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Echocardiographic features of right ventricular volume overload Lilam S Shah, AS Vengsarkar, KG NairDepartment of Cardiology, 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: 529179
Interventricular septal motion is studied in sixty tow cases classified into 3 groups; Gr. 1-right ventricular volume overload (RVVO); Gr. II-combined right ventricular volume overload and left ventricular volume overload (RVVO + LVVO); Gr. III-combined right ventricular volume overload and right ventricular pressure overload (RVVO + RVPO).
Echocardiography has now become an established, safe and non-invasive technique in diagnosing various cardiac conditions, both congenital [6] and acquired Edler et a [3] noted echoes between the tricuspid and mitral valves and suggested the ventricular septum as the source of these echoes. Popp et 15 in 1969 analysed these echoes in terms of location and motion. Analysis of septal echoes is -found-to be valuable in the diagnosis of various congenital heart diseases, cardiomyopathy, coronary artery disease and in the assessment of left ventricular function. An attempt is made in this paper to study the echocardiographic features of various condition giving rise to right ventricular volume overload with special emphasis on the role played by septal motion patterns. Two echocardiographic features are considered; abnormal septal motion and right ventricular dimension. [12],[19] These two diagnostic echocardiographic features are studied in three groups-(1) right ventricular volume overload (RVVO); .(2) combined right and left ventricular volume overload. (RVVO + LVVO); (3) combined right ventricular volume overload and pressure. overload (RVVO+RVPO). Lesion specific echocardiographic features in the right ventricular volume overload are described.
Sixty two cases were admitted in the Department of Cardiology,, K.E.M. Hospital, Bombay, from May 1975 onwards. Detailed case histories were taken and clinical examination was done in each case. Routine 12 lead electrocardiogram, X-ray chest and Frank Vectorcardiogram were taken for all patients. Cardiac catheterization and angiocardiography were performed in these cases. [Table 1] shows echocardiographic studies in three different groups. The group of right ventricular volume overload was comprised of atrial septal defect (38 cases), total anomalous pulmonary venous connection (1 case), and Ebstein's anomaly (3 cases). The second group of right ventricular volume overload + left ventricular volume overload was comprised of atrial septal defect with mitral regurgitation (4 cases), atrial septal defect, ventricular septal defect and mitral regurgitation (1 case), ventricular septal defect with tricuspid regurgitation (3 cases), rupture sinus of valsalva into the right atrium (1 case), and biventricular endmyocardial fibrosis with mitral regurgitation and tricuspid regurgitation (1 case). Third group of right ventricular volume overload plus right ventricular pressure volume overload was comprised of primary pulmonary hypertension with tricuspid regurgitation (8 cases), atrial septal defect with pulmonary hypertension (1 cases), and atrial septal defect with pulmonary stenosis (1 case). Echocardiographic study was carried out in all these cases. Patients were studied in supine position. Unirad Ultrasonoscope with 2.25 mHz. transducers, 1 cm. diameter focused for 4 to 7 cms. was used. Pulse repeatition rate was 1000 pulses/sec. Infants were studied with a 1 cm., 5 mHz transducer focused for 3 to 5 cms. Aquasonic jelly was used to have an airless firm contact between the transducer and anterior chest wall; ultrasounds were obtained on screen on `M' mode scan. Photographic recordings were made with a 400 ASA 120 Graflex roll film camera or more recently with a Honeywell strip chart recorder. We used the technique described by Popp et al [15] for recording interventricular septum (IVS). At the chordal level, transducer echoes, anterior chest wall echoes (ACW), anterior right ventricular wall echoes (ARVW) right septum (RS), left septum (LS), chordal echoes, L.V. post wail endocardial echoes were recognised in the same plane (See [Figure 1] on page 208A). Septal motion was studied and ventricular dimensions were measured in the same plane. ECG signal was recorded along with these echoes in order to study the