Real-time feedback on chest compression efficacy by hands-free carotid Doppler in a porcine model.

Aim: Current guidelines for cardiopulmonary resuscitation (CPR) recommend a one-size-fits-all approach in relation to the positioning of chest compressions. We recently developed RescueDoppler, a hands-free Doppler ultrasound device for continuous monitoring of carotid blood flow velocity during CPR. The aim of the present study is to investigate whether RescueDoppler via real-time hemodynamic feedback, could identify both optimal and suboptimal compression positions. Methods: In this model of animal cardiac arrest, we induced ventricular fibrillation in five domestic pigs. Manual chest compressions were performed for ten seconds at three different positions on the sternum in random order and repeated six times. We analysed Time Average Velocity (TAV) with chest compression position as a fixed effect and animal, position, and sequential time within animals as random effects. Furthermore, we compared TAV to invasive blood pressure from the contralateral carotid artery. Results: We were able to detect changes in TAV when altering positions. The positions with the highest (range 19 to 48 cm/s) and lowest (6-25 cm/s) TAV were identified in all animals, with corresponding peak pressure 50-81 mmHg, and 46-64 mmHg, respectively. Blood flow velocity was, on average, highest at the middle position (TAV 33 cm/s), but with significant variability between animals (SD 2.8) and positions within the same animal (SD 9.3). Conclusion: RescueDoppler detected TAV changes during CPR with alternating chest compression positions, identifying the position yielding maximal TAV. Future clinical studies should investigate if RescueDoppler can be used as a real-time hemodynamical feedback device to guide compression position.

Changes in cardiopulmonary exercise capacity and limitations 3-12 months after COVID-19.

RATIONALE: To describe cardiopulmonary function during exercise 12 months after hospital discharge for coronavirus disease 2019 (COVID-19), assess the change from 3 to 12 months, and compare the results with matched controls without COVID-19. METHODS: In this prospective, longitudinal, multicentre cohort study, hospitalised COVID-19 patients were examined using a cardiopulmonary exercise test (CPET) 3 and 12 months after discharge. At 3 months, 180 performed a successful CPET, and 177 did so at 12 months (mean age 59.3 years, 85 females). The COVID-19 patients were compared with controls without COVID-19 matched for age, sex, body mass index and comorbidity. Main outcome was peak oxygen uptake (V'O2  peak). RESULTS: Exercise intolerance (V'O2  peak <80% predicted) was observed in 23% of patients at 12 months, related to circulatory (28%), ventilatory (17%) and other limitations including deconditioning and dysfunctional breathing (55%). Estimated mean difference between 3 and 12 months showed significant increases in V'O2  peak % pred (5.0 percentage points (pp), 95% CI 3.1-6.9 pp; p<0.001), V'O2  peak·kg-1 % pred (3.4 pp, 95% CI 1.6-5.1 pp; p<0.001) and oxygen pulse % pred (4.6 pp, 95% CI 2.5-6.8 pp; p<0.001). V'O2  peak was 2440 mL·min-1 in COVID-19 patients compared to 2972 mL·min-1 in matched controls. CONCLUSIONS: 1 year after hospital discharge for COVID-19, the majority (77%), had normal exercise capacity. Only every fourth had exercise intolerance and in these circulatory limiting factors were more common than ventilator factors. Deconditioning was common. V'O2  peak and oxygen pulse improved significantly from 3 months.

Cardiopulmonary exercise capacity and limitations 3†months after COVID-19 hospitalisation.

