Longitudinal left ventricular function is globally depressed within a week of STEMI

Sixty percent of stroke volume (SV) is generated by atrioventricular plane displacement (AVPD) in a healthy left ventricle (LV). The aims were to determine the effect of ST‐elevation myocardial infarction (STEMI) on AVPD and contribution of AVPD to SV and to study the relationship between AVPD and infarct size (IS) and location. Patients from CHILL‐MI and MITOCARE studies with cardiovascular magnetic resonance within a week of STEMI (n = 177, 59 ± 11 years) and healthy controls (n = 20, 62 ± 11 years) were included. Left ventricular volumes were quantified in short‐axis images. AVPD was measured in six locations in long‐axis images. Longitudinal contribution to SV was calculated as AVPD multiplied by the short‐axis epicardial area. Patients (IS 17 ± 10% of LV) had decreased ejection fraction (48 ± 8%) compared to controls (60 ± 5%, P<0·001). Global AVPD was decreased in patients (11 ± 2 mm versus 15 ± 2 mm in controls, P<0·001) and this held true for both infarcted and remote segments. AVPD contribution to SV was lower in patients (58 ± 9%) than in controls (64 ± 8%) (P<0·001). There was a weak negative correlation between IS and AVPD (r²=0·06) but no differences in global AVPD linked to infarct location. Decrease in global and regional AVPD occur even in remote myocardium within 1 week of STEMI. Global AVPD decrease is independent of MI location, and MI size has only minor effect. Longitudinal pumping is slightly lower compared to controls but remains to be the main component to SV even after STEMI. These results highlight the difficulty in determining infarct location and size from longitudinal measures of LV function.     

Right ventricular long-axis function in relation to left ventricular systolic function

A decrease in left ventricular (LV) systolic function is accompanied by a decrease in maximal relaxation velocity in LV long‐axis direction, but is it also accompanied by a decrease in right ventricular (RV) long‐axis function? To study this 35 consecutive patients were examined by echocardiography. Ejection fraction (LVEF) and mitral annulus motion (MAM) were used as indices of LV systolic function and tricuspid annulus motion (TAM), that is the systolic shortening in RV long‐axis direction, was used as an index of RV systolic long‐axis function. In the same way the maximal relaxation velocity in LV long‐axis direction, that is the maximal diastolic velocity of MAM (MDV MAM), has been suggested as an index of LV diastolic function the maximal diastolic velocity of TAM (MDV TAM) can be supposed to be an index of RV diastolic function measuring the maximal relaxation velocity in the RV long‐axis direction. A significant positive correlation was found between MDV TAM and MAM (r = 0·64, P<0001) and LVEF (r = 0·54, P = 0·001) and between TAM and the two studied indices of LV systolic function, with the highest correlation to MAM (r = 0·68, P<0·001) and the lowest to LVEF (r = 0·57, P<0·001). Thus, a decrease in LV systolic function is accompanied by a decrease in both systolic and diastolic RV long‐axis function, findings that probably are due to the close anatomical connection between the ventricles and to changes that occur in afterload of the RV secondary to LV systolic dysfunction.     

The relation between mitral annulus motion and left ventricular ejection fraction in atrial fibrillation

Mitral annulus motion (MAM) has recently been introduced as an index of left ventricular function. Previous studies have shown a good agreement between MAM (mm) × 5 and ejection fraction in middle‐aged and elderly patients. These studies only included patients with sinus rhythm, while patients with atrial fibrillation were excluded. In the present study, MAM was reduced in patients with atrial fibrillation while ejection fraction (EF) did not differ from age‐matched control patients with sinus rhythm. The ‘conversion factor’ (EF/MAM) was 7·2 in the group with atrial fibrillation and 5·1 in controls with sinus rhythm. This difference must be taken into account when MAM is used to estimate left ventricular function in patients with atrial fibrillation. Patients with atrial fibrillation had lower stroke volume and higher heart rate than patients with sinus rhythm. A decreased systolic long‐axis shortening was found (P<0·005) compared to patients with sinus rhythm, but no difference in short‐axis diameter shortening.     

