To assess left atrial (LA) function by two dimensional speckle tracking echocardiography (2DSTE) in patients with hypertrophic obstructive cardiomyopathy (HOCM) before and one year after percutaneous transluminal septal myocardial ablation (PTSMA).

The study included 31 patients with HOCM who underwent PTSMA performed between November 2012 and December 2014 in Sir Run Run Shaw Hospital. Mean age was 51±13 years, and 13 patients were men, 18 patients were women. New York Heart Association class was 2.6±0.7 at baseline. If the target region was correctly marked by the injection of the echo contrast agent, ethanol was slowly (0.5 ml/min) injected to a maximum of 3 ml. Ten minutes after the injection of ethanol, the balloon was deflated. A successful procedure was defined as a≥50% reduction in the LV outflow tract peak systolic gradient compared to baseline level. Each patient with HOCM had a complete two-dimensional transthoracic echocardiography assessment before and one year after the PTSMA. The measurements included basal septal thickness, left ventricular outflow tract (LVOT) gradient, mitral regurgitation (MR) grade, left atrial dimensions, left ventricular (LV) ejection fraction and tissue Doppler parameters of lateral mitral annular e' and septal mitral annular e'. The LA wall was tracked on a frame-by-frame basis using 2D-STE, and LA volume waveforms were generated. The maximum LA volume (LAVmax), minimal LA volume (LAVmin), and the LA volume before atrial contraction (LAVpre-a) were measured. The LA reservoir function was calculated as left atrial expansion index (LAEI) and left atrial diastolic emptying index (LADEI). The LA conduit function was calculated as the passive emptying percentage of total emptying (PE) and the passive emptying index (PEI). The LA booster function was calculated as the active emptying percentage of total emptying (AE) and the active emptying index (AEI). The comparisons between patient New York Heart Association class, echocardiography and LA function parameter before and after PTSMA were conducted by paired t test.

Compared with pre-operative values, LVOTG, MR grade, LA end-diastolic size, E/ lateral e' ratio, septal mitral annular e' decreased in patients one year after the PTSMA [(35±26) mmHg vs (74±35) mmHg, 0.93±0.35 vs 2.27±0.73, (40±6) mm vs (45±6) mm, 12.6±3.8 vs 14.6±4.6, (4.3±1.1) cm/s vs (5.0±1.3) cm/s], whereas New York Heart Association class, Lateral mitral annular e', E/ septal e' ratio [1.4±0.5 vs 2.6±0.7, (6.9±2.3) cm/s vs (5.8±1.7) cm/s, 20.2±7.1 vs 17.0±5.2] increased (t=6.55, 4.78, 2.60, 2.84, 2.59, -3.32, -2.67, -2.93, all P<0.05). Compared with pre-operative values, LAVImax, LAVImin, LAVIpre-a, AE, AEI(%) decreased in patients one year after the PTSMA [(32.7±7.1) ml/m² vs (38.9±9.3) ml/m², (16.3±4.4) ml/m² vs (20.7±5.5) ml/m², (23.1±5.7) ml/m² vs (30.5±7.0) ml/m², (41.5±8.7)% vs (53.8±10.4)%, (29.4±3.9)% vs (32.1±4.6)%], (t=3.65, 3.11, 3.38, 3.92, 2.17, all P<0.05); whereas the LAEI(%), LADEI(%), PE(%), PEI(%) [(100.1±19.3)% vs (87.9±14.7)%, (50.2±9.8)% vs (46.7±9.1) %, (58.5±11.8) % vs (46.1±9.1) %, (26.9±5.2)% vs (21.6±4.8)%] increased (t=-2.82, -2.33, -3.89, -2.74, all P<0.05).

The study showed the improvement in LA reservoir and conduit function, while the reduction in LA booster pump function in patients one year after PTSMA.