[Show abstract][Hide abstract] ABSTRACT: Whether cardiac ventricles can acutely dilate during septic myocardial dysfunction.
A prospective echocardiographic study was performed to assess changes of left ventricular dimensions over time in patients with septic shock.
A 20-bed surgical intensive care unit of Pitié-Salpêtrière university hospital in Paris.
Forty-five patients were studied over the first 10 days of septic shock.
Left ventricular end-diastolic area (LVEDA), fractional area change (FAC), velocity time integral of the aortic flow, echocardiographic indices of left ventricular relaxation, and cardiac troponin I (cTnI) were measured at day 1, 2, 3, 4, 7, and 10. Three groups were defined: 29 patients without increased cTnI and cardiac impairment (group 1), eight patients with increased cTnI and left systolic ventricular dysfunction (group 2), and eight patients with increased cTnI and isolated impairment of left ventricular relaxation (group 3). At day 1, LVEDA was significantly higher in group 2 (13 +/- 3 cm/m, p < 0.05) compared with groups 1 (10 +/- 2 cm/m) and 3 (11 +/- 2 cm/m). LVEDA did not change in groups 1 and 3. In group 2, LVEDA and FAC returned within 10 days to values observed in groups 1 and 2. A significant correlation was found between aortic velocity time integral and LVDEA (r =.78, p = 0.022) and FAC (r =.89, p = 0.003) only in group 2.
Acute and reversible left ventricular dilation accompanies septic shock-induced systolic left ventricular dysfunction. When septic myocardial abnormalities are limited to reversible impairment of left ventricular relaxation, left ventricular dimensions remain unchanged.
Critical care medicine 01/2010; 37(2):441-7. · 6.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To evaluate the accuracy of B-type natriuretic peptide (BNP) and amino-terminal pro-brain natriuretic peptide (NT-proBNP) for the diagnosis of congestive heart failure (CHF) in dyspneic patients aged >or=85 years admitted to the Emergency Department (ED), and to define threshold values in this oldest-old population.
This study involved 210 oldest-old patients, and 360 patients aged from 65 to 84 years (<85 years), admitted to the ED for dyspnea.
Median BNP and NT-proBNP levels were significantly higher in CHF oldest-old patients (p<0.001). BNP and NT-proBNP threshold values were higher in oldest-old patients (290 and 2800 pg/mL, respectively) compared to that of patients <85 years (270 and 1700 pg/mL, respectively). In a multivariate analysis, both BNP and NT-proBNP were the strongest variables associated with CHF in oldest-old patients. Neither renal function nor gender had impact on the diagnostic utility of the two tests.
Both BNP and NT-proBNP could potentially be reliable biomarkers for the diagnosis of CHF in oldest-old patients admitted with acute dyspnea to the ED.
[Show abstract][Hide abstract] ABSTRACT: Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is useful for the triage of patients with dyspnea. Our aim was to determine whether NT-proBNP levels could predict in-hospital outcome in breathless elderly patients.
At admission, NT-proBNP plasma concentrations were determined in 324 dyspneic patients aged 75 years and older. The association between NT-proBNP values and in-hospital mortality was assessed.
Median NT-proBNP concentrations were not different in deceased patients (n = 43, 13%) compared to that of survivors (n = 281, 87%) (4354 vs 2499 pg/mL, respectively; P = .06). To predict in-hospital mortality, the optimum threshold of NT-proBNP was 3855 pg/mL, as defined by the receiver operating characteristic (ROC) curve, with a nonsignificant area under the ROC curve of 0.59. Mortality was significantly higher in patients (n = 139) with NT-proBNP levels 3855 pg/mL or higher (17.9% vs 9.7%, P = .045). After multivariate analysis, NT-proBNP level 3855 pg/mL or higher at admission was predictive of mortality (odds ratio, 2.41; 95% confidence interval, 1.02-5.68; P = .04).
NT-proBNP higher than 3855 pg/mL is associated with in-hospital mortality in patients aged 75 years and older admitted for dyspnea.
The American journal of emergency medicine 07/2008; 26(5):555-60. · 1.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Many patients with septic shock and increased cardiac troponin I (cTnI) do not exhibit significant left ventricular systolic dysfunction. We hypothesized that an isolated and reversible impairment of ventricular relaxation may be associated with the increase in cTnI.
