From the Guidelines
Act aberrancy is a phenomenon where an electrical impulse travels through an accessory pathway, bypassing the normal conduction system, and is commonly seen in patients with Wolff-Parkinson-White syndrome, requiring management based on symptom severity, including observation, antiarrhythmic medications, or catheter ablation, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Definition and Diagnosis
Act aberrancy refers to an unexpected change in the normal conduction pattern of electrical impulses through the heart, typically occurring when an electrical impulse travels through an accessory pathway instead of following the normal conduction system. This can be diagnosed through electrocardiogram (ECG) findings, including a shortened PR interval, widened QRS complex, and the presence of a delta wave. The 2015 ACC/AHA/HRS guideline defines supraventricular tachycardia (SVT) as an umbrella term used to describe tachycardias, including atrial and/or ventricular rates in excess of 100 bpm at rest, with mechanisms involving tissue from the His bundle or above 1.
Management
Management of act aberrancy depends on symptom severity and may include:
- Observation for asymptomatic patients
- Antiarrhythmic medications, such as beta-blockers (e.g., metoprolol 25-100 mg twice daily) or calcium channel blockers (e.g., diltiazem 120-360 mg daily), for mild symptoms
- Catheter ablation for severe or refractory cases, with a success rate of approximately 95% and considered curative 1 Patients with act aberrancy should avoid medications that enhance conduction through accessory pathways, such as digoxin and verapamil, as these can precipitate dangerous arrhythmias in certain conditions.
Key Considerations
- The 2015 ACC/AHA/HRS guideline provides recommendations for the management of adult patients with supraventricular tachycardia, including those with act aberrancy 1
- The guideline defines various types of SVT, including paroxysmal supraventricular tachycardia (PSVT), atrial fibrillation (AF), and atrial tachycardia (AT) 1
- Catheter ablation is a highly effective treatment option for patients with act aberrancy, with a high success rate and considered curative 1
From the Research
Act Aberrancy and Beta-Blockers
- Act aberrancy refers to abnormal heart rhythms, which can be treated with beta-blockers, a class of antiarrhythmic drugs 2, 3, 4
- Beta-blockers work by reducing the influence of the sympathetic nervous system on the heart, acting negatively inotropic, chronotropic, bathmotropic, and dromotropic 2
- They are commonly used to control the ventricular rate in patients with atrial fibrillation, the most common arrhythmia 2
Types of Beta-Blockers
- Beta-blockers can be selective or non-selective, blocking either β1 or β2 adrenergic receptors, or both 3
- Examples of beta-blockers include propranolol, metoprolol, and carvedilol, each with unique properties and effects 2, 3
- Carvedilol, for example, is a non-selective beta-blocker with antioxidant properties and the ability to inhibit alpha(1)-receptors and endothelin 3
Clinical Effects of Beta-Blockers
- Beta-blockers have been shown to reduce the incidence of sudden cardiac death, prolong survival, and ameliorate symptoms caused by arrhythmias in patients with cardiac disease 3, 4
- They have also been found to have anti-arrhythmic effects, extending beyond ventricular tissue to encompass atrial cells and helping to maintain sinus rhythm in patients with atrial fibrillation 3