Scoping review on the state of the integration of human physiological responses to evaluating heat-stress

OBJECTIVES

To determine the state of the literature on assessing heat-stress using physiological parameters. To provide recommendations to the nuclear industry regarding worker heat-stress management practices.

METHODS

A scoping review identified relevant articles. A search strategy was developed based on a research question concepts. Identified records were screened with inclusion-exclusion criteria. Included articles underwent data extraction using a qualitative data charting method. A thematic analysis and frequency counts were performed.

RESULTS

1687 articles were identified through four databases. The final inclusion consisted of 34 studies. Articles were classified by determinants of heat exposure risks: core body temperature (direct and indirect), scoring scale including core body temperature, scoring scale including human perception, and others. Heart rate and rectal temperature were the two most utilized physiological measurements.

CONCLUSION

A significant amount of literature examined estimation of core temperature using non-invasive methods, sometimes integrated into wearables. Heat-stress management practices could include perceptual measures to better evaluate heat-strain.

Excimer laser technology in percutaneous coronary interventions: Cardiovascular laser society's position paper

Excimer Laser Coronary Atherectomy (ELCA) is a well-established therapy that emerged for the treatment of peripheral vascular atherosclerosis in the late 1980s, at a time when catheters and materials were rudimentary and associated with the most serious complications. Refinements in catheter technology and the introduction of improved laser techniques have led to their effective use for the treatment of a wide spectrum of complex coronary lesions, such as thrombotic lesions, severe calcific lesions, non-crossable or non-expandable lesions, chronic occlusions, and stent under-expansion. The gradual introduction of high-energy strategies combined with the contrast infusion technique has enabled us to treat an increasing number of complex cases with a low rate of periprocedural complications. Currently, the use of the ELCA has also been demonstrated to be effective in acute coronary syndrome (ACS), especially in the context of large thrombotic lesions.

Reduced glomerular filtration rate and prior cardiovascular event entail similar risk for coronary atherosclerotic burden

OBJECTIVE

Prior cardiovascular event and kidney dysfunction are both strong risk factors for coronary artery disease. The aim of this study is to assess coronary atherosclerotic burden in a large population of patients undergoing coronary angiography, according to prior cardiovascular event or chronic kidney disease.

PATIENTS AND METHODS

We evaluated 700 consecutive patients who underwent coronary angiography (CA). Serum creatinine to estimate glomerular filtration rate (eGFR) was measured. Clinically significant coronary artery disease (CAD) was defined by the presence of a coronary lesion resulting in a luminal stenosis >50%. For the purpose of the study, the whole population was divided into 4 subgroups according to the presence/absence of eGFR <60 ml/min/1.73 m2 or prior cardiovascular event: eGFR≥60/no event (Group A), eGFR≥60/yes event (Group B), eGFR<60/no event (Group C), eGFR<60/yes event (Group D).

PATIENTS

As expected, patients in group D had the worst clinical and biochemical profile. These patients also presented the highest values of urinary albumin creatinine ratio (ACR, p<0.001) and the lowest values of eGFR (p<0.01). One-hundred-ninety-six patients had three-vessel disease. Patients who had undergone PCI procedure showed a lower eGFR as compared to patients who had not (p=0.009). Considering group A as reference, the risk of having three-vessel disease was increased in group B (OR= 2.09; 95% CI 1.37-3.19), in group C, (OR= 1.80; 95% CI 1.04-3.14), and finally in group D (OR= 3.35; 95% CI 2.01-5.58). The risk carried by group C was not significantly different from that carried by Group B: OR= 0.86; 95% CI 0.5-1.5.

CONCLUSIONS

In our study, low eGFR seems to have the same excess risk of prior CV event.

The effects of buthionine sulfoximine treatment on diaphragm contractility and SERCA pump function in adult and middle aged rats

This study examined the effects of 10 days of buthionine sulfoximine (BSO) treatment on in vitro contractility and sarcoplasmic reticulum calcium pump (SERCA) expression and function in adult (AD; 6–8 months old) and middle aged (MA; 14–17 months old) rat diaphragm in both the basal state and following fatiguing stimulation. BSO treatment reduced the cellular concentrations of free glutathione (GSH) by >95% and oxidized glutathione (GSSG) by >80% in both age cohorts. GSH content in AD Control diaphragm was 32% higher (P < 0.01) than in MA Control, with no differences in GSSG. The ratio of GSH:GSSG, an indicator of cellular oxidative state, was 34.6 ± 7.4 in MA Control, 52.5 ± 10.1 in AD Control, 10.6 ± 1.7 in MA BSO, and 9.5 ± 1.1 in AD BSO (BSO vs. Control, P < 0.05). Several findings suggest that the effects of BSO treatment are age dependent. AD BSO diaphragm had 26% higher twitch and 28% higher tetanic force (both P < 0.05) than AD Controls, whereas no significant difference existed between the two MA groups. In contrast to our previous work on BSO-treated AD rats, BSO treatment did not influence maximal SERCA ATPase activity in MA rat diaphragm, nor did SERCA2a expression increase in BSO-treated MA diaphragm. Biotinylated iodoacetamide binding to SERCA1a, a specific marker of free cysteine residues, was reduced by 35% (P < 0.05) in AD Control diaphragm following fatiguing stimulation, but was not reduced in any other group. Collectively, these results suggest an important role for redox regulation in both contractility and SERCA function which is influenced by aging.

Phospholamban overexpression in mice causes a centronuclear myopathy-like phenotype

Centronuclear myopathy (CNM) is a congenital myopathy that is histopathologically characterized by centrally located nuclei, central aggregation of oxidative activity, and type I fiber predominance and hypotrophy. Here, we obtained commercially available mice overexpressing phospholamban (Pln^OE), a well-known inhibitor of sarco(endo)plasmic reticulum Ca²⁺-ATPases (SERCAs), in their slow-twitch type I skeletal muscle fibers to determine the effects on SERCA function. As expected with a 6- to 7-fold overexpression of phospholamban, SERCA dysfunction was evident in Pln^OE muscles, with marked reductions in rates of Ca²⁺ uptake, maximal ATPase activity and the apparent affinity of SERCA for Ca²⁺. However, our most significant discovery was that the soleus and gluteus minimus muscles from the Pln^OE mice displayed overt signs of myopathy: they histopathologically resembled human CNM, with centrally located nuclei, central aggregation of oxidative activity, type I fiber predominance and hypotrophy, progressive fibrosis and muscle weakness. This phenotype is associated with significant upregulation of muscle sarcolipin and dynamin 2, increased Ca²⁺-activated proteolysis, oxidative stress and protein nitrosylation. Moreover, in our assessment of muscle biopsies from three human CNM patients, we found a significant 53% reduction in SERCA activity and increases in both total and monomeric PLN content compared with five healthy subjects, thereby justifying future studies with more CNM patients. Altogether, our results suggest that the commercially available Pln^OE mouse phenotypically resembles human CNM and could be used as a model to test potential mechanisms and therapeutic strategies. To date, there is no cure for CNM and our results suggest that targeting SERCA function, which has already been shown to be an effective therapeutic target for murine muscular dystrophy and human cardiomyopathy, might represent a novel therapeutic strategy to combat CNM.

Summary: Phospholamban overexpression in mouse slow-twitch muscle impairs SERCA function and causes histopathological features associated with human centronuclear myopathy.

