- Endocardial fibroelastosis (HP:0001706): Diffuse thickening of the ventricular endocardium and by associated myocardial dysfunction. Evidence: PCS. (OMIM:108770)
- Atrial standstill (HP:0025478): Atrial standstill or silent atrium is a rare condition presenting with the absence of electrical and mechanical activity in the atria. It presents with the absence of P waves, bradycardia, and wide QRS complex in the electrocardiogram. Evidence: PCS. Frequency: 1/1. Onset: Childhood onset (HP:0011463). (PMID:16188595)
- First degree atrioventricular block (HP:0011705): Delay of conduction through the atrioventricular node, which is manifested as prolongation of the PR interval in the electrocardiogram (EKG). All atrial impulses reach the ventricles. Evidence: PCS. (OMIM:108770)
- Atrial cardiomyopathy (HP:0200127): Any complex of structural, architectural, contractile or electrophysiological changes affecting the atria with the potential to produce clinically relevant manifestations. Evidence: TAS. (OMIM:108770)
- Ventricular escape rhythm (HP:0005155): A ventricular escape rhythm occurs whenever higher-lever pacemakers in AV junction or sinus node fail to control ventricular activation. Escape rate is usually 20-40 bpm, often associated with broad QRS complexes (at least 120 ms). Evidence: PCS. Frequency: 1/1. Onset: Childhood onset (HP:0011463). (PMID:16188595)
- Premature atrial contractions (HP:0006699): A type of cardiac arrhythmia with premature atrial contractions or beats caused by signals originating from ectopic atrial sites. Evidence: PCS. (OMIM:108770)
- Paroxysmal atrial fibrillation (HP:0004757): Episodes of atrial fibrillation that typically last for several hours up to one day and terminate spontaneously. Evidence: IEA. Frequency: 1/1. Onset: Childhood onset (HP:0011463). (PMID:16188595)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (OMIM:108770)
These phenotypes are associated with the disease atrial standstill 1 (OMIM:108770).