The relation between ejection fraction and mitral annulus motion before and after direct‐current electrical cardioversion

Mitral annulus motion (MAM) and the relation between left ventricular ejection fraction (EF) and MAM has been shown to differ between patients with sinus rhythm and patients with atrial fibrillation. However, it has not been investigated how the relation between EF and MAM changes on direct‐current (DC) electrical cardioversion to sinus rhythm. Therefore, 31 consecutive patients on the waiting list for DC electrical cardioversion were examined by echocardiography before DC electrical cardioversion, and those who maintained sinus rhythm (13 patients) were examined again 4–8 weeks after cardioversion. The conversion factor (CF) (ratio EF/MAM) decreased from 8·4 ± 1·7 before to 5·8 ± 0·8 SD after cardioversion (P<0·001). The EF increased slightly (P<0·05) but the MAM had a much greater increase (P<0·001), resulting in the decrease in CF. There was no significant difference in CF between patients after cardioversion and age‐ and gender‐matched control patients with sinus rhythm, indicating that CF is normalized or almost normalized 4–8 weeks after cardioversion. This indicates that when MAM is used for investigation of the left ventricular function, and the function is expressed as EF, the same CF as in other patients with sinus rhythm can be used 4–8 weeks after DC electrical cardioversion.     

Cardiac power output and its response to exercise in athletes and non‐athletes

Cardiac power output (CPO) is an integrative measure of overall cardiac function as it accounts for both, flow‐ and pressure‐generating capacities of the heart. The purpose of the present study was twofold: (i) to assess cardiac power output and its response to exercise in athletes and non‐athletes and (ii) to determine the relationship between cardiac power output and reserve and selected measures of cardiac function and structure. Twenty male athletes and 32 age‐ and gender‐matched healthy sedentary controls participated in this study. CPO was calculated as the product of cardiac output and mean arterial pressure, expressed in watts. Measures of hemodynamic status, cardiac structure and pumping capability were assessed by echocardiography. CPO was assessed at rest and after peak bicycle exercise. At rest, the two groups had similar values of cardiac power output (1·08 ± 0·2 W versus 1·1 ± 0·24 W, P>0·05), but the athletes demonstrated lower systolic blood pressure (109·5 ± 6·2 mmHg versus 117·2 ± 8·2 mmHg, P<0·05) and thicker posterior wall of the left ventricle (9·8 ± 1 mm versus 9 ± 1·1 mm, P<0·05). Peak CPO was higher in athletes (5·87 ± 0·75 W versus 5·4 ± 0·69 W, P<0·05) as was cardiac reserve (4·92 ± 0·66 W versus 4·26 ± 0·61 W, P<0·05), respectively. Peak exercise CPO and reserve were only moderately correlated with end‐diastolic volume (r = 0·54; r = 0·46, P<0·05) and end‐diastolic left ventricular internal diameter (r = 0·48; r = 0·42, P<0·05), respectively. Athletes demonstrated greater maximal cardiac pumping capability and reserve than non‐athletes. The study provides new evidence that resting measures of cardiac structure and function need to be considered with caution in interpretation of maximal cardiac performance.     

Assessment of left ventricular systolic function using tissue Doppler imaging in children after successful repair of aortic coarctation

Aim: Assessment of left ventricular systolic function in children after the successful repair of aortic coarctation using tissue Doppler imaging (TDI). Methods: The study group consisted of 32 patients (mean age 12·0 ± 4·2 years) after the aortic coarctation repair. The TDI parameters and the conventional echocardiographic endocardial and midwall indices of the left ventricular systolic function were analysed and compared with the results obtained from 34 healthy children. Results: The systolic mitral annulus motion velocity, systolic myocardial velocity of the medial segment of the left ventricular septal wall, left ventricular strain and Strain Rate (SR) in the study group were significantly higher than in the control group, respectively: 6·92 ± 0·75 cm s^?1 versus 6·45 ± 0·83 cm s^?1; 5·82 ± 1·03 cm s^?1 versus 5·08 ± 1·11 cm s^?1; ?28·67 ± 6·04% versus ?22·53 ± 6·44% and ?3·20 ± 0·76 s^?1 versus ?2·39 ± 0·49 s^?1. Except midwall shortening fraction the conventional endocardial and midwall echocardiographic indices in the study group were significantly higher in comparison to the healthy controls. The left ventricular systolic meridional fibre stress and end‐systolic circumferential wall stress did not differ between the examined groups. There were no differences of the TDI or conventional parameters between hypertensive and normotensive patients. Conclusions: Left ventricular systolic performance in children after the surgical repair of aortic coarctation reveals tendency to rise in late follow‐up despite a satisfactory result after surgery. Higher systolic strain and SR in children treated due to coarctation of the aorta may suggest the increased preserved left ventricular performance despite normalization of afterload.     