The role of estrogen receptor-α in estrogen-mediated regulation of basal and exercise-induced Hsp70 and Hsp27 expression in rat soleus

We examined the influence of estrogen receptor-alpha (ERα) activation on estrogen-mediated regulation of heat shock proteins 70 (Hsp70) and 27 (Hsp27) in soleus. Ovariectomized rats received estrogen (EST), an ERα agonist (propyl pyrazole triol, PPT), both (EST+PPT), or a sham, and they served as either unexercised controls or were subjected to exercise by having to run downhill (17 m/min, -13.5° grade) for 90 min. At 72 h postexercise, soleus muscles were removed and either immunohistochemically stained for Hsp70 and myosin heavy chain or homogenized for Western blotting for Hsp70 and Hsp27. Elevated (p < 0.05) basal Hsp70 in both type I and II fibres in the unexercised EST, PPT, and EST+PPT groups relative to unexercised sham animals was noted. Compared with Hsp70 levels in the unexercised animals, that in exercised animals was elevated (p < 0.05) in both sham and PPT groups but not in EST and EST+PPT groups. Western blot determined that Hsp27 levels were not significantly different between groups. Hence, the ability of estrogen to augment resting type I and type II muscle fibre Hsp70 content is primarily mediated via muscle ERα. However, the blunted Hsp70 response following damaging exercise in estrogen-supplemented animals does not appear to be fully accounted for by ERα-mediated effects.

High-fat diet-induced mitochondrial biogenesis is regulated by mitochondrial-derived reactive oxygen species activation of CaMKII

Calcium/calmodulin-dependent protein kinase (CaMK) activation induces mitochondrial biogenesis in response to increasing cytosolic calcium concentrations. Calcium leak from the ryanodine receptor (RyR) is regulated by reactive oxygen species (ROS), which is increased with high-fat feeding. We examined whether ROS-induced CaMKII-mediated signaling induced skeletal muscle mitochondrial biogenesis in selected models of lipid oversupply. In obese Zucker rats and high-fat-fed rodents, in which muscle mitochondrial content was upregulated, CaMKII phosphorylation was increased independent of changes in calcium uptake because sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) protein expression or activity was not altered, implicating altered sarcoplasmic reticulum (SR) calcium leak in the activation of CaMKII. In support of this, we found that high-fat feeding increased mitochondrial ROS emission and S-nitrosylation of the RyR, whereas hydrogen peroxide induced SR calcium leak from the RyR and activation of CaMKII. Moreover, administration of a mitochondrial-specific antioxidant, SkQ, prevented high-fat diet-induced phosphorylation of CaMKII and the induction of mitochondrial biogenesis. Altogether, these data suggest that increased mitochondrial ROS emission is required for the induction of SR calcium leak, activation of CaMKII, and induction of mitochondrial biogenesis in response to excess lipid availability.

Co-expression of SERCA isoforms, phospholamban and sarcolipin in human skeletal muscle fibers

Sarcolipin (SLN) and phospholamban (PLN) inhibit the activity of sarco(endo)plasmic reticulum Ca²⁺-ATPases (SERCAs) by reducing their apparent affinity for Ca²⁺. A ternary complex between SLN, PLN, and SERCAs results in super-inhibition of SERCA activity. Analysis of skeletal muscle homogenate has limited our current understanding of whether SLN and PLN regulate SERCA1a, SERCA2a, or both in skeletal muscle and whether SLN and PLN are co-expressed in skeletal muscle fibers. Biopsies from human vastus lateralis were analyzed through single fiber Western blotting and immunohisto/fluorescence staining to circumvent this limitation. With a newly generated SLN antibody, we report for the first time that SLN protein is present in human skeletal muscle. Addition of the SLN antibody (50 µg) to vastus lateralis homogenates increased the apparent Ca²⁺ affinity of SERCA (K_Ca, pCa units) (-Ab, 5.85 ± 0.02 vs. +Ab, 5.95 ± 0.02) and maximal SERCA activity (μmol/g protein/min) (-Ab, 122 ± 6.4 vs. +Ab, 159 ± 11) demonstrating a functional interaction between SLN and SERCAs in human vastus lateralis. Specifically, our results suggest that although SLN and PLN may preferentially regulate SERCA1a, and SERCA2a, respectively, physiologically they both may regulate either SERCA isoform. Furthermore, we show that SLN and PLN co-immunoprecipitate in human vastus lateralis homogenate and are simultaneously expressed in 81% of the fibers analyzed with Western blotting which implies that super-inhibition of SERCA may exist in human skeletal muscle. Finally, we demonstrate unequivocally that mouse soleus contains PLN protein suggesting that super-inhibition of SERCA may also be important physiologically in rodent skeletal muscle.

ATP consumption by sarcoplasmic reticulum Ca²⁺ pumps accounts for 40-50% of resting metabolic rate in mouse fast and slow twitch skeletal muscle

The main purpose of this study was to directly quantify the relative contribution of Ca²⁺ cycling to resting metabolic rate in mouse fast (extensor digitorum longus, EDL) and slow (soleus) twitch skeletal muscle. Resting oxygen consumption of isolated muscles (VO₂, µL/g wet weight/s) measured polarographically at 30^°C was ~20% higher (P<0.05) in soleus (0.326 ± 0.022) than in EDL (0.261 ± 0.020). In order to quantify the specific contribution of Ca²⁺ cycling to resting metabolic rate, the concentration of MgCl₂ in the bath was increased to 10 mM to block Ca²⁺ release through the ryanodine receptor, thus eliminating a major source of Ca²⁺ leak from the sarcoplasmic reticulum (SR), and thereby indirectly inhibiting the activity of the sarco(endo) plasmic reticulum Ca²⁺-ATPases (SERCAs). The relative (%) reduction in muscle VO₂ in response to 10 mM MgCl₂ was similar between soleus (48.0±3.7) and EDL (42.4±3.2). Using a different approach, we attempted to directly inhibit SERCA ATPase activity in stretched EDL and soleus muscles (1.42x optimum length) using the specific SERCA inhibitor cyclopiazonic acid (CPA, up to 160 µM), but were unsuccessful in removing the energetic cost of Ca²⁺ cycling in resting isolated muscles. The results of the MgCl₂ experiments indicate that ATP consumption by SERCAs is responsible for 40–50% of resting metabolic rate in both mouse fast- and slow-twitch muscles at 30^°C, or 12–15% of whole body resting VO₂. Thus, SERCA pumps in skeletal muscle could represent an important control point for energy balance regulation and a potential target for metabolic alterations to oppose obesity.

Sarcolipin trumps β-adrenergic receptor signaling as the favored mechanism for muscle-based diet-induced thermogenesis

Sarcolipin (SLN) regulates muscle-based nonshivering thermogenesis and is up-regulated with high-fat feeding (HFF). To investigate whether other muscle-based thermogenic systems compensate for a lack of Sln and to firmly establish SLN as a mediator of diet-induced thermogenesis (DIT), we measured muscle and whole-body energy expenditure in chow- and high-fat-fed Sln(-/-) and wild-type (WT) mice. Following HFF, resting muscle metabolic rate (VO2, μl/g/s) was increased similarly in WT (0.28±0.02 vs. 0.31±0.03) and Sln(-/-) (0.23±0.03 vs. 0.35±0.02) mice due to increased sympathetic nervous system activation in Sln(-/-) mice; however, whole-body metabolic rate (VO2, ml/kg/h) was lower in Sln(-/-) compared with WT mice following HFF but only during periods when the mice were active in their cages (WT, 2894±87 vs. Sln(-/-), 2708±61). Treatment with the β-adrenergic receptor (β-AR) antagonist propranolol during HFF completely prevented muscle-based DIT in Sln(-/-) mice; however, it had no effect in WT mice, resulting in greater differences in whole-body metabolic rate and diet-induced weight gain. Our results suggest that β-AR signaling partially compensates for a lack of SLN to activate muscle-based DIT, but SLN is the primary and more effective mediator.