Prospective, observational study.
Surgical intensive care unit in a university hospital.
Total of 54 patients with septic shock.
Fractional area change, early diastolic velocity of mitral annulus, flow propagation velocity of early diastolic mitral inflow, cTnI, tumor necrosis factor-alpha, interleukin (IL)-6, -1beta, -8, and -10 were measured at days 1, 2, 3, 4, 7, and 10 after onset of septic shock. Patients were classified into three groups: normal cTnI (group 1), increased cTnI and fractional area change <50% (group 2), and increased cTnI and fractional area change >50% (group 3).
A total of 22 patients had an increase in cTnI, 11 with both systolic and diastolic dysfunctions and 11 with isolated impairment of left ventricular relaxation. At day 1, early diastolic velocity of mitral annulus and flow propagation velocity of early diastolic mitral inflow were significantly lower and tumor necrosis factor-alpha, IL-8, and IL-10 significantly higher in groups 2 and 3 compared with group 1. With resolution of septic shock, early diastolic velocity of mitral annulus and flow propagation velocity of early diastolic mitral inflow measured in patients of groups 2 and 3 returned progressively to values observed in group 1, with a parallel normalization of tumor necrosis factor-alpha, IL-8, and IL-10.
Isolated and reversible impairment of left ventricular relaxation, associated with transient increases in cTnI, tumor necrosis factor-alpha, IL-8, and IL-10, was observed in 20% of patients with septic shock.
Critical care medicine 03/2008; 36(3):766-74. · 6.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We compared the usefulness of plasma N-terminal-pro B-type natriuretic peptide and troponin I levels for risk stratification of patients with pulmonary embolism.
This was a prospective study performed in an emergency department. N-terminal-B-type natriuretic peptide assay and troponin I were performed blindly at admission in patients with pulmonary embolism confirmed by imaging tests. A complicated pulmonary embolism was defined as any of the following: death, cardiopulmonary resuscitation, requirement for mechanical ventilation, use of pressors, thrombolysis, surgical embolectomy or admission in an intensive care unit.
Sixty patients (mean age+/-standard deviation of 72+/-15 years) were included. Seventeen (28%) patients had adverse events: all were admitted in intensive care unit, one was treated with surgical embolectomy and one with thrombolysis, and three died. The median N-terminal-pro B-type natriuretic peptide level (95% confidence interval) was higher in the group of patients with complicated pulmonary embolism, 4086 pg/ml (505-8998) versus 352 pg/ml (179-662), respectively (P<0.05). The mean value of troponin I was similar in the complicated pulmonary embolism group, 0.09+/-0.17 microg/l versus 0.08+/-0.41 microg/l, respectively (P=0.93). The best threshold value of N-terminal-pro B-type natriuretic peptide was 1000 pg/ml, and the receiver operating characteristic curve demonstrated that N-terminal-pro B-type natriuretic peptide significantly predicted the complicated pulmonary embolism with an area under the receiver operative curve of 0.72 (0.58-0.83) (P<0.05), whereas troponin I did not [area under the receiver operative curve of 0.58 (0.42-0.71)].
Unlike troponin I, N-terminal-pro B-type natriuretic peptide may be an accurate marker of in-hospital complication after pulmonary embolism.
European Journal of Emergency Medicine 09/2007; 14(4):207-11. · 1.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the usefulness of various laboratory results for differential diagnosis of bacterial (BM) and nonbacterial meningitis (NBM) with negative initial Gram stain.
A prospective multicenter study was conducted in the emergency departments of 3 teaching hospitals.
Consecutive adult patients with a diagnosis of meningitis based on compatible clinical features and cerebrospinal fluid (CSF) culture findings with a CSF leukocyte count greater than 5/mm(3) were included in the study. Symptoms, examination findings, data from laboratory results, including CSF results and serum C-reactive protein (CRP) levels, and clinical outcome were assessed.
