Reduced right ventricular myocardial strain in the elite athlete may not be a consequence of myocardial damage. "Cream masquerades as skimmed milk".

BACKGROUND: Latest research shows that the lower resting values of right ventricular (RV) myocardial % strain may represent a physiologic change rather than subclinical myocardial damage. Therefore, we assessed load-independent changes to the RV as a consequence of high intensity training by measuring the Isovolumic acceleration (IVA) of the free wall of the RV in conjunction with NT pro-BNP measured by an electrochemiluminescence assay. METHODS: Seventeen controls (mean age 27 ± 4), 24 soccer footballers (mean age 24 ± 4), and 18 elite rowers (mean age 22 ± 4) were studied. Left ventricular (LV) and RV % strain were measured using two-dimensional (2D) speckle based automated functional imaging (AFI) software. RV free wall IVA was measured using pulsed-wave tissue Doppler at the lateral tricuspid annulus. Standard 2D echo were used to measured RV parameters including the Tei index (systolic and diastolic function) and the total annular plane systolic excursion (TAPSE) of the RV annulus. NT pro-BNP was measured by an electrochemiluminescence assay. RESULTS: The RV diameter was increased in the footballers and elite rowers compared with controls (P < 0.001). RV wall size was greater in the elite rowers compared with controls and footballers (P = 0.002). The peak IVA of the RV was higher in the rowers, compared with the footballers and to controls (P < 0.001). The mean LV and RV % myocardial strain were lower in the elite athletes and the footballers compared with controls (P < 0.001). There was no difference in RV Tei index, levels of BNP, and TAPSE across all subjects. CONCLUSIONS: This study showed a significant increase in IVA of the RV of athletes despite reduced myocardial % strain and normal levels in NT-proBNP. This suggests that the decrease in % strain is not a consequence of myocardial damage, but may represents a part of the physiological response to endurance exercise. Therefore, a reduced IVA in a remodeled RV could herald a pathological response.

The heart of the endurance athlete assessed by echocardiography and its modalities: "embracing the delicate balance".

"To go too far is as bad as to fall short."Confucius (BC 551-BC 479) Chinese philosopher Echocardiography has contributed most to our current understanding and indeed our current dilemma regarding the heart of the endurance athlete. Echocardiography assesses and characterizes nicely the effects of Endurance exercise training. It allows us to assess both systolic and diastolic cardiac variables as they change with structure and function associated with intense sporting activity. Much research work using echocardiography has characterized the left and right ventricle of the endurance athlete over the last year. Indeed evidence suggests that intense prolonged exercise may result in myocardial dysfunction which predominantly affects the RV, and that chronic RV remodelling may represent a substrate for ventricular arrhythmias in athletes. This has been the source of many debates and articles over the last 12 months. The reasons underlying the predilection towards RV dysfunction with intense prolonged exercise and the variation between individuals in its occurrence are still under dispute. This article seeks to describe the recent literature over the last year which outlines the different areas research has focused on when we assess the heart of the endurance athletes using echocardiography. Ultimately the goal of all research on the heart of the endurance athletes is to search for the holy grail of when enough is enough and therefore recognize and embrace the delicate balance of endurance intensity, in other words the border line when endurance exercise is no longer beneficial but slumps and slides into the realms of induced cardiac pathology.

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.

The use of deformation imaging in the assessment of patients pre and post transcatheter aortic valve implantation.

