Rapid Ventricular Response Begins
Atrial fibrillation lets chaotic impulses flood the AV node.
- 400-600: Atrial rate (fibrillatory waves/min)
- >150: Ventricular rate (beats per minute)
- Irregular: Rhythm (irregularly irregular)
- Sudden: Onset (often abrupt symptomatic)
Why the ventricles race
Placeholder: AV node conducts too many chaotic atrial impulses through.
Palpitations and Breathlessness Emerge
Patients notice pounding, fluttering, and air hunger quickly.
- Common: Palpitations (felt as fluttering chest)
- Progressive: Dyspnea (worsens with rate)
- Frequent: Fatigue (reduced exertion tolerance)
- Elevated: Anxiety (symptom-driven distress)
Symptom drivers
Placeholder: irregular rapid beats reduce perfusion and oxygen delivery.
Diastole Shrinks as Rate Climbs
Faster rates shorten filling time before each contraction.
- Shortened: Filling time (less diastole per cycle)
- Reduced: Preload (less venous return time)
- Lost: Atrial kick (no coordinated contraction)
- Falling: Stroke volume (beat-to-beat variability)
Filling mechanics
Placeholder: shortened diastole plus lost atrial kick cuts filling volume.
Blood Pressure and Output Decline
Falling stroke volume drags cardiac output and pressure down.
- Dropping: Blood pressure (systolic trending low)
- Impaired: Cardiac output (rate x volume falls)
- Reduced: Perfusion (end-organ stress rising)
- Limited: Compensation (reserve-dependent)
Output math
Placeholder: cardiac output falls when stroke volume drops faster than rate rises.
Instability Demands Rate or Rhythm Control
Unstable patients need urgent cardioversion or rate control.
- Present: Instability signs (hypotension, dyspnea, dizziness)
- Considered: Cardioversion (if unstable urgently)
- Beta-blocker/CCB: Rate control (first-line stable cases)
- Assessed: Anticoagulation (stroke risk review)
Treatment path
Placeholder: unstable AFib with RVR triggers urgent rate or rhythm control.
Placeholder: urgent electrical cardioversion is considered when instability is severe.