Echocardiographic Profile of Hypertrophic Cardiomyopathy – A Single-Centre, Observational study

Background: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease of left ventricular hypertrophy (LVH). Phenotypic expression varies widely from subclinical hypertrophy to gross asymmetric septal hypertrophy causing left ventricular outflow tract (LVOT) obstruction. On top of genetic and phenotypic heterogeneity, the prevalence of different types of HCM may have geographical, as well as, ethnic variation. Methods: This observational study was carried out during 2010 to 2020 to determine the echocardiographic profile of HCM in Bangladeshi population. All patients undergoing transthoracic echocardiography (TTE) in a private consultation centre of Dhaka, Bangladesh were included. HCM was defined as the presence of a maximal end-diastolic wall thickness of e”15 mm anywhere in the left ventricle (LV), in the absence of another cause of hypertrophy in adults. HCM was further classified according to the pattern of myocardial hypertrophy and presence or absence of LVOT, or mid-left ventricular cavity obstruction. Results: Out of 76 cases, non-obstructive HCM was the commonest type (65.8%), followed by HCM causing LVOT obstruction (13.2%), HCM causing mid-LV cavity obstruction (10.5%), and the apical variety ( 10.5%). Asymmetric septal hypertrophy (ASH) was found in 42.1%, systolic anterior motion (SAM) of anterior mitral leaflet (AML) in 14.5%, mitral regurgitation (MR) in 50%, left ventricular systolic dysfunction in 5.3%, and raised pulmonary artery systolic pressure (PASP) in 15.8% of cases. Maximum LV wall thickness ≥30 mm was found in 66 out of 76 cases. Conclusion: The study highlights the clinically useful profile of HCM in Bangladeshi population based on conventional echocardiography. Further studies involving clinical, newer echocardiographic modalities and genetic analyses are warranted to discover the additional information in this ethnicity. Cardiovasc j 2021; 14(1): 5-11

Case report: iatrogenic left ventricular outflow tract to right atrium fistula after trans-femoral transcatheter aortic valve implantation associated with asymmetric septal hypertrophy

Background The transcatheter aortic valve implantation (TAVI) is becoming a leading treatment option for symptomatic aortic stenosis for patients in all surgical risk categories. Recognition and management of potential complications are essential to ensure patient life and comfort. We present here a case report of a left ventricular outflow tract (LVOT) to right atrium (RA) fistula which is an extremely rare complication after TAVI. Case summary An 85-year-old man with symptomatic severe aortic stenosis and non-obstructive asymmetric septal hypertrophy (ASH) underwent a transfemoral TAVI. Soon after the procedure, he developed chest pain and atrial fibrillation with rapid ventricular response. A transthoracic echocardiography followed by a transoesophageal echocardiography showed a small pseudo-aneurysm with a fistulous tract between the LVOT and the RA. This was confirmed by a contrast computed tomography scan of the heart. The patient remained asymptomatic throughout the rest of hospitalization. He was treated with diuretics and discharged home. One month follow-up showed increase in the width, jet size, and gradient of the fistula but the patient remained asymptomatic. The decision by Heart team was to closely monitor him for symptoms since the fistula is difficult to access percutaneously. Discussion We report a unique case of an LVOT to RA fistula in the setting of ASH that occurred post-TAVI. Alcohol septal ablation was proposed pre-TAVI for patients having septal thickening >15 mm and dynamic obstruction. Treatment options for iatrogenic fistula vary from symptomatic treatment to percutaneous or surgical closure.

P873 A rare and potentially treatable cause of left ventricular hypertrophy

Introduction A 67-year-old man was referred for care of "asymptomatic hypertrophic cardiomyopathy". He did not have hypertension. No significant positive family history could be elicited. Electrocardiogram showed sinus rhythm with voltage criteria of left ventricular hypertrophy (LVH). Outside Transthoracic Echocardiogram (TTE) reported normal ejection fraction with asymmetric septal hypertrophy without outflow obstruction. He was put on observation for few years and was not any treatment. On first encounter in our clinic, physical examination including skin and eye assessment, and laboratory tests including renal function were unremarkable. Procedure TTE was repeated in our clinic showing normal left ventricular size with ejection fraction 55%, and impaired diastolic relaxation. There was asymmetric septal hypertrophy with septal thickness 2.1 cm (Figure A). There was mild systolic anterior motion of mitral apparatus and mild mitral regurgitation, without resting or Valsalva provoked outflow obstruction. Global longitudinal strain was -7.7% with most prominent abnormalities seen at apex, mid to basal anteroseptal and anterior wall (Figure B). Further assessment by Cardiac MRI showed similar asymmetric septal wall thickening. Late gandolinium enhancement study demonstrated patchy fluffy hyperenhancement of the mid wall of the basal to mid anteroseptal segment, and mid to apical anterior segment, suggestive of myocardial fibrosis (Figure C1 and C2). Dried spot blood was sent to Taiwan for enzyme study which revealed partial acid alpha-galactosidase A deficiency. Further genetic study detected a mutation of Hemizygous NM_000169.2(GLA):c.640-801[G > A] at intron 4. Finally endomyocardial biopsy was done which confirmed the cardiac involvement of Fabry disease (Figure D, myelin body shown under electron microscopy). This gentleman was referred for consideration of Enzyme Replacement Therapy (ERT). Discussion Fabry disease is an X-linked glycolipid storage disease with accumulation of globotriaosylceramide in lysosomes in multiple cell types throughout the body leading to various organ involvement. Cardiac manifestations include unexplained LVH, valvular regurgitation, conduction abnormalities etc. It occurs in up to 0.3-5% of patients with hypertrophic cardiomyopathy. Fabry disease should be considered as a differential diagnosis in all men with sporadic or non-autosomal dominant transmission of unexplained LVH, since treatment with ERT is available which may reduce LVH and improve myocardial function, although any impact on long term outcome has not yet been established. Conclusion This case illustrated a rare but potentially treatable cause of hypertrophic cardiomyopathy. Myocardial strain imaging should be integrated in routine TTE study for assessment of unexplained left ventricular hypertrophy. Multi-modality imaging and multi-specialty approach help in identifying patients of cardiac variant of Fabry disease who may benefit from ERT. Abstract P873 Figure.

