Which electrolyte imbalances cause ECG changes?
Potassium. Potassium plays a key role in both depolarization and repolarization, which is why potassium imbalance may cause dramatic ECG changes.
What ECG changes occur with hyperkalemia?
ECG changes have a sequential progression, which roughly correlate with the potassium level. Early changes of hyperkalemia include tall, peaked T waves with a narrow base, best seen in precordial leads ; shortened QT interval; and ST-segment depression.
What ECG findings can be seen in hypocalcemia?
The ECG hallmark of hypocalcemia remains the prolongation of the QTcinterval because of lengthening of the ST segment, which isdirectly proportional to the degree of hypocalcemia or, as otherwisestated, inversely proportional to the serum calcium level. The exactopposite holds true for hypercalcemia.
What are the ECG changes in hypokalemia?
Hypokalemia results in slowed conduction, delayed ventricular repolarization, shortened refractory period and increased automaticity. ECG changes include flattening and inversion of T waves in mild hypokalemia, followed by Q-T interval prolongation, visible U wave and mild ST depression4 in more severe hypokalemia.
What causes U waves on ECG?
The ‘U’ wave is a wave on an electrocardiogram (ECG). It comes after the T wave of ventricular repolarization and may not always be observed as a result of its small size. ‘U’ waves are thought to represent repolarization of the Purkinje fibers.
Can dehydration cause ECG changes?
For example, a person with dehydration may have imbalanced electrolytes that are causing an abnormal EKG. This person may require fluids, electrolyte-containing beverages, or medications to restore electrolytes. Sometimes, a doctor may not recommend any treatments for an abnormal EKG.
What arrhythmias are caused by hyperkalemia?
Arrhythmia Mechanisms Severe hyperkalemia ([K+]o >7.0 mmol/L) can lead to heart block, asystole, and VT/VF. In humans, the precise level of hyperkalemia producing (or not producing) these changes varies considerably.
What heart rhythm is caused by hyperkalemia?
Hyperkalemia is a common clinical condition that can induce deadly cardiac arrhythmias. Electrocardiographic manifestations of hyperkalemia vary from the classic sine-wave rhythm, which occurs in severe hyperkalemia, to nonspecific repolarization abnormalities seen with mild elevations of serum potassium.
How does calcium affect ECG?
High levels of ionized serum calcium shorten the ST segment on the ECG. Conversely, low levels of ionized serum calcium prolong the ST segment. Variations in the QT interval and the QTc duration are caused by variations in the duration of the ST segment.
What ECG changes occur with hypercalcemia?
Additional ECG abnormalities that may occur in patients with severe hypercalcemia include ST segment elevation, biphasic T waves, and prominent U waves. Changes in T wave morphology, polarity, and amplitude appears with development of hypercalcemia and disappears with normalization of serum calcium level.
Where does the U wave appear?
This is known as a U wave. In a normal heart beat, the T wave represents repolarisation of the ventricles, specifically the repolarisation of the AV node and bundle branches. The U wave occurs when the ECG machine picks up repolarisation of the Purkinje fibres.
What does prominent U wave mean?
U Waves. Look for prominent U waves. These waves, usually most apparent in chest leads V2-V4, may be a sign of hypokalemia or drug effect or toxicity (e.g., amiodarone, dofetilide, quinidine, or sotalol).