Combined left and right ventricular volume determination by radionuclide angiocardiography using double bolus and equilibrium technique

Summary. Eighteen patients with ischaemic heart disease were studied. Left and right ventricular volumes including cardiac output (forward flow) were determined by radionuclide angiocardiography using a double bolus and equilibrium technique. As reference, cardiac output was simultaneously measured by indicator dilution. The radionuclide technique comprised four steps:

• 1 a first-pass study of right ventricle;
• 2 a bolus study of left ventricle;
• 3 an equilibrium study of left ventricle;
• 4 determination of the distribution volume of red blood cells.

Absolute volumes of left ventricle were determined from steps 2+3+4. Absolute volumes of right ventricle were calculated from stroke volume and right ventricular ejection fraction (EF) which in turn was determined from step 1 by creating composite systolic and composite diastolic images. There was an acceptable agreement between stroke volume determinations by radionuclide angiocardiography and indicator dilution (r= 0.74; P<0.001). Stroke volume determination by radionuclide was 83±20 ml (mean±SD) and by indicator dilution 84±20 ml with a difference of -1±15 ml (NS). Cardiac output determination by radionuclide was 5.24±1.37 1 min^-1 and by indicator dilution 5.28±1.23 1 min^-1 with a difference of -0.04±0.95 1 min^-1 (NS). Left ventricular EF was 0.44 ±0.14 and right ventricular EF 0.57 ±0.10. The intra-observer coefficient of variation for duplicate calculations of the radionuclide determinations was 5.5% for stroke volume, 2.5% for left ventricular EF and 4–8% for right ventricular EF.     

Muscular adaptations to fatiguing exercise with and without blood flow restriction

The purpose of this study was to determine the muscular adaptations to low‐load resistance training performed to fatigue with and without blood flow restriction (BFR). Middle‐aged (42–62 years) men (n = 12) and women (n = 6) completed 18 sessions of unilateral knee extensor resistance training to volitional fatigue over 6 weeks. One limb trained under BFR, and the contralateral limb trained without BFR [free flow (FF)]. Before and after the training, measures of anterior and lateral quadriceps muscle thickness (MTh), strength, power and endurance were assessed on each limb. The total exercise training volume was significantly greater for the FF limb compared with the BFR limb (P<0·001). Anterior quadriceps thickness and muscle function increased following the training in each limb with no differences between limbs. Lateral quadriceps MTh increased significantly more (P<0·05) in the limb trained under BFR (BFR: 3·50 ± 0·61 to 3·67 ± 0·62 cm; FF: 3·49 ± 0·73 to 3·56 ± 0·70 cm). Low‐load resistance training to volitional fatigue both with and without BFR is viable options for improving muscle function in middle‐aged individuals. However, BFR enhanced the hypertrophic effect of low‐load training and reduced the volume of exercise needed to elicit increases in muscle function.     

Elevated augmentation index derived from peripheral arterial tonometry is associated with abnormal ventricular–vascular coupling

