Typical features of supraventricular tachycardias (SVTs)*5,6
| Type of SVT | Mechanism | Heart rate, beats/min | Rhythm | ECG findings | Rate of termination with adenosine | Use of anticoagulation | Response to catheter ablation |
|---|---|---|---|---|---|---|---|
| AVNRT | AV re-entry involving 2 functional pathways in the AV node | 150–250 | Regular | Retrograde P wave after QRS complex | 78%–96% | No | Acute success rate 96%–97%; recurrence rate 5% |
| AVRT | Re-entry involving AV node and accessory pathway | 150–250 | Regular | Retrograde P wave after QRS complex | 78%–96% | No | Acute success rate 93%; recurrence rate 8% |
| Atrial tachycardia | Ectopic atrial focus with enhanced automaticity | 150–250 | Regular or irregular (if variable AV block) | Ectopic P wave before QRS complex | Unlikely to terminate; may unmask underlying rhythm | No | Acute success rate 80%–100%; recurrence rate 4%–27% |
| Atrial flutter | Macro–re-entrant circuit (typically in the right atrium) | 150 | Regular or irregular (if variable AV block) | Atrial flutter wave with 2:1 conduction block or variable conduction block | Unlikely to terminate; may unmask underlying rhythm | Yes if age ≥ 65 yr or CHADS2 score ≥ 1 (CCS guideline35) | Typical: acute success rate 97%; recurrence rate 10% Atypical: acute success rate 73%–100%; recurrence rate 7%–53% |
Note: AV = atrioventricular, AVNRT = atrioventricular nodal re-entrant tachycardia, AVRT = atrioventricular re-entrant tachycardia, CCS = Canadian Cardiovascular Society, CHADS2 score = score counts 1 point for history of congestive heart failure, hypertension, age ≥ 75 years or diabetes mellitus, and 2 points for previous stroke or transient ischemic attack, ECG = electrocardiogram.
↵* Typical features are summarized for each arrhythmia; however, different heart rates and atrioventricular conduction patterns are possible. The information in this table stems from multiple observational studies and registries.