Activation of blood coagulation in patients with mitral stenosis and sinus rhythm.

The aim of this study was to assess whether there is blood coagulation activation in patients with mitral stenosis (MS) and sinus rhythm (SR) and to investigate the value of left atrial spontaneous echo contrast (LASEC) as a predictive sign of increased coagulation activity. Using thrombin-antithrombin III complexes and prothrombin fragment 1+2 as in vivo hemostatic markers, we concluded that there is a hypercoagulable state in patients with MS and SR when LASEC is present.

Value of dobutamine stress echocardiography for diagnosis of coronary artery disease in patients with left bundle branch blockage.

BACKGROUND: Left bundle branch blockage (LBBB) is a strong predictor of cardiovascular mortality. Non-invasive tests such as exercise-stress testing and scintigraphy studies have no diagnostic value for diagnosis of coronary artery disease (CAD) in patients with LBBB. OBJECTIVE: To study the role of dobutamine stress echocardiography (DSE) in identification of CAD in patients with LBBB. METHODS: Thirty patients (19 men and 11 women, mean age 60 +/- 8 years) with permanent, complete LBBB were studied prospectively with DSE and coronary angiography. RESULTS: Results of DSE were compared with results of coronary angiography for left anterior descending artery and either left circumflex or right coronary artery territories, or both. Significant CAD was found in left anterior descending coronary arteries in 11 patients by coronary angiography; nine of whom were identified by DSE. Significant left circumflex or right coronary artery disease, or both, was found in nine patients; eight of whom were identified by DSE. The sensitivity, specificity and accuracy of DSE for identifying CAD in left anterior descending coronary artery territory were 82, 95 and 90%, respectively. For identifying CAD in the circumflex and right coronary artery territories sensitivity, specificity and accuracy were 88, 96 and 93%, respectively. CONCLUSION: We concluded that DSE is a very sensitive, specific and accurate non-invasive test for identification of CAD, both in left anterior descending and in left circumflex and right coronary artery territories of patients with LBBB.

Predictors of left ventricular thrombus formation in patients with anterior myocardial infarction: role of activated protein C resistance.

BACKGROUND: Left ventricular mural thrombus formation is a well-recognised consequence of acute anterior myocardial infarction. The vast majority of left ventricular thromboses occur in patients with anterior myocardial infarction and depressed left ventricular function. OBJECTIVE: To evaluate the factors predicting left ventricular thrombus formation in patients similar for left ventricular function and left ventricular score indexes. METHODS: We evaluated 45 consecutive patients who met the inclusion criteria of anterior myocardial infarction resulting in apical, anterior or septal asynergy (akinesia, dyskinesia), without non-Q-wave myocardial infarction, dilated cardiomyopathy, or renal or hepatic dysfunction. Patients were divided into two groups: group I with, and group II without, left ventricular mural thrombus. The groups were compared for clinical, echocardiographic and hematologic parameters (activated protein C resistance (APC-R), protein S and antithrombin III). RESULTS: Smoking and ACP-R were significantly greater in group I than in group II (P < 0.05 and P < 0.005 respectively). Multivariate regression analysis showed that APC-R was an independent risk factor for left ventricular thrombus formation in the patient group selected. Antithrombin III and protein S concentrations were not statistically different between two groups. All other clinical and echocardiographic characteristics of the patients were similar in both groups. CONCLUSION: APC-R is an independent risk factor for left ventricular thrombosis in patients with anterior myocardial infarction resulting in septal or anterior and apical akinesia or dyskinesia.

Increased systemic coagulation activity in patients with rheumatic mitral stenosis: assessment of the clinical and echocardiographic determinants.

In this study, we aimed to determine systemic coagulation activity in patients with rheumatic mitral stenosis and to define determinants of a possible prethrombotic state. Peripheral venous plasma level of thrombin-antithrombin III complex was measured in 84 consecutive patients with rheumatic mitral stenosis who had no left atrial thrombus by transesophageal echocardiography. The patients had significantly higher thrombin-antithrombin III complex values (mean +/- SD = 9.6+/-15.9 ng/ ml) compared with the healthy subjects (2.1+/-1.8 ng/ml) (P<0.001). Among many clinical and echocardiographic variables, severe mitral regurgitation (odds ratio = 6.7, P<0.001) and left atrial spontaneous echo contrast (odds ratio = 22.8, P<0.001) appeared as significant predictors of the increased systemic coagulation activity in multivariate logistic regression analysis. In conclusion, systemic coagulation activity is increased in the patients with rheumatic mitral stenosis, and coexistence of severe mitral regurgitation and presence of left atrial spontaneous echo contrast are determinants of this increment.

