How hyperkalemia can cause an arrhythmia?

Mechanism of cardiac arrhythmia in hyperkalemia. In normokalemia, the cell membrane of the cardiomyocyte is polarized (resting potential around −90 mV). In moderate hyperkalemia, the cell membrane becomes partially depolarized, bringing the resting potential closer to the threshold potential for AP initiation.

Why does hyperkalaemia cause ECG changes?

The ECG changes associated with hyperkalemia can be explained by the physiological effect of increasing serum potassium levels on myocardial cells. Mild to moderate hyperkalemia causes depression of conduction between adjacent cardiac myocytes, manifesting on ECG as prolongation of the PR and QRS intervals.

Which dysrhythmia is hyperkalemia?

Hyperkalemia is a commonly encountered electrolyte abnormality that can significantly alter normal cardiac conduction. Potentially lethal dysrhythmias associated with hyperkalemia include complete heart block and Mobitz Type II second-degree AV block.

Does hyperkalemia cause atrial fibrillation?

While ventricular arrhythmias and atrial fibrillation are occasionally seen with hyperkalemia, atrial flutter is rare [4,5].

How does potassium cause arrhythmia?

Irregular heartbeats(arrhythmias). Potassium helps keep your heart beating at the right pace. It does this by helping to control the electrical signals of the myocardium — the middle layer of your heart muscle. When your potassium level is too high, it can lead to an irregular heartbeat.

How does calcium chloride work in hyperkalemia?

Calcium antagonizes the cardiotoxicity of hyperkalemia by stabilizing the cardiac cell membrane against undesirable depolarization. Onset of effect is rapid (≤ 15 minutes) but relatively short-lived.

Why does hyperkalemia cause no P waves?

When serum potassium level decreases, the atrial myocardial cells regain excitability and may be captured from the SA nodal impulse inflicting a P wave on the surface EKG. At plasma potassium level >7.5 mEq/L, the P-wave disappears secondary to sino ventricular conduction.

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.

Why is QRS wide in hyperkalemia?

As serum potassium levels increase to greater than 6.5 mEq/L, the rate of phase 0 of the action potential decreases, leading to a longer action potential and, in turn, a widened QRS complex and prolonged PR interval. Electrophysiologically, this appears as delayed intraventricular and atrioventricular conduction.

Does hypokalemia cause dysrhythmia?

The most dangerous aspect of hypokalemia is the risk of ECG changes (QT prolongation, appearance of U waves that may mimic atrial flutter, T-wave flattening, or ST-segment depression) resulting in potentially lethal cardiac dysrhythmia.