BACKGROUND: Deformation imaging represents a method of measuring myocardial function, including global longitudinal strain (GLS), peak atrial longitudinal strain (PALS) and radial strain. This study aimed to assess subclinical improvements in left ventricular function in patients undergoing transcatheter aortic valve implantation (TAVI) by comparing GLS, PALS and radial strain pre and post procedure. METHODS: We conducted a single site prospective observational study of 25 patients undergoing TAVI, comparing baseline and post-TAVI echocardiograms. Individual participants were assessed for differences in GLS, PALS and radial strain in addition to changes in left ventricular ejection fraction (LVEF) (%). RESULTS: Our results revealed a significant improvement in GLS (mean change pre-post of 2.14% [95% CI 1.08, 3.20] p = 0.0003) with no significant change in LVEF (0.96% [95% CI - 2.30, 4.22], p = 0.55). There was a statistically significant improvement in radial strain pre and post TAVI (mean 9.68% [95% CI 3.10, 16.25] p = 0.0058). There was positive trend towards improvements in PALS pre and post TAVI (mean change of 2.30% [95% CI - 0.19, 4.80] p = 0.068). CONCLUSION: In patients undergoing TAVI, measuring GLS and radial strain provided statistically significant information regarding subclinical improvements in LV function, which may have prognostic implications. The incorporation of deformation imaging in addition to standard echocardiographic measurements may have an important role in guiding future management in patients undergoing TAVI and assessing response.

Cardiac Magnetic Resonance at 3.0 T in Patients With C282Y Homozygous Hereditary Hemochromatosis: Superiority of Radial and Circumferential Strain Over Cardiac T2* Measurements at Baseline and at Post Venesection Follow-up.

BACKGROUND: Iron-overload cardiomyopathy initially manifests with diastolic dysfunction and can progress to dilated cardiomyopathy if untreated. Previous studies have shown that patients with primary and secondary hemochromatosis can have subclinical left ventricle dysfunction with abnormalities on strain imaging. This study aimed to evaluate the relationship between cardiac T2* values and myocardial-wall strain in patients with hereditary hemochromatosis (HH) at the time of diagnosis and after a course of venesection treatment. MATERIALS AND METHODS: Baseline cardiac magnetic resonance (CMR) at 3 T was performed in 19 patients with newly diagnosed HH with elevated serum ferritin levels and repeated after a course of treatment with venesection. Quantitative T2* mapping and strain analysis were performed offline using dedicated relaxometry fitting and feature-tracking software. RESULTS: The majority (84%) of patients had normal baseline myocardial T2* values (mean 19.3 ms, range 8.9 to 31.2 ms), which improved significantly after venesection (mean 24.1 ms, range 11 to 38.1 ms) ( P =0.021). Mean global radial strain significantly improved from 25.0 (range: 15.6 to 32.9) to 28.3 (range: 19.8 to 35.8) ( P =0.001) and mean global circumferential strain improved, decreasing from -15.7 (range: -11.1 to -19.2) to -17.1 (range: -13.0 to -20.1) ( P =0.001). CONCLUSION: Patients with HH may have normal T2* values in the presence of subclinical left ventricle dysfunction, which can be detected by abnormal radial and circumferential strain. As strain imaging improves following venesection in HH, it may serve as a useful biomarker to guide treatment.

Improvements in cardiac function detected using echocardiography in patients with hereditary haemochromatosis.

BACKGROUND: Hereditary haemochromatosis is often not diagnosed until adulthood. Iron overload cardiomyopathy initially results in diastolic dysfunction and can result in arrhythmias and irreversible cardiac failure if untreated. The aim of this study was to investigate whether patients with newly diagnosed hereditary haemochromatosis without signs of heart failure exhibit subclinical alterations of cardiac function and to determine if cardiac function improved after 1 year of venesection. METHODS: Baseline echocardiography was performed on 25 patients with newly diagnosed hereditary haemochromatosis with elevated serum ferritin levels. The test was repeated after 1 year of treatment with venesection. Tissue Doppler imaging (TDI) and deformation (strain) imaging using speckle tracking were performed. Left atrial force was measured according to the Newtonian principle, in which force (dynes) = mass × acceleration. Left atrial force was calculated by the Manning method expressed as ρ × 0.53 × mitral annular orifice area × (peak A velocity)2. RESULTS: Radial strain showed a significant improvement after 1 year of venesection (increase from 38.8 to 52.6). The LAF showed a significant decrease after 1 year of venesection (median decrease = 0.6 (IQR 0, 1.60), p = 0.0004). Iso-volumetric relaxation time (IVRT) decreased significantly in patients after 1 year of venesection (decrease from 107.4 ± 16.2 to 97.68 ± 15.4 ms, p (0.0187)). CONCLUSION: Among all measurements, radial strain, IVRT and left atrial force were shown to significantly improve following a 1-year course of venesection, suggesting that these parameters could be used to identify subclinical cardiac dysfunction in patients with iron overload secondary to hereditary haemochromatosis and to guide intensification of venesection therapy.

