February 3, 2016 - A. Fib / Flutter / SVT

Question 1

Atrial Flutter

Answer 1

Sawtooth shape on an ECG.

Caused by a conduction loop in the heart where it circles around in the right atrium. The wavefront never meets the tail and therefore it never ends. Only some of these are translated into QRS complexes.

Typically very rapid, frequently at 300 BPM in the atrium, but regular and organized atrial activity because of the re-entry circuit.

Question 2

Atrial Flutter - Treatment

Answer 2

Cardioversion - more sensitive than atrial fibrillation, but can easily reccur

Ablation - because of the reentrant nature of atrial flutter, it is often possible to ablate the circuit that causes atrial flutter.

Question 3

Atrial Fibrillation

Answer 3

Atrial activity is chaotic. The rate and morphology change continuously throughout the ECG, which does not happen in atrial flutter. Because what is happening in the atrium is chaotic, so too, is what is happening in the ventricle.

The mechanism for atrial fibrillation is unclear. Unfortunately, this also means that there is no practical highly-effective solution.

Question 4

Associations with Atrial Fibrillation

Answer 4

Age

Hypertension

Hyperthyroidism*

Mitral valve disease

Heart disease

Lung disease

Obstructive sleep apnea

Surgery*

Alcohol

* = reversible

Question 5

Classification of Atrial Fibrillation

Answer 5

Paroxysmal: starts and stops on its own. Most (90%) of episodes are <24 hours and by definition they are <7 days

Persistent: starts and lasts >7 days. Most episodes need to be cardioverted. They are considered “longstanding persistent” if the AF lasts more than 1 year.

Permanent: The doctor and the patient throw in the towel and the patient is continuously in AF.

Question 6

Tachy-Brady Syndrome

Answer 6

A combination of paroxysmal atrial fibrillation and at other times bradycardia.

Usually has sinus bradycardia or sinus pauses at the termination of AF because of sinus node dysfunction.

Rate-slowing drugs are used to treat the “tachy” component, but will actually make the “brady” component worse. Patients often need a permanent pacemaker to manage the brady component.

Question 7

Symptoms of AF / AFL

Answer 7

Palpitation, dyspnea, and fatigue in response to the ventricular response being too fast, the ventricular response being irregular, and the loss of atrial kick.

Many patients present with no symptoms at all.

Question 8

Consequences of AF / AFL

Answer 8

Stroke

Pulmonary embolism is NOT caused by AF / AFL, however a pulmonary embolism can cause AF / AFL.

Question 9

Physical Findings of AF

Answer 9

Irregularly irregular pulse and volume.

Variable intensity of the first heart sound.

S4 is impossible, as there is no atrial kick.

Question 10

Treatment of AF / AFL

Answer 10

Consider anticoagulation

Consider underlying causes

Consider rate control or rhythm control

Question 11

CHA₂DS₂ VASc Score

Answer 11

C = CHF/LV Dysfunction = 1 pt

H = HTN = 1 pt

A = Age > 75 = 2 pt

D = DM = 1 pt

S = Stroke/TIA = 2 pt

V = Vascular = 1 pt

A = Age 65-75 = 1 pt

Sc = Sex category = Female = 1 pt

Question 12

Rate Control

Answer 12

Let AF happen when it happens or let it be permanent, just make sure the ventricular response to AF isn’t too fast.

This can be accomplished through the use of beta-blockers, calcium channel blockers, or digoxin (not by itself).

Question 13

Rhythm Control

Answer 13

Prevent AF and maintain normal sinus rhythm.

Can be done through the use of anti-arrythmic drugs (AAD’s).