ekg Flashcards
What is the normal pacemaker of the heart?
The sinoatrial (SA) node.
What is automaticity?
The ability of the heart to initiate an impulse spontaneously and continuously.
What is conduction in the heart?
The ability to transmit an impulse along a membrane in an orderly manner.
What is excitability in cardiac cells?
The ability of the heart cells to be electrically stimulated.
What is contractility?
The ability of the heart to respond mechanically to an impulse.
What does an electrocardiogram (ECG) represent?
A graphic tracing of the electrical impulses in the heart.
What do the waveforms on an ECG indicate?
The electrical activity of depolarization and repolarization caused by ion movement across heart cell membranes.
What is depolarization?
The electrical activation of the heart muscle.
What is repolarization?
The return of the heart muscle to its resting electrical state.
What is the lead placement mnemonic for a 5-lead ECG?
White on right, smoke over fire (black over red), brown in the middle.
What is the key principle in telemetry monitoring?
Treat the patient, NOT the monitor.
What does the P wave represent?
Atrial depolarization.
What does the PR interval represent?
The isoelectric period of AV delay, lasting 0.10-0.20 seconds.
What does the QRS complex represent?
Ventricular depolarization, lasting less than 0.12 seconds.
What does the ST segment represent?
An isoelectric period.
What does the T wave represent?
Ventricular repolarization.
What does a U wave indicate?
Rarely seen; possibly represents repolarization of the Purkinje fibers.
What are the five steps of rhythm interpretation?
- P waves: Are they present? Do they look the same? Where are they coming from? 2. Rate: Atrial (PR interval) and Ventricular (QRS). 3. Rhythm: Regular or irregular? 4. ST segment changes. 5. T wave characteristics.
What is a normal sinus rhythm?
A regular rhythm with normal P waves, PR interval (0.10-0.20 sec), QRS complex (<0.12 sec), and upright T waves.
What is the Rule of 6 Second Strip for calculating heart rate?
Count the number of complete QRS complexes in a 6-second strip and multiply by 10.
How does the Rule of 300 method calculate heart rate?
Count the number of large boxes between two R waves and divide by 300.
How does the Rule of 1500 method calculate heart rate?
Count the number of small boxes between two R waves and divide by 1500.
What should be assessed in a patient with a dysrhythmia?
Indicators of cardiac output and oxygenation, especially changes in level of consciousness.
What physical assessments are important for a patient with a dysrhythmia?
- Rate and rhythm of apical and peripheral pulses - Heart sounds - Blood pressure and pulse pressure - Signs of fluid retention