Background: Although typically derived from the contour of arterial pressure waveform, augmentation index (AIx) may also be derived from the digital pulse volume waveform using finger plethysmography (peripheral arterial tonometry, PAT). Little is known regarding the physiologic correlates of AIx derived from PAT. In this study, we investigated the relation of PAT‐AIx with measures of ventricular–vascular coupling. Methods: Pulse volume waves were measured via PAT and used to derive AIx. Using 2‐dimensional echocardiography, effective arterial elastance index (EaI) was estimated as end‐systolic pressure/stroke volume index. Left ventricular (LV) end‐systolic elastance index (E_LVI) was calculated as end‐systolic pressure/end‐systolic volume index. Ventricular–vascular coupling ratio was defined as EaI/E_LVI. Results: Given the bi‐directional nature of ventricular–vascular uncoupling as measured by echocardiography, patients were separated into three groups: low EaI/E_LVI (<0·6, n = 21), optimal EaI/E_LVI (mean 0·6–1·2, n = 16) and high EaI/E_LVI (>1·2, n = 10). Adjusting for potential confounders (age, mean arterial pressure, height and heart rate), patients with optimal EaI/E_LVI had lower AIx (1 ± 4%, P<0·05) compared to those with low EaI/E_LVI (13 ± 4%) and high EaI/E_LVI (19 ± 5%). Conclusions: Abnormal ventricular–vascular coupling, arising from either increased effective arterial elastance or increased ventricular elastance, is associated with increased AIx as measured by PAT. Additional research is needed to examine other vascular correlates of PAT‐AIx.     

Plasma lipid and lipoprotein profiles in pre- and post-menopausal middle-aged runners

Summary. Plasma lipid and lipoprotein profiles were compared in middle-aged trained and untrained women before and after menopause. Subjects were assigned to one of four groups: (1) pre-menopausal trained (Pre-T: n= 17, aged 42 ±5 years, body fat 19±5%, training distance 53 ±20 km week^-1, V?o_2max 49 ±4 ml kg^-1 min^-1, mean±SD); (2) pre-menopausal untrained (Pre-UT: n= 26, 42 ±5 years, 24 ±7%, 34 ±6 ml kg^-1 min^-1); (3) post-menopausal trained (Post-T: n= 16, 54 ±3 years, 20 ±4%, 43 ±19 km week^-1, 41 ±5 ml kg^-1 min^-1); and (4) post-menopausal untrained (Post-UT: n= 15, 55 ±3 years, 25 ±6%, 31 ±3 ml kg^-1 min^-1). There were no significant differences in total cholesterol (range 173–194 mg dl^-1), triglyceride (56–72 mg dl^-1), and HDL-cholesterol (HDLC: 76–85 mg dl^-1) among the four groups. LDL-cholesterol (LDLC) in the post-menopausal women (Post-T: 96 ±32 mg dl^-1; Post-UT: 104 ±23 mg dl^-1) tended to be higher than in the premenopausal women (Pre-T: 86 ± 25 mg dl^-1, Pre-UT: 81 ± 23 mg dl^-1). LDLC/HDLC ratio in Post-UT (1·42 ±0·38 unit) was higher than in the pre-menopausal women (Pre-T: 1·03±0·31 unit, P<0·01; Pre-UT: 1·10±0·38 unit, P<0·05), whereas the ratio in Post-T (1·20 ±0·38 unit) was not different from those of the pre-menopausal groups. These results suggest that endurance running protects against the increase in LDLC/HDLC ratio that frequently occurs after menopause.     

Cardiac performance during exercise in patients with Fabry's disease

Background Fatigability and dyspnoea on effort are present in many patients with Fabry's disease. We assessed the determinants of cardiac performance during exercise in patients with Fabry's disease and preserved left ventricular ejection fraction at rest. Materials and methods Sixteen patients with Fabry's disease and 16 control subjects underwent radionuclide angiography at rest and during exercise, tissue Doppler echocardiography and magnetic resonance imaging at rest. Results The exercise‐induced change in stroke volume was +25 ± 14% in controls and +5·8 ± 19% in patients with Fabry's disease (P < 0·001). In 10 patients (group 1), the stroke volume increased (+19 ± 10%), and in 6 patients (group 2) it decreased (–16 ± 9%) with exercise. Patients of group 2 were older, had worse renal function, higher left ventricular mass and impaired diastolic function compared to group 1. The abnormal stroke volume response to exercise in group 2 was associated with a decrease in end‐diastolic volume (P < 0·001) and a lack of reduction of end‐systolic volume (P < 0·01) compared with both controls and group 1. The ratio of peak early‐diastolic velocity from mitral filling to peak early‐diastolic mitral annulus velocity was the only independent predictor of exercise‐induced change in stroke volume (B –0·44; SE 0·119; β–0·70; P < 0·005). Conclusions The majority of patients with Fabry's disease were able to augment stroke volume during exercise by increasing end‐diastolic volume, whereas patients with more advanced cardiac involvement may experience the inability to increase cardiac output by the Frank Starling mechanism.     