Left ventricular vortex formation time in elite athletes.

Vortex formation time (VFT) is a continuous measure of the left ventricular (LV) filling that integrates all phases of diastole. This has been previously studied in patients with heart failure. This study examined the differences in VFT between healthy controls and elite athletes. We compared echocardiographic indices between elite male athletes (n = 41) and age-, weight- and sex-matched sedentary volunteers (n = 22). VFT was obtained using the validated formula: 4 × (1 - ß)/π × α3 × LVEF, where ß is the fraction of total transmitral diastolic stroke volume contributed by atrial contraction (assessed by time velocity integral of the mitral E- and A-waves) and α is the biplane end-diastolic volume (EDV)1/3 divided by mitral annular diameter during early diastole. Diastolic function was measured by the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (e') (E/e' ratio) and the ratio of E to mitral peak velocity of late filling (A) (E/A ratio). The heart rate was lower (63 ± 10 vs. 74 ± 6 beats per minute, p < 0.001) and the LV end diastolic diameter was larger in athletes as compared to controls (56 ± 3 vs. 50 ± 4 mm, p < 0.001). The VFT was lower in the sedentary group compared to athletes (3.1 ± 0.4 vs. 4.0 ± 0.8, p < 0.001). Similarly, E/e' was higher in sedentary controls compared to athletes (7.5 ± 1.8 vs 4.2 ± 1.0, p < 0.001). Furthermore, there was a modest correlation between VFT and E/A (r = 0.47, p < 0.001) as well as E/e' (r = - 0.33, p = 0.012). In conclusion, the VFT was elevated among elite athletes compared to healthy sedentary controls.

Comparison of echocardiographic measures of left ventricular diastolic function in early hypertension.

Left ventricular (LV) diastolic dysfunction identifies patients at risk of developing heart failure and may be common in patients with hypertension. The prevalence of LV diastolic dysfunction in patients with newly diagnosed hypertension was compared using criteria provided by the Canadian Consensus, European Study Group, and American Medical Association guidelines. One hundred twenty patients with newly diagnosed untreated hypertension (mean age 46.9 +/- 2.1 years; 62 men, 58 women) with increased blood pressure (clinic >140/90 mm Hg, daytime ambulatory >135/85 mm Hg) underwent comprehensive 2-dimensional echocardiography. Transmitral inflow velocities were measured using pulse-wave Doppler with and without Valsalva's maneuver, and a comprehensive assessment of tissue Doppler velocities was performed. The prevalence of LV diastolic dysfunction varied according to criteria used. There was a high prevalence of LV diastolic dysfunction (59%; n = 71) using Canadian Consensus guidelines; 27% of patients (n = 32) had a pseudonormal pattern unmasked using Valsalva's maneuver and 32% (n = 39) had impaired relaxation at rest. Significantly fewer patients (10%; n = 12) had this diagnosis using European or American Medical Association guidelines (23%; n = 27). Using tissue Doppler imaging (early-late diastolic velocity ratio <1), the prevalence of LV diastolic dysfunction was 59% (n = 71), identical to findings using the Canadian Consensus guidelines. In conclusion, current national consensus guidelines defining LV diastolic dysfunction varied widely and underdiagnosed LV diastolic dysfunction in patients with newly diagnosed hypertension. Tissue Doppler imaging assessment is a rapidly and widely available tool that is as sensitive as the most stringent national guidelines and should be systematically incorporated into a more comprehensive assessment of LV diastolic dysfunction in this population.

