Week 4: EKG Flashcards
1
Q
What does a standard ECG record?
A
The electrical activity of the heart during each cardiac cycle.
2
Q
What does the P wave represent?
A
Depolarization of the right and left atria.
3
Q
What initiates the P wave?
A
The sinoatrial (SA) node.
4
Q
What is the normal duration of the P wave?
A
≤0.12 seconds (≤3 small squares).
5
Q
What is the normal amplitude of the P wave in limb leads?
A
≤2.5 mm.
6
Q
In which leads is the P wave typically upright?
A
I, II, aVL, and V4–V6.
7
Q
What does a tall P wave indicate?
A
‘P pulmonale’ → right atrial enlargement.
8
Q
What does a broad/notched P wave indicate?
A
‘P mitrale’ → left atrial enlargement.
9
Q
What is the PR interval?
A
The time from onset of the P wave to the start of the QRS complex.
10
Q
What is the normal duration of the PR interval?
A
0.12–0.20 seconds (3–5 small squares).
11
Q
What does the PR interval represent?
A
Conduction from atria → AV node → His bundle → bundle branches → Purkinje fibers.
12
Q
What does a prolonged PR interval indicate?
A
1st-degree AV block.
13
Q
What is a short PR interval associated with?
A
Pre-excitation syndromes (e.g., WPW).
14
Q
What does the QRS complex represent?
A
Ventricular depolarization.
15
Q
What is the normal duration of the QRS complex?
A
<0.12 seconds.
16
Q
What are the components of the QRS complex?
A
- Q wave: Initial negative deflection.* R wave: First positive deflection.* S wave: Negative deflection following an R wave.
17
Q
What does a prolonged QRS indicate?
A
Bundle branch block or ventricular rhythm.
18
Q
What do deep Q waves signify?
A
Old myocardial infarction.
19
Q
What is the ST segment?
A
From end of QRS (J point) to start of T wave.
20
Q
What does the ST segment represent?
A
Early phase of ventricular repolarization; normally isoelectric.
21
Q
What does ST elevation indicate?
A
Acute myocardial injury/infarction.
22
Q
What does ST depression indicate?
A
Subendocardial ischemia, digitalis effect.
23
Q
What does the T wave represent?
A
Ventricular repolarization.
24
Q
In which leads is the T wave typically upright?
A
Most leads (except aVR, V1).
25
What is the normal amplitude of the T wave in limb leads?
<5 mm.
26
What is the normal amplitude of the T wave in precordial leads?
<10 mm.
27
What do inverted T waves indicate?
Ischemia, infarction, ventricular strain.
28
What do peaked T waves suggest?
Hyperkalemia.
29
What do flattened T waves indicate?
Hypokalemia.
30
What does the QT interval represent?
Total duration of ventricular depolarization and repolarization.
31
What is the normal duration of the QTc for men?
<440 ms.
32
What is the normal duration of the QTc for women?
<460 ms.
33
What is Bazett’s formula for QTc?
QTc = QT/√RR.
34
What does a prolonged QT interval indicate?
Risk of torsades de pointes.
35
What does a short QT interval indicate?
Hypercalcemia or channelopathies.
36
What is the U wave possibly due to?
Purkinje fiber repolarization or delayed ventricular repolarization.
37
Where is the U wave best seen?
V2-V3.
38
In which conditions is the U wave prominent?
Hypokalemia, bradycardia, antiarrhythmic drug use.
39
What does the P wave reflect?
Atrial depolarization
## Footnote
Indicates right and left atria; associated with atrial enlargement and arrhythmias.
40
What is the anatomical correlate of the PR interval?
AV node, His-Purkinje
## Footnote
Related to atrial to ventricular conduction; indicates AV block or pre-excitation.
41
What does the QRS complex represent?
Ventricular depolarization
## Footnote
Corresponds to ventricular myocardium; associated with BBB and ventricular arrhythmias.
42
What is reflected by the ST segment?
Early ventricular repolarization
## Footnote
Related to ventricles; indicates injury or ischemia.
43
What does the T wave signify?
Ventricular repolarization
## Footnote
Corresponds to ventricular myocardium; associated with ischemia and electrolyte disturbances.
44
What is the clinical insight associated with the QT interval?
Total ventricular activity
## Footnote
Related to ventricular conduction system; indicates Torsades and risk stratification.
45
What does the U wave reflect?
Late repolarization
## Footnote
Associated with Purkinje or papillary muscles; indicates hypokalemia and drug effect.
