Rare diseases · Sign or symptom

Atrial fibrillation

Quivering upper heart chambers resulting in irregular heartbeat

HP:0005110

What it means

An atrial arrhythmia characterized by disorganized atrial activity without discrete P waves on the surface EKG, but instead by an undulating baseline or more sharply circumscribed atrial deflections of varying amplitude an frequency ranging from 350 to 600 per minute.

The ventricular response to atrial fibrillation is irregularly irregular because of the large number of atrial impulses that transit the atrioventricular node, making the ventricle partially refractory to further impulses. Atrial fibrillation can cause a number of manifestations including excessive ventricular response with angina pectoris or hypotension in susceptible individuals, syncope, systemic embolization, fatigue, or anxiety. These features should be coded separately.

In everyday care

Most people with this sign do not have a rare disease — it appears in common conditions far more often. These general reference pages cover the same topic:

Rare diseases that can present with this26

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Atrial fibrillation

Tracking symptoms like this for someone? Eleplan keeps symptoms, diagnoses, medications and every specialist in one plan.

Start free with Eleplan

This page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.