Glutathione enhances endothelium-mediated control of coronary vascular resistance via a ROS- and NO intermediate-dependent mechanism

The purpose of this investigation was to determine the effects of acute physiological GSH administration on endothelium-mediated reduction in coronary vascular resistance (CVR) using isolated perfused Sprague-Dawley rat hearts. A dose-response curve to GSH was conducted to determine a threshold concentration of GSH. We demonstrate that 30 μM GSH was sufficient to reduce CVR, and maximal dilation was achieved with 1 mM. In subsequent experiments, GSH was administered at concentrations of 0 [control (CON)], 1 μM, or 10 μM (GSH10), and dose-response curves to the endothelial agonist bradykinin (BK) were constructed. These GSH concentrations were chosen because of the physiological relevance and because the effects of GSH on BK action could be assessed independent of baseline differences in CVR. Sensitivity to BK (EC50) was enhanced in GSH10 vs. CON ( P < 0.05). This enhancement remained in the presence of nitric oxide (NO) synthase inhibition l-ωnitro-l-arginine (lNAME) and/or soluble guanylate cyclase (sGC) inhibition. Treatment with 4-hydroxy (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPOL) enhanced the sensitivity to BK in CON, similar to the effects of GSH10 and GSH10 + TEMPOL. However, the GSH10-dependent enhancement of EC50 observed in the presence of lNAME did not occur in the presence of lNAME + TEMPOL or in the presence of lNAME + sGC inhibition and NO scavenging. Collectively, these results suggest that GSH enhances BK-mediated dilation and reduction in CVR through an antioxidant-dependent mechanism that involves a NO intermediate but is unrelated to acute production of NO and GC-dependent effects of NO. These results suggest a mechanism whereby physiologically relevant levels of GSH modulate the endogenous reactive oxygen species and NO control of endothelium-dependent coronary vascular function.

Enhanced Ca2+ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice

Sarcolipin (SLN) inhibits sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pumps. To evaluate the physiological significance of SLN in skeletal muscle, we compared muscle contractility and SERCA activity between Sln-null and wild-type mice. SLN protein expression in wild-type mice was abundant in soleus and red gastrocnemius (RG), low in extensor digitorum longus (EDL), and absent from white gastrocnemius (WG). SERCA activity rates were increased in soleus and RG, but not in EDL or WG, from Sln-null muscles, compared with wild type. No differences were seen between wild-type and Sln-null EDL muscles in force-frequency curves or maximum rates of force development (+dF/dt). Maximum relaxation rates (-dF/dt) of EDL were higher in Sln-null than wild type across a range of submaximal stimulation frequencies, but not during a twitch or peak tetanic contraction. For soleus, no differences were seen between wild type and Sln-null in peak tetanic force or +dF/dt; however, force-frequency curves showed that peak force during a twitch and 10-Hz contraction was lower in Sln-null. Changes in the soleus force-frequency curve corresponded with faster rates of force relaxation at nearly all stimulation frequencies in Sln-null compared with wild type. Repeated tetanic stimulation of soleus caused increased (-dF/dt) in wild type, but not in Sln-null. No compensatory responses were detected in analysis of other Ca(2+) regulatory proteins using Western blotting and immunohistochemistry or myosin heavy chain expression using immunofluorescence. These results show that 1) SLN regulates Ca(2+)-ATPase activity thereby regulating contractile kinetics in at least some skeletal muscles, 2) the functional significance of SLN is graded to the endogenous SLN expression level, and 3) SLN inhibitory effects on SERCA function are relieved in response to repeated contractions thus enhancing relaxation rates.

Initiating treadmill training in late middle age offers modest adaptations in Ca2+ handling but enhances oxidative damage in senescent rat skeletal muscle

Aging skeletal muscle shows an increased time to peak force and relaxation and a decreased specific force, all of which could relate to changes in muscle Ca(2+) handling. The purpose of this study was to determine if Ca(2+)-handling protein content and function are decreased in senescent gastrocnemius muscle and if initiating a training program in late middle age (LMA, 29 mo old) could improve function in senescent (34- to 36-mo-old) muscle. LMA male Fischer 344 x Brown-Norway rats underwent 5-7 mo of treadmill training. Aging resulted in a decrease in maximal sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) activity and a decrease in Ca(2+) release rate but no change in Ca(2+) uptake rate. Efficiency of the Ca(2+) pump was increased with age, as was the content of SERCA2a. Training caused a further increase in SERCA2a content. Aging also caused an increase in protein carbonyl and reactive nitrogen species damage accumulation, and both further increased with training. Consistent with the increase in oxidative damage, heat shock protein 70 content was increased with age and further increased with training. Together, these results suggest that while initiating exercise training in LMA augments the age-related increase in expression of heat shock protein 70 and the more efficient SERCA2a isoform, it did not prevent the decrease in SERCA activity and exacerbated oxidative damage in senescent gastrocnemius muscle.

ATP consumption by sarcoplasmic reticulum Ca2+ pumps accounts for 50% of resting metabolic rate in mouse fast and slow twitch skeletal muscle

In this study, we aimed to directly quantify the relative contribution of Ca(2+) cycling to resting metabolic rate in mouse fast-twitch (extensor digitorum longus, EDL) and slow-twitch (soleus) skeletal muscle. Resting oxygen consumption of isolated muscles (Vo(2), microl.g wet wt(-1).s(-1)) measured polarographically at 30 degrees C was approximately 25% higher in soleus (0.61 +/- .03) than in EDL (0.46 +/- .03). To quantify the specific contribution of Ca(2+) cycling to resting metabolic rate, cyclopiazonic acid (CPA), a highly specific inhibitor of sarco(endo)plasmic reticulum Ca(2+) ATPases (SERCAs), was added to the bath at different concentrations (1, 5, 10, and 15 microM). There was a concentration-dependent effect of CPA on Vo(2), with increasing CPA concentrations up to 10 microM resulting in progressively greater reductions in muscle Vo(2). There were no differences between 10 and 15 microM CPA, indicating that 10 microM CPA induces maximal inhibition of SERCAs in isolated muscle preparations. Relative reduction in muscle Vo(2) in response to CPA was nearly identical in EDL (1 microM, 10.6 +/- 3.0%; 5 microM, 33.2 +/- 3.4%; 10 microM, 49.2 +/- 2.9%; 15 microM, 50.9 +/- 2.1%) and soleus (1 microM, 11.2 +/- 1.5%; 5 microM, 37.7 +/- 2.4%; 10 microM, 50.0 +/- 1.3%; 15 microM, 49.9 +/- 1.6%). The results indicate that ATP consumption by SERCAs is responsible for approximately 50% of resting metabolic rate in both mouse fast- and slow-twitch muscles at 30 degrees C. Thus SERCA pumps in skeletal muscle could represent an important control point for energy balance regulation and a potential target for metabolic alterations to oppose obesity.

