ECG Interpretation and Cardiology Notes

Comprehensive vocabulary flashcards covering key concepts, definitions, waveforms, intervals, and arrhythmias from Cardiology ECG Interpretation notes.

Pericarditis

Inflammation of the pericardium that causes changes to a $12$\text{-lead ECG}, including ST elevation due to inflammation of the heart.

Veins

Blood vessels that carry blood toward the heart.

Arteries

Blood vessels that carry blood away from the heart.

Valve Prolapse

A condition that results in the heart valve "ballooning" backwards.

Regurgitation

Occurs when a heart valve cannot close properly, causing blood to leak back.

Stenosis

A narrowing of the heart valve opening resulting in reduced blood pumping.

Pericardial Effusion

A build up of fluid in the pericardial cavity caused by infection, inflammation, injury, or cancer, which can lead to cardiac tamponade.

Cardiac Tamponade

A condition caused by fluid accumulation (effusion) in the pericardial cavity; all tamponades are effusions, but not all effusions are tamponade.

Angina and Myocardial Infarction

Conditions within the coronary arteries caused by an embolus or thrombus that lead to an imbalance between oxygen supply and demand, ranging from ischemia to complete infarction.

Cardiac Monitor

The "brains" of the operation that converts electrode inputs into lead output tracings and performs various monitoring functions.

ECG Paper Axes

The horizontal x-axis measures time in seconds ($\text{sec}$), and the vertical y-axis measures voltage in millivolts ($\text{mV}$).

ECG Electrode

A conductive pad that is attached to the skin to record the electrical activity of the heart.

ECG Lead

A graphical representation of the heart's electrical activity calculated by analyzing data from several ECG electrodes.

Precordial Electrodes Placement (V1-V6)

Chest electrodes positioned across anatomical landmarks on the torso to record precordial chest leads V1 through V6.

Mean Electrical Vector

The sum of many simultaneous electrical depolarization vectors (having magnitude and direction) at any given point in time.

Cardiac Axis

The sum of all electrical vectors throughout a complete cardiac cycle, normally ranging from $-30^\circ$ to $+90^\circ$.

Bipolar Leads

ECG leads (Leads I, II, and III) that utilize a single positive electrode and a single negative electrode.

Unipolar Leads

Augmented ECG leads (aVR, aVL, and aVF) that use a single positive electrode while using an average of the others for the negative reference.

Cardiac Conduction System

The specialized electrical conduction pathway of the heart consisting of 1 - SA Node, 2 - AV Node, 3 - Bundle of HIS, 4 - Left & Right Bundle Branches, and 5 - Purkinje Fibers.

P Wave

The first positive deflection on an ECG representing atrial depolarization, with normal duration $< 0.12\,\text{s}$ ($< 3$ small squares) and amplitude $< 2.5\,\text{mm}$ ($0.25\,\text{mV}$).

Q Wave

Any negative deflection that precedes an R wave; frequently not seen in lead II.

R Wave

The first positive deflection following the P wave, usually the most dominant wave in the QRS complex.

S Wave

Any negative deflection immediately following an R wave.

QRS Complex

ECG waveform representing ventricular depolarization; normal adult duration varies between $0.06\,\text{s}$ and $0.10\,\text{s}$ ($< 0.12\,\text{s}$ or $3$ small squares) with amplitude of $5\text{ to }30\,\text{mm}$ ($0.5\text{ to }3\,\text{mV}$).

T Wave

Positive deflection following a QRS complex representing ventricular repolarization, with normal amplitude $< 5\,\text{mm}$ ($0.5\,\text{mV}$) in limb leads.

J Point

The junction point between the end of the QRS complex and the start of the ST segment.

PR Interval

The time from the start of the P wave to the start of the QRS complex ($0.12\text{ to }0.20\,\text{s}$ or $3\text{ to }5$ small boxes), representing atrial depolarization and conduction delay through the AV node.

ST Segment

The flat, isoelectric segment from the J point to the start of the T wave representing the period between ventricular depolarization and repolarization.

TP Segment

The flat, isoelectric segment from the end of the T wave to the start of the next P wave representing the time between ventricular repolarization and the next electrical impulse.

QT Interval

The duration from the start of the QRS complex to the end of the T wave representing total time for ventricular depolarization and repolarization.

Pathological Q Waves

Abnormal Q wave morphology on an ECG indicating a previous myocardial infarction (MI).

Delta Wave

A slurred beginning of the QRS complex seen in Wolff-Parkinson-White (WPW) syndrome due to pre-excitation through an accessory pathway (Bundle of Kent).

J Wave

An ECG wave abnormality associated with hypothermia.

Premature Atrial Complex (PAC)

An early ectopic beat originating in the atria, presenting with an abnormal-looking P wave followed by a narrow QRS complex.

