PMC9856278_01
Four echocardiac images showing the left ventricular outflow tract pressure gradient at each time point as follows: (A) before the percutaneous transluminal septal myocardial ablation at rest; (B) before exercise; (C) after exercise; (D) after percutaneous transluminal septal myocardial ablation at rest.
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The LVOT PG was 45 mmHg, which was not an indication for treatment (Figure 1A, Supplementary material online, Video S1). Therefore, exercise stress echocardiography was performed to confirm that HOCM was the cause for shortness of breath on exertion. The pre-loading LVOT PG of 78 mmHg (Figure 1B) increased immediately to 84 mm post loading (2 min, 5.4 metabolic equivalents), and MR worsened to a moderate grade (Figure 1C, Supplementary material online, Video S2). Although the PM adherent to the septum persisted and moved to the LVOT during systole, its gradient decreased from 84.0 to 24.2 mmHg due to the reduced septal myocardial thickness (Figure 1D).
(A) Transoesophageal echocardiography. (B) Cardiac magnetic resonance imaging long-axis image. (C) Cardiac magnetic resonance imaging short-axis image. All images demonstrate a papillary muscle structural abnormality (arrow).
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Therefore, exercise stress echocardiography was performed to confirm that HOCM was the cause for shortness of breath on exertion. The pre-loading LVOT PG of 78 mmHg (Figure 1B) increased immediately to 84 mm post loading (2 min, 5.4 metabolic equivalents), and MR worsened to a moderate grade (Figure 1C, Supplementary material online, Video S2). Transoesophageal echocardiography revealed an abnormal PM adhesion to the septal myocardium (Figure 2A). Cardiac MRI showed two parts of the anterior PM, one of which was attached to the septal myocardium (Figure 2BandC).
(A) Coronary angiography before the percutaneous transluminal septal myocardial ablation. We ablated the two septal branches (S1 and S2). (B) Coronary angiogram taken after percutaneous transluminal septal myocardial ablation.
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Figure 3). First, a balloon catheter was inserted into the selected septal branch.
Before percutaneous transluminal septal myocardial ablation and 1 month after percutaneous transluminal septal myocardial ablation. The septal myocardium (a) is smaller, whereas the thickness of the papillary muscle (b) attached to the septal myocardium has not changed.
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The interventricular septal thickness decreased from 21 to 18 mm (Figure 4).