Effects of ovarian sex hormones and downhill running on fiber-type-specific HSP70 expression in rat soleus

This study examined the influence of the ovarian sex hormones, estrogen and progesterone, on the fiber-type-specific response of the inducible 70-kDa heat shock protein (HSP70) to damaging exercise in rat soleus. Ovariectomized female rats were divided into three treatment groups (n = 16 per group): sham (S), progesterone (P; 25 mg pellet), and estrogen (E; 0.25 mg pellet). Each treatment group was divided into control and exercised groups. After 8 days of sham or hormone treatment, animals ran downhill intermittently for 90 min (17 m/min, -13.5 degrees grade) on a treadmill, and soleus muscles were removed 24 h postexercise. HSP70 expression was assessed in whole muscle homogenates by Western blotting and in individual muscle fiber types by immunohistochemical analysis of serial cross sections of soleus samples. Comparisons between control groups showed that HSP70 expression in soleus was increased (P < 0.05) in E compared with both S and P. No difference (P > 0.05) was observed between S and P. Following downhill running, HSP70 content in soleus was increased (P < 0.05) compared with control in S and P, but not (P > 0.05) in E. As a result, soleus HSP70 content following downhill running was not different (P > 0.05) between any of the treatment groups. Under all conditions, HSP70 content was higher in type I vs. type II fibers, and the effects of both estrogen and exercise on HSP70 expression in soleus were also more pronounced in type I vs. type II fibers. These results demonstrate that 1) estrogen regulates HSP70 expression in skeletal muscle, increasing basal HSP70 expression and preventing further increases in HSP70 in response to exercise; 2) progesterone is not involved in the regulation of HSP70 expression in skeletal muscle; and 3) the effects of estrogen and exercise on HSP70 expression in skeletal muscle are fiber type specific.

Interaction between Hsp70 and the SR Ca2+pump: a potential mechanism for cytoprotection in heart and skeletal muscle

The overexpression of heat shock protein 70 (Hsp70) provides cytoprotection to cells, making them resistant to otherwise lethal levels of stress. In this review, the role Hsp70 plays in protecting both cardiac and skeletal muscle against the pathophysiological effects of oxidative stress are examined, with a focus on the molecular basis for the cytoprotective effects of Hsp70. The ability of Hsp70 to maintain cell survival undoubtedly involves the regulation of multiple steps within apoptotic pathways, but could also involve the regulation of key upstream mediators of apoptosis (i.e., oxidative stress, Ca2+overload). Hsp70 can stabilize the structure and function of both the skeletal muscle and cardiac Ca2+pump under heat stress conditions. Given that Ca2+overload has long been implicated in cell death, Hsp70 might protect muscle cells by maintaining cellular Ca2+homeostasis, thereby preventing the initiation of apoptosis. The functional interaction between Hsp70 and Ca2+pumps might also promote improvements in muscle contractility after exposure to oxidative stress.

Prediction of functional capacity by low-dose dobutamine stress echocardiography in chronic heart failure

AIM

The aim of this study was to determine if low-dose dobutamine stress echocardiography (LD-DSE) is associated with functional capacity in unselected elderly patients with chronic heart failure.

METHODS

This was a prospective trial. Thirty five consecutive patients were included, with age >65 years and left ventricular dysfunction (12 ischemic), by blindly assessed LD-DSE and cardiopulmonary exercise testing (CPT). Contractile reserve was defined as a change (D) in wall motion score index (WMSI) = or <0.2 at peak dose dobutamine. At CPT treadmill exercise time, peak VO2, %Vo2 and VE/VCO2 slope were determined. Preserved functional capacity was defined as percent of maximal predicted O2 consumption (%VO2) >80%. Baseline NT-proBNP plasma levels were assessed.

RESULTS

CPT variables were not related to clinical and baseline echocardiography characteristics but were related to DWMSI (exercise time, P=0.004; peak VO2, P=0.008; %VO2, P<0.001; VE/Vco2, P<0.001). Contractile reserve was present in 16 of 17 patients with preserved functional capacity (sensitivity=94%) and in 2 of 13 patients without (specificity=85%). Baseline NT-proBNP levels were lower in patients with contractile reserve (476+/-365 pg/mL) than in those without (1 345+/-1 219 pg/mL) (P=0.019), but were mildly related to CPT variables (P=0.049 and 0.027 with exercise time and %VO2, respectively).

CONCLUSION

Contractile reserve elicited at LD-DSE is associated with functional capacity in unselected elderly patients with chronic heart failure.

Muscle fiber type-specific response of Hsp70 expression in human quadriceps following acute isometric exercise

To investigate the time course of fiber type-specific heat shock protein 70 (Hsp70) expression in human skeletal muscle after acute exercise, 10 untrained male volunteers performed single-legged isometric knee extensor exercise at 60% of their maximal voluntary contraction (MVC) with a 50% duty cycle (5-s contraction and 5-s relaxation) for 30 min. Muscle biopsies were collected from the vastus lateralis before (Pre) exercise in the rested control leg (C) and immediately after exercise (Post) in the exercised leg (E) only and on recovery days 1 (R1), 2 (R2), 3 (R3), and 6 (R6) from both legs. As demonstrated by Western blot analysis, whole muscle Hsp70 content was unchanged (P > 0.05) immediately after exercise (Pre vs. Post), was increased (P < 0.05) by approximately 43% at R1, and remained elevated throughout the entire recovery period in E only. Hsp70 expression was also assessed in individual muscle fiber types I, IIA, and IIAX/IIX by immunohistochemistry. There were no fiber type differences (P > 0.05) in basal Hsp70 expression. Immediately after exercise, Hsp70 expression was increased (P < 0.05) in type I fibers by approximately 87% but was unchanged (P > 0.05) in type II fibers (Pre vs. Post). At R1 and throughout recovery, Hsp70 content in E was increased above basal levels (P < 0.05) in all fiber types, but Hsp70 expression was always highest (P < 0.05) in type I fibers. Hsp70 content in C was not different from Pre at any time throughout recovery. Glycogen depletion was observed at Post in all type II, but not type I, fibers, suggesting that the fiber type differences in exercise-induced Hsp70 expression were not related to glycogen availability. These results demonstrate that the time course of exercise-induced Hsp70 expression in human skeletal muscle is fiber type specific.

Effects of buthionine sulfoximine treatment on diaphragm contractility and SR Ca2+ pump function in rats

The purpose of this study was to examine the effects of glutathione (GSH) depletion and cellular oxidation on rat diaphragm contractility and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) function in vitro under basal conditions and following fatiguing stimulation. Buthionine sulfoximine (BSO) treatment (n = 10) for 10 days (20 mM in drinking water) reduced (P < 0.05) diaphragm GSH content (nmol/mg protein) and the ratio of GSH to glutathione disulfide (GSH/GSSG) by 91% and 71%, respectively, compared with controls (CTL) (n = 10). Western blotting showed that Hsp70 expression in diaphragm was not increased (P > 0.05) with BSO treatment. As hypothesized, basal peak twitch force (g/mm(2)) was increased (P < 0.05), and fatigability in response to repetitive stimulation (350-ms trains at 100 Hz once every 1 s for 5 min) was also increased (P < 0.05) in BSO compared with CTL. Both Ca(2+) uptake and maximal SERCA activity (mumol.g protein(-1).min(-1)) measured in diaphragm homogenates that were prepared at rest were increased (P < 0.05) with BSO treatment, an effect that could be partly explained by a twofold increase (P < 0.05) in SERCA2a expression with BSO. In response to the 5-min stimulation protocol, both Ca(2+) uptake and maximal SERCA activity were increased (P < 0.05) in CTL but not (P > 0.05) in BSO diaphragm. We conclude that 1) cellular redox state is more optimal for contractile function and fatigability is increased in rat diaphragm following BSO treatment, 2) SERCA2a expression is modulated by redox signaling, and 3) regulation of SERCA function in working diaphragm is altered following BSO treatment.

