Atrial Flutter and Arrhythmia Review

Flashcards covering the mechanisms, ECG characteristics, and mapping procedures for Typical Atrial Flutter, Atypical Atrial Flutter, Focal AT, and Atrial Fibrillation.

Reentrant Circuit Requirements

Consists of two separate conduction pathways (Pathway A and Pathway B) joined by common tissue, characterized by different conduction velocities and different refractory periods.

Refractory Period

The time required by the tissue to recover from an electrical impulse before another one can be conducted.

Pathway A

A conduction pathway in a reentrant circuit that conducts impulses slower and has a faster recovery time (shorter refractory period).

Pathway B

A conduction pathway in a reentrant circuit that conducts impulses faster and has a slower recovery time (longer refractory period).

Initiation of a Reentrant Circuit

Occurs when a critically timed premature beat enters the circuit while Pathway B is refractory; the impulse travels down Pathway A, and by the time it reaches the bottom, Pathway B has recovered, allowing the impulse to travel back up Pathway B.

F waves

Also known as flutter waves, these represent the typical sawtooth pattern of atrial flutter seen on an ECG.

Atrial Flutter QRS Duration

Generally exhibits a normal range of $0.04\text{--}0.12\text{ sec}$, with a specific example noted at $0.12\text{ sec}$.

Typical Atrial Flutter

A supraventricular tachycardia (SVT) of the right atrium originating from a reentrant circuit around the tricuspid annulus using structures like the SVC, IVC, CS, and Crista Terminalis.

Counter-clockwise Typical Atrial Flutter

The most common presentation of typical flutter, showing negative flutter waves in leads $II$, $III$, and $aVF$, and positive flutter waves in lead $V1$.

Clockwise Typical Atrial Flutter

A presentation of typical flutter showing positive flutter waves in leads $II$, $III$, and $aVF$, and negative flutter waves in lead $V1$.

CavoTricuspid Isthmus (CTI)

A strip of tissue between the IVC and the Tricuspid Valve that is a critical part of the typical atrial flutter circuit and the gold standard location for ablation.

Atypical Atrial Flutter

Any atrial flutter that originates outside of the typical CavoTricuspid Isthmus (CTI) dependent location.

Causes of Atypical Atrial Flutter

Scarring in the atria from prior heart procedures (surgery or ablation) or heart diseases such as heart failure, CAD, cardiomyopathy, rheumatic heart disease, or pericarditis.

Left Atrial (LA) Atypical Flutter Locations

Commonly occurs around the pulmonary veins, around the mitral valve, or over the roof of the LA.

Distal to Proximal CS Activation

An intracardiac electrogram pattern during flutter that indicates a left atrial origin.

Proximal to Distal CS Activation

An intracardiac electrogram pattern that usually indicates a right atrial origin, though it can sometimes be left atrial.

Focal Atrial Tachycardia (AT)

Characterized by a rapid, regular rhythm that originates from a discrete area in the atria.

AT Segment Duration

Typical duration is approximately $80\text{--}150\text{ ms}$ for vMap analysis.

Atrial Fibrillation (AF)

The most common cardiac arrhythmia, associated with disorganized electrical activity, rapid triggers, functional reentry, and irregular ventricular contractions.

TQ segments

The atrial activity starting at the offset of a T wave and ending at the onset of the following Q wave, used for marking AF episodes in vMap.