Atrial Cardiomyopathy

Atrial cardiomyopathy (ACMP) is a structural, electrical, or contractile disorder of the atria that may lead to clinical manifestation. ACMP may manifest as:

Atrial fibrillation (AF) – most commonly
Premature atrial contractions
Atrial tachycardia
Thromboembolism

ACMP creates the substrate (trigger and substrate) for atrial fibrillation (AF):

The trigger manifests as atrial arrhythmias (premature beats, salvos, short episodes of atrial tachycardia). The trigger may initiate an episode of AF if a substrate is present.
The substrate manifests as an episode of AF initiated by a trigger.

Atrial cardiomyopathy
Atrial cardiomyopathy (ACMP) is a structural, electrical, or contractile disorder of the atria that may lead to clinical manifestation. ACMP most commonly manifests as atrial fibrillation.

ACMP develops due to risk factors: age, arterial hypertension, obesity, heart failure, alcohol, AF.

Rarely, it may develop on a genetic basis.

If AF occurs in young individuals (<45 years) without risk factors and without structural heart disease, the substrate for AF most likely developed due to ACMP of genetic origin.

ACMP is present in

90% of patients with AF
30–40% of patients with cryptogenic stroke
5–10% of the population aged >65 years

ACMP has 3 stages

Subclinical ACMP
Clinical ACMP
Advanced ACMP

Illustration comparing atrial cardiomyopathy with healthy atria, depicting atrial structural and tissue remodeling associated with atrial fibrillation.

Atrial cardiomyopathy and atrial fibrillation
Stage of ACMP	Atrial changes (structural, mechanical, electrical)	Clinical manifestation of ACMP
1. Subclinical ACMP	Minimal structural atrial changes (CMR) Mildly reduced atrial electrical activity (EPS) Normal atrial size (TTE, CMR)	No clinical manifestation
2. Clinical ACMP	More pronounced structural atrial changes (CMR) Reduced atrial electrical activity (EPS) Atria may be enlarged (TTE, CMR) ECG signs of ACMP	Premature atrial contractions Paroxysmal AF Atrial tachycardia Atrial flutter
3. Advanced ACMP	Severely reduced LA EF <35% (TEE, CMR) LAA emptying velocity <20 cm/s (TEE) Enlarged left atrium >5 cm (TTE) ECG signs of ACMP	Persistent AF Permanent AF

The examinations that demonstrate the given pathological atrial change are indicated in parentheses.
ACMP – Atrial cardiomyopathy, CMR – Cardiac magnetic resonance imaging, EPS – Electrophysiological study, TTE – Transthoracic echocardiography, ECG – Electrocardiography, EF – Ejection fraction, TEE – Transesophageal echocardiography, LA – Left atrium, AF – Atrial fibrillation, LAA – Left atrial appendage

Diagram of atrial cardiomyopathy illustrating ECG features including a deep terminal negative P wave in V1, prolonged P wave duration over 120 ms, and biphasic P waves in leads II, III, and aVF.

ECG changes in clinical or advanced ACMP (in sinus rhythm):

Deep terminal negative P wave (V1)
P-wave duration >120 ms
Biphasic P wave (II, III, aVF) – due to intra-atrial block or Bachmann’s bundle block