One hundred fifty-one patients (age, 35 +/- 15 years) with confirmed meningitis were admitted: 133 with NBM and 18 with BM. CRP and procalcitonin (PCT) levels, CSF white cell and absolute neutrophil counts, and CSF glucose/blood glucose and CSF protein levels were significantly higher in the BM group. However, as diagnostic indicators of BM, none of these variables except PCT was more efficient than that of the emergency physician. Values of the area under the receiver operating characteristic curve were 0.59 (95% confidence interval [CI], 0.21-0.82), 0.79 (95% CI, 0.47-0.92), 0.18 (95% CI, 0.0-0.43), 0.70 (95%CI, 0.30-0.89), 0.81 (95% CI, 0.58-0.92), and 0.98 (95% CI, 0.83-1.0) for CSF leukocyte count, percentage of CSF leukocyte, CSF/blood glucose ratio, CSF protein level, serum CRP, and serum PCT (P < .05 vs CRP), respectively.
CSF results have a modest role in distinguishing BM from NBM in a negative Gram stain for bacteria. PCT serum levels seem to be an excellent predictor of BM.
American Journal of Emergency Medicine 02/2007; 25(2):179-84. · 1.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We evaluated the use of plasma B-type natriuretic peptide (BNP) levels for risk stratification in elderly patients with acute pulmonary embolism (PE).
Bedside BNP assay was performed blindly at admission in consecutive patients older than 65 years with acute PE. A complicated PE was defined as any of the following: death, cardiopulmonary resuscitation, mechanical ventilation, use of vasopressors, thrombolysis, surgical embolectomy, or admission in intensive care unit.
Fifty-one patients (age, 79 +/- 9 years) were included. Thirteen patients had adverse events: 11 were admitted in the intensive care unit and 3 died. The median BNP level (95% confidence interval [CI]) was higher in the group of patients with complicated PE, 274 pg/mL (95% CI, 142-581 pg/mL) vs 78 pg/mL (95% CI, 33-230 pg/mL) (P < .05), respectively. The receiver operating characteristic curve showed that BNP significantly predicted a complicated PE with an area under the receiver operating characteristic curve of 0.72 (95% CI, 0.58-0.83) (P < .05). The best threshold value was 200 pg/mL with a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 0.69 (0.43-0.87), 0.63 (0.47-0.77), 0.39 (0.22-0.59), 0.86 (0.69-0.94), and 0.65 (0.51-0.77), respectively.
Our study suggests that BNP is not a reliable marker of complicated PE in elderly patients.
American Journal of Emergency Medicine 10/2006; 24(5):603-7. · 1.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Our objectives were to determine the causes of acute respiratory failure (ARF) in elderly patients and to assess the accuracy of the initial diagnosis by the emergency physician, and that of the prognosis.
In this prospective observational study, patients were included if they were admitted to our emergency department, aged 65 years or more with dyspnea, and fulfilled at least one of the following criteria of ARF: respiratory rate at least 25 minute-1; arterial partial pressure of oxygen (PaO2) 70 mmHg or less, or peripheral oxygen saturation 92% or less in breathing room air; arterial partial pressure of CO2 (PaCO2) > or = 45 mmHg, with pH < or = 7.35. The final diagnoses were determined by an expert panel from the completed medical chart.
A total of 514 patients (aged (mean +/- standard deviation) 80 +/- 9 years) were included. The main causes of ARF were cardiogenic pulmonary edema (43%), community-acquired pneumonia (35%), acute exacerbation of chronic respiratory disease (32%), pulmonary embolism (18%), and acute asthma (3%); 47% had more than two diagnoses. In-hospital mortality was 16%. A missed diagnosis in the emergency department was noted in 101 (20%) patients. The accuracy of the diagnosis of the emergency physician ranged from 0.76 for cardiogenic pulmonary edema to 0.96 for asthma. An inappropriate treatment occurred in 162 (32%) patients, and lead to a higher mortality (25% versus 11%; p < 0.001). In a multivariate analysis, inappropriate initial treatment (odds ratio 2.83, p < 0.002), hypercapnia > 45 mmHg (odds ratio 2.79, p < 0.004), clearance of creatinine < 50 ml minute-1 (odds ratio 2.37, p < 0.013), elevated NT-pro-B-type natriuretic peptide or B-type natriuretic peptide (odds ratio 2.06, p < 0.046), and clinical signs of acute ventilatory failure (odds ratio 1.98, p < 0.047) were predictive of death.
Inappropriate initial treatment in the emergency room was associated with increased mortality in elderly patients with ARF.
