Week 6- ECG Flashcards
PART 1: INTRODUCTION
PART 1: INTRODUCTION
- Routine cardiac events are triggered by _______ events.
- Electrical events can be detected and visualized via _____.
- Altered ECG patterns reflect a pathology in what?
- electrical events
- ECG
- conduction system or a process that alters these electrical events
What are the (3) unique properties of cardiac myocytes?
- Automaticity
- Rhythmicity
- Conductivity
CARdiac
Automaticity:
- What is automaticity?
- They __________ discharge.
- Think ________ heart.
- They are able to discharge/depolarize without stimulation from a nerve.
- automatically discharge
- transplanted heart
Rhythmicity:
- What is rhythmicity?
- Describe the hierarchy of rhythmicity and their discharge rates. (3)
- What creates the sinus rhythm?
- Depolarization occurs at regular intervals, therefore cardiac muscle cells can depolarize at regular intervals.
- SA Node (60-100/min), AV Node (40-60/min), His-Purkinje Fibers (30-40/min)
- SA Node
- What is important to know about the hierarchy of rhythmicity?
- What does this mean?
- The faster/higher discharge rate predominates. (Autonomic influence > SA > AV > Purkinje)
- This means that if the normally predominating (SA Node) one is malfunctioning, the next highest will take over.
Conductivity:
- What is conductivity?
- _____like squeeze. What is the purpose of this?
- Heart muscle cells have ability to spread impulses to adjoining cells very quickly without nerve involvement.
- Wavelike squeeze (to promote movement of blood through atria into ventricles, and out of heart)
Describe the AP in a 0-4 step process.
- ) Na+ influx making inside of cell more +.
- ) K+ leaves cell causing slight repolarization until plateau.
- ) Ca+ (in) and K+ (out) leads to sustained plateau.
- ) Eventually Ca+ (in) stops and K+ (out) remains, leading to repolarization.
- ) AP remains until next depolarization.
PART 2: WIGGERS DIAGRAM (ECG) & PQRST COMPLEX
PART 2: WIGGERS DIAGRAM (ECG) & PQRST COMPLEX
- When the wave of depolarization is moving a positive electrode located under the skin, the ECG records a simultaneous _______ deflection.
- A wave of repolarization moves over a positive electrode results in a _________ deflection.
- upward
- downward
ECG tracings are _________ recordings of electrical events/ionic events occurring within the myocytes.
superficial recordings
P Wave:
- ______ ________ is depicted on the ECG tracing as the P wave.
- Initiated via the ________.
- The impulse is spread to the L side via the _________ bundle.
- atrial depolarization
- SA Node
- Bachmann bundle
PR Interval:
- Determines time it takes impulse to travel from ________ to _________.
- How is this useful?
- SA Node to AV Node
- Helps to determine how healthy the heart is in terms of how fast it is able to spread electricity.
QRS Complex:
- ________ ________ is depicted on the ECG tracing as the QRS complex.
- What is the pathway of the His-Purkinje fibers and why does this matter?
- Higher QRS = ______ muscle
- ventricular depolarization
- His-Purkinje fibers travel in wall of ventricle and help to promote wavelike contraction. This directs blood flow into the pulmonary/aortic valves.
- Higher QRS = bigger muscle
T Wave:
- ________ _________ is depicted on the ECG tracing as the T wave.
- The interval from the beginning of the QRS Complex to the apex of the T wave corresponds to the ______ _______ period. What is this?
- In most leads, the T wave is _________ and reflects to repolarization of the myocytes.
- ventricular repolarization
- absolute refractory period, this is where it can no longer depolarize
- positive (upward deflection)
PART 3: ECG RECORDING/LEADS
PART 3: ECG RECORDING/LEADS
What is the isoelectric point?
- When looking at an ECG, the x-axis line that the ECG is hovering around.
- Above = + voltage change, Below = - voltage change
- The standard 12-lead ECG consists of ___ limb leads and ___ chest leads.
- Think of each lead as what?
- 6 limb leads and 6 chest leads
- Lead is a different view of the heart from a different angle.
- Standard limb leads = ?
- Augmented limb leads = ?
- I, II, and III
- aVR, AVL, and aVF
Chest Leads (views):
- Thee six chest leads of the ECG are ___, ____, ____, ____, ___, and _____.
- Show gradual changes in all the recordings.
- Record in a ________ plane.
- V1-V6
- horizontal plane
- Leads V1/V2 are placed over the ______.
- Leads V3/V4 located over ____________.
- Leads V5/V6 look at ________.
- V1/V2 = R side of heart
- V3/V4 = interventricular septum
- V5/V6 = L side of heart
Describe all 6 chest leads placement.
- V1 = 4th IC space to R of sternum
- V2 = 4th IC space to L of sternum
- V3 = Directly between leads V2 and V4
- V4 = 5th IC space at midclavicular
- V5 = level with V4 at left anterior axillary line
- V6 = level with V5 at left midaxillary line
-V4r = 5th IC space at R midclavicular
Describe telemetry lead placement.
- Right arm, left arm, right leg, left leg
- Can be done at shoulders/hips or wrists/ankles, but most often done proximal.
What is a way to remember telemetry lead placement?
- ) White right
- ) Snow over grass
- ) Brown ground
- ) Smoke over fire