Cardiac Physiology: Depolarization and ST Segment

Which factor does NOT directly affect repolarization?

What happens to tissue that experiences an infarct?

Which leads provide an anterior view of the heart wall?

Which lead is considered to give a view of the left lateral wall of the heart?

What does ST segment elevation typically indicate in terms of heart condition?

What leads look from the left arm for assessing the left lateral wall of the heart?

Which of the following leads primarily examines the inferior aspect of the heart?

What indicates that some electrical activity is still present from the apex of the heart?

What is the role of voltage-gated channels during depolarization?

Which leads are primarily used to visualize the septal wall of the heart?

Depolarization

Depolarization is not ATP driven
It is voltage-gated
Depolarization affects repolarization

The ST Segment

The ST segment is most affected by repolarization
The ST segment is explored to see the effects of repolarization

Ischemia

Decreased blood flow to the head means less blood flow to the heart
Ischemia affects repolarization
Cells are still alive in ischemia

Injury

Injury affects repolarization
The ST segment is elevated in injury
The Q wave is blocked in injury

Infarct

Tissue does not depolarize at all in an infarct
Infarct means that the tissue is dead
There is no repolarization is an infarct

MI

A big dip in the ST segment represents an MI

ECG Leads

2,3 and auf leads focus on the left leg and the posterior wall
Lead 1 and AVF look from the left arm
Lead 1, aVL, and V6 looks at the left lateral wall of the heart
V3 and V4 look at the anterior heart wall
V1 and V2 look at the inferior aspect of the heart and the septum
V1 and V2 also view from the sternal border
V1 and V2 also look at the septum
Leads V3, V4, and V6 look at the lateral aspect of the heart
V5 and V6 look at the lateral aspect of the heart and the apex
Left atrial leads aVL, lead 1, and lead 111 look at the septal wall
aVL and lead 1 look at the lateral leads

This quiz covers key concepts related to cardiac physiology, including depolarization, the ST segment, and the effects of ischemia and infarction on heart function. It explores how these elements interact during various cardiac events and the implications for ECG interpretation. Test your knowledge on these crucial aspects of cardiac health!