Prognostic significance of the dobutamine echocardiography test in idiopathic dilated cardiomyopathy

Dobutamine stress echo provides potentially useful information on idiopathic dilated cardiomyopathy (IDC). From February 1, 1997, to October 1, 1999, 186 patients (131 men and 55 women, mean age 56 +/- 12 years) with IDC, ejection fraction <35%, and angiographically normal coronary arteries were studied by high-dose (up to 40 micro/kg/min) dobutamine echo in 6 centers, all quality controlled for stress echo reading. In all patients, wall motion score index (WMSI) (from 1 = normal to 4 = dyskinetic in a 16- segment model of the left ventricle) was evaluated by echo at baseline and peak dobutamine. One hundred eighty-four patients were followed up (mean 15 +/- 13 months) and only cardiac death was considered as an end point. There were 29 cardiac deaths. Significant parameters for survival prediction at univariate analysis are: DeltaWMSI (chi-square 20.1; p <0.0000), New York Heart Association (NYHA) class (chi-square 17.57; p <0.0000), rest ejection fraction (chi-square 10.41; p = 0.0013), angiotensin-converting enzyme inhibitors (chi-square 8.23; p = 0.0041), and hypertension (chi-square 8.08, p = 0.0045). In the multivariate stepwise analysis only DeltaWMSI and NYHA were independent predictors of outcome (DeltaWMSI = hazard ratio 0.02, p < 0.0000; NYHA class = hazard ratio 3.83, p < 0.0000). Kaplan-Meier survival estimates showed a better outcome for patients with a large inotropic response (DeltaWMSI > or =0.44, a cutoff identified by receiver-operating characteristic curves analysis) than for those with a small or no myocardial inotropic response to dobutamine (93.6% vs 69.4%, p = 0.00033). Thus, in patients with IDC, an extensive contractile reserve identified by high-dose dobutamine stress echocardiography is associated with a better survival.

Dipyridamole stress echocardiography vs dipyridamole sestamibi scintigraphy for diagnosing coronary artery disease in left bundle-branch block

STUDY OBJECTIVES

To evaluate dipyridamole stress echocardiography (DSE) for predicting coronary artery diseases (CADs) in patients with complete left bundle-branch block (LBBB).

DESIGN

Comparison of DSE and dipyridamole sestamibi myocardial perfusion scintigraphy (sestamibi).

SETTING

Tertiary-care cardiac referral center.

PATIENTS

Fifty-four consecutive patients (26 men; mean [+/- SD] age, 59 +/- 7 years) with complete LBBB (14 patients with left ventricular [LV] dilatation) and intermediate probability of CAD.

METHODS

Simultaneous single photon emission CT scan (20 mCi technetium Tc 99m stress/rest sestamibi) and echocardiography (second harmonic imaging) during a two-step (0.56 to 0.84 mg/kg) dipyridamole infusion protocol. Two sestamibi readings were performed. The first reading considered only those studies with reversible defects (sestamibi-1) to be positive. The second reading considered those studies with any defect (sestamibi-2) to be positive. CAD was defined as a >or= 50% reduction in diameter in at least one major vessel seen on coronary angiography.

RESULTS

CAD was present in 17 patients (31.5%). The global predictive accuracy for CAD was significantly higher for DSE (87.0%) and sestamibi-1 (79.6%) than for sestamibi-2 (57.4%) [p < 0.01 vs DSE; p < 0.05 vs sestamibi-1]. No significant differences in sensitivity were present, but specificity was significantly higher for DSE (94.6%) and sestamibi-1 (81.1%) than for sestamibi-2 (43.2%; p < 0.01 vs both the other two tests). Of 14 patients with LV dilatation, 26.8% were falsely positive for CAD (in some cases for posterior defects) as determined by sestamibi-1 and 64.3% were falsely positive for CAD by sestamibi-2 vs none by DSE.

CONCLUSIONS

DSE is at least as accurate as dipyridamole sestamibi scintigraphy for predicting CAD in patients with complete LBBB and tends to be more specific in those patients with underlying LV dilatation.

Bisoprolol reduces cardiac death and myocardial infarction in high-risk patients as long as 2 years after successful major vascular surgery

AIM

To assess the long-term cardioprotective effect of bisoprolol in a randomized high-risk population after successful major vascular surgery. High-risk patients were defined by the presence of one or more cardiac risk factor(s) and a dobutamine echocardiography test positive for ischaemia.

METHODS

1351 patients were screened prior to surgery, 846 patients had one or more risk factor(s), and 173 of these patients also had ischaemia during dobutamine echocardiography. One hundred and twelve patients could be randomized for additional bisoprolol therapy or standard care. Eleven patients died in the peri-operative period (up to 1 month after surgery). Randomized patients continued bisoprolol or standard care after surgery. During follow-up of 101 survivors (median 22 months, range 11-30) cardiac death or myocardial infarction was noted. No patient was lost during follow-up. Results The incidence of cardiac events during follow-up in the bisoprolol group was 12% vs 32% in the standard care group (P=0.025). Cardiac death occurred in 15 patients, nine patients in the standard care and in six in the bisoprolol group; myocardial infarction occurred in six patients, five in the standard care and one in the bisoprolol group. The odds ratio for cardiac death or myocardial infarction after surgery in high-risk patients with additional bisoprolol therapy was 0.30 (0.11-0.83).

CONCLUSIONS

Bisoprolol significantly reduced long-term cardiac death and myocardial infarction in high-risk patients after successful major cardiac vascular surgery.

Prognostic value of pharmacologic stress echocardiography in patients with left bundle branch block

PURPOSE

Although coronary artery disease is a frequent cause of left bundle branch block, the prognostic value of myocardial ischemia in patients with this conduction abnormality has not been defined. We investigated the value of pharmacologic stress echocardiography in risk stratification of patients with left bundle branch block.

PATIENTS AND METHODS

Three hundred eighty-seven patients [230 men and 157 women, mean (+/- SD) age, 64 +/- 9 years] with complete left bundle branch block on the resting electrocardiogram underwent dobutamine (n = 217) or dipyridamole (n = 170) stress echocardiography to evaluate suspected or known coronary artery disease. A summary wall motion score (on a one to four scale) was calculated. The primary end points were cardiac death and nonfatal myocardial infarction.

