Atrial arrhythmia in the critically ill patients

Sherif H Zaky, MD

Professor of critical care medicine,

Cairo University

Emergency medicine and critical care are fields that

often require rapid diagnosis and intervention for

specific situations.

cardiac arrhythmias in intensive care are not only

common ,but can be life threatening or a clue to

more serious prognosis.

AF in The ICU

The purpose of this presentation is to summarize

Atrial tachyarrhythmias in the ICU and strategies

for their management.

AF in The ICU

We mean by atrial tachyarrhythmias ;

Frequent premature atrial ectopies

Atrial tachycardia.

Atrial flutter, and

Atrial fibrillation.

AF in The ICU

Why critically ill ? Structural heart disease

Pulmonary diseases ( hypoxia, acidosis, 2ry pulmonary HTN)

Electrolyte imbalance (K+, Mg+2)

Incidence with sepsis as high as 45% ( Cytokines ?).

AF in The ICU

Atrial Fibrillation: Cardiac Causes Hypertensive heart disease

Ischemic heart disease

Valvular heart disease

Rheumatic: mitral stenosis

Non-rheumatic: aortic stenosis, mitral regurgitation

Pericarditis

Cardiac tumors: atrial myxoma

Sick sinus syndrome

Cardiomyopathy

Hypertrophic

Idiopathic dilated (? cause vs. effect)

Post-open heart surgery

AF in The ICU

Atrial Fibrillation: Non-Cardiac Causes Pulmonary

COPD

Pneumonia

Pulmonary embolism

Metabolic

Thyroid disease: hyperthyroidism

Electrolyte disorder

Septicemia.

AF in The ICU

“Lone” Atrial Fibrillation Absence of identifiable cardiovascular,

pulmonary, or associated systemicdisease

Approximately 0.8 - 2.0% of patients with atrialfibrillation (Framingham Study).

In one series of patients undergoing electrical cardioversion, 10% had lone AF.

1 Brand FN. JAMA. 1985;254(24):3449-3453.2 Van Gelder IC. Am J Cardiol. 1991;68:41-46.

AF in The ICU

AF in The ICU

Most common arrhythmia requiring hospitalization.

Structural changes

• Left atrium and left atrial appendage enlargement.

• Reduced atrial contractility.

• Decrease in cardiac output (loss of AV synchrony and

rapid ventricular rate.)

• Histologic: cardiomyocyte degeneration.

• Increased propensity for clot formation.

Electrophysiologic background

Shortening of atrial refractory periods

Loss of normal adaptation of atrial refractoriness to

heart rate.

Longer duration of AF results in shorter AF intervals

“AF begets AF” (electric remodeling)

AF in The ICU

Management :

I) Rhythm control

Intravenous amiodarone (150 mg IV) in the

treatment of critically ill patients with recent-

onset atrial fibrillation, there are an increasing

number of reports highlighting occasional

serious acute pulmonary toxicity.

AF in The ICU

Ibutilide (1 mg IV; in the case of persisting

arrhythmia and body weight > 70 kg, has a

71% conversion rate with adjustment of

magnesium level and high normal K+ level.

AF in The ICU

II) Rate control :

According to the AFFIRM and the RACE studies

, Lower mortality and hospitalizations are

documented with rate control rather than

rhythm control.

AF in The ICU

Digoxin may be helpful for rate control, with an initial dose of 0.5 mg. After 30 minutes, 0.25 mg should be administered again.

verapamil (5 to 10 mg IV)

diltiazem (20 mg IV)

AF in The ICU

Beta-blockade

Propranolol (1 to 5 mg IV, additional infusion of 10 to 120 mgper day) and

Esmolol (500 µg/kg over 1 minute, followed

by a 4-minute maintenance infusion of 50 µg/kg/min

with further dose adjustment as necessary)

AF in The ICU

In one study done on critically ill ,60 patients

with atrial tachy-arrhythmias (atrial fibrillation

57 patients, atrial flutter 2 patients, atrial

tachycardia 1 patient)

The primary end-point was a >30% heart rate

reduction within 4 hours.

The secondary endpoint was a heart rate <120

beats/min

AF in The ICU

Patients were randomized to :

diltiazem (25 mg bolus followed by a

continuous infusion of 20 mg/h for 24 hours)

(group I),

amiodarone (300 mg bolus) (group II) or

amiodarone (300 mg bolus followed by 45

mg/h for 24 hours) (group III).

AF in The ICU

The primary endpoint was achieved in

70% of group I patients, 55% of patients in group II, and in 75% of patients in group III (P = 0.38).

In patients achieving heart rate control, diltiazem showed a significantly better rate reduction when compared with group II and III (P < 0.01

AF in The ICU

AF in The ICU

Atrial tachycardia

Defined as a supraventricular tachycardia (SVT)

that does not require the atrioventricular (AV)

junction, accessory pathways, or ventricular

tissue for initiation and maintenance of the

tachycardia. Its rate varies between 150-250

BPM.

The ectopic P waves, easily

seen in this example, occur

in groups, separated by

short pauses. This is because

not all of the P waves make it

to the ventricles so, 2nd

degree AV block.

Diagnosis

The primary abnormality noted upon physical

examination is a rapid pulse rate. In most atrial

tachycardias this is regular. However, in rapid

atrial tachycardias with variable AV conduction

and in multifocal atrial tachycardia (MAT), the

pulse may be irregular.

Very Subtle Atrial Tachycardia With 2:1 Block-KH

Multifocal Atrial Tachycardia (MAT)

MAT often occurs in patients experiencing an

exacerbation of chronic obstructive pulmonary

disease, a pulmonary thromboembolism, an

exacerbation of congestive heart failure, or severe

illness especially under critical care with Inotropic

infusion or Digitalis toxicity. Abnormal thyroid

function should also be in the differential

diagnosis

ManagementCarotid sinus massage and adenosine do not

terminate the tachycardia even if they

produce a transient AV nodal block.

Electrical cardioversion is ineffective

(being equivalent to attempting electrical

cardioversion in a sinus tachycardia

Again Rate control with agents mentioned in AF

management.

However treating the primary pathology is the

main stay.

Unlike AF anticoagulation is not necessary.

Thanks