Electrolyte EKG lecture highlights

Question 1

Presence of any EKG changes due to K+ is a better measure of clinically significant K+ toxicity than it is the ________________

Answer 1

serum K+ level

Question 2

What is a key characteristic of hyperkalemia on an EKG?

Answer 2

Peaking of T waves [in all leads]

Question 3

The presence of RAD may be an important clue that the wide QRS complexes are the result of ________________

Answer 3

hyperkalemia

Question 4

Hyperkalemia: Ultimately the QRS complex widens until merging with T wave forming a _____ wave

Answer 4

sine

Question 5

Hyperkalemia:
1) What may you also see?
2) What may eventually develop?

Answer 5

1) May also see high degree AV block and BBB
2) Asystole or V-Fib may eventually develop

Question 6

Hypokalemia: Where is the U wave best seen?

Answer 6

Anterior leads

Question 7

Hypokalemia: ECG changes are better measure of ________________ than ________________

Answer 7

serious toxicity than serum K+ levels

Question 8

1) Hypocalcemia = _________ QT interval
2) Hypercalcemia = ___________ QT interval

Answer 8

1) prolongs
2) shortens

Question 9

What 3 electrolyte imbalances can cause prolonged QT intervals?

Answer 9

Hypocalcemia
Hypokalemia
Hypomagnesemia

Question 10

Hypothermia: Describe the EKG changes

Answer 10

1) ST elevation called Osborn wave
-Abrupt ascent at J point with equally sudden plunge back to baseline
-Disappear as the patient is re-warmed

Question 11

ST segment depression very gradual with what?

Answer 11

Digitalis

Question 12

Do abx typically cause prolonged QT interval?

Answer 12

usual doses rarely cause issues; risk increases with take multiple drugs or if metabolism is compromised – Grapefruit juice affects cytochrome p-450

Question 13

Antiarrhythmic agents and antidepressants agents – sodium channel blocking agents:
Sotalol, quinidine, procainamide, amiodarone, etc. & TCA

What do you need to do in these pts?

Answer 13

Monitor QT interval in all patients taking one or more of these drugs – may increase risk of VT, Torsades, VF

Question 14

QT interval = _____% of normal cardiac cycle as measured by R-R duration, varies with rate, shorter with faster rates

Answer 14

40%

Question 15

QTc should not exceed ________ms during therapy with meds that may prolong QT interval

Answer 15

500ms

Question 16

Pericarditis causes diffuse _________ elevation

Answer 16

ST segment

Question 17

S1Q3T3 may be seen in what?

Answer 17

Acute massive PE

Question 18

Pre-participation sports exam