Hypokalemia electrocardiogram: Difference between revisions
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The most notable EKG findings in [[hypokalemia]] are due to the delayed ventricular repolarization, manifesting as (QT-U) with prominent [[U waves]]. The EKG changes of hypokalemia are commonly seen at potassium levels < 3 meq/Li. 90% of the patients with potassium levels <2.7 meq/L have abnormal ECG findings. | The most notable EKG findings in [[hypokalemia]] are due to the delayed ventricular repolarization, manifesting as (QT-U) with prominent [[U waves]]. The EKG changes of hypokalemia are commonly seen at potassium levels < 3 meq/Li. 90% of the patients with potassium levels <2.7 meq/L have abnormal ECG findings. | ||
== | ==Electrocardiogram== | ||
===ECG | ===ECG Changes=== | ||
# [[ST segment depression]], decreased [[T wave]] amplitude, prominent [[U waves]] | # [[ST segment depression]], decreased [[T wave]] amplitude, and prominent [[U waves]]: | ||
#* | #* Seen in 78% of patients with a K < 2.7 meq | ||
#* | #* Seen in 35% of patients with a K > 2.7 and < 3.0 | ||
#* | #* Seen in 10% of patients with a K > 3.0 and < 3.5 | ||
#* [[U waves]] are also prominent in [[bradycardia]] and [[LVH]] | #* [[U waves]] are also prominent in [[bradycardia]] and [[LVH]] | ||
# [[Prolongation of the QRS]] duration | # [[Prolongation of the QRS]] duration | ||
#* | #* Uncommon except in severe hyperkalemia | ||
# Increase in the amplitude and duration of the [[P-wave]] | # Increase in the amplitude and duration of the [[P-wave]] | ||
# [[Cardiac arrhythmias]] and [[AV block]] | # [[Cardiac arrhythmias]] and [[AV block]] | ||
# | # Contrary to popular belief there is not prolongation of the QTc, this is artifactually prolonged due to the U wave. In some cases there is fusion of the T and U waves making interpretation impossible. | ||
# Ventricular ectopy | |||
#* [[Premature ventricular complex]] | |||
#* [[Ventricular tachycardia]] | |||
#* [[Ventricular fibrillation]] | |||
===ECG Examples=== | ===ECG Examples=== | ||
[[ | Shown below is an example of [[hypokalemia]] with [[long QT interval]], [[ST segment depression]], low T waves amplitude and TU wave fusion. | ||
[[Image:Hypokalemia.jpg|center|500px]] | |||
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Shown below is an example of hypokalemia with [[Left Ventricular Hypertrophy]]. | |||
[[Image:V10.ht14.jpg|center|500px]] | |||
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The EKG below demonstrates characteristics of [[hypokalemia]] including: [[T wave inversion]]s and U waves circled in red; flattening of [[ST segment]] and prolonged Q- U interval as circled in green. | |||
[[Image:Untitled.png|center|500px]] | |||
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The EKG changes of hypokalemia are rapidly reversible with potassium repletion. | The EKG changes of hypokalemia are rapidly reversible with potassium repletion. | ||
Latest revision as of 20:36, 21 October 2014
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Assistant Editor(s)-In-Chief: Jack Khouri
Overview
The most notable EKG findings in hypokalemia are due to the delayed ventricular repolarization, manifesting as (QT-U) with prominent U waves. The EKG changes of hypokalemia are commonly seen at potassium levels < 3 meq/Li. 90% of the patients with potassium levels <2.7 meq/L have abnormal ECG findings.
Electrocardiogram
ECG Changes
- ST segment depression, decreased T wave amplitude, and prominent U waves:
- Seen in 78% of patients with a K < 2.7 meq
- Seen in 35% of patients with a K > 2.7 and < 3.0
- Seen in 10% of patients with a K > 3.0 and < 3.5
- U waves are also prominent in bradycardia and LVH
- Prolongation of the QRS duration
- Uncommon except in severe hyperkalemia
- Increase in the amplitude and duration of the P-wave
- Cardiac arrhythmias and AV block
- Contrary to popular belief there is not prolongation of the QTc, this is artifactually prolonged due to the U wave. In some cases there is fusion of the T and U waves making interpretation impossible.
- Ventricular ectopy
ECG Examples
Shown below is an example of hypokalemia with long QT interval, ST segment depression, low T waves amplitude and TU wave fusion.
Shown below is an example of hypokalemia with Left Ventricular Hypertrophy.
The EKG below demonstrates characteristics of hypokalemia including: T wave inversions and U waves circled in red; flattening of ST segment and prolonged Q- U interval as circled in green.
The EKG changes of hypokalemia are rapidly reversible with potassium repletion.