Critical care (London, England) 01/2006; 10(3):R82. · 4.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Differentiating cardiogenic pulmonary edema (CPE) from respiratory causes of dyspnea is difficult in elderly patients. The aim of this study was to compare the usefulness of B-type natriuretic peptide (BNP) and amino-terminal fragment BNP (proBNP), to diagnose CPE in patients aged 65 and older.
Medical emergency department of a 2,000-bed urban teaching hospital.
Patients aged 65 and older presenting with acute dyspnea and a respiratory rate of 25 breaths/min or greater, a partial pressure of oxygen of 70 mmHg or less, or an oxygen saturation of 92% or less were included.
Rapid BNP and proBNP assays, performed blind at admission, were compared with the final diagnosis (CPE or no CPE) as defined by an expert team.
Two hundred two patients (mean age+/-standard deviation 80+/-9) were included; 88 (44%) had CPE. There was a strong correlation between proBNP and BNP values (correlation coefficient=0.91, P<.001). The median BNP and proBNP were higher in the group of patients with CPE (377 vs 74 pg/mL, P<.001, and 3,851 vs 495 pg/mL, P<.001, respectively). The best threshold values of BNP and proBNP were 250 pg/mL and 1,500 pg/mL, respectively. The area under the receiver operating characteristic curve was greater with BNP than with proBNP (0.85 vs 0.80, P<.05). BNP assay was more accurate in diagnosis than the emergency physician, whereas proBNP was not. Higher values of BNP and proBNP were associated with greater in-hospital mortality.
BNP assay is a more useful diagnostic indicator for CPE than proBNP in patients aged 65 and older.
Journal of the American Geriatrics Society 05/2005; 53(4):643-8. · 4.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Differentiating cardiogenic pulmonary edema (CPE) from respiratory causes of dyspnea is particularly difficult in elderly patients. The aim of our study was to evaluate B-type natriuretic peptide (BNP) in patients older than 65 years presenting with acute dyspnea.
Medical emergency department of a 2000-bed urban teaching hospital.
Patients aged over 65 years presenting with acute dyspnea and a respiratory rate more than 25/min or a PaO(2) below 70 mmHg, SpO(2 )less than 92%, PaCO(2) higher than 45 mmHg with pH less than 7.35, were included. BNP levels, measured blind at admission were compared with the final diagnosis (CPE or no CPE) as defined by experts.
Three hundred eight patients (mean age of 80 years) were enrolled in the study. The median BNP was 575 pg/ml [95% confidence interval (CI): 410-898] in the CPE group (n=141) versus 75 pg/ml (95% CI: 59-98) in the no CPE group (n=167) (p<0.001). The best threshold value of BNP was 250 pg/ml, with a sensitivity and specificity for CPE of 0.78 (95% CI: 0.71-0.84) and 0.90 (95% CI: 0.84-0.93), respectively. The area under the ROC curve was 0.874+/-0.081 (p<0.001). The accuracy of BNP-assisted diagnosis was higher than that of the emergency physician (0.84 versus 0.77, p<0.05).
Analysis of BNP is useful in elderly patients with acute dyspnea, but the threshold value is higher than that previously determined.
Intensive Care Medicine 01/2005; 30(12):2230-6. · 5.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aseptic meningitis is a frequent diagnosis in emergency departments. Nevertheless, viral investigations are not carried out currently and the viral etiology in adult population has not been studied extensively. We conducted a prospective study including all consecutive patients undergoing lumbar puncture during a 15 months period in an adult emergency department. Bloody and purulent cerebrospinal fluid (CSF) were excluded. The main tests undertaken were: CSF genomic amplification by the polymerase chain reaction (PCR) for neurotropic viruses and serum and CSF interferon-alpha (IFN-alpha) measurements. Among 194 patients included, 45 had and 149 did not have aseptic meningitis. Of 45 patients with aseptic meningitis, 10 had alternative non-virological final diagnosis, and 35/45 were presumed to have neurological disorders of viral origin. Patients (27/35) completed virological analysis: 21/27 (78%) had either positive viral PCR (enterovirus: 8 patients, Varicella zoster virus (VZV): 5, Epstein-Barr virus (EBV): 2, herpes simplex virus (HSV): 1, human herpes virus 6: 1) or only raised serum or CSF IFN-alpha (4 patients). Overall, 59% of patients with a positive viral PCR had either CSF or serum raised IFN-alpha. Twentyone patients without meningitis had either positive viral PCR (enterovirus: 3 patients) or only high serum IFN-alpha level (18 patients). In the setting of aseptic meningitis diagnosed in an adult emergency department, viruses are the most common agents encountered, with enterovirus and VZV as the two main etiological agents. Current CSF viral genome amplification and IFN-alpha measurement are informative and could be useful to confirm the viral origin of various neurological disorders, although the sensitivity and specificity of IFN-alpha measurement for the diagnosis of viral infection need further confirmation.
