BNP: an indicator of progression of left ventricular dysfunction?
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Atrial Natriuretic Factor↗
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Right ventricular dysfunction.
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Heart Diseases↗
Neuroendocrine activation in left ventricular dysfunction.
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Biomarkers↗
Diagnosing left ventricular dysfunction after myocardial infarction: the Dundee algorithm.
Large-scale trials of angiotensin converting enzyme (ACE) inhibitors after acute myocardial infarction (AMI) suggest that the benefits are greatest in patients with left ventricular (LV) dysfunction. However, early evaluation of LV function in all patients after AMI by current methods can be difficult due to a lack of resources and skilled personnel. Thus a clinical algorithm that could be used at the bedside to reliably identify patients with a left ventricular ejection fraction (LVEF) < or = 40% would be helpful as an occasional alternative to echocardiography. We have devised such an algorithm based on the presence of one of: (i) clinical signs of heart failure; (ii) an index Q-wave anterior myocardial infarction; (iii) lack of thrombolytic therapy when there is a history of two or more previous myocardial infarctions and a CK rise > 1000 U/l. We tested this new algorithm prospectively in the coronary care units of two hospitals (one UK and one USA). In the UK centre, the sensitivity and specificity of the algorithm at identifying patients with a LVEF < or = 40% were 82% and 72%, respectively. In the US centre, the sensitivity of the algorithm was 91% and the specificity 78% at identifying patients with LV dysfunction. We have validated a simple clinical algorithm which can be used at the bedside for identifying patients who would benefit from an ACE inhibitor after AMI.
Aged↗
Use of cyclic variation of integrated backscatter to assess contractile reserve and myocardial viability in chronic ischemic left ventricular dysfunction.
The detection of viable myocardium has important implications for management, but use of stress echocardiography to detect this is subjective and requires exposure to dobutamine. We investigated whether cyclic variation (CV) of integrated backscatter (IB) from the apical views could provide a resting study for detection of contractile reserve (CR) and prediction of myocardial viability in 27 patients with chronic ischemic left ventricular (LV) dysfunction. Repeat echocardiography was performed after 6.7 +/- 3.8 months of follow-up; 14 patients underwent revascularization and 13 were treated medically. Using a standardized dobutamine echocardiography (DbE) protocol, images from three apical views were acquired at 80-120 frames/sec at rest and during stress. CR was identified if improvement of wall motion was observed at low dose (5 or 10 microg/kg/min) DbE. Myocardial viability was characterized by improvement at follow-up echocardiography in patients with revascularization. CVIB at rest and low dose dobutamine were assessed in 194 segments with resting asynergy (severe hypokinesis or akinesis), of which 88 (45%) were in patients who underwent revascularization. Of these, CVIB could be measured in 190 (98%) segments at rest and 185 (95%) at low dose dobutamine. Sixty-two (33%) segments had CR during low dose DbE and 50 (57%) segments showed wall-motion recovery (myocardial viability) at follow-up echocardiography. Segments with CR had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P = 0.005) than segments without CR. Using optimal thresholds of CVIB (> 8.2 dB) at rest, the accuracy of CVIB for detecting CR was 70%. Compared with nonviable segments, viable segments had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P < 0.001). Using optimal thresholds of CVIB (> 5.3 dB) at rest, the accuracy of CVIB for detecting myocardial viability was 85%, which was higher than that in conventional DbE (62%, P < 0.01). Thus, assessment of CVIB from the apical views is a feasible and accurate tool for detecting CR and predicting myocardial viability in chronic LV dysfunction.
Adult↗
Effects of epanolol, a selective beta1-blocker with intrinsic sympathomimetic activity, in patients with ischemic left ventricular dysfunction.