BACKGROUND: This study aimed to describe cardiopulmonary function during exercise 3 months after hospital discharge for COVID-19 and compare groups according to dyspnoea and intensive care unit (ICU) stay. METHODS: Participants with COVID-19 discharged from five large Norwegian hospitals were consecutively invited to a multicentre, prospective cohort study. In total, 156 participants (mean age 56.2 years, 60 females) were examined with a cardiopulmonary exercise test (CPET) 3 months after discharge and compared with a reference population. Dyspnoea was assessed using the modified Medical Research Council (mMRC) dyspnoea scale. RESULTS: Peak oxygen uptake (V'O2  peak) <80% predicted was observed in 31% (n=49). Ventilatory efficiency was reduced in 15% (n=24), while breathing reserve <15% was observed in 16% (n=25). Oxygen pulse <80% predicted was found in 18% (n=28). Dyspnoea (mMRC ≥1) was reported by 47% (n=59). These participants had similar V'O2  peak (p=0.10) but lower mean±sd V'O2  peak·kg-1 % predicted compared with participants without dyspnoea (mMRC 0) (76±16% versus 89±18%; p=0.009) due to higher body mass index (p=0.03). For ICU- versus non-ICU-treated participants, mean±sd V'O2  peak % predicted was 82±15% and 90±17% (p=0.004), respectively. Ventilation, breathing reserve and ventilatory efficiency were similar between the ICU and non-ICU groups. CONCLUSIONS: One-third of participants experienced V'O2  peak <80% predicted 3 months after hospital discharge for COVID-19. Dyspnoeic participants were characterised by lower exercise capacity due to obesity and lower ventilatory efficiency. Ventilation and ventilatory efficiency were similar between ICU- and non-ICU-treated participants.

High day-to-day and diurnal variability of oxidative stress and inflammation biomarkers in people with type 2 diabetes mellitus and healthy individuals.

Objective: Assess the variability and differences in oxidative stress, antioxidant, and inflammatory biomarkers in people with type 2 diabetes mellitus (T2D) and healthy controls. Methods:: Ten men and women diagnosed with T2D and ten healthy matched controls (CON) were recruited. Participants had venous blood taken at six different time points on different days, three in the morning (after overnight fast) and three in the afternoon. Inflammation (IL-6, 8, 10 and TNF-α), oxidative stress/antioxidant biomarkers (F2-isoprostanes, protein carbonyls, total antioxidant capacity (TAC), glutathione peroxidase activity, IL-6, 8 & 10 and TNF-α) were assessed. Results:: Biomarker concentrations were similar between groups. There was large variability in nearly all biomarkers for both groups. For inflammatory measures, intra-individual coefficients of variation (CV) ranged from 64.0-92.1% and 100.9-259.0% for inter-individual differences. CVs for oxidative stress markers were lower (7.4-31.2% for intra-individual and 8.6-43.0% for inter-individual). TAC had the lowest intra-individual CV - 7% for T2D and 8% for CON. Protein carbonyls were more variable in the afternoon (34% CV) compared to morning (24% CV) in CON. IL-6 intra-individual CV was different between groups for afternoon measurements (93% T2D, 60% CON). Conclusion:: Oxidative stress and inflammatory biomarkers show considerable variation in both T2D and healthy populations. Trial registration: ClinicalTrials.gov identifier: NCT01206725.

Cardiac function in newborns of obese women and the effect of exercise during pregnancy. A randomized controlled trial.

BACKGROUND: The prevalence of maternal obesity is rising. Pre-pregnancy obesity is associated with later cardiovascular disease in the child and the underlying pathogenesis begins in early life. Therefore, pregnancy and infancy are key periods for potential intervention. The aim of this study was to study the cardiac function in newborns of obese women compared to newborns of normal-weight women, and to determine if exercise intervention during pregnancy could have an effect on cardiac function of newborns to obese women. MATERIAL AND METHODS: Fifty-five pregnant women, 51 obese (BMI ≥ 30 kg/m2) and four overweight (BMI 28-30 kg/m2), were randomized to an exercise training group (n = 27) or a control group (standard maternity care, n = 28). From gestational week 14 until delivery participants in the intervention group were offered supervised training sessions three times weekly. In addition, they were told to exercise at home once weekly. All newborns had an echocardiogram performed 1-3 days and 6-8 weeks after delivery. The results were compared with newborns of normal weight women (n = 20, standard maternity care). RESULTS: Newborns of obese women had an impaired systolic and diastolic cardiac function with reduced global strain, strain rate, tissue Doppler velocities and a thicker intraventricular septum at birth and after 6-8 weeks after delivery compared to newborns of normal weight women. Exercise had no statistically significant effect on either of the cardiac function parameters. The mean (± standard deviation) adherence to the exercise protocol was 1.3 ± 0.8 sessions per week for supervised training and 0.8 ± 0.7 sessions per week for home-based exercise training. CONCLUSIONS: Newborns of obese women had reduced cardiac function and thicker intraventricular septum compared to newborns of normal weight women. Exercise training during pregnancy had no significant effect, potentially due to a low number of subjects and low adherence to the exercise protocol. TRIAL REGISTRATION: ClinicalTrials.gov NCT01243554.