Cardiac sympathetic activity is associated with inflammation and neurohumoral activation in patients with idiopathic dilated cardiomyopathy

Background: Idiopathic dilated cardiomyopathy (IDC) is characterized by sympathetic nervous overactivity, inflammation and neurohumoral activation; however, their interrelationships are poorly understood. Methods and results: We studied 99 patients with IDC (age 54 ± 1 years, left ventricular ejection fraction (EF) 40 ± 1%, maximum oxygen uptake (VO₂max) 20 ± 1 ml kg^?1 min^?2, mean ± SEM) by using ¹²³I‐metaiodobenzylguanidine (MIBG) imaging. MIBG washout and MIBG heart/mediastinum (H/M)‐ratio at 4 h postinjection were calculated. In addition, the plasma levels of interleukin (IL)‐6 and N‐terminal B‐type natriuretic peptide (NT‐proBNP) were measured. MIBG washout and MIBG H/M ratio had a significant correlation with IL‐6 (r = 0·42, P<0·001 and r = ?0·31, P<0·01) and NT‐proBNP (r = 0·48, P<0·001 and r = ?0·40, P<0·001). During a median follow‐up of 4·1 years, 20 patients (20%) had an adverse cardiac event (death, heart transplantation or application of biventricular pacemaker or implantable cardioverter–defibrillator). In these patients, MIBG washout was higher (53 ± 4 versus 40 ± 2%, P = 0·01) and H/M ratio lower (1·38 ± 0·04 versus 1·51 ± 0·02, P = 0·01) than in patients without an event. Conclusions: In dilated cardiomyopathy, myocardial sympathetic innervation and activity are related to inflammation and neurohumoral activation. These relationships are at least partly independent of left ventricular function and exercise capacity.     

Forearm composition and muscle function in trained and untrained limbs

Summary. The influence of a period of training, which lasts for several years, on the proportions of muscle, fat and bone present in the human forearm has been investigated by comparing trained and untrained limbs of nine experienced male tennis players. Ten healthy but untrained males of similar age served as a control group. Computed tomography (CT) scans of the forearm were made at intervals along its length to identify fat, muscle and bone and to calculate the volumes occupied by each of these components. Total forearm volume was greater in the dominant limb compared with the contralateral side in both trained (by 135±59 cm³, mean±SD, P<0·001) and untrained subjects (by 41±45 cm³, P<0·02). Forearm muscle volume was also greater in dominant limbs of trained (by 117±52 cm³, P<0·001) and untrained by 35±41 cm³, P<0·025) subjects. Muscle accounted for 75·4±2·7% of the total volume in the dominant arm of trained subjects compared with 71·4±4·2% in the control group (P<0·05). There was a greater proportion of muscle (P<0·05) and a smaller proportion of fat (P<0·001) in the trained limb compared with the contralateral limb of the same subjects. No differences in proportions of fat, muscle and bone were observed in dominant and non-dominant limbs of the control subjects. Trained subjects were able to exert a greater isometric force with the dominant limb (549±76N) than with the non-dominant limb (496±48N; P<0·005). There was no difference in grip strength between the arms of the untrained group (dominant: 516±107N; non-dominant: 491±91N). The ratio of strength to muscle volume was, however, the same in dominant and non-dominant arms of both groups of subjects.     