Recently, different beta-blockers have been shown to be effective in the treatment of chronic heart failure (CHF), but the importance of their ancillary properties is not clear. Epanolol is a selective beta1-blocker with intrinsic sympathomimetic activity, which has been shown useful in angina pectoris, but its value in patients with left ventricular (LV) dysfunction and CHF is unknown. We examined the effects of epanolol in patients with LV dysfunction (n = 8; mean LV ejection fraction, 0.33 +/- 0.08) and compared them with patients with normal LV function (n = 8; mean LV ejection fraction, 0.52 +/- 0.04). Measurement of invasive hemodynamics and neurohormones was performed at rest and during myocardial ischemia, which was induced by atrial pacing. All measurements were performed before and after epanolol. Before epanolol, pacing-induced ischemia led to a similar increase in norepinephrine and coronary sinus blood flow in both groups. After epanolol, the increase in neurohormones was more pronounced in the group with LV dysfunction (norepinephrine, 1,130 +/- 164 pg/ml for patients with LV dysfunction vs. 637 +/- 41 pg/ml for normal subjects; p < 0.05). A similar effect was observed for angiotensin II. Further, in the LV-dysfunction group, coronary sinus blood flow increased less, and coronary vascular resistance decreased less (both values, p < 0.05). Despite the fact that the increase in double product was decreased to a similar extent in both groups, ischemia was reduced only in normal LV function (p < 0.05). In ischemic LV dysfunction, neurohumoral activation after epanolol may impair adequate coronary flow response, and this may limit its antiischemic properties. Because of the small size of the study, no definitive inference on the clinical benefit of epanolol in patients with ischemic LV function can be made from this study.
Adrenergic beta-Antagonists↗
Effects of a DA2/alpha2 agonist and a beta1-blocker in combination with an ACE inhibitor on adrenergic activity and left ventricular remodeling in an experimental model of left ventricular dysfunction after coronary artery occlusion.
Renin-angiotensin-aldosterone and sympathetic nervous systems overactivity play a major role in worsening the extent of heart failure. Attenuation of neurohumoral activation with angiotensin-converting enzyme (ACE) inhibitors and beta-blockers has proven beneficial in congestive heart failure. Because ACE inhibition is a recommended treatment for heart failure, this study was designed to test the effects on neurohumoral activation, hemodynamics, and left ventricular (LV) volume of the combination of an ACE inhibitor (delapril) with a DA2-dopaminergic receptor/alpha2-adrenoceptor agonist (CHF-1024) or a beta1-adrenoceptor antagonist (metoprolol) after a moderate to large myocardial infarction (MI) in rats. MI was induced by left coronary artery ligation in 134 rats, and six were not operated on. After 2 months, the animals with ECG evidence of MI were treated for 1 more month with CHF- 1024, 0.33 mg/kg/day or with metoprolol (10 mg/kg/day), delivered through implanted osmotic minipumps, in addition to delapril (6 mg/kg/day) in the drinking water. Daily urinary excretion of norepinephrine (NE) and circulating concentration were measured. Hemodynamic variables were measured, and three-dimensional morphometric analysis was done on the diastole-arrested hearts to quantify infarct size and LV geometry. In conscious animals, delapril alone or with CHF-1024 or metropolol did not modify heart rate or systolic blood pressure. Both combination treatments, however, significantly reduced heart rate in anesthetized animals compared with the group receiving vehicle. Infarct size was not different between treatments, averaging 20-22% of LV volume. The threefold increase of LV chamber volume in infarcted rats was significantly attenuated by delapril alone or with CHF-1024 or metoprolol (-37 to -44%, p<0.05). Treatment with a combination of the ACEi and CHF-1024 tended to normalize the shape of the LV cavity. Urinary NE excretion was unaffected by delapril alone but was reduced by the addition of CHF-1024 or metoprolol. In conclusion, 1 month of treatment with doses of delapril having no hemodynamic effect, reduced LV volume in a model of chronic heart failure. When CHF-1024 or metoprolol was given with delapril, sympathetic activation decreased with no unwanted effects, such as excessive hypotension.
Adrenergic alpha-Agonists↗
Nitrate-enhanced gated technetium 99m sestamibi SPECT for evaluating regional wall motion at baseline and during low-dose dobutamine infusion in patients with chronic coronary artery disease and left ventricular dysfunction: comparison with two-dimensional echocardiography.