Exercise Training Normalizes Timing of Left Ventricular Untwist Rate, but Not Peak Untwist Rate, in Individuals with Type 2 Diabetes and Diastolic Dysfunction: A Pilot Study.

BACKGROUND: There is limited information regarding the role of left ventricular (LV) twist and the effect of exercise in type 2 diabetes (T2D). The aim of this study was to compare LV twist parameters in patients with T2D versus healthy control subjects and the effects of high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on LV twist in patients with T2D with diastolic dysfunction. METHODS: This study, which included both prospective and retrospective components, included 47 patients with T2D and diastolic dysfunction and 37 healthy individuals. Patients with T2D were randomized to HIIE (4 × 4 min at 90%-95% of maximal heart rate, three times a week, 120 min/wk; n = 24) or MIE (210 min/wk; n = 23) for 12 weeks and examined with echocardiography (LV twist by speckle-tracking method) at baseline and posttest. The control subjects received no intervention and were matched according to age, gender, and body mass index to those completing the intervention. RESULTS: In total, 37 subjects completed 12 weeks of MIE (n = 17) or HIIE (n = 20). LV peak untwist rate (UTR) was similar in patients with T2D and control subjects (P Ëƒ .05). At baseline, LV peak UTR, relative to total diastolic period, occurred 5.8 percentage points later in patients with T2D compared with control subjects (P = .004). Time to peak UTR was shortened by 6.5 percentage points (P = .002) and 7.7 percentage points (P < .001) after MIE and HIIE, respectively. Time to peak UTR was similar to that in control subjects after exercise interventions. CONCLUSIONS: In patients with T2D and diastolic dysfunction, LV peak UTR was similar, but time to peak LV UTR was delayed compared with control subjects. Twelve weeks of endurance exercise normalized the timing of UTR.

Fast food increases postprandial cardiac workload in type 2 diabetes independent of pre-exercise: A pilot study.

BACKGROUND: Type 2 diabetes aggravates the postprandial metabolic effects of food, which increase cardiovascular risk. We investigated the acute effects of fast food on postprandial left ventricular (LV) function and the potential effects of pre-exercise in type 2 diabetes individuals. METHODS: We used a cross-over study including 10 type 2 diabetes individuals (7 male and 3 females; 53.4 ± 8.1 years; 28.3 ± 3.8 kg/m(2); type 2 diabetes duration 3.1 ± 1.8 years) and 10 controls (7 male and 3 females; 52.8 ± 10.1 years; 28.5 ± 4.2 kg/m(2)) performing high intensity interval exercise (HIIE; 40 min, 4 × 4 min intervals, 90-95% HRmax), moderate intensity exercise (MIE; 47 min, 70% HRmax) and no exercise (NE) in a random order 16-18 hours prior to fast-food ingestion. Baseline echocardiography, blood pressure and biochemical measurements were recorded prior to and 16-18 hours after exercise, and 30 minutes, 2 hours and 4 hours after fast food ingestion. RESULTS: LV diastolic (peak early diastolic tissue velocity, peak early diastolic filling velocity), and systolic workload (global strain rate, peak systolic tissue velocity, rate pressure product) increased after consumption of fast food in both groups. In contrast to controls, the type 2 diabetes group had prolonged elevations in resting heart rate and indications of prolonged elevations in diastolic workload (peak early diastolic tissue velocity) as well as reduced systolic blood pressure after fast food consumption. No significant modifications due to exercise in the postprandial phase were seen in any group. CONCLUSIONS: Our findings indicate that fast-food induces greater and sustained overall cardiac workload in type 2 diabetes individuals versus body mass index and age matched controls; exercise 16-18 hours pre-meal has no acute effects to the postprandial phase. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01991769.

