II. Definition
- Form of Supraventricular Tachycardia (60% of cases) in which reentry occurs within the AV Node
- AV Node in AVNRT contains two pathways (one slow and one fast)
III. Epidemiology
- Most common in young women
- Typically there is no underlying structural heart disease
- Increased onset with low Estrogen and high Progesterone states
- Luteal Phase of Menstrual Cycle (after Ovulation)
- Less common during pregnancy
IV. Findings: General
- Heart Rate typically 160 to 190 (up to 260)
- P Waves are often hidden within the QRS (or appear immediately after the QRS)
V. Types: Typical (slow/fast) - 90% of AVNRT
- Course
- Starts with PAC passed down slow accesory path
- Signal travels retrograde up fast path
- Signal cycles back down slow accesory pathway
- EKG findings
- PR interval > RP Interval
- Negative P Waves in III and avF
VI. Types: Atypical (fast/slow) - 10% of AVNRT
- Course: Reverse of typical pathway
- EKG findings
- PR interval < RP Interval
- Pseudo-S Wave in leads I, II, aVF
VII. Symptoms
- Regular, rapid, pounding sensation in the neck (pathognomonic, LR+ 177)
- Provocative
- Standing up, after bending over
- May occur while lying supine in bed
VIII. Signs
- Visible neck pulsations (LR+ 2.7)
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| Concepts | Finding (T033) |
| ICD10 | I47.1 |
| English | Atrioventricular re-entrant (nodal) tachycardia [AVNRT] [AVRT] |