46
What is recorded in a standard 12-lead ECG?
Electrical signals from 12 viewpoints using 10 electrodes.
47
What are the limb leads in the frontal plane?
* Bipolar: I (RA→LA), II (RA→LL), III (LA→LL)
* Augmented Unipolar: aVR (RA), aVL (LA), aVF (LL)
48
What are the precordial leads in the horizontal plane?
* V1: 4th ICS, RSB – RV
* V2: 4th ICS, LSB – septum
* V3: between V2 and V4 – anterior wall
* V4: 5th ICS, MCL – LV apex
* V5: anterior axillary line – lateral wall
* V6: midaxillary line – lateral wall
49
What does an upward (positive) deflection in an ECG indicate?
Depolarization toward the lead.
50
What does a downward (negative) deflection in an ECG indicate?
Depolarization away from the lead.
51
What is meant by isoelectric in an ECG?
When wavefront is perpendicular to the lead axis.
52
What is the cardiac axis?
Mean electrical vector of ventricular depolarization in the frontal plane.
53
How is the cardiac axis determined?
Lead I and aVF quadrant method.
54
What is the normal cardiac axis range?
–30° to +90°.
55
What does LAD stand for and its axis range?
Left Axis Deviation: –30° to –90°.
56
What clinical conditions are associated with LAD?
* Left anterior fascicular block
* Inferior MI
57
What does RAD stand for and its axis range?
Right Axis Deviation: +90° to +180°.
58
What clinical conditions are associated with RAD?
* Right Ventricular Hypertrophy (RVH)
* Pulmonary disease
59
True or False: Axis deviations in an ECG can suggest chamber hypertrophy, conduction blocks, or infarction.
True.
60
What can misplacement of leads in an ECG simulate or mask?
Pathology such as dextrocardia vs misplacement of limb leads.
61
What is a systematic approach to ECG interpretation used for?
Ensures accuracy, reduces oversight, and supports clinical decision-making
62
What mnemonic is commonly used for ECG interpretation?
Rate – Rhythm – Axis – Intervals – Hypertrophy – Ischemia/Infarction
63
What is the normal sinus rate range for heartbeats per minute?
60–100 bpm
64
How can you quickly determine the heart rate using ECG?
300 ÷ number of large squares between R-R intervals
65
What is considered bradycardia?
<60 bpm
66
What is considered tachycardia?
>100 bpm
67
What should be assessed when determining the rhythm of an ECG?
Regularity of R-R intervals and P wave morphology
68
What does a sinus rhythm indicate?
Regular, upright P in II, with consistent PR
69
What characterizes an irregularly irregular rhythm?
Classic for atrial fibrillation
70
What does a regularly irregular rhythm suggest?
Second-degree AV block or atrial flutter with variable block
71
How is the axis of an ECG determined?
Using leads I and aVF
72
What is a normal axis in an ECG?
QRS positive in both leads I and aVF
73
What indicates left axis deviation (LAD)?
Positive in lead I, negative in lead aVF
74
What indicates right axis deviation (RAD)?
Negative in lead I, positive in lead aVF
75
What is indicated by an extreme axis?
Negative in both leads – rare (e.g., ventricular rhythms, misplacement)
76
What is the normal range for the PR interval?
0.12–0.20 sec
77
What is the maximum duration of a normal QRS complex?
<0.12 sec
78
What formula is used to correct the QT interval?
Bazett’s formula
79
What does QTc prolongation indicate?
Arrhythmogenic potential
80
What defines left ventricular hypertrophy (LVH)?
S in V1 + R in V5 or V6 ≥35 mm
81
What conditions are associated with left ventricular hypertrophy (LVH)?
* Hypertension
* Aortic stenosis
82
What defines right ventricular hypertrophy (RVH)?
R > S in V1 or R in V1 >7 mm
83
What conditions can lead to right ventricular hypertrophy (RVH)?
* Pulmonary hypertension
* COPD
84
What are the ECG changes associated with ischemia?
ST depression, T wave inversion
85
What ECG change indicates injury?
ST elevation
86
What defines infarction in an ECG?
Pathological Q waves (>0.04 sec, >25% of R wave)
87
What leads indicate anterior localization of infarction?
V1–V4
88
What leads indicate lateral localization of infarction?
I, aVL, V5–V6
89
What leads indicate inferior localization of infarction?
II, III, aVF
90
What indicates posterior localization of infarction?
V1–V2 ST depression + tall R waves
91
What is tachyarrhythmia?