Early diastolic filling dynamics in diastolic dysfunction.

BACKGROUND: The aim of the study was to determine the relationship between the rate of peak early mitral inflow velocity and the peak early diastolic mitral annular tissue velocities in normal controls and to compare them with subjects with diastolic dysfunction. METHODS: The relationship between early passive diastolic transmitral flow and peak early mitral annular velocity in the normal and in diastolic dysfunction was studied. Two groups comprising 22 normal controls and 25 patients with diastolic dysfunction were studied. RESULTS: Compared with the normal group, those with diastolic dysfunction had a lower E/A ratio (0.7 +/- 0.2 vs. 1.9 +/- 0.5, p < 0.001), a higher time-velocity integral of the atrial component (11.7 +/- 3.2 cm vs. 5.5 +/- 2.1 cm, p < 0.0001), a longer isovolumic relaxation time 73 +/- 12 ms vs. 94 +/- 6 ms, p < 0.01 and a lower rate of acceleration of blood across the mitral valve (549.2 +/- 151.9 cm/sec2 vs. 871 +/- 128.1 cm/sec2, p < 0.001). They also had a lower mitral annular relaxation velocity (Ea) (6.08 +/- 1.6 cm/sec vs 12.8 +/- 0.67 cm/sec, p < 0.001), which was positively correlated to the acceleration of early diastolic filling (R = 0.66), p < 0.05. CONCLUSIONS: This investigation provides information on the acceleration of early diastolic filling and its relationship to mitral annular peak tissue velocity (Ea) recorded by Doppler tissue imaging. It supports not only the premise that recoil is an important mechanism for rapid early diastolic filling but also the existence of an early diastolic mechanism in normal.

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.

Left ventricular structural and functional changes in the metabolic syndrome.

To test the hypothesis that the cardiac structural and functional abnormalities of the metabolic syndrome (MS) are independent of body mass index (BMI), 160 untreated patients (aged 47+/-1 years [mean +/- SEM], 53% male) underwent 2-dimensional echocardiography and tissue Doppler imaging and evaluation for MS. Participants with MS and controls were similar in age, BMI, and ejection fraction, but those with MS had greater left ventricular relative wall thickness (RWT) (0.43+/-0.008 vs 0.39+/-0.005, P<.001), reduced midwall fractional shortening (MFS) (13%+/-0.3% vs 14.2%+/-0.3%, P<.05), and reduced peak mitral annular velocity (Em) (9.9+/-0.5 vs 12.3+/-0.5 cm/sec, P<.01) than controls. There was a linear relationship between the number of features of MS and Em velocity (P<.001), RWT (P<.001), and MFS (P<.05). In a stepwise multiple regression analysis adjusting for likely determinants, MS was an independent predictor of Em in addition to age and nonindexed left ventricular mass. MS is associated with left ventricular concentric remodeling and reduced systolic and diastolic function independent of BMI.

Blood pressure control determines improvement in diastolic dysfunction in early hypertension.