致心律不齐性右心室型心肌病患者右心室室壁脂肪浸润或纤维化程度与右心室功能及容积的相关性

目的 探讨致心律不齐性右心室型心肌病（ARVC）患者右心室室壁脂肪浸润或纤维化程度与右心室功能及容积的相关性。方法 对20例ARVC患者行多序列MR扫描,测量左右心室流出道横径、左右心室舒张末横径（EDD）、左右心室射血分数（EF）、左右心室舒张末容积指数（EDVI）、左右心室收缩末容积指数（ESVI）、左右心室心输出量指数（CI）、右心室心肌质量指数（MASSI）及室壁脂肪浸润或纤维化程度情况,采用线性相关分析观察右心室室壁脂肪浸润或纤维化程度与右心室功能及容积的相关性。结果 ARVC患者右心室流出道横径（52.42±11.80） mm,右心室EDD、EF、EDVI、ESVI、CI、MASSI分别为（50.13±8.71） mm、（18.13±6.71）%、（169.13±72.11） ml/m²、（117.01±67.31） ml/m²、（1.81±0.20） L/（min·m²）、（17.62±1.80） g/m²。20例右心室游离壁/前壁均受累,10例下壁受累,14例心尖部受累,15例右心室流出道受累;右心室室壁脂肪浸润或纤维化指数（70.00±22.33）%,与右心室EF值呈负相关（r=-0.627,P=0.003）,与右心室EDVI（r=0.695,P=0.001）和ESVI均呈正相关（r=0.676,P=0.001）。结论 右心室室壁脂肪浸润或纤维化程度与右心室功能及容积的相关性可反映ARVC患者心脏功能变化。     

Comparison of bioimpedance and radioisotope methods in the estimation of extracellular water volume before and after coronary artery bypass grafting operation

To estimate extracellular water volume (ECW) changes in connection with coronary artery bypass grafting operation, simultaneous ECW estimations by ⁵¹Cr‐EDTA dilution and whole‐body bioimpedance techniques were performed in 15 patients. The assessments of ECW were compared with patients’ weighing results. Whole‐body bioimpedance‐derived ECW correlated significantly with ⁵¹Cr‐EDTA dilution‐based ECW in the pre‐operative period (r=0·74; P<0·005); the bias was 0·2 ± 1·1 l (±SD). In the post‐operative period, the agreement between these methods was poor, the bias being 0·5 ± 2·5 l, and no significant correlation between the methods was found (r=0·38; P>0·05). Whole‐body bioimpedance‐derived ECW changes correlated significantly with weight changes of the patient induced by the operation (r=0·52; P<0·05). ⁵¹Cr‐EDTA dilution‐based ECW changes correlated neither with weight changes (r=0·33; P>0·05) nor with bioimpedance‐derived ECW changes (r=0·03; P>0·05). Alterations in radioisotope tracer distribution and loss of it due to blood leakage in the post‐operative period were presumed to explain the discrepancy between dilution technique and weighing results. The results suggest that bioimpedance is a useful non‐invasive method for assessment of extracellular volume changes induced by coronary artery bypass grafting operations. ⁵¹Cr‐EDTA dilution‐based ECW determination is not suitable in related conditions.     

Left ventricular geometry and function are related to electrocardiographic characteristics and diagnoses

We investigated the relationships between echocardiographic indices of left ventricular geometry and function and major electrocardiographic (ECG) abnormalities in 540 elderly (69–74 years old) male participants of a health survey conducted in Uppsala county, Sweden. Comparing men with major ECG abnormalities that were present or absent in various hierarchic mutually exclusive categories, left ventricular mass indexed to body surface area (LVMI) was significantly increased with major Q-waves (P = 0·0002), ST or T-wave abnormalities (P = 0·005), left bundle-branch block (P = 0·005) and also with atrioventricular block type 1 (P = 0·008) and frequent premature beats (P = 0·02). The left atrial diameter was also significantly increased with most ECG abnormalities. The increased LVMI was in left bundle-branch block mainly due to an increased left ventricular diameter, whereas left ventricular wall thickness was increased with frequent premature beats, atrioventricular block type 1 and ST or T-wave abnormalities. The prevalence of Q-waves was highest in eccentric left ventricular hypertrophy, whereas the prevalence of ST or T-wave abnormalities and atrioventricular block type 1 was highest in concentric left ventricular hypertrophy. Both left ventricular systolic (ejection fraction) and diastolic function (E/A ratio) were inversely related to Sokolow–Lyon QRS amplitude (r = ?0·25, P < 0·02 and r = ?0·22, P < 0·03 respectively). In conclusion, LVMI was increased in subjects with ECG signs of coronary artery disease as well as in subjects with several other ECG diagnoses. Furthermore, both left ventricular systolic and diastolic dysfunction were related to increased QRS amplitudes. Thus, the finding of ECG abnormalities in elderly men should raise the suspicion of structural and/or functional left ventricular abnormality.     