RESULTS

A positive echocardiographic result (evidence of ischemia) was detected in 109 (28%) patients. During a mean follow-up of 29 +/- 26 months, there were 21 cardiac deaths and 20 myocardial infarctions, 63 patients underwent coronary revascularization, and 1 patient received a heart transplant. In a multivariate analysis, four clinical and echocardiographic variables were associated with increased risk of cardiac death: resting wall motion score index [hazard ratio (HR) = 7.5 per unit; 95% confidence interval (CI), 2.8 to 20; P = 0.001], previous myocardial infarction (HR = 2.9; 95% CI, 1.1 to 7.3; P = 0.02), diabetes (HR = 2.7; 95% CI, 1.1 to 6.6; P = 0.03), and the change in wall motion score index from rest to peak stress (HR = 3.0 per unit; 95% CI, 1.0 to 8.6; P = 0.04). The 5-year survival was 77% in the ischemic group and 92% in the nonischemic group (P = 0.02). Four variables were associated with increased risk of cardiac death or infarction: previous myocardial infarction (HR = 3.4; 95% CI, 1.7 to 6.8; P = 0.0005), diabetes (HR = 2.4; 95% CI, 1.2 to 4.6; P = 0.01), resting wall motion score index (HR = 2.2 per unit; 95% CI, 1.1 to 4.1; P = 0.02), and positive echocardiographic result (HR = 2.2; 95% CI, 1.1 to 4.5; P = 0.03). The 5-year infarction-free survival was 60% in the ischemic group and 87% in the nonischemic group (P < 0.0001). Stress echocardiography significantly improved risk stratification in patients without previous myocardial infarction (P = 0.0001), but not in those with previous myocardial infarction (P = 0.08). In particular, it provided additional value over clinical and resting echocardiographic findings in predicting cardiac events among patients without previous infarction.

CONCLUSIONS

Myocardial ischemia during pharmacologic stress echocardiography is a strong prognostic predictor in patients with left bundle branch block, particularly in those without previous myocardial infarction.

Usefulness and limitations of dobutamine-atropine stress echocardiography for the diagnosis of coronary artery disease in patients with left bundle branch block. A multicentre study

BACKGROUND

Patients with left bundle branch block exhibit abnormal septal motion which may limit the interpretation of stress echocardiograms. This study sought to assess the diagnostic value of dobutamine-atropine stress echocardiography in left bundle branch block patients.

METHODS AND RESULTS

Sixty-four left bundle branch block patients (mean age 59 years, 24 men) with suspected coronary artery disease underwent dobutamine-atropine stress echocardiography and coronary arteriography. Myocardial ischaemia was defined as new or worsening wall thickening abnormalities. Coronary artery disease was quantitatively defined as a diameter stenosis >/=50% in a major epicardial artery. Rest septal motion was normal (apart from the early systolic septal notch) in 34 patients (53%) and abnormal in 30 patients (47%). Rest septal thickening was normal in 32 patients (50%) and abnormal in 32 patients (50%). All seven patients with a QRS duration >/=160 ms and an abnormal QRS axis had abnormal rest septal motion and thickening. Inter-observer agreement for ischaemia was 88%. In all but one patient disagreement was in the septum. For the anterior and posterior circulation, respectively, sensitivity was 60% (9/15) and 67% (8/12), specificity was 94% (46/49) and 98% (51/52), and accuracy was 86% (55/64) and 92% (59/64). Sensitivity for the anterior circulation tended to be better in patients with normal rest septal thickening (83% vs 44%).

CONCLUSIONS

Dobutamine-atropine stress echocardiography has excellent diagnostic specificity in left bundle branch block patients with suspected coronary artery disease. In patients with abnormal rest septal thickening, however, dobutamine-atropine stress echocardiography may lack good sensitivity for detection of coronary artery disease in the anterior circulation. Left bundle branch block patients who potentially most benefit from dobutamine-atropine stress echocardiography may initially be selected by their resting electrocardiogram.

Neuroadrenergic activation and response to dobutamine in congestive heart failure secondary to idiopathic dilated cardiomyopathy

Detection of contractile reserve is important in heart failure patients. To determine if detection of contractile reserve is influenced by neuroadrenergic activation, we examined the relation between dobutamine stress echocardiography (DSE) findings and plasma norepinephrine levels (NE) at rest in 35 patients with nonischemic left ventricular (LV) dysfunction (New York Heart Association class >III in all; LV ejection fraction 0.27 +/- 0.5). Changes in global wall motion score (WMS), and separately in WMS of hypokinetic segments and akinetic segments, were analyzed. A patient was considered to be responsive to dobutamine if the change in global WMS was >/=4. Twenty-three patients were responsive and 12 were not responsive to dobutamine. Plasma NE and baseline heart rate were significantly higher in nonresponsive patients (p <0.001). Changes in global WMS and in hypokinetic segment WMS were inversely related to either plasma NE (r -0.68 and -0.67, respectively) or baseline heart rate (r -0.60 and -0.66, respectively). The change in akinetic segment WMS was related to plasma NE only (r -0.50). Changes in WMS were not related to age, diastolic and systolic LV volume, baseline global WMS, or number of akinetic segments at baseline. Plasma NE >602 pg/ml predicted a blunted or absent contractile reserve at DSE (sensitivity 92%; specificity 87%). Neuroadrenergic activation may influence contractile reserve found at DSE in patients with heart failure due to nonischemic LV dysfunction.

The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography Study Group

BACKGROUND

Cardiovascular complications are the most important causes of perioperative morbidity and mortality among patients undergoing major vascular surgery.

METHODS

We performed a randomized, multicenter trial to assess the effect of perioperative blockade of beta-adrenergic receptors on the incidence of death from cardiac causes and nonfatal myocardial infarction within 30 days after major vascular surgery in patients at high risk for these events. High-risk patients were identified by the presence of both clinical risk factors and positive results on dobutamine echocardiography. Eligible patients were randomly assigned to receive standard perioperative care or standard care plus perioperative beta-blockade with bisoprolol.

RESULTS

A total of 1351 patients were screened, and 846 were found to have one or more cardiac risk factors. Of these 846 patients, 173 had positive results on dobutamine echocardiography. Fifty-nine patients were randomly assigned to receive bisoprolol, and 53 to receive standard care. Fifty-three patients were excluded from randomization because they were already taking a beta-blocker, and eight were excluded because they had extensive wall-motion abnormalities either at rest or during stress testing. Two patients in the bisoprolol group died of cardiac causes (3.4 percent), as compared with nine patients in the standard-care group (17 percent, P=0.02). Nonfatal myocardial infarction occurred in nine patients given standard care only (17 percent) and in none of those given standard care plus bisoprolol (P<0.001). Thus, the primary study end point of death from cardiac causes or nonfatal myocardial infarction occurred in 2 patients in the bisoprolol group (3.4 percent) and 18 patients in the standard-care group (34 percent, P<0.001).

CONCLUSIONS

Bisoprolol reduces the perioperative incidence of death from cardiac causes and nonfatal myocardial infarction in high-risk patients who are undergoing major vascular surgery.

Central pulmonary artery lesions in chronic obstructive pulmonary disease: A transesophageal echocardiography study

BACKGROUND

In patients with acute pulmonary embolism, transesophageal echocardiography (TEE) often reveals presumably thrombotic lesions within the central pulmonary arteries (CPAs). These CPA lesions, when found in patients with primary pulmonary hypertension, have been attributed to in situ thrombosis or atherosclerosis. We hypothesized that similar CPA lesions may also develop in patients with chronic obstructive pulmonary disease (COPD) in the absence of pulmonary embolism.