Influence of thrombolytic therapy on the incidence of left ventricular thrombi after acute anterior myocardial infarction: role of successful reperfusion.

BACKGROUND: Previous studies have reported controversial results regarding the effectiveness of systemic thrombolysis in preventing left ventricular (LV) thrombus after acute myocardial infarction (MI). HYPOTHESIS: This study was performed to evaluate the influences of thrombolysis, and particularly successful reperfusion, on the incidence of LV thrombus formation after acute anterior MI. METHODS: In all, 191 patients suffering from a first attack of acute anterior MI were prospectively evaluated by two-dimensional echocardiography and coronary angiography, performed at the end of the first week and within the first two weeks of MI, respectively. Of these, 98 who presented within 12 h of onset of symptoms received intravenous streptokinase (1.5 million IU), while the remaining 93 patients who, either because of contraindications or late admission, did not receive thrombolytic treatment served as control group. All patients received aspirin and full-dose anticoagulation with intravenous heparin. Successful reperfusion in the streptokinase group was assessed by enzymatic and electrocardiographic evidence. RESULTS: The overall incidence of LV thrombi was 24.6% (47/191). When all patients were evaluated, no statistically significant difference was found between the frequency of LV thrombi in the patients who had thrombolysis (22.4%) and those who did not (26.8%), despite a trend toward the formation of fewer thrombi in the initial group (p > 0.05). However, the patients who had successful reperfusion with streptokinase (n = 64) had significantly reduced incidence of LV thrombi compared with those who did not receive thrombolytic therapy (20 vs. 26.8%, p < 0.05). Stepwise multivariate analysis suggested that LV abnormal wall motion score (p = 0.01) and presence of LV aneurysm were independent predictors of LV thrombus formation in patients with acute anterior MI. CONCLUSION: Not all patients who received streptokinase for acute anterior MI, but only those with successful reperfusion had reduced incidence of LV thrombi. The favorable effects of thrombolysis on LV thrombus formation are probably due to the preservation of global LV systolic function.

Increased levels of plasma thrombomodulin in patients with acute myocardial infarction who had thrombolytic therapy and achieved successful reperfusion.

BACKGROUND: There is a growing body of evidence from animal and in vitro studies for the existence of reperfusion injury after thrombolytic therapy for acute myocardial infarction (AMI), but the patient data are limited. HYPOTHESIS: We aimed to examine the plasma thrombomodulin (TM) levels as a marker of endothelial injury and to investigate the effect of successful reperfusion on these levels. METHODS: The study included 32 patients who had a first episode of acute myocardial infarction (AMI) and received intravenous streptokinase therapy. RESULTS: Thrombomodulin levels increased significantly at 60 min after thrombolysis compared with the levels before thrombolytic therapy (0 min) in 21 (66%) patients who had successful reperfusion (49.09 +/- 10.51 vs. 25.76 +/- 5.55 ng/ml, p < 0.001). There was no difference between the TM levels at 0 and at 60 min of thrombolysis in the remaining 11 (34%) patients who could not achieve reperfusion (27.81 +/- 6.32 vs. 28.72 +/- 7.28 ng/ml, p = 0.35). CONCLUSION: There was a significant increase in TM levels at 60 min after thrombolysis in a group of patients with AMI who achieved successful reperfusion; this increase may have been caused by the activation/injury of endothelial cells. Data also suggest that the increment in TM levels may be predictive of the potential success of thrombolytic therapy.

Thrombopoietin and mean platelet volume in coronary artery disease.

BACKGROUND: Large platelets are shown to be hemostatically more active. It has been suggested that mean platelet volume (MPV) is increased during acute myocardial infarction (AMI) and unstable angina pectoris (USAP). However, the underlying mechanism of the phenomenon remains unclear. HYPOTHESIS: In this study, platelets, MPV, and thrombopoietin (TP) levels were investigated in patients with coronary artery disease (CAD) and healthy controls. METHODS: Twenty patients with AMI and 20 patients with USAP were included in this study. Seventeen healthy adult subjects served as controls. Venous blood samples of the subjects were drawn within 12 h after admission. Thrombopoietin levels were measured by ELISA and platelet counts and MPV were assayed by autoanalyzer. RESULTS: Patients with AMI and USAP had higher platelet counts than those in the control group. Although the platelet counts were slightly higher in AMI than in USAP, this did not reach statistical significance. Mean platelet volume and levels of TP were found to be elevated in patients with AMI and USAP compared with control subjects (p < 0.001). Thrombopoietin levels were higher in AMI than USAP, but this was not statistically significant. There was a positive correlation between TP levels and MPV values (p < 0.05). CONCLUSION: Increased TP levels may increase both platelet counts and platelet size, resulting in hemostatically more active platelets, which may contribute to the development and progression of CAD.