BACKGROUND: The value of gated single photon emission computed tomography (SPECT) in the assessment of wall motion (WM) in patients with severe perfusion defects and in the evaluation of low-dose dobutamine (LDD)-induced changes is not yet established. In patients with chronic coronary artery disease who have left ventricular (LV) dysfunction, the results of nitrate-enhanced technetium 99m sestamibi (sestamibi) gated SPECT for the evaluation of resting and LDD WM were compared with those of baseline and LDD echocardiography (LDDE). METHODS AND RESULTS: Thirty-seven patients underwent echocardiography and nitrate-enhanced sestamibi gated SPECT within 1 week at rest and during LDD infusion. WM was scored from 1 (normal) to 4 (dyskinetic) by using a 16-segment model. Segments with sestamibi uptake less than 30% were considered unsuitable for WM analysis (36 of 592 segments). Echocardiography was technically unreliable in 10 of 592 segments. The precise agreement between echocardiography and gated SPECT for baseline regional WM was 68.4% (kappa = 0.54), without significant differences for the involved coronary artery territory. The agreement for +/- 1 WM scoring was 96.5% (kappa = 0.94). Contractile reserve during LDD was detected by means of echocardiography in 36% and by means of sestamibi gated SPECT in 33% of baseline asynergic segments. Agreement for detection of WM improvement in response to LDD was 74% (kappa = 0.41). The overall and +/-1 WM score agreement for LDD WM was 67.5% (kappa = 0.50) and 94.7% (kappa = 0.91), respectively. A significant correlation between echocardiography and gated SPECT was observed for both baseline (p = 0.78) and LDD (p = 0.74) WM score index. CONCLUSIONS: In patients with coronary artery disease who have LV dysfunction, nitrate-enhanced sestamibi gated SPECT allows a reliable WM evaluation, both at rest and during LDD infusion, in almost all segments and provides results in agreement with LDDE.
Adult↗
Restricted diastolic opening of the mitral leaflets in patients with left ventricular dysfunction: evidence for increased valve tethering.
OBJECTIVES: We tested the hypothesis that patients with incomplete systolic mitral leaflet closure (IMLC: apically displaced coaptation) also have restricted diastolic leaflet opening that is independent of mitral inflow volume and provides evidence supporting increased leaflet tethering. BACKGROUND: Competing hypotheses for functional mitral regurgitation (MR) with IMLC include global left ventricular (LV) dysfunction per se (reduced leaflet closing force) versus geometric distortion of the mitral apparatus by LV dilation (augmented leaflet tethering). These are inseparable in systole, but restricted leaflet motion has also been observed in diastole, and attributed to reduced mitral inflow. METHODS: Diastolic mitral leaflet excursion and orifice area were measured by two-dimensional echocardiography in 58 patients with global LV dysfunction, 36 with and 22 without IMLC, compared with 21 normal subjects. The biplane Simpson's method was used to calculate LV ejection volume, which equals mitral inflow volume in the absence of aortic regurgitation. RESULTS: The diastolic mitral leaflet excursion angle was markedly reduced in patients with IMLC compared with those without IMLC, whose ventricles were smaller, and normal subjects (17 +/- 10 degrees vs. 58 +/- 13 degrees vs. 67 +/- 8 degrees, p < 0.0001). Excursion angle was dissociated from mitral inflow volume (r2 = 0.04); excursion was reduced in patients with IMLC despite a normal inflow volume in the larger ventricles with MR (60 +/- 25 vs. 61 +/- 12 ml in normal subjects, p = NS), and excursion was nearly normal in patients without IMLC despite reduced inflow volume (40 +/- 10 ml, p < 0.001 vs. normal subjects). The anterior leaflet when maximally open coincided well with the line connecting its attachments to the anterior annulus and papillary muscle tip (angular difference = 3 +/- 7 degrees vs. 25 +/- 9 degrees vs. 32 +/- 10 degrees in patients with and without IMLC vs. normal subjects, p < 0.0001). In patients with IMLC, the leaflet tip orifice was smaller in an anteroposterior direction but wider than in the other groups, giving a normal total area (6.8 +/- 1.8 vs. 7.1 +/- 1.2 vs. 6.9 +/- 0.8 cm2, p = NS). CONCLUSIONS: Patients with LV dysfunction and systolic IMLC also have restricted diastolic leaflet excursion that is independent of inflow volume, coincides with the tethering line connecting the annulus and papillary muscle and reflects limitation of anterior motion relative to the posteriorly placed papillary muscles without a decrease in total orifice area. These observations are consistent with increased tethering by displaced mitral leaflet attachments in the dilated ventricles of patients with IMLC that can restrict both diastolic opening and systolic closure.