METHODS AND RESULTS

We examined by TEE 25 patients with COPD and 27 control patients with left heart disease. None of the patients had previous pulmonary embolism or ileofemoral and popliteal vein thrombosis. By use of TEE, CPA lesions were found in 12 COPD patients (48%) and 2 control patients (7.4%) (P<0.01). When CPA lesions were subdivided into types 1 (protruding and mobile) and 2 (wall-adherent), type 1 lesions proved to be uncommon, being found within the pulmonary trunk in 12% and 3.7% of COPD and control patients, respectively (P=NS). Conversely, type 2 lesions, which were always localized in the right pulmonary artery, were frequent in COPD patients (36%) and rare in control patients (3.7%) (P<0.01). When available, helical CT and MR angiography confirmed TEE findings, supporting an atherosclerotic origin of type 2 lesions, which were different from typical thrombotic lesions. FEV(1)/FVC ratio, RV/TLC ratio, PaO(2), hematocrit value, and pulmonary artery systolic pressure were not significantly different in COPD patients with and without CPA lesions. At TEE, however, COPD patients with CPA lesions showed a larger size of the main and right pulmonary arteries.

CONCLUSIONS

TEE often reveals CPA lesions in stable patients with COPD even in the absence of significant pulmonary hypertension and not in close relation with the severity of pulmonary dysfunction.

Comparison of steerable continuous-wave versus pulsed-wave Doppler ultrasonography to renal artery angiography in diagnosing renal artery stenosis

Pulsed-wave Doppler ultrasonography is widely used to noninvasively diagnose renal artery stenosis. The use of steerable continuous-wave Doppler has never been tested. We compared pulsed and steerable continuous-wave Doppler ultrasonography, demonstrating that although both methods are highly sensitive for severe stenoses, continuous-wave Doppler shows a better sensitivity for mild to moderate stenoses.

[Doppler flow-velocity analysis of the renal arteries in left ventricular dysfunction]

AIM OF THE STUDY

Chronic heart failure leads to renal hypoperfusion. Clinical methods for monitoring renal artery flow have several limitations. We analyzed the renal artery flow-velocity in patients with left ventricular dysfunction and normal controls by pulsed-wave (PW) color-guided Doppler technique. The relation between PW Doppler quantitative indexes and left ventricular ejection fraction (LVEF), creatinine clearance, and age, was also assessed.

METHODS

We studied 53 patients with left ventricular dysfunction (LVEF by 2D echo < or = 40%) and no systemic hypertension, diabetes, parenchymal nephropathy, serum creatinine levels > 150 mmol/l, nor renal artery stenosis. Five patients were excluded for suboptimal renal artery PW Doppler recordings. Thus, the study group was constituted of 48 patients (mean age: 64 +/- 13 years). Twenty-eight normal subjects (mean age: 61 +/- 9 years) were the control group. By PW Doppler we measured the maximum (Vmax), the minimum (Vmin) and the mean (Vmean) velocities of both renal arteries. The resistivity index (RI), obtained from the formula (Vmax-Vmin)/ Vmax, and the pulsatility index (PI), obtained from the formula (Vmax-Vmin)/Vmed were calculated. Creatinine clearance was determined in each patient.

RESULTS

RI and PI were greater in patients with left ventricular dysfunction than in normal controls. In normal controls, RI and PI were related to age (r: 0.63, p < 0.001; and r: 0.45, p < 0.05) and creatinine clearance (r: -0.44 and -0.40, respectively; both: p < 0.05), not to LVEF. In patients with left ventricular dysfunction, RI and PI were related to LVEF (r: -0.67 and -0.59; both: p < 0.001), other than to age (r: 0.57 and 0.55; both: p < 0.001) and creatinine clearance (r: -0.59, p < 0.001, and r = -0.46, p < 0.01, respectively). In this group, however, there was no sharp separation of RI and PI between patients with different degree of left ventricular dysfunction (LVEF < or = 30% and > 30%).

CONCLUSIONS

In patients with left ventricular dysfunction, by renal artery PW Doppler analysis it is possible to detect noninvasively a reduction in regional flow-velocity and an increase in Doppler-derived vascular resistance indexes. These Doppler changes mainly depend on severity of left ventricular dysfunction and less on age of patients.

Regional wall motion analysis by dobutamine stess echocardiography to distinguish between ischemic and nonischemic dilated cardiomyopathy

To distinguish between ischemic and nonischemic dilated cardiomyopathy (DCM), we studied 43 patients with left ventricular dysfunction (15 ischemic and 28 nonischemic detected by coronary angiography) by dobutamine stress echocardiography. At rest, there were more normal segments (p<0.001) and a trend toward more akinetic segments (p, not significant) per ischemic than per nonischemic DCM patient. However, either at rest or with low-dose dobutamine, individual data largely overlapped. At peak dose, in ischemic DCM, regional contraction worsened in many normal or dys-synergic regions at rest (in the latter case after improvement with low-dose dobutamine); in contrast, in nonischemic DCM, further mild improvement was observed in a variable number of left ventricular areas. Thus with peak-dose dobutamine, more akinetic and less normal segments were present per ischemic than per nonischemic DCM patient (both, p<0.001). A value of six or more akinetic segments was 80% sensitive and 96% specific for ischemic DCM. Our data show that analysis of regional contraction by dobutamine stress echocardiography can distinguish between ischemic and nonischemic DCM.

Color Doppler ultrasonography for the assessment of renal blood flow in heart failure

To validate color Doppler ultrasonography of renal arteries for the assessment of renal blood flow (RBF), we compared left and right RBF estimates and their sum (total RBF) by echo-Doppler with data obtained by iodine 123-123I-p-aminohippuric acid (PAH) scintigraphy in 19 patients with heart failure and 7 normal control subjects. Single-side and total RBF estimates by echo-Doppler ranged, respectively, between 179 and 428 mL/min/m2 and from 378 to 835 mL/min/m2 in patients with heart failure and between 265 and 601 mL/min/m2 and from 564 to 1,182 mL/min/m2 in normal control subjects. Single-side and total RBF estimates by echo-Doppler correlated well with measurements obtained by scintigraphy (r = 0.74 and 0.76, respectively, in patients with heart failure; both: p < 0.001). At Bland and Altman's analysis of correspondence between the 2 techniques, there were 17 disagreements (33.7%) for single-side RBF and 8 disagreements (31.8%) for total RBF. However, the two techniques disagreed markedly in only two single-side and one total RBF estimates. Thus, in patients with heart failure, RBF assessed noninvasively by color Doppler ultrasonography has a good correlation with 123I-PAH renal scintigraphy data over a wide range of blood flow.

[Thromboembolism of the right branch of the pulmonary artery: its diagnosis by biplanar transesophageal echocardiography]

We report on a patient with pulmonary thromboembolism, primarily diagnosed by urgent TEE. The thrombus was localized in the distal portion of the right pulmonary artery and was easily recognized by transversal plane TEE inspection. Pulmonary scintigraphy was subsequently performed and confirmed TEE findings.