Premature Junctional Complex (PJC)

An early ectopic beat originating in the AV junction, where the P wave may be absent, inverted, or appear after a usually narrow QRS complex.

Premature Ventricular Complex (PVC)

An early ectopic beat originating in the ventricles with no preceding P wave and a wide, unusual-looking QRS complex.

Normal Sinus Rhythm

A regular rhythm originating from the SA node with a rate of $60\text{ to }100\,\text{bpm}$, normal P waves paired with each QRS, PR interval $0.12\text{ to }0.20\,\text{s}$, and narrow QRS $< 0.10\,\text{s}$.

Sinus Tachycardia

A regular rhythm resembling normal sinus rhythm sped up, with a rate over $100\,\text{bpm}$, paired P waves, PR $0.12\text{ to }0.20\,\text{s}$, and narrow QRS $< 0.10\,\text{s}$.

Sinus Bradycardia

A regular rhythm resembling normal sinus rhythm slowed down, with a rate under $60\,\text{bpm}$ (or $< 50\,\text{bpm}$), paired P waves, PR $0.12\text{ to }0.20\,\text{s}$, and narrow QRS $< 0.10\,\text{s}$.

Atrial Fibrillation

An irregularly irregular rhythm with no clear P waves (fibrillatory baseline), non-measurable PR interval, and usually narrow QRS; atrial rate is $350\text{ to }650\,\text{bpm}$.

Atrial Flutter

An atrial rhythm characterized by sawtooth flutter waves (F waves) replacing P waves, with an atrial rate of $250\text{ to }350\,\text{bpm}$ and non-measurable PR interval.

Supraventricular Tachycardia (SVT)

A very fast, regular, narrow-complex tachycardia with a rate over $140\,\text{bpm}$ (usually $180\text{ to }250\,\text{bpm}$), non-measurable PR interval, and hidden, absent, or retrograde P waves.

First-Degree AV Block

A regular rhythm characterized by a fixed, prolonged PR interval ($> 0.20\,\text{s}$) without interruption, where every P wave conducts to a QRS.

Second-Degree AV Block Type I (Mobitz I / Wenckebach)

A regularly irregular rhythm featuring progressive lengthening of the PR interval until a P wave fails to conduct and a QRS complex is dropped.

Second-Degree AV Block Type II (Mobitz II)

A rhythm in which the PR interval remains constant on conducted beats, but QRS complexes are intermittently dropped without progressive PR prolongation.

Third-Degree AV Block (Complete Heart Block)

A rhythm caused by a complete failure of electrical conduction between atria and ventricles, resulting in total AV dissociation where P waves and QRS complexes have no relationship.

Idioventricular Rhythm

A slow, regular ventricular escape rhythm with a rate of $20\text{ to }40\,\text{bpm}$, absent P waves, non-measurable PR, and wide QRS complex ($> 0.12\,\text{s}$).

Ventricular Tachycardia (VT)

A fast, usually regular, wide-complex rhythm with a rate over $100\,\text{bpm}$ (usually over $150\,\text{bpm}$), absent or dissociated P waves, non-measurable PR, and QRS $> 0.12\,\text{s}$.

Ventricular Fibrillation (VF)

A chaotic, disorganized cardiac arrest waveform with no identifiable QRS complexes or effective cardiac output.

Torsades de Pointes

A type of polymorphic ventricular tachycardia specific to patients with QT prolongation, often initiated by an R-on-T PVC, featuring QRS complexes that twist around the baseline.

Pulseless Electrical Activity (PEA)

An organized electrical rhythm present on the monitor screen in a patient who has no detectable pulse.

Wolff-Parkinson-White (WPW) Syndrome

A congenital disorder with an accessory pathway (Bundle of Kent) bypassing the AV node, characterized on ECG by a short PR interval ($< 0.12\,\text{s}$), delta wave, and wide QRS ($> 0.12\,\text{s}$).

Wandering Atrial Pacemaker (WAP)

An irregularly irregular atrial rhythm with a rate of $60\text{ to }100\,\text{bpm}$ characterized by P waves with at least three varying morphologies and variable PR intervals.

Multifocal Atrial Tachycardia (MAT)

An irregularly irregular atrial rhythm with a rate over $100\,\text{bpm}$ featuring P waves with at least three varying morphologies and variable PR intervals.

Synchronized Cardioversion

Electrical therapy synchronized to the R wave used to treat unstable tachyarrhythmias in patients with a pulse, avoiding energy delivery during the vulnerable T wave.

Unsynchronized Defibrillation

Immediate, unsynchronized electrical shock delivered to depolarize myocardial cells in shockable pulseless cardiac arrest rhythms (VF or pulseless VT).

Transcutaneous Pacing

Temporary cardiac pacing using defibrillator pads (set rate $60\text{ to }80\,\text{bpm}$, output $70\text{ to }120\,\text{mA}$) to deliver electrical impulses until capture is achieved.