Adult↗
Exercise-induced Wall Motion Abnormalities and Resting Left Ventricular Dysfunction in the Morbidly Obese as Assessed by Radionuclide Ventriculography.
Rest and exercise first pass radionuclide ventriculograms were obtained in 62 morbidly obese subjects (56 women, six men, mean age 38 years, mean weight 269.2 +/- 46.0 lb, mean height 65.2 +/- 3.1 in., mean Body Mass Index 44.5 +/- 6.2 kg/m(2), mean excess body weight 134.1 +/- 41.1 lb) scheduled for vertical banded gastroplasty. Fifty-six percent demonstrated exercise-induced wall motion abnormalities mimicking coronary disease, compared to 12% of controls (p = 0.03). No subject with exercise-induced abnormalities had coronary disease at cardiac catheterization although only those with an anginal chest pain history underwent angiography. Twenty-six percent demonstrated resting left ventricular systolic dysfunction as manifested by a reduced resting left ventricular ejection fraction ( <0.50). Thirty-one percent of these patients demonstrated exercise-induced abnormalities, versus 65% of morbidly obese subjects with normal resting ejection fractions (p = 0.04). Obesity-induced left ventricular hypertrophy with associated reduced coronary vasodilator reserve could explain the abnormalities. Six month post-gastroplasty follow-up radionuclide ventriculograms show group normalization of the resting left ventricular ejection fraction in those with preoperative dysfunction, possibly due to left ventricular unloading with some regression of hypertrophy.
Journal Article↗
Detection of occult left ventricular dysfunction in patients without prior clinical history of myocardial infarction by technetium-99m sestamibi myocardial perfusion gated single-photon emission computed tomography.
BACKGROUND: In the absence of a prior history of myocardial infarction (MI), left ventricular (LV) dysfunction is commonly due to hypertension, valvular heart disease, or hibernating myocardium. HYPOTHESIS: Since technetium-99m sestamibi gated single-photon emission computed tomography (SPECT) may be used to determine both stress/rest myocardial perfusion and resting LV function, we attempted to evaluate the ability of gated SPECT imaging to detect occult LV dysfunction. METHODS: We evaluated the ability of this technique to detect occult LV dysfunction among 179 patients without history MI and angiographically documented coronary artery disease (CAD). All patients underwent both gated SPECT and cardiac catheterization within a 6-month time period. Left ventricular volume and ejection fraction (EF) values were determined according to a previously validated technique using Simpson's rule. Normal limit values for LV volumes and EF were derived from a control population of 93 patients with normal coronary angiograms. RESULTS: Based on normal limit-derived criteria, 15% of the CAD study cohort had occult LV dysfunction (> 2 standard deviations below gender-specific normal limit means for LVEF). Mean LV end-diastolic volume index (EDVi) was significantly increased (p < 0.05) and LVEF decreased (p < 0.05) in patients with triple-vessel CAD. End-diastolic volume index was also increased in the cohort of patients with both hypertension and LV hypertrophy (LVH) (p < 0.05). However, multivariate logistic regression analysis revealed that only CAD extent, but not hypertension or LVH, was a significant predictor of occult LV dysfunction (p = 0.009). CONCLUSION: Occult LV dysfunction can be detected in patients with CAD by gating technetium-99m sestamibi SPECT studies, and its presence may signify the presence of extensive CAD.