Effect of 24 sessions of high-intensity aerobic interval training carried out at either high or moderate frequency, a randomized trial.

PURPOSE: The training response of an intensified period of high-intensity exercise is not clear. Therefore, we compared the cardiovascular adaptations of completing 24 high-intensity aerobic interval training sessions carried out for either three or eight weeks, respectively. METHODS: Twenty-one healthy subjects (23.0±2.1 years, 10 females) completed 24 high-intensity training sessions throughout a time-period of either eight weeks (moderate frequency, MF) or three weeks (high frequency, HF) followed by a detraining period of nine weeks without any training. In both groups, maximal oxygen uptake (VO2max) was evaluated before training, at the 9(th) and 17(th) session and four days after the final 24(th) training session. In the detraining phase VO2max was evaluated after 12 days and thereafter every second week for eight weeks. Left ventricular echocardiography, carbon monoxide lung diffusion transfer factor, brachial artery flow mediated dilatation and vastus lateralis citrate maximal synthase activity was tested before and after training. RESULTS: The cardiovascular adaptation after HF training was delayed compared to training with MF. Four days after ending training the HF group showed no improvement (+3.0%, p = 0.126), whereas the MF group reached their highest VO2max with a 10.7% improvement (p<0.001: group difference p = 0.035). The HF group reached their highest VO2max (6.1% increase, p = 0.026) twelve days into the detraining period, compared to a concomitant reduction to 7.9% of VO2max (p<0.001) above baseline in the MF group (group difference p = 0.609). CONCLUSION: Both HF and MF training of high-intensity aerobic exercise improves VO2max. The cardiovascular adaptation following a HF programme of high-intensity exercise is however delayed compared to MF training. TRIAL REGISTRATION: ClinicalTrials.gov NCT00733941.

Aerobic exercise training improves right- and left ventricular systolic function in patients with COPD.

OBJECTIVE: The aim of this study was to investigate the effects of moderate continuous training (MCT) and high intensity aerobic interval training (AIT) on systolic ventricular function and aerobic capacity in COPD patients. METHODS: Seventeen patients with COPD (64 ± 8 years, 12 men) with FEV1 of 52.8 ± 11% of predicted, were randomly assigned to isocaloric programs of MCT at 70% of max heart rate (HR) for 47 minutes) or AIT (~90% of max HR for 4×4 minutes) three times per week for 10 weeks. Baseline cardiac function was compared with 17 age- and sex-matched healthy individuals. Peak oxygen uptake (VO(2-peak)) and left (LV) and right ventricular (RV) function examined by echocardiography, were measured at baseline and after 10 weeks of training. RESULTS: At baseline, the COPD patients had reduced systolic function compared to healthy controls (p < 0.05). After the training, AIT and MCT increased VO(2-peak) by 8% and 9% and work economy by 7% and 10%, respectively (all p < 0.05). LV and RV systolic function both improved (p < 0.05), with no difference between the groups after the two modes of exercise training. Stroke volume increased by 17% and 20%, LV systolic tissue Doppler velocity (S') by 18% and 17% and RV S' by 15% after AIT and MCT, respectively (p < 0.05). CONCLUSION: Systolic cardiac function is reduced in COPD. Both AIT and MCT improved systolic cardiac function. In contrast to other patient groups studied, higher exercise intensity does not seem to have additional effects on cardiac function or aerobic capacity in COPD patients.

High-intensity knee extensor training restores skeletal muscle function in COPD patients.

