Echocardiographic study of left atrial myxomaJJ Dalal, AS Vengsarkar, Suman G Kinare, KG Nair
Departments of Cardiology and Pathology, K.E.M. Hospital and Seth G. S. Medical College, Parel, Bombay-400 012, India
Four cases of left atrial myxoma were diagnosed pre-operatively by echocardiography. All cases showed characteristic echocardiographic features of variegated shadows behind the mitral valve in diastole and within the left atrium in systole. In two cases the myxomas were surgically removed and confirmed on histology. In one case the post-operative echocardiogram showed complete disappearance of the abnormal shadows. Echocardiography is the most reliable method today for the diagnosis of a myxoma.
Atrial myxomas have often been considered in the diagnosis of mitral valve obstruction but rarely diagnosed clinically. Since the advent of echocardiography there has been a resurgence of interest in this rare cardiac tumor. Kirnkby and Leren  were the first to make an antemortem diagnosis of a left atria] myxoma, from variations of the symptoms with posture. In 1952 the first angiographic diagnosis was made by Goldberg and his colleagues.  Crafoord  for the first time performed a removal of the tumor in 1954. Effert and Domanig  were the first to publish an echocardiogram of a patient with a left atrial myxoma.
This is a report on the echocardiographic diagnosis of left atrial myxoma in four cases. A detailed history was recorded and physical examination, electrocardiography and roentgenography were performed in all the cases.
Echocardiograms were recorded in all four cases pre-operatively and in one case post-operatively using a diagnostic Unirad Sonograph equipment.
The transducer used was a 2.25 mHz non-focus type with a diameter of 10 mm, a penetration range of 4 to 7 cm and a pulse frequency of 1000 pulses per second.
Recordings were made on a photographic film roll 400 ASA, 120 size using a Graflex 197 A camera or on a Honey Well strip chart recorder.
Awater soluble gel was used as a coupling medium. For the location of the mitral valve the transducer was positioned in the left 3rd or 4th intercostal space with a posterior beam orientation. For the left atrial visualization the transducer was angulated medially and superiorly from the same position.
The echocardiographic criteria for the diagnosis of myxoma include:
(1) Reduction of the EF slope of the anterior mitral leaflet.
(2) Wavy echo lines posterior to the anterior mitral leaflet in diastole.
(3) Echo lines within the left atrial cavity appearing only in systole.
Phonocardiograms were recorded in all cases using a three channel NEK-1 recorder at a frequency range of 35 to 240 Hertz with suitable band pass filters. Recordings were made in the lying, sitting and standing positions.
Surgical confirmation was obtained in two cases along with a histological study.
Four cases of atrial myxoma have been studied non-invasively by echocardiography. Two of the four cases have subsequently been shown to have left atrial myxomas at surgery with pathological confirmation of the diagnosis. The other two patients have refused surgery.
Miss S.P., an 18 year old school girl was admitted with a sudden right sided hemiparesis. She had no cardiac complaints. Her pulse rate was regular and all pulsations were well felt. On ausculation, she had features of classic mitral stenosis with no evidence of change of heart sounds or murmurs with change in posture. Her ECG and X-ray chest were normal. Echocardiographic study revealed the presence of variegated shadows behind the anterior mitral leaflet and within the left atrial cavity suggestive of atrial myxoma (See [Figure 1] on page 226A).
The patient recovered from the neurological deficit and later refused surgery and took her discharge from the hospital.
About three months later she was readmitted with a complete right-sided hemiplegia. This time in addition to her- mitral stenotic murmur she also had a grade II pansystolic murmur al the apex. Surgery revealed a tumour in the left atrium, 7.5 x 7.5 cms with a stalk attached on the lower part of the atrial septum. It was very friable and could be removed only piecemeal. Post-operative echocardiogram revealed disappearance of all tumor echoes (See [Figure 2] on page 226A). The patient was discharged with partial recovery of her hemiplegia.
Mrs. P.G., a 45 year old housewife was admitted with history of progressive breathlessness for the last 6 months. She had no history suggestive of embolism or rheumatic fever. On examination she was fuond to have a regular pulse with all pulsation well felt. She was in congestive cardiac failure. She had a right ventricular heave and palpable P 2 . At the apex the first sound was loud and she had a grade II presystolic murmur. No tumour plop was heard. There was no change of the murmur with posture.
Her ECG showed low voltage complexes with no evidence of ventricular hypertrophy. Her X-ray chest showed significant cardiomegaly with a prominent pulmonary artery and pulmonary venous congestion. Her echocardiogram revealed a left atrial myxoma (See [Figure 3] on page 226B). At surgery, she was found to have a 5 x 5 cms pedunculated gelatinous tumour with a stalk attached to the atrial septum in the region of fossa ovalis. She suddenly deteriorated and died 48 hours after surgery.