Reduced preload elicits increased LV twist in healthy humans: an echocardiographic speckle-tracking study during lower body negative pressure

Background: In normal left ventricles (LV), counterclockwise rotation (CCR) and net twist angle (NTA) have shown important roles during ejection. We investigated the effect of reduced preload by lower body negative pressure (LBNP) on CCR and NTA. Methods and Results: Twelve healthy men were examined at rest, LBNP ?20 and ?40 mmHg. By two‐dimensional speckle‐tracking imaging, we measured rotation at four short‐axis levels: basal, papillary, sub‐papillary and apical. LV NTA was calculated as apex‐to‐base difference in rotation. Additionally, regional end‐diastolic (EDA) and end‐systolic area (ESA) were measured and regional area fraction (RAF) calculated [(EDA‐ESA)/EDA] × 100). From rest to LBNP ?40 mmHg, rotation at basal and papillary levels was unchanged. At sub‐papillary level, rotation increased from 3·2 ± 3·6 to 5·8 ± 4·7° (P<0·05), while apical rotation increased from 9·3 ± 3·4 to 12·8 ± 4·7° (P<0·05). Correspondingly, LV NTA increased for each load reduction by 1·6 ± 1·8° (P<0·05) and 4·2 ± 2·3° (P<0·05). RAF increased at sub‐papillary and apical levels from 57·6 ± 3·7 to 64·7 ± 8·8% and from 63·4 ± 8·8 to 74·8 ± 10·1%, respectively (P<0·05). From rest to LBNP ?40 mmHg, changes in rotation and RAF correlated significantly at sub‐papillary and apical levels (r = 0·94, P<0·01, and r = 0·63, P<0·05, respectively). Conclusions: Preload reduction in normal LV elicits increased systolic CCR and regional area fraction at sub‐papillary and apical levels as well as net twist angle. These findings might be of physiological importance to minimize reduction in stroke volume and maintain arterial blood pressure.     

Acute resistance exercise using free weights on aortic wave reflection characteristics

Aortic wave reflection characteristics such as the augmentation index (AIx), wasted left ventricular pressure energy (ΔE_w) and aortic haemodynamics, such as aortic systolic blood pressure (ASBP), strongly predict cardiovascular events. The effects of acute resistance exercise (ARE) using free‐weight exercises on these characteristics are unknown. Therefore, we sought to determine the effects of acute free‐weight resistance exercise on aortic wave reflection characteristics and aortic haemodynamics in resistance‐trained individuals. Fifteen young, healthy resistance‐trained (9 ± 3 years) individuals performed two randomized sessions consisting of an acute bout of free‐weight resistance exercise (ARE) or a quiet control (CON). The ARE consisted of three sets of 10 repetitions at 75% one repetition maximum for squat, bench press and deadlift. In CON, the participants rested in the supine position for 30 min. Measurements were made at baseline before sessions and 10 min after sessions. A two‐way ANOVA was used to compare the effects of condition across time. There were no significant interactions for aortic or brachial blood pressures. Compared to rest, there were significant increases in augmentation pressure (rest: 5·7 ± 3·0 mmHg; recovery: 10·4 ± 5·7 mmHg, P = 0·002), AIx (rest: 116·8 ± 4·2%; recovery: 123·2 ± 8·4%, P = 0·002), AIx normalized at 75 bpm (rest: 5·2 ± 7·6%; recovery: 27·3 ± 13·2%, P<0·0001), ΔE_w (rest: 1215 ± 674 dynes s cm^?2; recovery: 2096 ± 1182 dynes s cm^?2, P = 0·008), and there was a significant decrease in transit time of the reflected wave (rest: 150·7 ± 5·8 ms; recovery 145·5 ± 5·6 ms, P<0·001) during recovery from ARE compared to CON. These data suggest that ARE using free‐weight exercises may have no effect on aortic and brachial blood pressure but may significantly alter aortic wave reflection characteristics.     