Single coronary artery with "high take-off" origin in a patient with rheumatic mitral stenosis--a case report.

In this case report, a patient with rheumatic mitral stenosis and R-1 subtype single coronary artery arising from the ascending aorta ("high take-off" origin) and coursing between the aorta and pulmonary artery is presented. The clinical significance and differential diagnosis are discussed. To the authors' knowledge, this is the first case reported in the literature with a single R-1 subtype coronary artery that shows "high take-off" origin.

Changes in QT dispersion magnitude during respiratory phases: role of maximum inspiration and expiration.

There is still controversy about the reliability and prognostic value of QT interval dispersion because of interobserver and intraobserver variability. The authors aimed to study the effect of respiratory phases on QT dispersion. Sixty healthy volunteers (38 men, 22 women, mean age 25+/-3 years) from the medical staff comprised the study group. Electrocardiograms were recorded by the same technician with a rate of 50 mm/s during normal breathing, maximum inspiration and expiration. QT dispersion was defined as the difference between the maximal and minimal QT interval measurement occurring among any of the 12 leads. Corrected QT (QTc) interval was calculated according to Bazzet's formula. There were no significant differences between QTc max interval during maximum inspiration and expiration compared with those in normal breathing (409+/-20 ms vs 417+/-26 ms, p>0.05 and 412+/-18 vs 417+/-26 ms, p>0.05 respectively). QTc dispersion during maximum inspiration and expiration was significantly lower than that of normal breathing (36+/-8 ms vs 44+/-9 ms, p<0.003 and 32+/-7 vs 44+/-9 ms, p< 0.003, respectively). And the QTc dispersion during maximum expiration was also lower than that during maximum inspiration (p<0.01). QT dispersion magnitude is affected by the respiratory phases in healthy subjects and decreases during both maximum inspiration and expiration as compared with normal respiration.

QTc dispersion measurement for risk of syncope in patients with aortic stenosis.

The purposes of this study are to evaluate the clinical usefulness of maximum QTc and QTc dispersion determination in aortic stenosis, and to compare the effects of maximum QTc and QTc dispersion on the risk of syncope in aortic stenosis. The QT interval dispersion has long been known to be a marker of dispersion of ventricular repolarization and, hence, electrical instability. Additionally, it has been shown that these patients have a propensity to ventricular tachyarrhythmic syncope. The study included 86 patients with aortic stenosis who underwent left-heart catheterization and coronary angiography during investigation of syncope and 30 healthy subjects. The patients were characterized with regard to the presence or absence of a history of syncope and the severity of aortic stenosis (the degree of peak transvalvular gradient). In addition, QT max and QT dispersion measurements were corrected for heart rate according to Bazett's formula. The QTc max and QTc dispersion were greater in patients with aortic stenosis than in the healthy subjects (477 +/- 49 ms vs 370 +/- 22 ms, p < 0.001; 60 +/- 13 ms vs 38 +/- 1 ms, p < 0.001). Similarly, the QTc max and QTc dispersion were greater in the patients with a history of syncope than in the patients with no history of syncope (493 +/- 48 ms vs 459 +/- 4 ms, p < 0.001; 68 +/- 12 ms vs 53 +/- 10 ms, p < 0.001). In addition, both parameters were greater in the patients with a high transvalvular gradient than in the patients with a low transvalvular gradient (489 +/- 49 ms vs 451 +/- 39 ms, p < 0.001; 65 +/- 12 ms vs 50 +/- 9 ms, p < 0.001). Multivariate logistic regression analysis showed that only a increased QTc dispersion had significant value for the risk of syncope in aortic stenosis. An increased QTc dispersion caused a 10.4% increase in the occurrence of syncope in aortic stenosis. These results suggest that high values of QTc dispersion are sensitive noninvasive markers to determine the risk for syncope in aortic stenosis.