Improving reduced skeletal muscle function is important for optimising exercise tolerance and quality of life in chronic obstructive pulmonary disease (COPD) patients. By applying high-intensity training to a small muscle group, we hypothesised a normalisation of muscle function. Seven patients with COPD performed 6 weeks (3 days·week(-1)) of high-intensity interval aerobic knee extensor exercise training. Five age-matched healthy individuals served as a reference group. Muscle oxygen uptake and mitochondrial respiration of the vastus lateralis muscle were measured before and after the 6-week training programme. Initial peak work and maximal mitochondrial respiration were reduced in COPD patients and improved significantly after the training programme. Peak power and maximal mitochondrial respiration in vastus lateralis muscle increased to the level of the control subjects and were mainly mediated via improved complex I respiration. Furthermore, when normalised to citrate synthase activity, no difference in maximal respiration was found either after the intervention or compared to controls, suggesting normal functioning mitochondrial complexes. The present study shows that high-intensity training of a restricted muscle group is highly effective in restoring skeletal muscle function in COPD patients.

Aerobic interval training compensates age related decline in cardiac function.

OBJECTIVES: To study the effect of aerobic interval training (AIT) on myocardial function in sedentary seniors compared to master athletes (MA) and young controls. DESIGN: Sixteen seniors (72 ± 1 years, 10 men) performed AIT (4 × 4 minutes) at ≈ 90% of maximal heart rate three times per week for 12 weeks. Results were compared with 11 male MA (74 ± 2 years) and 10 young males (23 ± 2 years). RESULTS: Seniors had an impaired diastolic function compared to the young at rest. AIT improved resting diastolic parameters, increased E/A ratio (44%, p <0.01), early diastolic tissue Doppler velocity (e') (11%, p <0.05) and e' during exercise (11%, p <0.01), shortened isovolumic relaxation rate (IVRT) (13%, p <0.01). Left ventricle (LV) systolic function (S') was unaffected at rest, whereas S' during stress echo increased by 29% (p <0.01). Right ventricle (RV) S' and RV fractional area change (RFAC) increased (9%, p <0.01, 12%, p =0.01, respectively), but not RV e'. MA had the highest end-diastolic volume, stroke volume, diastolic reserve and RV S'. CONCLUSION: AIT partly reversed the impaired age related diastolic function in healthy seniors at rest, improved LV diastolic and systolic function during exercise as well as RV S' at rest.

Aerobic interval training reduces blood pressure and improves myocardial function in hypertensive patients.

AIMS: Exercise is recommended as prevention, management, and control of all stages of hypertension. There are still controversies about the optimal training dose, frequency, and intensity. We aimed to study the effect of aerobic interval training on blood pressure and myocardial function in hypertensive patients. METHODS AND RESULTS: A total of 88 patients (52.0 ± 7.8 years, 39 women) with essential hypertension were randomized to aerobic interval training (AIT) (>90% of maximal heart rate, correlates to 85-90% of VO(2max)), isocaloric moderate intensity continuous training (MIT) (~70% of maximal heart rate, 60% of VO(2max)), or a control group. Exercise was performed on a treadmill, three times per week for 12 weeks. Ambulatory 24-hour blood pressure (ABP) was the primary endpoint. Secondary endpoints included maximal oxygen uptake (VO(2max)), mean heart rate/24 hour, flow mediated dilatation (FMD), total peripheral resistance (TPR), and myocardial systolic and diastolic function by echocardiography. Systolic ABP was reduced by 12 mmHg (p < 0.001) in AIT and 4.5 mmHg (p = 0.05) in MIT. Diastolic ABP was reduced by 8 mmHg (p < 0.001) in AIT and 3.5 mmHg (p = 0.02) in MIT. VO(2max) improved by 15% (p < 0.001) in AIT and 5% (p < 0.01) in MIT. Systolic myocardial function improved in both exercise groups, diastolic function in the AIT group only. TPR reduction and increased FMD were only observed in the AIT group. CONCLUSIONS: This study indicates that the blood pressure reducing effect of exercise in essential hypertension is intensity dependent. Aerobic interval training is an effective method to lower blood pressure and improve other cardiovascular risk factors.

