ECG Lead Placement, Sinus & Atrial Arrhythmias

Fill-in-the-blank flashcards covering ECG lead orientations, ventricular depolarization/repolarization, definitions and rules for sinus and atrial arrhythmias, clinical significance, and monitoring systems.

Lead I views the heart at an angle of __ degrees.

0°

Lead II is oriented at __ degrees in the axial reference system.

+60°

Lead III looks at the heart from __ degrees.

+120°

Lead aVR records electrical activity at approximately __ degrees.

-150°

Lead aVF has its positive pole oriented at __ degrees.

+90°

Lead aVL views the heart at __ degrees.

-30°

Precordial lead V1 is placed at the __ intercostal space, right sternal border.

4th

A wave of depolarization moving toward a chest electrode produces a __ deflection.

positive

The inferior leads are __, __ and __.

II, III, aVF

Leads I, aVL, V5 and V6 examine the __ wall of the left ventricle.

lateral

Leads V3 and V4 primarily view the __ wall of the heart.

anterior

Leads V1 and V2 are known as the __ leads.

septal

During ventricular depolarization, the impulse spreads from the to the .

endocardium, epicardium

Repolarization of the ventricles moves from the toward the .

epicardium, endocardium

A Q wave is present only if the first deflection after the P wave is __.

negative

T waves are normally upright in leads with dominant __ waves.

positive R

An arrhythmia is a deviation from normal __ rhythm.

sinus

An ectopic beat originates outside the __ node.

SA

A beat that occurs later than expected because the dominant pacemaker fails is called an __ beat.

escape

Sinus rhythm requires a heart rate between and bpm.

60, 100

Sinus bradycardia is defined as a sinus rhythm with a rate less than __ bpm.

60

Sinus tachycardia usually ranges from to bpm.

100, 160

Sinus arrhythmia is identified when the heart rate varies by more than __ %.

10

In sinus block, the pause is an exact multiple of the baseline __ interval.

R-R

A pause longer than a multiple of two R-R intervals suggests __.

sinus arrest

Relative bradycardia refers to a heart rate that is slow for the patient’s __ condition.

clinical

Sinus tachycardia can be dangerous in __ because it may extend the infarct.

acute myocardial infarction (AMI)

Respiratory sinus arrhythmia typically shows heart rate during inspiration and during expiration.

increases, decreases

In sinus arrest, another pacemaker may assume control, producing an __ rhythm.

escape

When the atria become the pacemaker, the P waves are often __, __, flattened or diphasic.

notched, peaked

A premature atrial beat produces an early P wave called a __ wave.

P′ (P prime)

PACs interrupt the __ of the underlying sinus rhythm.

regularity

Atrial tachycardia usually has a rate between and bpm.

130, 250

Paroxysmal atrial tachycardia (PAT) appears __ and stops just as quickly.

suddenly

A rhythm showing at least three different P-wave morphologies and a rate < 100 bpm is called __.

wandering atrial pacemaker

Atrial flutter typically has an atrial rate of – bpm.

250, 350

The classic ECG pattern of atrial flutter is a __ waveform.

sawtooth (flutter waves)

Atrial fibrillation is described as being __ irregular.

irregularly

In atrial fibrillation the atrial rate is thought to exceed __ bpm.

350

Controlled AFib is defined when the ventricular rate is less than __ bpm.

100

Loss of the atrial “kick” in atrial flutter or fibrillation can significantly reduce __ output.

cardiac

Both atrial flutter and atrial fibrillation increase the risk of and emboli.

pulmonary, cerebral

Pharmacological or electrical __ may be required for unstable atrial tachycardia.

cardioversion

Anticoagulants are recommended for all patients with or .

atrial fibrillation, atrial flutter

Digoxin toxicity is a common precipitating factor for __ tachyarrhythmias.

atrial

Three-lead monitoring gives two inferior and one __ view of the heart.

lateral

A five-lead system adds an __ view via the precordial electrode.

anterior

A 12-lead ECG uses __ electrodes to generate twelve views.

10

The six chest leads are considered __ (type) leads.

unipolar (precordial)

The ground electrode in a standard ECG is placed on the __ leg (RL).

right

Normal P-wave amplitude should be less than __ mm in limb leads.

2.5

Normal T-wave amplitude should be less than __ mm in limb leads.

5

A compensatory tachycardia often occurs in conditions like fever, anxiety or __.

hypovolemia