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ECG: Key terms
Interpretation of Electrocardiogram Tracings CH 11
Question | Answer |
---|---|
Action Potential | a brief reversal in the electrical potential difference across a nerve cell or muscle fiber membrane that occurs in response to a stimulus |
Atrial Kick | the added filling of the ventricles during diastole caused by atrial contractions |
Automaticity | the ability of cardiac tissue ti stimulate depolarization spontaneously |
Depolarization | an electrical change in an excitable cell in which the inside becomes positive; associated with contraction of cardiac muscle cells |
Dysrhythmia | any deviation of the heart's normal sinus rhythm |
Ectopic impulse | a heartbeat originating outside the SA node |
Escape beat | a heartbeat that originates outside the sinus node after a period of SA node inactivity |
First -Degree heart block | a dysrhythmia in which the PR interval is prolonged, exceeding 200 msec; there are no missed beats, and the rhythm typically is regular |
Focus | the site within the heart from which an ectopic impulse originates |
Heart block | a category of dysrhythmias caused by defective transmission of the heart's electrical impulses through its conducting system |
Hypertrophy | as applied to the heart, a pathologic increase in the bulk of the myocardial fibers, typically due to a chronic increase in afterload |
QRS Complex | central and most visually obvious part of an ECG tracing. It corresponds to the depolarization of the right and left ventricles of the human heart. |
QT Interval | time between the start of the Q wave and the end of the T wave in an ECG that represents electrical depolarization and repolarization of the left and right ventricales |
Repolarization | the return of a negative charge within the cell; occurs during relaxation of the myocardial cells |
RR interval | the time elapsing between two consecutive R waves in an ECG |
ST segment | the interval between the end of the QRS complex and T wave |
ST-Elevation Myocardial Infarction (STEMI) | a type of "heart attack" or myocardial infarction characterized by the elevation in the ST segment |