The regional myocardial microvascular dysfunction differences in hypertrophic cardiomyopathy patients with or without left ventricular outflow tract obstruction: assessment with first-pass perfusion imaging using 3.0-T cardiac magnetic resonance.

PURPOSE: To assess regional myocardial microvascular dysfunction differences in hypertrophic cardiomyopathy (HCM) patients with or without left ventricular outflow tract obstruction using 3.0-T cardiac magnetic resonance (CMR) first-pass perfusion imaging. MATERIALS AND METHODS: Forty-two HCM patients, including 25 HCM patients with left ventricular outflow tract obstruction (HOCM), 17 HCM patients without left ventricular outflow tract obstruction (NOHCM), and 14 healthy subjects underwent CMR. The left ventricular (LV) function, left ventricular end-diastolic wall thickness (EDTH), and diameter of left ventricular outflow tract (LVOT) were measured and calculated. Based on the signal-time curve of the first-pass myocardium perfusion imaging, perfusion parameters including upslope, time to peak, and peak intensity, were assessed and compared by using one-way analysis of variance and independent t tests. RESULTS: On the first-pass perfusion imaging, lower upslope and peak intensity and longer time to peak were found in HCM patients compared with normal subjects (all p<0.05). In contrast to the NOHCM group, the average time to peak of the HOCM group was increased (13.30 ± 4.82 s vs 16.28 ± 4.90 s, p<0.05), but first-pass perfusion upslope was reduced (4.96 ± 2.55 vs 2.58 ± 0.77, p<0.05). According to the bull's-eye model, the HOCM group's average thickness of basal segments was thicker than the NOHCM group, especially the anteroseptal, inferolateral, and anterior wall values, with a corresponding lower first-pass perfusion upslope than the NOHCM group (all p<0.05). A significant correlation was observed between first-pass perfusion upslope and LV EDTH (r=-0.551, p<0.001) and LVOT diameter (r=0.472, p<0.001). CONCLUSIONS: The regional myocardial microvascular dysfunction differences in hypertrophic cardiomyopathy (HCM) patients with or without left ventricular outflow tract obstruction can be detected with first-pass perfusion CMR imaging.

An assessment of regression of left ventricular hypertrophy following alcohol ablation of the interventricular septum in patients with hypertrophic cardiomyopathy with left ventricular outflow tract obstruction.

BACKGROUND: Hypertrophic obstructive cardiomyopathy (HOCM) is characterised by asymmetric myocardial hypertrophy, which is most pronounced in the interventricular septum (IVS) and is responsible for the dynamic obstruction of the left ventricular outflow tract (LVOT). Successful alcohol septal ablation (ASA) of the IVS allows to reduce the thickness of the parabasal part of the IVS myocardium and, in most cases, to permanently reduce the gradient in the LVOT. AIM: To assess, using cardiac magnetic resonance imaging (MRI) and transthoracic echocardiography (TTE), the impact of gradient reduction in the LVOT on the type and severity of left ventricular (LV) remodelling. METHODS: The study included 30 patients (aged 56.9 ± 11.9 years) with HOCM and the mean peak gradient (PG) in the LVOT of 123 ± 33 mm Hg who underwent ASA. MRI measurements were performed before and at 6 months after ASA and TTE measurements were performed before, at 3 months and at 6 months after ASA. RESULTS: PG in the LVOT decreased to an average of 52 ± 37 mm Hg (p 〈 0.0001) at 3 months after ASA and to 37 ± 28 mm Hg (p 〈 0.0001) at 6 months after ASA. TTE revealed a decrease in IVS thickness outside the scar following ASA from 23.6 ± 3.5 mm to 19.3 ± 4.0 mm (p 〈 0.0001) and 19.4 ± 0.4 mm (p 〈 0.0001) at 3 and 6 months, respectively. There was also a decrease in lateral wall (PW) thickness from 15.9 ± 3.2 mm to 14.9 ± 2.9 mm (p = 0.046) and 14.16 ± 2.00 (p = 0.0065) at 3 and 6 months, respectively. MRI revealed a decrease in IVS thickness from 23.7 ± 2.8 mm to 18.04 ± 4.00 mm (p = 0.0001) at 6 months following ASA. We observed a regression of the PW hypertrophy from 13.2 ± 3.35 mm to 12.18 ± 2.4 mm (p = 0.0225). There was a decrease in IVS mass from 108.9 ± 20 g to 91.5 ± 29 g (p = 0.0006). There was a trend towards a decreased LV mass and LV mass excluding IVS mass at 6 months. CONCLUSIONS: A significant decrease in PG in the LVOT is associated with a decrease in LV mass and with regression of LV hypertrophy outside the scar after ASA.

Echocardiographic assessment of obstructive lesions in atrioventricular septal defects.

OBJECTIVES: We sought to determine the accuracy of transthoracic echocardiography (TTE) in identifying risk factors in patients with an atrioventricular septal defect (AVSD). BACKGROUND: Atrioventricular septal defect is a common lesion, and many decisions about it are based on echocardiography alone. The identification of associated left-sided inflow and outflow obstructive lesions is important, as they are responsible for mortality and morbidity. METHODS: Between 1983 to 1998, 549 patients with AVSD underwent repair. The TTE findings were correlated with surgery, angiocardiography, autopsy or postoperative TTE. Papillary muscle measurements were made in those with either a left ventricular outflow tract (LVOT) or left ventricular inflow abnormality and compared with those measurements from control subjects. Measurements of the LVOT were made in patients with an identified LVOT abnormality. RESULTS: There were 63 missed lesions, decreasing over time. Double-orifice left atrioventricular valve (DOLAVV) and nonobstructive chordae in the LVOT were more often missed. Reoperation was performed to address a missed lesion in 2 of 68 patients. Two of 55 patients died of reasons related to a missed lesion. In 67% of patients, DOLAVV was missed. Abnormal papillary muscle angles were seen with either a LVOT abnormality or DOLAVV. High insertion of the anterolateral papillary muscle was a risk factor for death or residual LVOT obstruction. Abnormal LVOT measurements were found in patients with tunnel obstruction and those with an acquired subaortic ridge. CONCLUSIONS: Transthoracic echocardiography provides accurate preoperative information on AVSD.