BACKGROUND: Diastolic dysfunction is common in early hypertension. We hypothesized that improvement in diastolic dysfunction is blood pressure (BP) dependent and may occur early with treatment in newly diagnosed untreated hypertensive patients. METHODS: Forty untreated hypertensive subjects (age 52 +/- 1.4 years, mean +/- s.e.m.) with diastolic dysfunction based on Canadian Consensus Guidelines, received either bendroflumethiazide 2.5 mg (1.25 mg for the first month), or candesartan 16 mg (8 mg for the first month). Left ventricular (LV) structure and function, early diastolic velocity (E') and systolic velocity, and systolic myocardial velocity (Sm) were assessed echocardiographically using M-mode, 2-dimensional, and tissue Doppler imaging (TDI) before and at 1 and 3 months following treatment. RESULTS: Antihypertensive treatment reduced BP significantly at 3 months (168 +/- 2/97 +/- 1-143 +/- 2/86 +/- 1 mm Hg, P < 0.0001). Both drugs had similar and significant effects on TDI E' which increased from 7.8 +/- 0.2 to 10 +/- 0.3 cm/s (P < 0.001). The improvement in TDI E' was independent of LV mass index (LVMI) regression but was significantly related to the improvement in Sm (r = 0.73, P < 0.0001) and the fall in systolic BP (R = 0.51, P < 0.001). Normalization of diastolic function was associated with better control of BP (130 +/- 4/81 +/- 2 mm Hg vs. 149 +/- 2/88 +/- 1 mm Hg, P < 0.05). In a stepwise regression model, reduction in systolic BP (P < 0.001) and TDI Sm (P < 0.0001) emerged as independent determinants of improvement in TDI E' with no contribution from age, gender or change in relative wall thickness (RWT) (R(2) = 0.68, P < 0.0001). CONCLUSIONS: Achieving good BP control and enhancement in systolic function determines the improvement in diastolic function in early hypertension.

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.

Physical activity and the elderly.

Functional ageing processes are characterized by a loss of performance capabilities regarding coordination, flexibility, strength, speed, and endurance. The effects of ageing processes on the cardiovascular system and skeletal muscle are the foci of attention. After age 30, the maximum aerobic dynamic performance capacity decreases by an average of 8% per decade. The causes are mainly a reduction in the maximum cardiac output and decreases in capillarization and in the skeletal muscle mass. An improvement in the maximum oxygen uptake by 18% and in the aerobic-anaerobic threshold by 22% was achieved in untrained men aged 55-70 years, in a 12-week-long bicycle ergometer-training programme. The strength of the skeletal muscle decreases particularly after 50-60 years of age. The main cause is the reduction in the number of motor units and muscle fibres. Further, modifications of the endothelial function and the development of sarcopenia are of particular importance in ageing processes. General aerobic dynamic training can improve the endothelial function in old age and thus help prevent cardiovascular diseases. Strength training is most appropriate for the prevention of sarcopenia. Imaging techniques over the last 20 years have provided new findings on the influence and the significance of physical activity on the brain. We call this new interdisciplinary area 'Exercise Neuroscience'. Demands on coordination and aerobic dynamic endurance are suitable in counteracting age-related neuronal cellular loss, synapsis hypotrophy, and in improving neurogenesis and capillarization. Adjusted physical activity is thus capable of counteracting age-related changes and performance loss not only in the cardiovascular system but also in the brain.

Myocardial stiffness and the timing difference between tissue Doppler imaging Ea and peak mitral valve opening can distinguish physiological hypertrophy in athletes from hypertrophic cardiomyopathy.

AIM: To differentiate between physiological and pathological left ventricular hypertrophy in athletes using echocardiography. METHODS AND RESULTS: Eleven patients with mild hypertrophic cardiomyopathy were compared against 17 international rowers with mild left ventricular hypertrophy, and 30 age matched controls. The time difference between peak Ea (Doppler tissue imaging) and peak mitral valve opening (using M-mode) was measured simultaneously. A novel index (E/Ea)/LVEDD, as a measure of left ventricular stiffness was recorded. In athletes the peak Ea preceded peak mitral opening by: median (interquartile range) 20 ms (10,20), control group 15 ms (0,30), compared with HCM where Ea followed peak mitral opening by 10 ms (0,20), P<0.0001. In athletes the index of left ventricular stiffness was lower than controls 1.2 (0.93,1.4) versus 1.5 (1.3,1.6), and HCM 2.2 (2.0,2.3), P<0.0001. CONCLUSION: Physiological hypertrophy can be differentiated from hypertrophic cardiomyopathy in athletes using the Ea-peak mitral opening difference, and our index of ventricular stiffness.