Adult↗
Biocompatibility of heparin-coated cardiopulmonary bypass circuits in coronary patients with left ventricular dysfunction is superior to PMEA-coated circuits.
BACKGROUND: Several coating techniques for extracorporeal circulation have been developed to diminish the systemic inflammatory response during cardiopulmonary bypass (CPB). The aim of this study was to evaluate the clinical effectiveness and biocompatibility of heparin-coated and poly-2-methoxyethylacrylate (PMEA)-coated CPB circuits on coronary patients with left ventricular systolic dysfunction. METHODS: Thirty-six patients who underwent elective coronary artery bypass grafting were divided into two equal groups: group H (n = 18), heparin-coated; group P (n = 18), PMEA coated. Clinical outcomes, hematologic variables, cardiac enzymes, malondialdehyde (MDA), and acute phase inflammatory response (including myeloperoxidase (MPO), catalase, hsCRP, and IL-8) were analyzed perioperatively. RESULTS: Demographic, CPB, and clinical outcome data were similar for both groups. Plasma fibrinogen, total protein, albumin, and platelet count decreased, neutrophil count, MDA, IL-8, MPO, and catalase levels increased during CPB. During CPB, MPO and catalase values were significantly higher in group P (p = 0.02 and p = 0.01) and postoperative MDA concentration was lower in group H (p = 0.03). Platelet counts were better preserved in group H during and after CPB but neutrophil count and IL-8 level did not differ between the groups. Postoperative total protein, albumin, and fibrinogen levels were higher in group H (p < 0.05). The postoperative first day levels of troponin-I, CK-MB, and CRP increased in both groups without any significant differences between the groups. CONCLUSIONS: Heparin-coated circuit provided better suppression of perioperative inflammatory markers and exhibited more favorable effects on hematologic variables than PMEA-coated circuit.
Acrylates↗
Aortic stenosis with severe left ventricular dysfunction and low transvalvular pressure gradients: risk stratification by low-dose dobutamine echocardiography.
OBJECTIVES: We sought to assess risk stratification by using dobutamine stress echocardiography (DSE) in patients with aortic stenosis (AS) and severe left ventricular (LV) dysfunction. BACKGROUND: Few data are available on risk stratification for valve replacement in patients with AS, LV dysfunction and low transvalvular gradients. METHODS: Low-dose DSE was performed in 45 patients (16 women and 29 men; median [quartile range] age in years: 75 [69 to 79]; left ventricular ejection fraction: 0.29 [0.23 to 0.32]; aortic valve area [cm2]: 0.7 [0.5 to 0.8]; mean transaortic gradient [mm Hg]: 26 [21 to 33]). Patients were classified into two groups: group I (n = 32, LV contractile reserve on DSE) and group II (n = 13, no contractile reserve). Valve replacement was performed in 24 and 6 patients in groups I and II, respectively. RESULTS: Perioperative mortality was 8% in group I and 50% in group II (p = 0.014). Survival at five years after the operation was 88% in group I. Compared with medical therapy, valve surgery was associated with better long-term survival in group I (hazard ratio for death [HR-D] 0.13, 95% confidence interval [CI] 0.002 to 0.49) and reduced survival in group II (HR-D 19.6, 95% CI 2.7 to 142). The effect of valve surgery on survival remained significant in both groups after adjustment for age, diabetes, respiratory disease and hypertension. Medical therapy had the same effect in both groups. CONCLUSIONS: In patients with AS, LV dysfunction and low transvalvular gradients, contractile reserve on DSE is associated with a low operative risk and good long-term prognosis after valve surgery. In contrast, operative mortality remains high in the absence of contractile reserve.
Aged↗
Thiazolidinediones and congestive heart failure--exacerbation or new onset of left ventricular dysfunction?
