Exam 10: Post-Test

The first segment of the left coronary artery is the _____ artery.

The six limb leads view the heart in the frontal plane as if the body were flat.

The _____ originate from small mounds of myocardium called papillary muscles and serve as anchors to prevent the cusps of the AV valves from inverting into the atria.

In an adult,the normal duration of the QRS complex is _____ seconds.

Sometimes,when a premature atrial complex (PAC)occurs very prematurely and close to the T wave of the preceding beat,only a P wave may be seen with no QRS after it (appearing as a pause).This type of PAC is termed a(n)_____ PAC.

Which side of the heart is a high-pressure system that pumps arterial blood to the systemic circulation?

The axes of leads I,II,and III form an equilateral triangle with the heart at the center (Einthoven's triangle).If the augmented limb leads are added to this configuration and the axes of the six leads moved in a way in which they bisect each other,the result is the _____ _____ _____.

Explain the benefits of a dual-chamber pacemaker.

An accessory pathway that has one end attached to normal conductive tissue is called a(n)_____ _____.

Explain the meaning of the letters in aVR,aVL,and aVF.

Indicate the inherent rates for each of the following pacemaker sites: Sinoatrial (SA) node___________________ Atriovertricular (AV) junction_______________________ Ventricles____________________

A macroreentrant circuit is one that involves a small area of heart tissue,usually a few centimeters or less.

The myocardium is thickest in the ____.

An ECG machine's sensitivity must be calibrated so that a 1-mV electrical signal will produce a deflection measuring exactly _____-mm tall.

_____ is a term used to describe the period of recovery that cells need after being discharged before they are able to respond to a stimulus.

Which of the following correctly reflects the ECG indicators of ischemia?

Myocardial ischemia delays the process of repolarization; therefore the ECG changes characteristic of ischemia include _____.

A(n)_____ _____ is a vertical line on the ECG that indicates the pacemaker has discharged.

When reviewing a 12-lead ECG,intervals and duration are usually expressed in _____.

Explain the difference between a PVC and a ventricular escape beat.