Atrial fibrillation with rapid ventricular response

Atrial Fibrillation with Rapid Ventricular Response (afib with RVR) is a type of abnormally fast heart rate (tachyarrhythmia) that may present as a medical emergency. It may be considered a form of supraventricular tachycardia(SVT). It is characterized by chaotic atrial activity known as atrial fibrillation with an associated rapid heart rate of greater than 100 beats per minute.

Patient Population

Afib with RVR occurs almost exclusively in adults, as atrial fibrillation is rare in children.

ymptoms

Presentation is similar to other forms of rapid heart rate (tachycardia), and in some cases may actually be asymptomatic.

The patient may complain of palpitations or chest discomfort.

The rapid heart rate may result in the heart being unable to provide adequate blood flow and oxygen delivery to the rest of the body, a condition which is technically considered heart failure.

Therefore, common symptoms may include shortness of breath which often worsens with exertion (dyspnea on exertion), shortness of breath when lying flat (orthopnea), and sudden onset of shortness of breath during the night (paroxysmal nocturnal dyspnea), and may progress to swelling of the lower extremities (peripheral edema).

Due to inadequate blood flow, patients may also complain of light-headedness, may feel like they are about to faint (presyncope), or may actually lose consciousness (syncope).

igns

The patient may be in significant respiratory distress.

Due to inadequate oxygen delivery, the patient may appear blue (cyanosis).

By definition, the heart rate will be greater than 100 beats per minute. Blood pressure will be variable, but is most concerning if lower than usual, as hypotension may be developing. Respiratory rate will be increased in the presence of respiratory distress. Pulse oximetry may confirm the presence of hypoxia.

Examination of the jugular veins may reveal elevated pressure (jugular venous distention).

Lung exam may reveal rales or crackles, which are suggestive of pulmonary edema.

Heart exam will reveal an irregularly irregular but rapid rhythm.

Diagnosis

Other forms of tachyarrhythmia must be ruled-out, as some may be immediately life threatening, such as ventricular tachycardia. While most patients will be placed on continuous cardiorespiratory monitoring, an electrocardiogram (EKG) is essential for diagnosis.

Atrial fibrillation will be present, characterized as chaotic electrical activity between QRS complexes. However, this may be difficult to determine if the rate is extremely rapid.

QRS complexes should be narrow, signifying that they are initiated by normal conduction of atrial electrical activity through the intraventricular conduction system. Wide QRS complexes are worrisome for ventricular tachycardia, although in cases where there is disease of the conduction system, wide complexes may be present in afib with RVR.

The R-R interval will likely be irregular.

Provoking causes should be sought out. A common cause of any tachycardia is dehydration, as well as other forms of hypovolemia. Acute coronary syndrome should be ruled out. Intercurrent illness such as pneumonia may be present.

Treatment

The primary goal is to reduce the heart rate so that cardiac function is restored.

Symptomatic patients may benefit from intravenous (IV) rate-controlling agents, either calcium-channel blockers or beta-adrenergic blockers.A patient with hemodynamic instability, mental status changes, preexcitation, or angina will require urgent synchronized DC cardioversion.