Medical Terminology Simplified

5–87 The prefix that means rapid is __________; the prefix that means slow is

__________.

5–88 Tachy/cardia is a heart rate that is ____________________; brady/cardia

is a heart rate that is _______________.

The following summary provides a brief, general interpretation of an ECG. A more comprehensive explanation

of ECG abnormalities is beyond the scope of this book. Refer to Figure 5–6 as you read the text that follows.

A normal heart rhythm, or sinus rhythm,shows five waves on the ECG strip, which represent electrical changes
as they spread through the heart. The waves are known as the P wave, QRS waves, and T wave.
The P waverepresents atrial depolarization, conduction of an electrical impulse through the atria. These electrical
changes cause atrial contraction. The QRS waves,commonly referred to as the QRS complex,represent ventricular
depolarization, conduction of electrical impulses through the ventricle by way of the bundle of His and the Purkinje
fibers. These electrical changes cause ventricular contraction. The T waverepresents the electrical recovery and relax-
ation of the ventricles (during diastole).

5–89 Although the heart itself generates the heartbeat, such factors as hormones,

drugs, and nervous system stimulation can also influence the heart rate.

To evaluate a patient’s heart rate, a physician may order an ECG, an abbreviation for

____________________ / _____ / ____________________ / _____ / __________.

5–90 Micro/cardia, an abnormal smallness of the heart, is a condition that is not

usually compatible with a normal life.

A person diagnosed with an underdeveloped heart suffers from the condition called

____________________ / ____________________.

5–91 Megal/o/cardia is an enlargement of the heart. Cardi/o/megaly also means

____________________ of the ____________________.

5–92 In patients with high blood pressure, the heart must work extremely hard.

As a result, it enlarges, similar to any other muscle in response to excessive activity or

exercise.

A patient who develops an enlarged heart has a condition called

____________________ / _____ / ____________________ or

____________________ / _____ / ____________________.

5–93 Use your medical dictionary to define angina pectoris and lumen.

Frame 5–80to Frame 5–93

Cardiovascular System • CHAPTER 5 177

tachy-, brady-

rapid, slow

electr/o/cardi/o/gram

ē-lĕk-trō-KĂR-dē-ō-grăm

micro/cardia

mī-krō-KĂR-dē-ă

enlargement, heart

cardi/o/megaly,

megal/o/cardia

kăr-dē-ō-MĔG-ă-lē,

mĕg-ă-lō-KĂR-dē-ă

!