various echoes during the different phases of cardiac cycle. On the basis of septal motion pattern each case was classified as having normal or paradoxical septal motion (type A or B). Right ventricular dimension (RVD) was measured from right ventricular epicardium to right septum (RS) in ventricular end diastole, (see [Figure 2] on page 208A), right ventricular dimension index was obtained as RVD/BSA (BSA = body surface area obtained from the height and weight of the patient from Dubois' chart) The other echocardiographic measurements included left ventricular dimension during end-diastole (LVIDd) and end-systole (LVIDs), left ventricular posterior wall thickness (LVPW), left atrial size; all these were computed by standard measurements reported earlier. [4],[8]
The findings obtained in all the 62 patients are depicted in [Table 2]. [Table 2] shows that in group I (RVVO) all the cases showed abnormal septal motion; 35 cases showed type A(see [Figure 2] on page 208A) and 7 cases showed type B (see [Figure 3] on page 208 A) motion. In group II (RVVO + LVVO) paradoxical septal motion was normalized in all but one case. In group III (RVVO + RVPO) 6 cases showed normal septal motion, 3 cases showed type A and 1 case showed type B septal motion. In case of right ventricular volume overload (RVVO), in group I (RVVO) right ventricular dimension index (RVDI) obtained echocardiographically was plotted against PBF (Pulmonary blood flow/ systemic blood flow = Qp/Qs) obtained at cardiac catheterization (See [Figure 4] below). This showed a linear relationship between the two (r = 0.473) ; (p <0.01).
Diamond et al [1] were the first to describe septal motion pattern in right ventricular volume overload; they divided them into two types: Type A and Type B. Both patterns were characterized by an abnormal anterior systolic movement of the interventricular septal echoes. In Type A septal echoes at chordal level move anteriorly during the ventricular systole along with the normal systolic anterior motion of left ventricular posterior wall endocardium. In type B septal echoes at chordal level are flattened out during ventricular systole, after an initial anterior movement. Two echo cardiographic criteria are employed to diagnose right ventricular volume overload; (1) paradoxical septal motion at chordal level and (2) increased right ventricular dimension index (RVDI). The normal range of right ventricular dimension index is 0.3 to 1.1cm /m 2 (mean 0.7 cm/m 2 ) [1],[20] Abnormal septal motion is therefore seen in ostium secondum ASD, ostium primum ASD, Ebstein's anomaly, tricuspid insufficiency, pulmonary insufficiency and anomalous pulmonary venous connection. In our study of 42 cases of right ventricular volume overload (RVVO), 35 showed type A septal motion and 7 cases showed type B septal motion. It is of crucial importance to take meticulous care while recording septal echoes to have the beam oriented below the septal pivot; this will eliminate the possibility of false positives . [7] Tajik et al [18] have suggested that the magnitude of the shunt may be an important factor in determining interventricular septal motion. This is supported by Kerber's experimental model. [9] This experiment suggests that the type of septal motion abnormality and RVD are. directly related to the degree of left to right shunt at atrial level. In the present study of 30 cases of left to right shunt at atrial level a linear relationship between the RVD obtained echocardiographically with Qp/Qs obtained on cardiac catheterization was observed. No definite correlation was observed between the septal motion pattern and the magnitude of the left to right shunt. Normal interventricular sptal motion has been observed in proven cases of left to right shunt at atrial level where the shunt magnitude (Qp/Qs) was less than 1.2. [16],[18] There were two such cases in this series where echoes showed normal interventricular septal motion. The first case (M.S. F/9) had clinical findings and the ECG and X-ray suggestive of A.S,D.; cardiac catheterization proved haemodynamically insignificant left to right shunt at the atrial level (Op/Qs). Her echocardiogram showed normal septal motion and RVD within normal range. Another case (S.P. F/12) was clinically suspected to have an ASD. Echocardiogram showed normal I.V.S. motion, RVDI was 1.2 cm/m. 2 Cardiac catheterization was