Role of activated protein C resistance in left atrial thrombogenesis in patients with mitral stenosis.

Activated protein C resistance (APC-R) is the most common inherited cause of clinically apparent venous thromboembolism. Previous data indicate that left atrial thrombus (LAT) formation is a common complication in mitral stenosis (MS) and a hypercoagulable state exists in these patients. The aim of this study was to invastigate the association between APC-R and LAT formation in patients with MS. Seventy-seven consecutive patients with rheumatic MS were included in this study. Transesophageal echocardiography was performed on all patients to assess the presence of any thrombus or spontaneous echo contrast (LASEC) in the left atrial cavity or appendage. Thirty four of the patients had LAT and 43 did not. Prevelance of APC-R was smiliar between the two groups of patients with and without LAT (23% vs 16%, p=0.425). LAT(+) patients had higher incidence of atrial fibrillation (AF, 74% vs 51%, p=0.046) and LASEC (71% vs 19%, p<0.001) compared to LAT(-) patients. On multivariate regression analysis, only the presence of LASEC achieved statistical significance as an independent risk factor for LAT formation (p=0.0001, odds ratio=9.589, 95% confidence interval [CI] =3.143-29.251). Because onunivariate analysis both LASEC and AF were associated with LAT, we also compared the prevelance of APC-R in the subgroups of patients who have these risk factors with and without LAT. There was a correlation between the presence of APC-R and LAT in the AF(+) subgroup of MS patients (p=0.033, odds ratio=8.167, 95% CI=1.001-72.812). However, the presence of APC-R was not associated with the increased risk of LAT in LASEC(+) patients (p=0.217, odds ratio=1.200, 95% CI=1.003-1.435). Although the presence of APC-R itself is not an independent risk factor for LAT formation in MS, it may increase the risk of LAT when present in combination with AF (as an additional risk factor) in these patients.

Diagnosis of coronary artery disease with Tl-201 SPECT in patients with left bundle branch block: importance of alternative interpretation approaches for left anterior descending coronary lesions.

Left bundle branch block (LBBB) is a strong predictor of mortality in the presence of coronary artery disease (CAD). Noninvasive evaluation of CAD in these patients has some difficulties. Exercise-induced electrocardiographic ST segment changes are nondiagnostic, and several scintigraphic studies have reported false-positive anteroseptal and septal perfusion defects up to 80%. The authors aimed to assess the diagnostic accuracy of thallium-201 (Tl-201) exercise myocardial single photon emission computerized tomography (SPECT) in comparison with coronary angiography (CAG) for detection of CAD in patients with LBBB. Seventy-seven consecutive patients suffering from chest pain with complete and permanent LBBB were included in the study. All patients (40 women, 37 men, mean age = 54 +/- 7 years) were studied with Tl-201 exercise SPECT and coronary angiography. Tl-201 exercise SPECT for diagnosis of left anterior descending (LAD) artery lesions was interpreted by using three different approaches: method A (conventional approach), method B (involvement of anterior and septal wall regardless of apical wall), and method C (apical approach: involvement of anterior septal and apical wall). Methods A and B gave a sensitivity of 100% each but a specificity of 47% and 56%, respectively. Although method C gave a higher value of specificity than that of methods A and B (98% vs 47% and 56%, respectively p < 0.05), the sensitivity of method C significantly decreased in respect to methods A and B (33% vs 100% p < 0.01). Isolated septal defects were evaluated separately. Isolated septal defects on exercise Tl-201 SPECT were detected in 11 patients, and none of them had CAD according to CAG results. Isolated septal wall involvement had a sensitivity of 0% and a specificity of 74%. The sensitivity and specificity of Tl-201 SPECT for diagnosis of CAD in the right coronary and left circumflex artery territories were 91% and 89%, respectively. In conclusion, the apical approach increased the specificity and decreased the sensitivity of the test. Isolated septal defects seem to have no value for diagnosis of CAD in patients with left bundle branch block.

Circulating cytokines and complements in chronic heart failure.

