the EKG tracing.

Answer 10

QT interval
○ Hypocalcemia prolongs the QT interval
○ Hypercalcemia shortens the QT interval

Question 11

EKG changes with hypothermia:

Answer 11

○ Everything slows down.
■ Sinus bradycardia is common and all the segments and intervals
become prolonged
○ A distinct and virtually diagnostic type of ST elevation may appear.
■ Abrupt elevation at the J point with an abrupt plunge, which we call a J wave or Osborn wave

Question 12

Slow Atrial Fibrillation is the most common rhythm disturbance of _____

Answer 12

Hypothermia

Question 13

Acute pericarditis EKG changes:

Answer 13

can sometimes cause
ST-segment elevation and T wave flattening
or inversion

Question 14

EKG features helpful in differentiating pericarditis from infarction

Answer 14

In pericarditis, T wave inversion usually
occurs only after the ST segments have
returned to baseline (in infarction, T
wave inversion usually precedes
normalization of the ST segment)
○ In pericarditis, Q wave formation does not occur.
○ The PR interval is sometimes depressed (but not always/consistently)

Question 15

When a Pericardial Effusion occurs, which is fluid outside of the heart but
within the pericardial sac, electrical output of the heart can become______

Answer 15

dampened, resulting in low voltage tracings in all the leads

Question 16

Electrical Alternans

Answer 16

Phenomenon that can occur with Pericardial Effusion/Tamponade, when the electrical axis of the heart varies with each beat because the heart may actually rotate or
swing back-and-forth freely within the fluid-filled sac.
○ Recognized by the varying amplitude of each waveform from beat to beat

Question 17

A patient with Chronic Obstructive Pulmonary
Disease, especially Emphysema-type, may
have the following EKG findings:

Answer 17

○ Low voltage tracings
■ Due to the dampening effects of the
over-inflated lungs
○ Right Axis Deviation
■ Overexpansion cause vertical or even
rightward orientation of the heart
○ Poor R wave progression in precordials