Myocardial strain: a clinical review.

BACKGROUND: Myocardial strain-change in myocardial fibre length over the cardiac cycle-is a measure of cardiac muscle function. It is obtained using conventional techniques such as echocardiography and magnetic resonance imaging, adding additional clinical information to augment the current techniques. METHODS: A narrative review of the current relevant literature with respect to myocardial strain, with a focus on strain measured by echocardiography. RESULTS: Myocardial strain identifies global and regional abnormalities in myocardial function and differentiates types of cardiomyopathy. It is an earlier marker of myocardial disease than ejection fraction and is predictive of cardiovascular adverse events. Accurate measurement requires high-quality images and experienced practitioners. CONCLUSION: This review explains advantages and disadvantages of myocardial strain imaging and explains why, through adding increased precision without additional burden, it should be a standard part of cardiac assessment.

Subclinical anthracycline- and trastuzumab-induced cardiotoxicity in the long-term follow-up of asymptomatic breast cancer survivors: a speckle tracking echocardiographic study.

OBJECTIVE: To examine the long-term effects of standard chemotherapy on myocardial function in asymptomatic breast cancer survivors using two-dimensional speckle tracking echocardiography. METHODS: Seventy women (chemotherapy group) aged 54+/-8 years who had received anthracycline treatment with (n=19) or without (n=51) adjuvant trastuzumab up to 6 years previously, and 50 female controls were studied. Left ventricular systolic (ejection fraction (EF%), peak systolic myocardial excursion, (Sm)) and diastolic (peak mitral E and A velocities, six-point average of mitral annular E' velocities) function, 2D global and regional longitudinal and radial strain were determined using standard 2D Doppler and tissue Doppler echocardiographic methods and speckle tracking software. RESULTS: Despite normal EF% (62+/-4% vs 60+/-3%, p=0.051) the chemotherapy group had reduced E/A ratios (0.9+/-0.3 vs 1.1+/-0.3, p=0.003), global E' (10.2+/-2 vs 11.2+/-2.3, p=0.036), global Sm (9.0+/-1.3 vs 9.6+/-1.3, p=0.029) and global longitudinal 2D strain (-18.1+/-2.2 vs -19.6+/-1.8, p=0.0001) in comparison with controls. In 18 (26%) of the chemotherapy group, global longitudinal strain was below the lower limit of the control group. Cigarette smoking was a negative predictor of longitudinal strain, but only in the chemotherapy group. Radial strain did not differ significantly between the two groups. There were no significant differences in EF%, global Sm and longitudinal strain between trastuzumab-treated individuals and controls. CONCLUSIONS: Subclinical systolic and diastolic myocardial abnormalities were present in asymptomatic breast cancer survivors up to 6 years after standard chemotherapy. Cigarette smoking had a negative effect on longitudinal strain in these individuals. Adjuvant trastuzumab treatment did not appear to have an additive adverse impact on myocardial function in the medium-long term.

Feasibility study of percutaneous transvalvular endomyocardial cryoablation for the treatment of hypertrophic obstructive cardiomyopathy.

BACKGROUND: Left ventricular outflow tract (LVOT) obstruction in the setting of hypertrophic cardiomyopathy (HCM) confers negative adverse outcomes. Current nonpharmacologic treatment options include surgical myectomy and percutaneous transcoronary ablation of septal hypertrophy (TASH). While TASH negates a more invasive procedure, concern remains with particular regard to the arrhythmogenic potential of the resultant myocardial scar. Percutaneous transvalvular endomyocardial septal cryoablation (PTESC) may circumvent some of these potential limitations and offer a novel treatment strategy. OBJECTIVES: The purpose of this study was to report our early experience and outcomes with percutaneous endomyocardial cryoablation of the interventricular septum in obstructive HCM. METHODS AND RESULTS: Between March 2005 and May 2006, 3 patients (2 male, 1 female) with symptomatic obstructive HCM underwent PTESC. Basal LVOT gradients measured during left heart catheterization were 70, 126 and 100 mmHg for Patients 1, 2 and 3, respectively. Using 7 Fr and 9 Fr 8 mm tip CryoCath Freezor catheters (CryoCath Technologies, Inc., Montreal, Quebec, Canada), cryothermal energy was applied to the interventricular septum under fluoroscopic guidance. A total of 20 to 32 applications of cryothermal energy were delivered, with the mean nadir temperature sustained during cryoablation being -88 degrees Celcius. Two of the 3 patients had an immediate reduction in the LVOT gradient. However, at 6 months, only 1 patient had a significant sustained reduction in LVOT gradient. No adverse events relating to the procedure were experienced. CONCLUSION: PTESC is feasible, but did not result in a significant, sustained reduction in LVOT gradient in 2 of the 3 patients in this small series of obstructive HCM patients. The technique warrants further study to improve the consistency and duration of reduction in outflow gradient.