Impaired cardiac function among obese adolescents: effect of aerobic interval training.

OBJECTIVES: To measure cardiac function before and after 3 months of aerobic interval training in obese adolescents and to compare the findings with those in lean counterparts. DESIGN: Exercise intervention study. Cardiac function was assessed by echocardiography and maximal oxygen uptake by ergospirometry. SETTING: The obese adolescents were referred from general practice to the St Olav University Hospital, Trondheim, Norway, and the control group was recruited from 2 schools. PARTICIPANTS: Ten obese adolescents (mean [SD] age, 14.8 [1.2] years; mean [SD] body mass index {BMI; calculated as weight in kilograms divided by height in meters squared}, 33.5 [4.3]) and 10 lean counterparts (mean [SD] age, 14.9 [1.3] years; mean [SD] BMI, 20.4 [3.0]) participated. Intervention Aerobic interval training (4 x 4 minutes at 90% of maximal heart rate, 40 minutes of training in total) was performed twice per week for 13 weeks among the obese adolescents, whereas the lean counterparts only performed the tests. MAIN OUTCOME MEASURES: Left ventricular end-diastolic volume, stroke volume, and maximal oxygen uptake. RESULTS: Maximal oxygen uptake was 41.4% lower among the obese adolescents compared with the lean counterparts, but the maximal oxygen uptake increased by 8.6% (P = .008) after intervention. Obese adolescents initially had 7.8% and 14.5% lower left ventricular end-diastolic and stroke volumes, 21.3% reduced global strain rate and 16.3% global strain, reduced mitral annulus excursion and systolic/diastolic tissue velocity, longer isovolumic relaxation time, and longer deceleration time compared with the lean counterparts. No group difference was observed after the intervention. Aerobic interval training increased the ejection fraction but was lower compared with the lean counterparts. Aerobic interval training reduced fat content by 2.0% (P = .005) among the obese adolescents. CONCLUSIONS: Aerobic interval training almost restored an impaired systolic and diastolic cardiac function among obese adolescents when compared with lean counterparts. These results may have implications for future treatment programs for obese adolescents.

Recovery of function after acute myocardial infarction evaluated by tissue Doppler strain and strain rate.

BACKGROUND: The aim of this study was to investigate the changes and time course of recovery of regional myocardial function within the first week following successful primary coronary intervention in patients with first-time ST-segment elevation myocardial infarctions using myocardial deformation analysis, which is more quantitative and thus more objective than the wall motion score. METHODS: Thirty-one consecutive patients admitted with ST-segment elevation myocardial infarctions were studied on days 1, 2, 3, and 7 using strain and strain rate tissue Doppler echocardiography. RESULTS: The mean peak troponin T level was 7.0 microg/L, and 15 patients had anterior and 16 had inferior infarct localization. Peak systolic strain rate and end-systolic strain increased significantly on day 2, both in segments with moderately reduced function (-0.6 to -1.0 s(-1) vs -8% to -15%, P < .001) and in severely reduced function (-0.2 to -1.0 s(-1) vs 1% to -12%, P < .001), but there were no further changes. Mean wall motion score in infarct related segments decreased significantly from day 1 to day 2 (2.7 to 2.4, P = .001) and from day 3 to day 7 (2.3 to 2.2, P = .001). CONCLUSIONS: Recovery of regional function after ST-segment elevation myocardial infarction occurred within 2 days and could be detected by wall motion score, strain rate, and strain. However, strain and strain rate were better discriminative parameters for the changes in function as well as being better to assess near normalization on day 2. This could have a clinical impact on early management in patients who undergo percutaneous coronary intervention.

Interaction of left ventricular geometry and myocardial ischemia in the response of myocardial deformation to stress.