Mr. X. P., a 45 year old clerk, gave history of having been first detected to have a cardiac lesion at the age of 13 years. He had no complaints at that time and was well till 10 years ago, when he had a short episode of syncope. About four months ago he noticed transient weakness of the right arm. One and a half months after this episode he presented with markedly reduced vision in his left eye. He also had grade II dyspnoea.
On examination he had a regular pulse rate of 75/min. All the peripheral pulsations were well felt. His blood pressure was 120/78 mm Hg. He had a loud first heart sound and normal P 2 . A grade II presystolic murmur and a grade III pansystolic murmur were heard at the apex. There was a significant increase in both murmurs on upright posture.
Examination of his optic fundi suggested embolic lesions. His ECG was normal. Chest X-ray showed mild cardiomegaly. Echocardiogram revealed the presence of a left atrial tumor (See [Figure 4] on page 226B). The patient has refused surgery.
Mr. RR a 40 year old male patient presented with a grade I dyspnoea of one years' duration. He had a history of pulmonary tuberculosis 2 years ago. On examination he had a regular pulse rate of 78/min. His BP was 134/70 mm Hg. Precordial examination revealed a loud 1st heart sound and a grade 3/6 late systolic murmer at the apex. He had no evidence of pulmonary hypertension.
His ESR was 6 mm/hr. His ECG was normal. His X-ray showed a normal heart size with mild pulmonary venous congestion.
Echo showed shadows behind the anterior mitral leaflet strongly suggestive of atrial myxoma. It also revealed a late systolic prolapse of both the anterior and posterior leaflets of the mitral valve (See [Figure 5] on page 226B).
The patient was not first willing for surgery but lateron opted for surgery. At surgery no myxoma was found within the cavity of the left atrium or left ventricle. The posterior leaflet which was thickened and had a slightly bulbous margin was seen to prolapse within the left atrial cavity during systole. One of the chordae to the posterior leaflet was broken. Gramiak and Nanda  have described a case of posterior leaflet prolapse showing multiple shadows suggestive of an atrial myxoma. This case represents a similar problem.
The variability of presentation, the close mimicking of a common valvular disease and often, absence of changing murmurs with posture, make the clinical diagnosis of atrial myxoma a difficult one. The variability of the murmur has been seen in two of our cases. Every case of mitral stenosis cannot be subjected to angiocardiography to rule out the very occasional possibility of myxoma. Bigelow et ale have suggested that all mitral commissurotomies should be done on cardiopulmonary bypass, to facilitate removal of the tumor, if encountered. This is certainly not practical.
The introduction of echocardiography to clinical medicine has solved this dilemma. Since the first published case by Effert and Domanig  of a left atrial myxoma echocardiography has become the most efficient mode of diagnosis. Unlike angiography no false negative or false positive diagnosis has been reported. , At our institute only two cases of myxoma were detected antemortem in a twelve year span prior to echocardiography  Since the introduction of echocardiography we have detected four cases within a period of two and a half years. It is conceivable however that small and sessile tumors that do not prolapse through the mitral orifice may not be visualized during routine echocardiography of the left ventricle. However, it may be possible to detect these small non-prolapsing tumors if the beam is directed through the aortic root or the cardiac apex into the left atrial cavity  or by suprasternal approach. 
The diagnosis of myxoma echocardiographically is certainly rare. Solitary cases have been reported in the literature. ,,, Tallury and DePasquale have however reported five echocardiographically proved cases. 
It is recommended that echocardiography should be performed in all patients with a following features: 
(1) Suspected mitral valve obstruction.
(2) Unexplained syncope.
(3) Suspected subacute bacterial endocarditis.
(4) After removal of myxoma as occasionally they recur.
The echograms should be obtained in three p:anes: 
(1) Through both leaflets of the mitra valve and the left ventricle.
(2) Through the aorta and left atrium
(3) Through an intermediate plane displaying the anterior leaflet o the mitral valve and the left atrium.
A suprasternal placement with the beam oriented through the vertical axis of the left atrium is also of value in non prolapsing myxoma. 
The wavy echo lines posterior to the mitral leaflet recorded echocardiographically are due to non-homogeneity of the tumor mass as suggested by Effert anc Domanig.  The motion of the tumor mass produces a characteristic wavy appearance. Artefacts do not have this wavy appearance and thrombi have characteristic dense layered appearance. 
The appearance of an echo free space posterior to the anterior leaflet of the mitral valve early in ventricular diastole with the appearance of abnormal echoes late in ventricular diastole is a strong evidence of tumor prolapsing through the mitral orifice. The lesser the degree of echo free space, the earlier the prolapse of the myxoma. The systolic echo in the left atrial cavity corresonds with the return of the myxoma into the left atrium, during ventricular contraction..
The echocardiographic diagnosis of right atrial myxoma has also been reported. ,. This appears more difficult than left atrial myxomas but the mode of diagnosis is similar.
We are thankful to Dr. C. K. Deshpande, Dean, K.E.M. Hospital, Bombay 400012, for allowing us to publish the work.
Thanks are also due to Mr. S. B. Sorab, Technician, Vakil Institute of Cardiology.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]