BACKGROUND: Patients with diabetes mellitus have a high incidence of coronary heart disease and congestive heart failure (CHF). Thiazolidinediones (TZD) are a new class of pharmacological agents for the treatment of Type 2 diabetes mellitus, which have many beneficial cardiovascular effects. Peripheral oedema and weight gain have been reported in 4.8% of subjects on TZDs alone, with a higher incidence noted in those receiving combination insulin therapy (up to 15%), but there is limited data on the occurrence of CHF. METHODS AND RESULTS: In this paper, we report on six cases of TZD-induced fluid retention with symptoms and signs of peripheral oedema and/or CHF that occurred in subjects attending our diabetic clinic. The predominant finding in all cases was of diastolic dysfunction. All subjects were obese and hypertensive, with 5/6 having the additional risk factor of LVH, 5/6 subjects had microvascular complications, whilst 3/6 were also on insulin therapy. CONCLUSION: We suggest that obese, hypertensive diabetics may benefit from echocardiographic screening prior to commencement of TZDs, as these agents may exacerbate underlying undiagnosed left ventricular diastolic dysfunction.
Aged↗
Impact of diabetes mellitus on prediction of clinical outcome after coronary revascularization by 18F-FDG SPECT in patients with ischemic left ventricular dysfunction.
UNLABELLED: Nuclear imaging using (18)F-FDG is an established method for the noninvasive assessment of myocardial viability. Data on the value of (18)F-FDG imaging in patients with diabetes mellitus are scarce. The aim of this study was to assess whether, in patients with diabetes mellitus and ischemic left ventricular (LV) dysfunction, (18)F-FDG imaging can predict improvement of LV function and heart failure symptoms after coronary revascularization. METHODS: A total of 130 consecutive patients with ischemic LV dysfunction who were already scheduled for surgical revascularization were studied; 34 of the patients had diabetes mellitus. All patients underwent radionuclide ventriculography to assess left ventricular ejection fraction (LVEF), resting 2-dimensional echocardiography to identify dysfunctional myocardial tissue, and dual-isotope (18)F-FDG/(99m)Tc-tetrofosmin SPECT after oral administration of acipimox. Nine to 12 mo after coronary revascularization, radionuclide ventriculography and echocardiography were repeated. An improvement in LVEF by at least 5% was considered significant. RESULTS: (18)F-FDG SPECT demonstrated that 610 (50%) of 1,212 dysfunctional segments were viable. Patients with and without diabetes mellitus had a comparable number of dysfunctional but viable segments per patient. Also, the number of patients with a substantial amount of dysfunctional but viable myocardium (>or=4 viable segments) was comparable between the groups with and without diabetes mellitus. The presence of substantial viability on (18)F-FDG SPECT was predictive of improvement in LVEF and heart failure symptoms postoperatively (sensitivity and specificity of 82% and 89%, respectively, in patients with diabetes and 83% and 93%, respectively, in patients without diabetes; not statistically significant). CONCLUSION: (18)F-FDG SPECT is practical for routine assessment of myocardial viability in patients with ischemic LV dysfunction with or without diabetes mellitus. Patients with substantial myocardial viability on (18)F-FDG SPECT have a high probability of improvement of LV function and symptoms after coronary revascularization, irrespective of the absence or presence of diabetes mellitus.
Comorbidity↗
Dobutamine stress echocardiography and technetium-99m-tetrofosmin/fluorine 18-fluorodeoxyglucose single-photon emission computed tomography and influence of resting ejection fraction to assess myocardial viability in patients with severe left ventricular dysfunction and healed myocardial infarction.