Abnormal rhythms with HR >100 bpm, caused by enhanced automaticity, reentry, or triggered activity.
92
What are common clinical manifestations of tachyarrhythmias?
* Palpitations
* Chest discomfort
* Dyspnea
* Syncope
* Fatigue
* Lightheadedness
93
Tachyarrhythmias can be classified as paroxysmal or _______.
sustained
94
What is a common complication of untreated tachyarrhythmias?
Hemodynamic instability
95
What is the etiology of Ventricular Tachycardia (VT)?
* Prior MI (scar tissue)
* Structural heart disease
* Electrolyte imbalance
* Prolonged QT
96
What ECG characteristics are associated with Ventricular Tachycardia (VT)?
* Wide QRS (>120 ms)
* Rate >100 bpm
* AV dissociation
* Capture/fusion beats
97
What is the pathophysiology of Ventricular Tachycardia (VT)?
Reentrant circuit within diseased myocardium; can be monomorphic or polymorphic.
98
True or False: Ventricular Tachycardia (VT) may progress to Ventricular Fibrillation (VF) if untreated.
True
99
What is the etiology of Ventricular Fibrillation (VF)?
* Acute MI
* Hypokalemia
* Hypothermia
* Cardiomyopathies
100
What are the ECG characteristics of Ventricular Fibrillation (VF)?
No identifiable QRS, chaotic baseline.
101
What is the pathophysiology of Ventricular Fibrillation (VF)?
Multiple, disorganized depolarizations → no effective contraction.
102
What emergency treatment is required for Ventricular Fibrillation (VF)?
Immediate defibrillation
103
What is the etiology of Atrial Fibrillation (AF)?
* Hypertension
* Valvular disease
* Alcohol
* Hyperthyroidism
* Age
104
What are the ECG characteristics of Atrial Fibrillation (AF)?
Absent P waves, irregularly irregular ventricular response.
105
What is the pathophysiology of Atrial Fibrillation (AF)?
Ectopic atrial foci, especially in pulmonary veins, cause chaotic atrial activity.
106
What is the risk associated with Atrial Fibrillation (AF) if CHA₂DS₂-VASc ≥2?
Thromboembolism (stroke)
107
What are the ECG characteristics of Atrial Flutter?
Sawtooth flutter waves (esp. II, III, aVF), usually 2:1 AV block → ventricular rate ~150 bpm.
108
What is the pathophysiology of Atrial Flutter?
Macroreentrant circuit in right atrium.
109
What are the treatment options for Atrial Flutter?
* Rate control
* Anticoagulation
* Ablation
110
What is the etiology of Supraventricular Tachycardia (SVT)?
* AVNRT (most common)
* AVRT (e.g., WPW)
* Atrial tachycardia
111
What are the ECG characteristics of Supraventricular Tachycardia (SVT)?
Narrow QRS, regular tachycardia; P waves hidden or retrograde.
112
What is the pathophysiology of Supraventricular Tachycardia (SVT)?
Reentry within AV node or accessory pathway.
113
What are the treatment options for Supraventricular Tachycardia (SVT)?
* Vagal maneuvers
* Adenosine
* CCBs
* Ablation
114
Define bradyarrhythmia
Bradyarrhythmias are characterized by HR <60 bpm, arising from SA node dysfunction, or AV conduction disturbances.
## Footnote
Common symptoms include fatigue, dizziness, and syncope.
115
What are the clinical manifestations of bradyarrhythmias?
Symptoms include:
* Fatigue
* Dizziness
* Syncope
* Heart failure
* Mental clouding
## Footnote
Can result in hemodynamic compromise if escape rhythms are inadequate.
116
What is the ECG finding in First-Degree AV Block?
PR interval >0.20 sec, constant.
## Footnote
Caused by vagal tone, medications (β-blockers, digoxin), or ischemia.
117
What is the cause of First-Degree AV Block?
Vagal tone, medications (β-blockers, digoxin), ischemia.
## Footnote
It results from delayed AV nodal conduction.
118
Describe Second-Degree AV Block – Mobitz Type I (Wenckebach)
ECG shows progressive PR prolongation followed by dropped QRS.
## Footnote
Often benign; monitor if asymptomatic.
119
What is the localization of Second-Degree AV Block – Mobitz Type I?
AV node.
## Footnote
Common causes include inferior MI and high vagal tone.
120
Describe Second-Degree AV Block – Mobitz Type II
ECG shows constant PR with intermittent dropped QRS.
