From the Guidelines
A tachycardia workup should begin with a thorough history and physical examination, followed by an ECG to determine the type of tachycardia, as recommended by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. The ECG is crucial in determining the type of tachycardia, which can be narrow-complex or wide-complex, and regular or irregular.
- For narrow-complex tachycardias, vagal maneuvers may be attempted first, followed by medications like adenosine (6-12mg IV), beta-blockers (metoprolol 5mg IV or 25-100mg orally twice daily), or calcium channel blockers (diltiazem 0.25mg/kg IV or 120-360mg orally daily) 1.
- For wide-complex tachycardias, the management depends on the patient's stability, and immediate DC cardioversion is recommended for hemodynamically unstable patients 1. Additional diagnostic tests may include:
- Laboratory tests, such as complete blood count, electrolytes, thyroid function tests, and cardiac enzymes, to identify underlying causes.
- Echocardiogram to assess cardiac structure and function.
- Holter or event monitoring for intermittent symptoms.
- Exercise stress testing. For persistent or concerning tachycardias, electrophysiology studies may be necessary. Treatment depends on the specific type and cause of tachycardia, and long-term management may include catheter ablation for recurrent episodes or implantable cardioverter-defibrillators for life-threatening arrhythmias 1. The workup is essential because tachycardia can result from various conditions, including cardiac disease, electrolyte abnormalities, hyperthyroidism, anemia, or medication effects, and proper identification of the underlying cause guides appropriate treatment 1.
From the FDA Drug Label
Verapamil Hydrochloride Injection, USP is indicated for the following: • Rapid conversion to sinus rhythm of paroxysmal supraventricular tachycardias, including those associated with accessory bypass tracts (Wolff-Parkinson-White [W-P-W] and Lown-Ganong- Levine [L-G-L] syndromes). • Temporary control of rapid ventricular rate in atrial flutter or atrial fibrillation except when the atrial flutter and/or atrial fibrillation are associated with accessory bypass tracts (Wolff-Parkinson-White (W-P-W) and Lown-Ganong-Levine (L-G-L) syndromes)
The initial workup for tachycardia may involve the use of verapamil to convert paroxysmal supraventricular tachycardias to normal sinus rhythm or to control rapid ventricular rate in atrial flutter or fibrillation, as stated in the drug label 2.
- Key considerations for the use of verapamil include:
- Attempting vagal maneuvers prior to administration
- Monitoring for potential adverse responses, such as rapid ventricular rate or marked hypotension
- Using the medication in a treatment setting with monitoring and resuscitation facilities, if possible.
From the Research
Tachycardia Workup
- The initial evaluation of a patient with suspected tachycardia should include a comprehensive history and physical examination, as well as electrocardiography (ECG) to document the tachycardia and classify it according to its regularity and QRS width 3.
- The history is important to elicit episodic symptoms because physical examination and ECG findings may be normal 4.
- A Holter monitor or event recorder may be needed to confirm the diagnosis of supraventricular tachycardia (SVT) 4, 5.
Diagnosis of Supraventricular Tachycardia
- SVT refers to rapid rhythms that originate and are sustained in atrial or atrioventricular node tissue above the bundle of His 4.
- The most common types of SVT include atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and atrial tachycardia 4, 5, 6.
- Presenting symptoms of SVT may include palpitations, light-headedness, chest discomfort, anxiety, dyspnea, or fatigue 4, 5.
Management of Supraventricular Tachycardia
- Vagal maneuvers may terminate the arrhythmia, and if this fails, adenosine is effective in the acute setting 4, 6.
- Calcium channel blockers (diltiazem or verapamil) or beta blockers (metoprolol) can be used acutely or as long-term therapy 4.
- Catheter ablation has a high success rate and is recommended as the first-line method for long-term management of recurrent, symptomatic paroxysmal SVT, including Wolff-Parkinson-White syndrome 4, 5, 6.