Coronary flow reserve: measurement with transthoracic Doppler echocardiography is reproducible and comparable with positron emission tomography

Detection of early vascular changes indicated by lowered coronary flow reserve (CFR) would allow early treatment and prevention of atherosclerosis. The purpose of this study was to test whether it is possible to reproducibly measure CFR with transthoracic Doppler echocardiography (TTE) in healthy volunteers. We measured CFR using dipyridamole infusion in ten healthy male volunteers with two methods: TTE and positron emission tomography (PET) with oxygen‐15‐labelled water (group A). However, CFR was assessed twice with TTE in eight healthy male volunteers (group B) to study the reproducibility of this method. We compared CFRs obtained using TTE flow measurements in the left anterior descending coronary artery (LAD) and PET flow measurements in the corresponding myocardial area. Coronary flow in LAD could be measured in all subjects using TTE. By TTE, an average CFR based on peak diastolic flow velocity (PDV) was 2·72 ± 1·16, mean diastolic flow velocity (MDV) 2·56 ± 1·06 and velocity time integral (VTI) 1·87 ± 0·49. The results were reproducible in two repeated TTE studies (coefficient of variation in MDV 6·1 ± 4·3%, n=8). By PET, CFR was 2·52 ± 0·84. CFR assessed by TTE correlated closely with that measured by PET (MDV r=0·942, P<0·001; PDV r=0·912, P<0·002 and VTI r=0·888, P<0·006) and intraclass correlation was 0·929 (MDV) and tolerance limits for differences of CFRs was ?0·78 to 0·72. We show that CFR measured by TTE has an excellent correlation with CFR measured by PET. We also found that TTE measurements of CFR were highly reproducible.     

Cardiac troponin I and ventricular arrhythmia in patients with chronic heart failure

Background Both detectable serum cardiac troponin I (cTnI) and ventricular dysrhythmias are common in patients with chronic heart failure (CHF) and are paralleled with the severity of the CHF. However, the relationship between serum cTnI and ventricular arrhythmia severity in patients with CHF remains unknown; the mechanism of the ventricular arrhythmia in the CHF patients also remains unclear. Materials and methods The study group included 218 patients with CHF who had cTnI assay drawn at the time of initial presentation. Patients with acute myocardial infarction or myocarditis were excluded from the analysis. The patients were divided into two groups: cTnI‐positive with serum cTnI > 0·5 ng mL^?1 (n = 98) and cTnI‐negative with serum cTnI ≤ 0·5 ng mL^?1 (n = 120). The severity of ventricular dysrhythmias was assessed by 24‐h Holter monitoring, using prospectively defined measures of ventricular arrhythmic burden. Results Prevalence of risk factors for ventricular dysrhythmias was equal in both groups. All measures of ventricular ectopy were much higher in patients of the cTnI‐positive groups. Mean hourly ventricular pairs (13·59 ± 10·3 vs. 11·1 ± 6·01, P = 0·027), mean hourly repetitive ventricular beats (26·01 ± 13·67 vs. 22·01 ± 13·56, P = 0·032), and the frequency of ventricular tachycardia episodes per 24 h (12·54 ± 16·68 vs. 7·68 ± 11·54, P = 0·012) were higher in patients with detectable cTnI levels. After inclusion of clinical variables and drug therapies in a multivariate analysis, the positive relationship between cTnI and the frequency of ventricular pairs (P = 0·03), repetitive ventricular beats (P = 0·037), and ventricular tachycardia (P = 0·03) remained independent. In multivariate logistic regression, the risk of developing ventricular tachycardia was higher in patients with detectable cTnI levels with an adjusted odds ratio (OR) of 2·31 (95% CI, 1·22–2·65, P = 0·003). Conclusions In patients with CHF, serum cTnI is closely related to increased occurrence of ventricular dysrhythmias and could identify a subgroup of patients with ventricular tachycardia. The minimal myocardial injury detected by serum cTnI might be the abnormal substrate for ventricular dysrhythmias.