Myocardial deformation parameters are sensitive markers of global left ventricular (LV) systolic function, but their interaction with LV geometry is unknown. We sought to investigate the effect of LV geometry on myocardial deformation and its interaction with coronary artery disease (CAD). A total of 126 patients with normal resting LV function who underwent dobutamine stress echocardiography subsequently underwent coronary angiography within 6 months. Longitudinal myocardial deformation was calculated using tissue Doppler echocardiography. The extent of CAD was identified by quantitative coronary angiography. Patients with an increased relative wall thickness had a significantly lower peak strain rate (SR) and a smaller change in SR with stress, with no differences in the at rest values. Those with CAD, had significantly lower peak SR values and change in SR with no difference in resting measures. A linear regression model showed that the relative wall thickness and extent of CAD were the strongest predictors of change in SR. An increasing extent of CAD caused a steady degradation in the peak SR and change in peak SR. Markers of longitudinal myocardial deformation at peak stress reflect both myocardial and interstitial properties. In conclusion, a major determinant of subendocardial function is the wall thickness, as measured by the relative wall thickness, and not LV hypertrophy.

Association of myocardial deformation with mortality independent of myocardial ischemia and left ventricular hypertrophy.

OBJECTIVES: The aim of this study was to investigate the relative contributions of left ventricular hypertrophy (LVH) and myocardial ischemia to the association between abnormal myocardial deformation during dobutamine stress echocardiography (DSE) and mortality. BACKGROUND: Both left ventricular hypertrophy (LVH) and myocardial ischemia are known to convey a significant adverse prognostic impact. In addition, myocardial deformation is an independent predictor of outcome in patients undergoing DSE. The mechanism of this association, however, is undefined. METHODS: We studied 223 consecutive individuals with normal resting LV function undergoing DSE. The LV mass was indexed to height (g/m(2.7)) (LVMI), and LVH was designated as LVMI >or=51 g/m(2.7). Myocardial ischemia was defined on the basis of new, inducible wall motion abnormalities. Customized software was used to measure global strain rate (SRs), which was averaged in 18 myocardial segments at peak stress. Individuals were followed for all-cause mortality over a mean of 5.4 +/- 1.4 years. RESULTS: Left ventricular hypertrophy was identified in 83 individuals (37%), and 63 (28%) had ischemia documented at DSE. In a Cox proportional hazards model, the strongest predictor of all-cause mortality for the total population was SRs (hazard ratio: 2.16, 95% confidence interval: 1.63 to 2.87, p < 0.01). Both LVH (p < 0.01) and ischemia (p < 0.05) had a significant adverse prognostic impact. Individuals with both LVH and ischemia had the worst outcome (p = 0.02) in comparison with the rest of the population. Among LV geometric patterns, concentric LVH had the worst outcome (p < 0.01). However, SRs was the strongest predictor of mortality in both LVH and ischemia. In a model reflecting clinical practice, SRs provided a significant increment in model power over baseline and variables identified at DSE. CONCLUSIONS: The SRs is a powerful, independent predictor of all-cause mortality in individuals undergoing DSE and provides incremental information over baseline clinical and echocardiographic variables. Whereas SRs is influenced by both LVH and myocardial ischemia, both independently and additively, its predictive power for mortality is independent of both.

Automatic timing of aortic valve closure in apical tissue Doppler images.

Ultrasound color tissue Doppler imaging (TDI) can be used to estimate velocities of moving left ventricular cardiac tissue. Aortic valve closure (AVC) can be observed as a notch in apical TDI velocity/time curves occurring after ejection, but before early relaxation. This work sought to evaluate automatic and automated algorithms using TDI for timing AVC. Mitral valve position and the time point of early relaxation were extracted and used to accomplish the task. To test the algorithms, phonocardiogram of the second heart sound was recorded simultaneously with TDI and used as a reference method. The algorithms were tested on apical views of 16 healthy subjects. In 98% of the cardiac cycles, the automatic algorithm estimated the time point of AVC within 25 ms of the reference. Automatic detection of AVC might save manual effort and provide a marker separating ejection and diastole for further automated analysis.