From the Guidelines
Investigations for tachycardia should begin with a thorough history and physical examination, followed by an electrocardiogram (ECG) to document the heart rhythm and rate, and may include additional tests such as echocardiography, ambulatory 24-hour Holter recording, event or wearable loop recorder, and invasive electrophysiological investigation as needed. When evaluating a patient with tachycardia, it is essential to consider the clinical presentation and the frequency of episodes. According to the acc/aha/esc guidelines for the management of patients with supraventricular arrhythmias 1, an echocardiographic examination should be considered in patients with documented sustained SVT to exclude the possibility of structural heart disease. The choice of additional investigations depends on the frequency and severity of symptoms. For example:
- An ambulatory 24-hour Holter recording can be used in patients with frequent but transient tachycardias 1.
- An event or wearable loop recorder is often more useful than a 24-hour recording in patients with less frequent arrhythmias 1.
- Implantable loop recorders may be helpful in selected cases with rare symptoms associated with severe symptoms of hemodynamic instability 1.
- Invasive electrophysiological investigation with subsequent catheter ablation may be used for diagnoses and therapy in cases with a clear history of paroxysmal regular palpitations 1. It is crucial to tailor the investigation strategy to the individual patient, taking into account the clinical presentation, the frequency and severity of symptoms, and the potential risks and benefits of each test.
From the Research
Investigations for Tachycardia
The following investigations are used to diagnose and manage tachycardia:
- A 12-lead electrocardiogram (ECG) to document the tachycardia and classify it according to its regularity and QRS width 2
- Analysis of the surface ECG to identify characteristics such as AV dissociation, negative or positive concordant pattern in V(1)-V(6), and a notch in V(1) to differentiate between supraventricular and ventricular tachycardia 3
- Evaluation of the QRS complex characteristics to suggest the origination site of ventricular tachycardia 4
- Electrocardiogram (ECG) to diagnose supraventricular tachycardia, including evaluation of heart rate, P wave axis, PR and RP interval, and presence or absence of AV block 5
- A systematic approach to the 12-lead ECG to diagnose the difference between ventricular and supraventricular tachycardia, and to diagnose the mechanism and site of origin of the supraventricular tachycardia 6
Diagnostic Techniques
Additional diagnostic techniques may be used to evaluate patients with tachycardia, including:
- Echocardiogram
- Holter monitoring
- Stress test
- Electrophysiologic evaluation (rarely performed for diagnostic purpose)
- Trans-esophageal atrial stimulation (less invasive than intracardiac evaluation) 5
Documentation of Tachycardia
If a tachycardia is not documented, a careful history of the palpitations should be taken to see if further monitoring and investigations are required 2