Sinus Node Reentry

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Heart rate 100–160 bpm

• Each QRS preceded by a P wave identical with the P wave of normal sinus rhythm

• Abrupt onset and termination

• Organic heart disease in many patients

GENERAL CONSIDERATIONS

• Accounts for less than 5% of supraventricular tachycardia

• Reentry uses the sinus node or perinodal tissue

• Heart rate similar to that in sinus tachycardia

• Longitudinal dissociation as seen in atrioventricular node may be substrate for reentry in the sinoatrial node

• This tachycardia is not physiologic unlike sinus tachycardia

• Tachycardia is precipitated by an ectopic beat and exhibits characteristics of a reentry circuit

• The arrhythmia can be acutely terminated by adenosine, verapamil, or carotid sinus massage

• The tachycardia may be induced in the electrophysiologic lab with premature atrial stimuli or burst pacing

• May be an incidental arrhythmia during a study for another diagnosis

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Palpitations

• Dyspnea

PHYSICAL EXAM FINDINGS

• Depends on precipitating cause

• Elevated jugular venous pressure

• S₃

DIFFERENTIAL DIAGNOSIS

• Sinus tachycardia

• Inappropriate sinus tachycardia

• Atrial tachycardia

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• CBC

• Thyroid-stimulating hormone

ELECTROCARDIOGRAPHY

• ECG to document rhythm disorder

• Holter monitoring to determine frequency

IMAGING STUDIES

• None required

• Echocardiogram for underlying myocardial disease

DIAGNOSTIC PROCEDURES

• Electrophysiologic study to confirm mechanism and determine suitability for ablation

TREATMENT

CARDIOLOGY REFERRAL

• If the tachycardia is precipitating recurrent heart failure, then electrophysiology referral recommended

HOSPITALIZATION CRITERIA

• Symptomatic patients may require hospitalization for control with medications or ablation

MEDICATIONS

• Digoxin and calcium channel blockers are the most useful drugs

• Beta blockers may not be very useful

THERAPEUTIC PROCEDURES

• Radiofrequency ablation is usually curative

SURGERY

• Generally not required

MONITORING

• ECG monitoring if hospitalized

DIET AND ACTIVITY

• Depends on underlying heart disease

ONGOING MANAGEMENT

HOSPITAL DISCHARGE CRITERIA

• Symptomatic stability

FOLLOW-UP

• Depends on underlying heart disease

COMPLICATIONS

• Exacerbations of heart failure

PROGNOSIS

• Depends on underlying heart disease

RESOURCES

PRACTICE GUIDELINES