Q. Lo

Subclinical Cardiac Dysfunction Detected by Strain Imaging During Breast Irradiation With Persistent Changes 6 Weeks After Treatment

PURPOSE To evaluate 2-dimensional strain imaging (SI) for the detection of subclinical myocardial dysfunction during and after radiation therapy (RT). METHODS AND MATERIALS Forty women with left-sided breast cancer, undergoing only adjuvant RT to the left chest, were prospectively recruited. Standard echocardiography and SI were performed at baseline, during RT, and 6 weeks after RT. Strain (S) and strain rate (Sr) parameters were measured in the longitudinal, circumferential, and radial planes. Correlation of change in global longitudinal strain (GLS % and Δ change) and the volume of heart receiving 30 Gy (V30) and mean heart dose (MHD) were examined. RESULTS Left ventricular ejection fraction was unchanged; however, longitudinal systolic S and Sr and radial S were significantly reduced during RT and remained reduced at 6 weeks after treatment [longitudinal S (%) -20.44 ± 2.66 baseline vs -18.60 ± 2.70* during RT vs -18.34 ± 2.86* at 6 weeks after RT; longitudinal Sr (s(-1)) -1.19 ± 0.21 vs -1.06 ± 0.18* vs -1.06 ± 0.16*; radial S (%) 56.66 ± 18.57 vs 46.93 ± 14.56* vs 49.22 ± 15.81*; *P<.05 vs baseline]. Diastolic Sr were only reduced 6 weeks after RT [longitudinal E Sr (s(-1)) 1.47 ± 0.32 vs 1.29 ± 0.27*; longitudinal A Sr (s(-1)) 1.19 ± 0.31 vs 1.03 ± 0.24*; *P<.05 vs baseline], whereas circumferential strain was preserved throughout. A modest correlation between S and Sr and V30 and MHD was observed (GLS Δ change and V30 ρ = 0.314, P=.05; GLS % change and V30 ρ = 0.288, P=.076; GLS Δ change and MHD ρ = 0.348, P=.03; GLS % change and MHD ρ = 0.346, P=.031). CONCLUSIONS Subclinical myocardial dysfunction was detected by 2-dimensional SI during RT, with changes persisting 6 weeks after treatment, though long-term effects remain unknown. Additionally, a modest correlation between strain reduction and radiation dose was observed.

Evaluation of traditional and novel echocardiographic methods of cardiac diastolic dysfunction post radiotherapy in breast cancer

BACKGROUND To investigate alterations in left ventricular (LV) diastolic function using traditional and novel echocardiographic parameters, following radiation therapy (RT) in breast cancer patients in the acute setting. METHODS 40 chemotherapy-naïve women with left-sided breast cancer undergoing RT were prospectively recruited. A comprehensive transthoracic echocardiogram (TTE) was performed at baseline, during RT and 6weeks post-RT. Traditional echocardiographic diastolic parameters and diastolic strain rate were measured and analysed. The relationship between alterations in diastolic parameters, changes in global longitudinal systolic strain (GLS) and radiation dose were investigated. RESULTS Traditional diastolic parameters remained largely unchanged; however diastolic strain parameters, E-Sr and A-Sr were significantly reduced 6weeks post-RT [Longitudinal E-Sr (s-1) 1.47+/-0.32 vs 1.29+/-0.27*; Longitudinal A-Sr (s-1) 1.19+/-0.31 vs 1.03+/-0.24*; *p<0.05 vs baseline]. When patients were divided by a reduction ≥10% versus <10% in GLS post-RT, a greater reduction in both traditional diastolic and diastolic strain parameters was observed in the group with >10% reduction in systolic function as evaluated by GLS. When patients were divided by mean v30 dose, a greater % change in E-Sr was noted in those receiving more than mean V30 dose. CONCLUSION Diastolic dysfunction was only evident acutely, post-RT with the use of newer methods like strain analysis. A significant reduction in diastolic function was seen in the patient subgroup with ≥10% reduction in systolic function, enhancing the notion of diastolic function as a potential indicator for systolic dysfunction. Future longitudinal studies are required to determine the specific prognostic value of these observations.

Echocardiographic evaluation of systolic heart failure

Echocardiography is the most commonly used modality for evaluating left ventricular size and function in the context of systolic heart failure. Traditional techniques, though extensively used, have their limitations and more recently several newer technologies have emerged that are more reproducible, provide prognostic information, guide therapies and have an important role in monitoring progress. This review will evaluate the traditional and more novel techniques used and briefly provide an overview of the role of echocardiography in guiding and monitoring therapies in patients with systolic heart failure.

Echocardiographic evaluation of diastolic heart failure

The term “diastology” characterises left ventricular (LV) relaxation, filling dynamics and their integration into clinical practice. Recent advances in echocardiography have enabled the understanding of this complex process, particularly relevant in the setting of an aging population and rising prevalence of heart failure (HF) with preserved systolic function. Data from the Mayo Clinic and others indicate that diastolic heart failure (DHF) accounts for approximately 50% of all HF cases and carries a poor prognosis with survival being similar to those with a reduced ejection fraction, (5-year mortality ~ 50% in new onset symptomatic DHF). Additionally, the prevalence of asymptomatic diastolic dysfunction (DD) in the general community is ~ 25–30% in individuals ≥ 45 years. Diastolic dysfunction (DD) is defined as “inability of the LV to fill during rest or exercise, to a normal end-diastolic volume without an abnormal increase in LV end diastolic pressure (LVEDP)”. Diastolic function is frequently abnormal in patients with reduced LVEF and HF. Hence, the recent criteria of The European Society of Cardiology recommends the diagnosis of DHF or HF with normal Ejection Fraction (HFNEF) be based on the following: (i) signs or symptoms of HF; (ii) normal or mildly abnormal LV systolic function without LV dilatation (LVEF > 50%, LV end-diastolic volume index (LVEDVI) < 97 mL/m.) and (iii) evidence of LV DD.