Right atrial enlargement (RAE) is a form of
cardiomegaly, or heart enlargement. It can broadly be classified as either right atrial hypertrophy (RAH), overgrowth, or dilation, like an expanding balloon. Common causes include
pulmonary hypertension, which can be the primary defect leading to RAE, or pulmonary hypertension secondary to
tricuspid stenosis;
pulmonary stenosis or
Tetralogy of Fallot i.e. congenital diseases; chronic lung disease, such as
cor pulmonale. Other recognised causes are:
right ventricular failure,
tricuspid regurgitation, and
atrial septal defect.[1] Right atrial enlargement (RAE) is clinically significant due to its prevalence in diagnosing supraventricular arrhythmias. Further, early diagnosis using risk factors like RAE may decrease mortality because patients with RAE are at 9x more risk of arrhythmias and other cardiac conditions compared to their healthy counterparts.[2]
Most authors have classified this condition as congenital, but the etiology is still unknown.[3]
Diagnosis
Right Atrial Enlargement (RAE) increases the
p wave, representing
atrial depolarization, on an ECG to an amplitude > 2.5mm in lead II, an abnormality referred to as p-pulmonale, likely due to weakened right atrial
myocardium close to the
Sinoatrial (SA) node.[4]
ECG criteria for RAE:P wave amplitude in lead II > 2.5 mm and upward deflection of the P wave in lead V1 > 1.5 mm in amplitude.[5]
Large "a" waves on the
JVP waveform can also aid in diagnosis.
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abTerada, Tadashi; Oiwake, Hisanori; Nakanuma, Yasuni; Ohta, Goroku; Nishino, Tomoichi (1988). "An Autopsy Case of Idiopathic Enlargement of the Right Atrium, and a Review of the Literature". Pathology International. 38 (3): 361–370.
doi:
10.1111/j.1440-1827.1988.tb02308.x.
ISSN1320-5463.
PMID2969171.
S2CID41759734.