not performed in this case. At surgery she was found to have secundum ASD (2 cm. x 1.5 cm). In both these cases therefore the left to right shunt was not large enough to produce RVVO and abnormal I.V.S. motion. Our findings are thus consistent with the reported observations. The technique of non-invasive detection of RVVO echocardiographically by studying septal motion has a high sensitivity; the reports on false negatives, in the laterature are indeed very scarce. Combined Right Ventricular Volume Overload and Left Ventricular Volume Overload: Kerber [9] in his experimental studies produced shunts between aorta to left atrium and right atrium to left atrium producing biventricular volume overload. He showed that there was no change in I.V.S. motion, and postulated that abnormality of I.V.S. motion during ventricular ejection in pure RVVO was a manifestation of unequal stroke volume, the right ventricular stroke volume being larger and exceeding the left ventricular stroke volume. Conditions giving rise to LVVO will increase the LV stroke volume balancing the RV stroke volume and thus normalizing the paradoxical motion. The conditions known to modify abnormal I.V.S. motion in case of RVVO are- 1.Small left to right shunt at atrial level (Qp/Qs less than 1.2) 2. Associated LVVO caused by VSD, PDA, MR, AR. 3. Increased LVEDP. 4. Relative degree of pulmonary hypertension. [16] In the present series ten cases of combined RVVO and LVVO were included. In all except one case echogram showed normal systolic posterior I.V.S. motion. The exception (N.G. M/12) was a case of corrected VSD and anomalous obstructive right ventricular muscle bands. As the patient presented with remanifestation of symptoms a repeat haemodynamic study was done. It showed significant left to right shunt in the ventricle and severe tricuspid regurgitation. Echogram showed Type A septal motion and RVD 2 cm. In this case therefore the RVVO and RV stroke volume was larger and exceeded LV stroke volume producing a paradoxical septal motion (See [Figure 5] on page 208 A). Right Ventricular Volume and Pressure Overload (RVVO + RVPO): In this group there were 10 cases of combined right ventricular volume and pressure overload. Three cases showed type A septal motion; one showed type B motion; the remaining 6 showed normal septal motion. Lesion Specific Echocardiographic Features in Right Ventricular Volume Overload: Echocardiographic features of Ebstein's anomaly, total anomalous pulmonary venous return and endocardial cushion defects have been discussed below with a few examples of each condition. In two of our three cases of Ebstein's anomaly, a simultaneous high speed recording of both A-V valve echoes displayed excessively delayed tricuspid closure only in one case (100 msec.) (see [Figure 6] on page 208 B). In the other two cases tricuspid closure delay was 55 msec. and 50 msec. respectively. All these cases, however, showed abnormal septal motion and increased RVDI to suggest severe RVVO. As reported earlier [10],[11],[13],[14],[17], there was a greater easy of recording tricuspid valve than the mural valve in three cases of Ebstein's anomaly in the present series. In one case of total anomalous pulmonary venous return (TAPVR) echocardiogram showed paradoxical septal motion and increased RVD (2.5 cm) suggesting RVVO. An echo free space was indentified posterior to the posterior LA wall representing the common pulmonary venous channel. [5] , [15] (See [Figure 7] on page 208 B). Four echocardiographic features of A-V communis have been described by Williams and Rudd. [20] In this series two cases of ostium primum showed paradoxical septal motion and increased RVD. Both these cases showed exaggerated anterior mitral leaflet excursions in early diastole, traversing through the interventricular septum and seen in right ventricular cavity. There was absence of mitral valve echoes in late diastole due to prolonged mitral septal diastolic opposition. These findings suggest the presence of associated cleft mitral valve with ostium primum defects (See [Figure 8] on page 208 B). Thus echocardiography has helped to diagnose pure RVVO, associated volume overload of the left ventricle, pressure overload of the right ventricle and specific lesions causing RVVO.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2]
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