[02.03] CMD - Clinical Correlation of ECG V2.pdf

Willem Einthoven

Who discovered the galvanometer and has an equilateral triangle named after him?

August Waller

Who used his dog to demonstrate the first electrocardiogram?

Luigi Galvani

Who proved the presence of electrical fluid in living organisms by experimenting with frog legs?

Large size requiring buckets of water for the limbs

What was the original physical scale and setup of the galvanometer?

Left atrium, left ventricle, right atrium, and right ventricle

What are the four chambers of the human heart?

Three

How many chambers does a chicken heart have?

Sinoatrial node

Where does the normal electrical impulse of the heart originate?

Interatrial connections

What discrete fibers connect the SA node to the AV node?

Atrioventricular node

Which part of the conduction system is referred to as the junction?

40 to 60 bpm

What is the escape rate of the AV node if the SA node fails to deliver an impulse?

Bundle of His

What structure begins the conduction of electrical signals specifically to the ventricles?

Left and right bundle branches

Into what two paths does the bundle of His divide?

Purkinje fibers

What fibers terminate in the myocardium and move the impulse through the ventricles for contraction?

20 to 40 bpm

What is the escape rate of the Purkinje fibers?

P wave

Which ECG component is not the sinus node itself but represents atrial depolarization?

Immediately before the P wave

Where is the sinus node impulse located relative to the P wave on an ECG?

Between the P wave and the QRS complex

Where are the impulses for the AV node and bundle of His located on an ECG?

Ventricular depolarization

What does the QRS complex represent?

Atrial depolarization

What does the P wave indicate?

Summation of left and right atria

The P wave represents the electrical activity of which chambers?

Left

In a right bundle branch block, which chamber is assumed to receive the signal first?

Right

In a left bundle branch block, which chamber receives the signal before the other?

Sinus rhythm

What does a normal P wave indicate?

Ventricles are already contracting

What does the QRS complex indicate regarding the state of the ventricles?

Ventricular repolarization

What does the T wave represent?

Relaxation

What is the heart doing during the T wave phase?

SA node depolarization

What specific event occurs before the P wave but is too small to be seen on the ECG?

Buried by the QRS complex

Where is atrial repolarization located on an ECG strip?

Distance from the atrium to the actual ventricular depolarization

What does the flat interval between the P wave and the beginning of the QRS complex represent?

Failure of the heart to relax

Most arrhythmias arise during the repolarization phase because of what issue?

R on T phenomenon

What condition involves the R wave of a QRS complex overlapping with a T wave?

Premature ventricular contractions

The R on T phenomenon is caused by a high frequency of what?

Torsades de pointes

What arrhythmia is expected when an R wave hits a T wave?

American Heart Association and International Electrotechnical Commission

What are the two major guidelines for ECG lead placement?

IEC

Which lead placement guideline is most commonly used in clinical practice?

Red

What is the IEC color code for the right arm lead?

Yellow

What is the IEC color code for the left arm lead?

Black

What is the IEC color code for the right leg lead?

Green

What is the IEC color code for the left leg lead?

Red is for Marcos and N is for dead

What is the mnemonic for remembering the right side IEC leads?

L is for Cory and F is for alive

What is the mnemonic for remembering the left side IEC leads?

Precordial leads

What are the leads V1 through V6 called?

Einthoven triangle

What is produced when limb leads are placed on a patient?

Right arm

Where is lead aVR positioned?

Left arm

Where is lead aVL positioned?

Foot

Where is lead aVF positioned?

Right arm and left arm

Lead I is positioned between which two points?

Right arm and left foot

Lead II is positioned between which two points?

Left arm and left foot

Lead III is positioned between which two points?

Apex is flipped to the other direction

What occurs in the condition known as dextrocardia?

Three limb leads, three augmented leads, and six precordial leads

What is the composition of a standard 12 lead ECG?

Hexaxial system

What diagram is created by plotting all the vectors of the heart leads?

Vertical center

Where is lead aVF located on the hexaxial system?

Positive deflection

What kind of deflection is shown on an ECG if electrical activity moves toward the positive electrode?

Negative deflection

What kind of deflection is shown on an ECG if electrical activity moves away from the positive electrode?

Upright in Leads I, II, and aVF

What is one of the primary criteria for identifying sinus rhythm on an ECG?

Absent or inverted

In sinus rhythm, the P wave should never be what in leads where it is usually upright?

25 mm per s

What is the standard paper speed for a normalized ECG?

Waveforms appear farther apart

What happens to the appearance of an ECG at a faster paper speed of 50 mm per s?

Waveforms appear closer together

What happens to the appearance of an ECG at a slower paper speed of 12.5 mm per s?

10 mm per mV

What is the standard voltage standardization for an ECG?

0.04 seconds

How much time is represented by one small horizontal square on ECG paper?

0.20 seconds

How much time is represented by one big horizontal square on ECG paper?

Five

How many big squares are contained in a one second ECG strip?

3 to 5 big boxes

What is the normal range of R-R intervals on an ECG?

Bradycardia

What is the term for a heart rate less than 60 bpm?

Tachycardia

What is the term for a heart rate greater than 100 bpm?

Regularity, rate, P wave sinus, and intervals

What are the four main steps in ECG interpretation?

Beat to beat intervals are the same

What defines a rhythm as regular?

Complete heart block

What is suggested by dissociation between atrial and ventricular rhythms?

1500 divided by the number of small squares

What is the small square method equation for heart rate?

300 divided by the number of big squares

What is the big square method equation for heart rate?

6 second method

What method is used to determine the heart rate of an irregular rhythm?

30

How many big boxes are in a 6 second strip?

Multiply by 10

How do you calculate bpm using the 6 second strip method?

Atrial Fibrillation

For which specific fast rhythm is the 6 second method recommended?

Upright P wave

What is the specific requirement for a P wave to be considered sinus in ACLS?

Atropine

What is the first line treatment for unstable or symptomatic bradycardia?

1 mg every 3 minutes

What is the dosage and frequency of Atropine?

3 mg

What is the maximum total dose of Atropine for bradycardia?

Dopamine or Epinephrine infusion

What are the alternative infusions if Atropine is ineffective for bradycardia?

Pacing

What is the last resort management for slow rhythms?

0.12 to 0.2 seconds

What is the normal duration of a PR interval?

3 to 5 small boxes

How many small boxes define a normal PR interval?

First degree AV block

What is likely present if the PR interval exceeds 5 small boxes?

Myocardial infarction

The ST segment is critical for diagnosing which condition?

Ischemia

What does ST depression usually indicate?

450 ms

Arrhythmias commonly arise when the QT interval exceeds what duration?

Hormonal differences

Why do females generally have longer QT intervals than males?

Sinus bradycardia and sinus tachycardia

Which two deviations are still considered normal sinus rhythms?

Arrhythmia

What is the general term for any deviation from sinus rhythm?

Less than 0.12 seconds

What is the definition of a narrow QRS complex?

Greater than 0.12 seconds

What is the definition of a wide QRS complex?

Junctional rhythm

What is a slow rhythm with a narrow QRS and no P wave?

Idioventricular rhythm

What is a slow rhythm with a wide QRS complex?

Cardiac arrest

In what state does a patient progress from asystole to idioventricular bradycardia after CPR?

Prolonged PR interval

What is the primary finding in 1st degree AV block?

Wenkebach

What is the alternative name for 2nd degree AV block Type I?

Progressively prolonging PR interval with a QRS drop

What characterizes 2nd degree AV block Type I?

Fixed prolonged PR interval with a QRS drop

What characterizes 2nd degree AV block Type II?