Journal of Medical Virology 06/2004; 73(1):137-46. · 2.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The coronary vascular endothelium could mediate some of the coronary effects of halogenated anaesthetic agents. The role of the endothelial vasodilator substances nitric oxide (NO) and prostaglandins (PGs) in the coronary effects of halothane and isoflurane remains to be determined and has not been investigated for desflurane. In this study, the roles of NO and cyclooxygenase pathways in the coronary effects of halothane, isoflurane and desflurane were studied in isolated red blood cell-perfused rabbit hearts.
Rabbit hearts were perfused by a Langendorf technique with red blood cells mixed with modified Krebs-Henseleit buffer. Coronary blood flow (CBF), oxygen consumption and myocardial performance were evaluated during exposure to 0.5, 1 and 2 rabbit minimum alveolar concentrations of halothane, desflurane and isoflurane. Thereafter, the same protocol was applied with the addition of N(G)-nitro-L-arginine (L-NNA), indomethacin or a combination of both inhibitors.
Similar and significant increases in CBF were observed with increasing concentrations of isoflurane and desflurane. In contrast, CBF did not change with halothane. The combination of the two antagonists abolished desflurane-induced vasodilation, whereas it did not change the isoflurane-mediated increase in CBF. Halothane-induced vasoconstriction was observed in the presence of a combination of indomethacin with L-NNA.
Halothane and desflurane induce the release of vasodilating prostaglandins and NO in rabbit coronary arteries. In contrast, these mediators are not involved in the coronary vasodilating properties of isoflurane.
BJA British Journal of Anaesthesia 04/2002; 88(3):399-407. · 4.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pericardial fluid can reflect the composition of cardiac interstitium in myocardial ischemia. This study investigated the hypothesis that pericardial cardiac troponin I (CTnI) measurements could be a more accurate marker of perioperative myocardial infarction (MI) than serum CTnI after coronary artery bypass grafting (CABG). Postoperative arterial and pericardial blood samples were taken in 102 subjects undergoing elective CABG allocated to one of three groups according to the 12-lead electrocardiogram (ECG) abnormalities observed during the first postoperative 24 h: Group 1 = normal ECG; Group 2 = nonspecific ECG abnormalities; and Group 3 = perioperative Q-wave MI. Peak pericardial CTnI concentrations were much higher than peak serum concentrations in all subjects and significantly greater in Group 3 than in Groups 1 and 2 (1,318 +/- 1,810 ng/mL vs 367 +/- 339 ng/mL and 558 +/- 608 ng/mL, respectively; P < 0.01). However, no significant difference between groups occurred at any time for pericardial/serum CTnI ratios, indicating that time courses of CTnI were not different in pericardial fluid and serum. A significant correlation was found between serum and pericardial CTnI concentrations (R = 0.70, P < 0.001). Pericardial CTnI was not more accurate than serum CTnI in predicting Q-wave MI as shown by the low value of the area under the receiver-operator characteristic curve (= 0.71). Peak and early pericardial CTnI were also not accurate in predicting an increase of serum CTnI greater than a cutoff value of 19 ng/mL. Thus, pericardial CTnI measurements were less useful than serum CTnI measurements in the diagnosis of perioperative MI after CABG. IMPLICATIONS: Although cardiac troponin I concentrations were much higher in pericardial fluid than in serum and significantly increased in subjects who experienced perioperative Q-wave myocardial infarction, pericardial cardiac troponin I measurements were of less value than serum cardiac troponin I measurements for the diagnosis of perioperative myocardial infarction after coronary artery bypass grafting and cannot be recommended in routine clinical practice.
[Show abstract][Hide abstract] ABSTRACT: Myocardial contusion may induce life-threatening complications, but its diagnosis is difficult. Circulating cardiac troponin T is considered a highly sensitive and specific marker of myocardial cell injury. We investigate the value of cardiac troponin T measurement in the diagnosis of myocardial contusion.