The purpose of this study was to compare 2 different techniques--dobutamine-atropine stress echocardiography (DSE) and dual-isotope simultaneous acquisition (technetium-99-m-tetrofosmin/fluorine 18-fluorodeoxyglucose) single-photon emission computed tomography (DISA-SPECT)--for assessment of viable myocardium. One hundred ten patients (mean age 55 +/- 9 years) with left ventricular (LV) dysfunction (mean LV ejection fraction 27 +/- 13%) underwent both DISA-SPECT and DSE. A 16-segment scoring model was adopted for both techniques. Four types of wall motion during DSE were assessed: (1) biphasic, improvement at low dose (10 microg/kg/min) with worsening at high dose; (2) worsening, deterioration without initial improvement; (3) sustained, persistent or late improvement; and (4) no change. Viability criteria were biphasic, worsening, and sustained improvement with DSE. Viability criteria with DISA-SPECT were normal perfusion and metabolism (normal), concordantly mildly reduced perfusion and metabolism (subendocardial scar), or severely reduced perfusion and increased metabolism (mismatch). Myocardium was considered nonviable with DSE in case of unchanged wall motion, or moderate reduction or absence in both technetium-99m-tetrofosmin perfusion and fluorodeoxyglucose uptake with DISA-SPECT. Of 1,756 of 1,760 analyzable LV segments, 1,373 (78%) had severe wall motion abnormalities at baseline (severe hypokinesia, akinesia, or dyskinesia). Of these abnormal segments, 282 (21%) were considered viable during DSE (63 [5%] with biphasic response, 47 [3%] with ischemia, and 172 [13%]) with sustained improvement, whereas 1,091 (79%) were considered nonviable. With DISA-SPECT, 396 (29%) segments were considered viable (312 [23%] with matched perfusion/metabolism and 84 [6%] with mismatch), whereas 977 segments (71%) were considered nonviable. Both techniques showed agreement for viability in 201 segments and 896 were concordantly classified as nonviable. Disagreement was present in 276 segments of which 195 (71%) were nonviable with DSE and viable with DISA-SPECT. Overall agreement between the 2 techniques was 81% (kappa 0.46) in a subgroup of patients with an ejection fraction <25% 78% (kappa 0.39). Thus, DSE and DISA-SPECT show good agreement for assessing viable myocardium not influenced by resting ejection fraction. DSE underestimated the amount of viable tissue compared with DISA-SPECT.
Blood Pressure↗
Basal release of endothelium-derived nitric oxide plays an important role in the prevention of afterload mismatch in acute left ventricular dysfunction.
The basal release of endothelium-derived nitric oxide (EDNO) is considered to play an important role in regulating the vascular tone in normal subjects; however, its role in the presence of acute heart failure is unknown. This study was designed to clarify the role of a basal release of EDNO in the presence of acute heart failure. Acute ischemic left ventricular (LV) dysfunction was produced in 22 dogs by coronary microembolization. After the embolization, only saline solution was intravenously infused for sixty minutes in 10 dogs. In another 12 dogs, NG-monomethyl-L-arginine (L-NMMA), which is known to inhibit the formation of EDNO in the vascular endothelium, was intravenously infused at a rate of 20 micrograms/kg/minute for sixty minutes. Infusion of saline solution did not produce any changes in hemodynamic variables. Infusion of L-NMMA caused increases in mean aortic pressure, systemic vascular resistance, and LV end-diastolic pressure without changes in the LV peak + and - dP/dt (time constant) of LV pressure fall, and these changes were associated with a giant "v" wave in the tracing of left atrial pressure and a decrease in cardiac output. The basal release of EDNO may play an important role in the prevention of afterload elevation, subsequent cardiac output reduction, and afterload mismatch in the presence of acute heart failure.
Acute Disease↗
The impact of right ventricular dysfunction on the prognosis and therapy of normotensive patients with pulmonary embolism.
The prognosis and optimal therapy of patients with pulmonary embolism (PE) are strongly influenced by the presence or absence of associated hemodynamic derangements. Patients with normal systemic arterial pressure have a relatively low risk of recurrent PE and death when treated promptly with therapeutic anticoagulation. Those who present with hypotension, shock, or cardiac arrest, however, have a much higher mortality rate and often receive thrombolytic therapy. Recent evidence indicates that the presence of right ventricular (RV) dysfunction identifies a subgroup of normotensive patients with a much more guarded prognosis who may benefit from more intensive therapy with thrombolytic agents. This article reviews our current understanding of the pathophysiology and diagnosis of RV dysfunction and its impact on the prognosis and therapy of normotensive patients with PE.
Humans↗