Doppler analysis of portal vein flow in tricuspid regurgitation

Portal and hepatic vein flow-velocity profiles were examined by pulsed Doppler in 66 patients with tricuspid regurgitation (color Doppler grading: severe: 37, moderate: 18; mild: 11) and 20 normal subjects to determine if portal vein flow analysis is useful in the evaluation of tricuspid regurgitation. Portal vein flow was defined as one of the following categories: subcontinuous (dependent on respiration), pulsatile systolic (not inverted), inverted after systole, and continuous (not dependent on respiration). An index of portal vein flow pulsatility was also calculated. Standard classification of hepatic vein flow pattern was performed. Portal vein flow was pulsatile in 20% of normals subjects, and in 27.3% 44.5% and 51.3% of patients with respectively mild, moderate and severe tricuspid regurgitation; portal vein flow was inverted after systole in further 32.4% of patients with severe tricuspid regurgitation. Portal vein pulsatility index correlated with color Doppler grading of tricuspid regurgitation (r:0.63; p < 0.001) and right ventricle-atrium pressure gradient (r:0.39; p < 0.01). However, when compared with hepatic vein flow, both sensitivity and specificity of quantitative portal vein flow analysis was less reliable in diagnosing and grading tricuspid regurgitation. In particular, in patients with severe tricuspid regurgitation, the portal vein flow pattern was quite variable (pulsatile in 19 patients, inverted after systole in 12, and continuous in six). Liver biopsy was performed in nine patients, four of them with severe tricuspid regurgitation and continuous portal vein flow. Histology showed severe liver fibrosis in all four.(ABSTRACT TRUNCATED AT 250 WORDS)

Left atrial thrombus and spontaneous echo-contrast in nonanticoagulated mitral stenosis. A transesophageal echocardiographic study

OBJECTIVE

The aim of the study was to investigate if evidence at transthoracic echocardiography (TTE) of left atrial (LA) thrombus and LA spontaneous echo-contrast (LA SEC), which are potential precursors of embolization, can be predicted by clinical and TTE variables in nonanticoagulated mitral valve stenosis (MS).

DESIGN

Clinical (age, NYHA class, rhythm, previous embolization) and TTE variables were related to transesophageal echocardiography (TEE) evidence of LA thrombus and/or LA SEC.

SETTING

Nonanticoagulated MS was the setting.

PATIENTS

Fifty-nine patients had MS, and they were not receiving anticoagulant or antiplatelet therapy (24 in sinus rhythm and 35 in atrial fibrillation). Previous arterial embolization had occurred in 12 patients (20.3 percent).

MEASUREMENTS

The following TTE variables were analyzed: mitral orifice area (pressure half-time method), mitral gradient (Bernouilli's equation), LA end-systolic area, and mitral regurgitation (color Doppler grading). LA thrombus and LA SEC were analyzed by monoplane TEE.

RESULTS

LA thrombus was found by TEE in 12 patients (20.3 percent). Of these 12, 11 (91.6 percent) were in atrial fibrillation. LA SEC was found by TTE in 2 patients (3.5 percent) and by TEE in 40 (67.8 percent) (p < 0.001). Previous embolization had occurred only in patients with LA SEC, of whom 5 had and 7 did not have LA thrombus. Patients with LA SEC, compared with those without LA SEC, were characterized by more frequent advanced NYHA class, atrial fibrillation, smaller mitral valve area, and larger LA size. By multivariate regression analysis, atrial fibrillation and LA end-systolic area were factors related to both LA thrombus and LA SEC, whereas mitral area was related only to LA SEC. However, whereas LA SEC was accurately predicted by the presence of atrial fibrillation (sensitivity: 87.5 percent; specificity: 100 percent) and a LA area > or = 30 cm2 (sensitivity: 72.5 percent; specificity: 89.5 percent), among patients with LA SEC no clinical or TTE variable accurately identified those with actual LA thrombus.

CONCLUSIONS

TEE is not necessary in many patients with MS in order to recognize LA SEC. However, when actual LA thrombus detection is necessary for clinical decision making, TEE should be performed.

Systolic ejection murmurs in the elderly: aortic valve and carotid arteries echo-Doppler findings

Two-dimensional echographic and color Doppler studies of the heart and carotid arteries (CA) were performed in 45 patients greater than sixty-five years old without aortic stenosis, 23 with (Group 1) and 22 without (group 2) precordial ejection systolic murmur (SM). Aortic cusps thickening was found in 11 Group 1 (48%) and 2 Group 2 (9%) patients (p less than 0.001). Aortic root and aortic arch size were similar in the two groups. Maximum aortic flow velocity was significantly greater in Group 1 (200 60 cm/sec) than in Group 2 (120 20 cm/sec) (p less than 0.001). Left ventricular outflow systolic maximum velocity was similar in the two groups. A bilateral neck murmur was heard in 10/23 Group 1 patients (43%); in this group, patients with cervical SM had a greater maximum aortic flow velocity than those without cervical SM (230 + 60 cm/sec vs 172 + 32 cm/sec, p less than 0.001). In Group 1, 3 patients had a cervical SM louder on one neck side; only in these 3 patients were ipsilateral obstructive CA plaques found. A unilateral neck SM was heard in 4/22 Group 2 patients (18%); in these 4, ipsilateral obstructive CA were found.

CONCLUSIONS

(1) in the elderly, precordial ejection SM is related to mild increase in maximum aortic flow velocity and thickening of aortic cusps; (2) in patients with precordial SM radiated to both neck sides, maximum aortic flow velocity tends to be more markedly increased; (3) in patients with precordial SM, a cervical SM louder on one neck side should suggest coexistent ipsilateral CA stenosis.

[Diagnosis of recent posterolateral myocardial infarction: an electrocardiographic, echocardiographic and scintigraphic study]

ECG and 2D echocardiography were studied in 64 patients with previous myocardial infarction and evidence of posterolateral fixed defect at 201 TI scintigraphy. The defect was isolated posterolateral in 47 patients (group 1), and posterolateral + inferoapical in 17 (group 2). Thirty subjects with no history of myocardial infarction and no 201 TI defects constituted the control group. We calculated sensitivity, specificity and predictive value of ECG and 2D echocardiography (pertinent wall motion abnormality) in the recognition of posterolateral infarction. ECG data were also analyzed using multivariate analysis. Among the ECG criteria, a positive T wave in V1 proved to be 100% sensitive and 76% specific both in group 1 and in group 2. At multivariate analysis, a 2-variable model (positive T wave inV1 + R/S ratio greater than or equal to 1 in V1-V2) had a sensitivity of 95 and 100% in group 1 and 2, respectively; the specificity was 80%. A 3-variable model (+ R wave duration in V1-V2 greater than or equal to 0.04 sec) proved to be less sensitive (70 and 88% in group 1 and 2, respectively), with a specificity of 97%. A pertinent dyssynergy at 2D echocardiography was 70% sensitive for posterolateral myocardial infarction in group 1, but only 29% in group 2, with a specificity of 100%. These results indicate: 1) standard ECG is more sensitive but less specific than 2D echocardiography in the recognition of previous postolateral myocardial infarction; 2) the recognition of posterolateral involvement can be frequently missed by 2D echocardiography in patients with associated inferior myocardial infarction.

[Forme fruste of Gorlin's syndrome with a left ventricular neoplasm]

We report on a 25-year-old man, referred for atypical chest pain and negative T waves in leads V5-V6. A cardiac tumor, localized in the posterolateral left ventricular wall was diagnosed in this patient by nuclear techniques and bidimensional echocardiography. A complex form of pluridistrectual dysmorphic disorder (hypertelorism, prognathism, frontal bossing, multiple cysts of the mandible, calcification in falx cerebri, etc) was also present, suggesting a limited form of Gorlin's syndrome (nevoid basal cell carcinoma syndrome).