Level 1 trauma center.
We prospectively measured circulating cardiac troponin T and performed echocardiography and continuous Holter monitoring in patients who had suffered blunt trauma. Myocardial contusion was diagnosed in patients who fulfilled one of the following criteria: (1) an abnormal echocardiography compatible with myocardial contusion; (2) severe cardiac rhythm abnormalities; (3) severe cardiac conduction abnormalities; and (4) hemopericardium.
One hundred twenty-eight patients were included and myocardial contusion was diagnosed in 29 patients. Patients with myocardial contusion had more severe trauma, experienced more frequently associated thoracic lesions, and had a lower left ventricular ejection fraction area (48 +/- 15 vs 61 +/- 10%; p < 0.001). Elevated circulating cardiac troponin T concentrations were significantly more frequent in patients with a myocardial contusion (31 vs 9%; p < 0.007). An elevated circulating cardiac troponin T concentration (> or = 0.5 microgram/L) was more accurate than MB fraction of creatine kinase (CK) (CK-MB) and CK-MB/CK ratio in the diagnosis of myocardial contusion, as shown by an area under the receiver operating characteristic (ROC) curve (AROC), which was significantly different from 0.50 (AROC = 0.69; 95% confidence interval, 0.56 to 0.80). However, this improvement was not clinically acceptable (sensitivity, 0.31; specificity, 0.91).
Circulating cardiac troponin T measurement had a slightly greater diagnostic value than usual biological parameters (CK-MB, CK-MB/CK) in myocardial contusion. Nevertheless, it was concluded that an elevated circulating cardiac troponin T concentration has no important clinical value in the diagnosis of myocardial contusion.
[Show abstract][Hide abstract] ABSTRACT: In isolated rabbit hearts perfused with suspension of red blood cells, we investigated the role of the endothelium and of several substances in the coronary vasoconstriction induced by a high arterial blood oxygen tension (PaO2). Red blood cells in Krebs-Henseleit buffer were oxygenated to obtain control and high-PaO2 perfusates. Arterial oxygen content was kept constant in both perfusates by reducing hemoglobin concentration in the high-PaO2 perfusate. Coronary blood flow was kept constant so that oxygen supply would not vary with the rise in PaO2. Increases in perfusion pressure therefore reflected increased coronary resistance. The high PaO2-induced coronary vasoconstriction was not affected by administration of indomethacin, nordihydroguaiaretic acid, NG-nitro-L-arginine, or superoxide dismutase and catalase but was abolished after endothelium damage or by cromakalim. These results demonstrate that 1) the endothelium contributes to the high PaO2-induced coronary vasoconstriction; 2) this effect is independent of cyclooxygenase or lipoxygenase products, nitric oxide, or free radicals; and 3) the closure of ATP-sensitive K+ channels mediates this vasoconstriction.
The American journal of physiology 02/1997; 272(1 Pt 2):H67-75. · 3.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hypertonic saline improves organ perfusion and animal survival during hemorrhagic shock because it expands plasma volume and increases tissue oxygenation. Because both decreased and increased myocardial performance have been reported with hypertonic saline, the effects of hyperosmolarity and the mechanism accounting for it were investigated in isolated blood-perfused rabbit hearts. Coronary blood flow (CBF), myocardial contractility, relaxation, and oxygen consumption were measured during administration of blood perfusates containing 140-180 mmol sodium concentrations ([Na+]). In two other series of experiments, the role of Na(+)-Ca2+ exchange in the inotropic effect of hyperosmolarity (160 mmol sodium concentration) and hypertonicity (sucrose) were also investigated. Hypertonic [Na+] induced a significant increase in contractility and relaxation, combined with a coronary vasodilation. Myocardial oxygen consumption (MVO2) increased at all hypertonic [Na+] without significant change in coronary venous oxygen tension (PVO2) and content (CVO2). Amiloride (0.3 mmol) inhibited the improved contractility observed with 160 mmol sodium. Similar Na(+)-Ca2+ exchanger blockade did not inhibit the inotropic effect of sucrose. These results confirm the positive inotropic effect of hypertonic [Na+]. The inhibition of this improvement by amiloride suggests that calcium influx through the sarcolemna could be the major mechanism of this effect.