## Footnote
It is localized below the AV node (His-Purkinje).
121
What is the clinical significance of Second-Degree AV Block – Mobitz Type II?
Risk of progression to complete block. Requires pacing.
## Footnote
Commonly caused by anterior MI and conduction disease.
122
What is the ECG finding in Third-Degree (Complete) AV Block?
No association between P waves and QRS complexes.
## Footnote
Escape rhythm can be junctional (narrow QRS) or ventricular (wide QRS).
123
What are the etiologies of Third-Degree AV Block?
Fibrosis, infarction, Lyme disease, drugs.
## Footnote
This condition requires a permanent pacemaker.
124
What is the initial tool for capturing a rhythm snapshot in arrhythmia diagnosis?
12-lead ECG
## Footnote
The 12-lead ECG provides a detailed view of the heart's electrical activity.
125
How long does a Holter Monitor record for arrhythmia symptoms?
24–48 hours
## Footnote
Holter Monitors are used for continuous monitoring to capture frequent symptoms.
126
What is the purpose of an Event Monitor?
Patient-activated for infrequent symptoms
## Footnote
Event Monitors allow patients to record their heart activity when symptoms occur.
127
What device is used for episodic syncope or unexplained palpitations?
Implantable Loop Recorder
## Footnote
This device continuously records heart rhythms over extended periods.
128
What is assessed during Pacemaker/ICD Interrogation?
Stored arrhythmia data and device function
## Footnote
This process helps evaluate the performance and history of the implanted device.
129
What are the complications of Tachyarrhythmias?
Stroke (AF), syncope, cardiomyopathy, sudden cardiac death (VT/VF)
## Footnote
These complications can have serious health implications for patients.
130
What complications are associated with Bradyarrhythmias?
Syncope, hypotension, heart failure, Stokes-Adams attacks, cognitive decline
## Footnote
Bradyarrhythmias can lead to significant health issues if not managed properly.
131
What is the mechanism of Class I antiarrhythmic drugs?
↓ Conduction velocity
## Footnote
Class I drugs, such as Flecainide and procainamide, block sodium channels.
132
Which class of drugs targets the AV node and reduces sympathetic tone?
Class II (β-blockers)
## Footnote
Examples include Metoprolol and esmolol.
133
What is the effect of Class III antiarrhythmic drugs on the action potential duration?
↑ APD, QT interval
## Footnote
Amiodarone and sotalol are examples of Class III drugs.
134
What is the primary action of Class IV antiarrhythmic drugs?
↓ Conduction, ↑ refractoriness
## Footnote
Verapamil and diltiazem are examples of Class IV drugs.
135
When is defibrillation indicated?
In pulseless VT/VF
## Footnote
Defibrillation is a critical emergency intervention for life-threatening arrhythmias.
136
What type of cardioversion is used for AF/flutter?
Synchronized cardioversion
## Footnote
This method is used for unstable supraventricular tachycardia (SVT) as well.
137
What is the purpose of transcutaneous pacing?
Temporary emergency pacing
## Footnote
This method is often used in acute settings to stabilize patients.
138
What is the indication for permanent pacemakers?
Chronic bradycardia, AV blocks
## Footnote
Permanent pacemakers are implanted for long-term management of specific arrhythmias.
139
What does ablation target in arrhythmia management?
Arrhythmogenic foci
## Footnote
Techniques like radiofrequency or cryothermal ablation are utilized.
140
What lifestyle modification can improve rhythm control in AF?
Weight loss
## Footnote
Weight management is particularly beneficial for patients with atrial fibrillation.
141
How does alcohol reduction impact arrhythmias?
Prevents 'holiday heart' syndrome
## Footnote
Excessive alcohol can lead to arrhythmias, especially in binge drinking scenarios.
142
What is recommended regarding exercise to reduce arrhythmia burden?
Avoid excessive endurance sports
## Footnote
Moderate exercise is beneficial, but extreme endurance activities may exacerbate arrhythmias.
143
Why is sleep apnea management critical in AF?
It significantly impacts arrhythmia control
## Footnote
Addressing sleep apnea can improve overall cardiovascular health.
144
Fill in the blank: Patients should avoid stimulants like _______.
Caffeine, cocaine, decongestants
## Footnote
Stimulants can trigger or worsen arrhythmias.
145
What comorbidities should be optimized to help manage arrhythmias?
HTN, diabetes, hyperthyroidism
## Footnote
Effective management of these conditions can improve arrhythmia outcomes.
