Question 1

What is the Meaning of Cardiac Action Potential?

Accepted Answer

The Cardiac Action Potential is the rapid, transient electrical voltage change across heart muscle cell membranes, essential for myocardial contraction. This precise sequence of depolarization, plateau, and repolarization drives heart's rhythmic pumping. It is the fundamental electrical signal initiating each heartbeat.

Question 2

What is the Context of Cardiac Action Potential?

Accepted Answer

Within the heart's conduction system, Cardiac Action Potential originates from sinoatrial node pacemaker cells. It propagates through atria, atrioventricular node, and Purkinje fibers to the ventricular myocardium. This timed electrical propagation coordinates mechanical cardiac chamber contraction, enabling efficient blood circulation.

Question 3

What is the Significance of Cardiac Action Potential?

Accepted Answer

Understanding Cardiac Action Potential is clinically vital, directly underpinning normal heart rhythm and contractile force. Aberrations in its phases can lead to various cardiac arrhythmias, from minor palpitations to life-threatening ventricular fibrillation. Clinical assessment, including electrocardiography and antiarrhythmic drug selection, relies on these electrical principles, impacting patient care.

Question 4

What is the Mechanism of Cardiac Action Potential?

Accepted Answer

Cardiac Action Potential generation involves orchestrated ion movement across cell membranes via voltage-gated ion channels. Rapid depolarization results from sodium influx. A plateau phase is sustained by calcium influx balanced with potassium efflux, preventing premature repolarization. Repolarization follows through potassium efflux, restoring resting potential for the next impulse.

Question 5

What is the Application of Cardiac Action Potential?

Accepted Answer

In clinical practice, Cardiac Action Potential knowledge guides antiarrhythmic medication development, targeting specific ion channels to normalize aberrant rhythms. It is also foundational for interpreting electrocardiograms, where wave forms correspond to distinct action potential phases. This understanding informs cardiac pacemaker and defibrillator use.

Question 6

What is the Metric of Cardiac Action Potential?

Accepted Answer

Cardiac Action Potential characteristics are indirectly assessed via electrocardiography (ECG), where intervals like PR, QRS, and QT reflect summed myocardial action potentials. For direct evaluation, invasive electrophysiology studies measure action potential durations and conduction velocities, aiding complex arrhythmia diagnosis. Serum electrolytes, particularly potassium and calcium, are monitored for their influence on ion channel function.

Question 7

What is the Risk of Cardiac Action Potential?

Accepted Answer

Dysregulation of the Cardiac Action Potential carries significant clinical risks, predisposing to severe cardiac arrhythmias. Conditions like inherited or acquired long QT syndrome, with prolonged repolarization, elevate Torsades de Pointes risk, a potentially fatal ventricular arrhythmia. Short QT syndrome or drug-induced ion channel dysfunction can also precipitate dangerous rhythm disturbances, necessitating careful management.

Cardiac Action Potential

Meaning

Context

Significance

Mechanism

Application

Metric

Risk

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