AV Nodal Block in Atrial Flutter

How to use it

1. 1

   Identify atrial rate. Flutter waves (sawtooth) typically 250–350 bpm. Measure F-F interval.

2. 2

   Count AV ratio. Identify QRS relative to flutter waves. 2:1 = every other flutter wave conducts (most common, HR ~150 bpm from flutter rate 300).

3. 3

   Rate control. Target HR <80 bpm at rest. AV nodal agents: metoprolol, verapamil, diltiazem, digoxin.

When to use it

ECG interpretation of regular SVT at 150 bpm

Flutter with 2:1 block is the classic cause. Look for flutter waves in V1, II, III, aVF if not obvious.

Rate control titration

Increasing AVB ratio (2:1 → 4:1) with AV nodal agents.

Pre-cardioversion

Rhythm control (cardioversion or ablation) is preferred for flutter — rate control often inadequate long-term.