Evolution of ventricular hypertrophy and myocardial mechanics in physiological and pathological hypertrophy

Left ventricular hypertrophy (LVH) is an adaptive response to physiological or pathological stimuli, and distinguishing between the two has obvious clinical implications. However, asymmetric septal hypertrophy and preserved cardiac function are noted in early stages in both cases. We characterized the early anatomic and functional changes in a mouse model of physiological and pathological stress using serial echocardiography-based morphometry and tissue velocity imaging. Weight-matched CF-1 male mice were separated into Controls ( n = 10), treadmill Exercise 1 h daily for 5 days/wk ( n = 7), and transverse aortic constriction (TAC, n = 7). Hypertrophy was noted first in the left ventricle basal septum compared with other segments in Exercise (0.84 ± 0.02 vs. 0.79 ± 0.03 mm, P = 0.03) and TAC (0.86 ± 0.05 vs. 0.77 ± 0.04 mm, P = 0.02) at 4 and 3 wk, respectively. At 8 wk, eccentric LVH was noted in Exercise and concentric LVH in TAC. Septal E/E′ ratio increased in TAC (32.6 ± 3.7 vs. 37 ± 6.2, P = 0.002) compared with the Controls and Exercise (32.3 ± 5.2 vs. 32.8 ± 3.8 and 31.2 ± 4.9 vs. 28.2 ± 5.0, respectively, nonsignificant for both). Septal s′ decreased in TAC (21 ± 3.6 vs. 17 ± 4.2 mm/s, P = 0.04) but increased in Exercise (19.6 ± 4.1 vs. 29.2 ± 2.3 mm/s, P = 0.001) and was unchanged in Controls (20.1 ± 4.2 vs. 20.9 ± 5.1 mm/s, nonsignificant). With similar asymmetric septal hypertrophy and normal global function during the first 4–8 wk of pathological and physiological stress, there is an early marginal increase with subsequent decrease in systolic tissue velocity in pathological but early and progressive increase in physiological hypertrophy. Tissue velocities may help adjudicate between these two states when there are no overt anatomic or functional differences. NEW & NOTEWORTHY Pathological and physiological stress-induced ventricular hypertrophy have different clinical connotations but present with asymmetric septal hypertrophy and normal global function in their early stages. We observed a marginal but statistically significant decrease in systolic tissue velocity in pathological but progressive increase in velocity in physiological hypertrophy. Tissue velocity imaging could be an important tool in the management of asymmetric septal hypertrophy by adjudicating between these two etiologies when there are no overt anatomic or functional differences.

Residual left ventricular hypertrophy with adverse clinical outcomes in patients with severe aortic stenosis and asymmetric septal hypertrophy after aortic valve replacement

OBJECTIVES The aim of this study is to describe the temporal pattern of left atrial (LA) and left ventricular (LV) reverse remodelling and to evaluate the impact of residual LV hypertrophy on the prognosis of patients with severe aortic stenosis and asymmetric septal hypertrophy undergoing aortic valve replacement (AVR). METHODS We retrospectively reviewed 59 consecutive patients who underwent AVR for severe aortic stenosis and asymmetric septal hypertrophy. They were divided into the normal LV mass group and the residual LV hypertrophy group according to the LV mass index (LVMI) 2 years after AVR. Thirty patients were eligible for analysis of the time-dependent changes in LA and LV reverse remodelling. RESULTS The interventricular septal thickness and LVMI gradually decreased and reached their lowest points 2 years after operation, whereas the LA dimension rapidly decreased in the early postoperative period and plateaued at 3 months. The multivariable analysis revealed a higher preoperative LVMI [odds ratio 6.36 (1.678–24.11); P = 0.007] as an independent predictor of residual hypertrophy 2 years after operation. The Cox proportional hazards model showed that a higher postoperative peak velocity [hazard ratio 6.715 (1.405–32.104); P = 0.017] was an independent predictor of long-term non-fatal cardiovascular hospitalization. Patients with residual hypertrophy 2 years after AVR had a higher rate of non-fatal cardiovascular hospitalization (P = 0.014). CONCLUSIONS For patients with severe aortic stenosis and asymmetric septal hypertrophy, maximum LA recovery occurred 3 months after AVR, whereas maximum LV recovery occurred 2 years thereafter. A higher preoperative LVMI may lead to postoperative residual hypertrophy, which is associated with adverse clinical outcomes.

Cardiac amyloidosis: The great masquerader

Cardiac amyloidosis is an elusive condition that is notorious for mimicking various cardiovascular conditions that present with left ventricular hypertrophy (LVH). The hypertrophy in amyloidosis is typically diffuse; however, rare reports of echocardiographic resemblances with hypertrophic cardiomyopathy (HCM) exist, such as asymmetric septal hypertrophy and left ventricular outflow tract obstruction. Cardiac MRI can help differentiate amyloidosis from hypertrophic cardiomyopathy in unclear situations. This differentiation from HCM and other forms of cardiomyopathy has important treatment implications. Here we present the case of a 76-year-old man with cardiomyopathy who had echocardiographic features of asymmetric hypertrophic cardiomyopathy but was correctly diagnosed with amyloidosis with the help of cardiac MRI and ECG.