1Department of Cardiology, S. Chiara Hospital, Trento, Italy
2Department of Physics, University of Trento and ITC Trento, Trento, Italy
3Department of Radiology, S. Chiara Hospital, Trento, Italy
4Laboratory of Molecular Diagnostics, Transplant Area, IRCCS Policlinico San Matteo, Pavia, Italy
* Corresponding author. E-mail address: mpasotti72{at}yahoo.it
A 62-year-old woman came to our clinical attention 21 years ago for non-cardiac problems. The clinical evaluation disclosed a persistent idiopathic atrial standstill (PIAS) with mitral incompetence. The family screening documented a familial form of PIAS with three affected living relatives. During the follow-up, she developed a cerebral thrombo-embolic episode and, 12 years after the diagnosis, she underwent permanent electrical stimulation (VVIR). She is currently in NYHA functional class II. Last echocardiographic study showed slightly increased right and left ventricular end-diastolic diameters (30 and 63 mm, respectively), conserved left ventricular ejection function (62%), significant mitral and tricuspid regurgitation, and increased systolic pulmonary artery pressure (55 mmHg). Three-dimensional segmentation of cardiac cavities was achieved by semiautomatic analysis of tomographic multi-slice images (MX 8000 IDT® Philips Medical System). Accurate measurements of atrial and ventricular volumes demonstrated an enormous bi-atrial enlargement (more evident than by echocardiography) and slightly increased ventricular volumes. Specifically, the volume of the right atrium (744 mL) was double that of the left atrium (426 mL), three times larger than the right ventricle (252 mL), and five times larger than the left ventricle (138 mL).
At the top, targeted maximum intensity projection slabs of computed tomography data depict the anomalous size of right and left atria. (A) Transversal and (B) sagittal sections. At the bottom, (in C and D), a semiautomatic segmentation procedure was applied to the computer tomographic data to separate the internal volume of the different cardiac chambers and vascular structures, thus highlighting the enlargement of the right and left atria. Coloured surface-rendered inner surfaces of these districts are shown in the epicardial views. (C) Left anterior and cranial tilts and (D) anteroposterior view. Volumes of ventricular and atrial chambers, estimated on the basis of segmented images, demonstrate the increased size of the atria and the abnormal proportion between atrial and ventricular volumes.
Right atrium (RA), left atrium (LA), right ventricle (RV), left ventricle (LV), pulmonary arteries (PA), ascending aorta (AA), and superior vena cava (SVC).