Cor triatriatum : Echocardiographic error in diagnosisAS Vengsarkar, JJ Dalal, AV Katdare, S Bhattacharya, KG Nair
Department of Cardiology and Thoracic Surgery, K.E.M. Hospital and Seth G. S. Medical College, Parel, Bombay-400 012, India
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 529184
Source of Support: None, Conflict of Interest: None
Echocardiographic features in a sixteen year old female patient with primary pulmonary hypertension, and a persistent left superior vena cava draining into the coronary sinus are discussed; they led to a false positive diagnosis o f an infra-aerial fibromuscular membrane (cor triatriatum)
Cor triatriatum is a rare congenital heart malformation in which the left atrium is subdivided into a proximal and a distal chamber. 
Echocardiographic features of cor triatriatum have been reported both in the M-mode, ,,, as well as in the real time two dimension technique . 
This report relates to a patient in whom a false positive diagnosis of cor triatriatum was made mainly on the basis of Mmode echocardiography.
Miss R.S., a 16 year old school girl presented with complaints of marked exertional dyspnoea and palpitations of one years' duration.
On general examination, she was found to have a regular pulse rate of 85/min. and a blood pressure of 120/76 mm Hg. There was no cyanosis or clubbing. There were prominent `a' waves in the jugular venous pulse. Precordial examination revealed the apex beat in the 5 th left intercostal space within the midclavicular line. A significant right ventricular lift was present. At auscultation, a grade 2/6 ejection systolic murmur along with a very loud P2 was heard in the pulmonary area.
The electrocardiogram showed a QRS axis of + 120° with marked right ventricular hypertrophy.
The X-ray showed a normal sized heart with a prominent main pulmonary artery and pulmonary venous congestion (See [Figure 1] on page 23213). The left atrium was not enlarged.
The cardiac catheterization data are depicted in [Table 1]. The presence of a left superior vena cava draining into the coronary sinus and an anomalous pulmonary vein entering the right atrium was detected by catheter passage.
The echocardiogram in M-mode (See [Figure 2] on page 232B), in the base apex scan showed presence of an abnormal echo in the left atrium. It was an intense uninterrupted linear echo situated midway between the anterior and posterior limits of the left atrium; it made its appearance in the downward scan behind the inferior part of the aortic root and continued in the lower region of the left atrium behind the mitral valve echo, but separated from it by a distance of 7 mm. in systole. This echo moved anteriorly in diastole and posteriorly in systole resembling atrioventricular valve movement. The excursion of movement measured 9 mm. The left atrial dimension (20 mm) was normal for the age and bodyweight; the anterior mitral leaflet echoes were normal and the EF slope was 75 mm/sec; however the posterior mitral leaflet was not discernible.
At surgery no evidence of cor triatriatum was detected.
There are reports in the literature ,,, which underline the importance of echocardiography in differentiating the various lesions causing pulmonary venous obstruction.
This case report relates to a patient who had severe pulmonary hypertension with the chest X-ray suggesting pulmonary venous obstruction. Partial opacification of the left atrium in the angiogram, due to severe pulmonary vascular disease was erroneously interpreted as suggestive of cor triatriatum (See [Figure 3] on page 232B). This diagnosis was mainly entertained however on account of the intense, easily recorded linear echo in the left atrium. An abnormal uninterrupted linear echo in the left atrium with a motion pattern associated with the mitral valve echo similar to our case has been reported in cor triatriatum  The abnormal echo was thought to originate from an intra-atrial membrane as it moved with atrial events, for the same reason it was not attributed to the persistent left superior vena cava. The standard beam angulation ruled out linear intra-atrial echoes observed at times in healthy subjects. 
While submitting this report we have come across an excellent documentation of material of similar nature by Orsmond et al  the authors have conclusively proved that such echoes originate from the coronary sinus by using contrast echocardiography after saline injection. Our findings appear similar to them.
We are thankful to Dr. C. K. Deshpande, Dean, K.E.M. Hospital for allowing us to publish this material.
[Figure 1], [Figure 2], [Figure 3]