CVS 105 Exam 1 Review

Flashcards for the CVS 105 Exam 1, covering Electrocardiograms (EKG/ECG), waveforms, and lead placements.

What is an electrocardiogram?

A tracing of the heart's electrical activity.

What is the machine that produces an electrocardiogram called?

Electrocardiograph

What are the different types of electrocardiograms?

Continuous, portable, static, and dynamic.

What is a Holter monitor used for?

Tracking electrical activity over a period of time.

Where should EKG leads NOT be placed?

On bone.

What is conductivity in the context of the heart?

The ability of the heart to receive and transmit an electrical signal.

What is automaticity in the context of the heart?

The ability of the heart cells to spontaneously initiate an electrical impulse.

What is the SA node and its function?

Pacemaker of the heart that initiates the electrical pathway.

Where is the SA node located?

Upper walls of the Right Atrium besides the SVC (superior vena cava).

What is the function of the AV node?

Delays further firing.

Where is the AV node located?

In the Right Atrium at the junction between the RA and RV.

What is the function of the Bundle of His system?

Sends charges down the Left/Right bundle branches.

What is the function of the Purkinje fibers?

Branches off the L/R bundle branches and depolarize the ventricles.

What happens during atrial depolarization, and what wave does it create?

SA Node firing a positive charge towards the AV Node, Ventricular Diastole, which creates a Positive deflection - P wave.

What occurs during IVCT (isovolumic contraction time), and what segment corresponds to it?

AV node holds the positive charge but delays firing towards the Bundle of His system, resulting in no net stimulus, which isoelectric line, or PR segment.

What is the PR interval?

Period between the beginning of Atrial depolarization to the start of Ventricular depolarization

What happens in Phase 1 of Right and Left Ventricular depolarization and what deflection is created?

Interventricular septum depolarization – IVS becomes depolarized through the left and right bundle branches from Left to right leading to early depolarization of the ventricles which leads to a negative deflection, or Q wave.

What happens in Phase 2 of Right and Left Ventricular depolarization and what deflection is created?

Right and left ventricular apical portions are depolarized through the Purkinje fibers and right ventricular depolarization is complete which results in a Positive deflection, or R Wave.

What happens in Phase 3 of Right and Left Ventricular depolarization and what deflection is created?

Mid and basal portions of the Left ventricle are depolarized through the Purkinje fibers toward the left lateral wall which results in a negative deflection, or S wave.

What occurs during IVRT (Isovolumic relaxation time) and what ECG segment correlates?

The Right and Left ventricle are positively charged and depolarized with no further movement of charge, which results in an Isoelectric line, or ST segment.

What happens during Ventricular Repolarization and what deflection is created?

Positively charged myocardial cells become negative slowly towards its resting state where it can become depolarized again which results in a Positive deflection or T wave.

When does a positive charge that depolarizes a cell from negative end towards a positive end occur?

Positive deflection

When does a positive charge that depolarizes a cell positive towards a negative end occur?

Negative deflection

When does a negative charge that repolarizes a cell from positive towards a negative occur?

Negative deflection

What plane does the impulse from the limb leads receive?

Frontal plane of the heart

Which leads view the Lateral walls of the heart?

Lead I, Lead AVl, V5, V6.

Which leads view the Inferior walls of the heart?

Lead II, Lead III,Lead AVf.

Are Leads I, II, III Bipolar or Unipolar?

Bipolar – measure between 2 specific points

Are Leads AVr, AVl, AVf Unipolar or Bipolar?

Unipolar – only uses one reference point

Which wall does Lead AVr view?

Basal septum & RV and depicts Negative waveforms

Which wall does Lead AVf view?

Interior walls of the heart

Which wall does Lead AVl view?

Lateral walls of the heart

Where should the Limb Locations for a 12 lead be placed?

RA – Right side of chest below clavicle in the midclavicular line. LA – Left side of the chest below clavicle in the midclavicular line. LL – in the left hip or Left leg. RL – in the Right hip or Right leg

What is Einthovens triangle?

A conceptual triangle formed by leads I, II, III

Are Precordial chest leads (V1, V2, V3, V4, V5, V6) Unipolar or Bipolar?

Unipolar – they are Positive and use just one reference point

Where is V1 located and which wall does it view?

In the 4th intercostal space to the right of the sternum.

Where is V2 located?

In the 4th intercostal space to the left of the sternum.

Where is V3 located?

Located midway between the V1 and V2

Where is V4 located?

Located at the 5th intercostal space

Where is V5 located?

Located at the 5th intercostal space at the anterior axillary line

Where is V6 located?

Located horizontally level with V4 - V5

Which leads view the Septal walls?

V1, V2

Which leads view the Anterior wall?

V3, V4

What do Vertical lines on ECG paper represent?

Amplitude

What do Horizontal lines on ECG paper represent?

Time

How much amplitude does 1 mm in height on ECG paper translate to?

0.1MV

How much amplitude does one large box in height on ECG paper translate to?

0.5 MV

How much time does 1 mm in width on ECG paper translate to?

0.04 seconds

How much time does one large box in width on ECG paper translate to?

0.20 second

What duration is considered normal for a P wave?

<0.12 seconds

What amplitude is considered normal for a P wave?

2.5mm

What duration is considered normal for the PR interval?

0.12 - 0.20 seconds

What duration is considered normal for the QRS complex?

<0.12 duration

What is considered a normal ST segment?

No elevation or depression