Elevated levels of cytokines and complements have been reported in patients with advanced heart failure, but the exact clinical significance remains unclear. Therefore, assessments correlated with hemodynamic and clinical variables may provide important insight into the actions of cytokines and complements in chronic heart failure. The authors evaluated the clinical significance of cytokines and complements. The study included 60 subjects (50 men, 10 women); 34 had idiopathic dilated cardiomyopathy (DCM) and 26 had ischemic heart disease (IHD). Tumor necrosis factor alpha and interleukin-2 receptor concentrations in chronic heart failure were greater than in control subjects (20.0 +/- 0.4 vs 18.0 +/- 0.5 pg/mL, p<0.05 and 817.23 +/- 63.50 vs 642.75 +/- 27.31 pg/mL, p<0.05, respectively). There was no significant difference between DCM and IHD patients in circulating levels of the cytokines and the components complements (p=NS). Additionally, although functional classes III and IV heart failure patients showed a tendency to increase the levels of the cytokines and the component complements, these differences were not statistically significant (p=NS). Similarly, correlation analysis showed that the levels of the circulating cytokines and the component complements had independent value for mortality. These results suggest that humoral and cellular immunity abnormalities may play an important role in the pathogenesis of heart failure and dilated cardiomyopathy.

Comparison of clinical echocardiographic and hemodynamic characteristics of male and female patients who underwent mitral balloon valvuloplasty.

The clinical echocardiographic and hemodynamic characteristics and outcome of male and female patients before and after valvuloplasty were evaluated. The study population consisted of 34 male and 122 female consecutive patients who successfully underwent percutaneous balloon mitral valvuloplasty (PBMV). Clinical, echocardiographic, and hemodynamic variables were compared between male and female patients. Male patients were significantly older than female patients at the time of PBMV (39 years vs 34 years p < 0.05). Mitral valve score was significantly higher in male patients (p < 0.01). The mitral valve area before PBMV in male patients was significantly less than that in female patients (0.97 +/- 0.22 cm2 vs 1.09 +/- 0.25 cm2, respectively, p < 0.05). The pulmonary artery pressures of female patients before PBMV were higher than those of males (48 mm Hg vs 40 mm Hg, respectively, p < 0.05). The restenosis rates in male and female patients at the end of the follow-up period (38 months) were 20% and 9%, respectively (p < 0.05). In conclusion, male patients are older than female patients at the time of the PBMV procedure, and male patients have worse echocardiographic parameters and restenosis rates than female patients with the exception of pre-procedural pulmonary artery pressure.

Increased QT interval dispersion after hemodialysis: role of peridialytic electrolyte gradients.

Chronic renal failure patients on maintenance hemodialysis (HD) have a number of ECG abnormalities and cardiac arrhythmias. Clinical and experimental data have shown that increased QT dispersion is associated with severe ventricular arrhythmias and sudden cardiac death. Therefore, the aim of this study was to investigate whether the uremic patients receiving long-term HD have increased QTc interval and/or QTc dispersion compared to normal subjects and to evaluate the effect of electrolyte changes between the predialysis and postdialysis phases on these parameters. Forty patients with end-stage renal failure on long-term HD (22 men, 18 women, mean age 44 years) were included in this study. Serum concentrations of K+, Na+, Ca++, Mg++, Cl-, phosphate, urea, creatinine, HCO3-, and arterial blood gases (PO2, PCO2), together with blood pH, were monitored and QTc intervals and QTc dispersion were measured from 12-lead ECG in predialysis and postdialysis phases. The hemodialyzed patients had an increased predialysis QTc maximum interval and QTc dispersion compared to normal subjects (480 +/- 51 vs 310 +/- 38 msec, p < 0.001 and 61 +/- 17 vs 42 +/- 14 msec, p < 0.001, respectively). Both QTc maximum interval and QTc dispersion increased significantly at the end of the HD (480 +/- 51 vs 505 +/- 49 msec p < 0.001 and 61 +/- 17 vs 86 +/- 18 msec, p < 0.001, respectively). The serum K+ (5.3 +/- 0.56 vs 3.36 +/- 0.41 mEq/L, p < 0.001), phosphate (7.19 +/- 1.62 vs 3.81 +/- 1.02 mg/dL, p < 0.001), magnesium (0.87 +/- 18 vs 0.75 +/- 0.14 mg/dL) and urea concentrations (174 +/- 22 vs 74 +/- 14 mg/dL, p < 0.001) significantly decreased, whereas the Ca++ (2.21 +/- 0.18 vs 2.47 +/- 0.24 mg/dL, p < 0.001), HCO3- (15.5 +/- 3.2 vs 20.1 +/- 3.4 mmol/L, p<0.001) concentrations and pH (7.27 +/- 1.1 vs 7.43 +/- 1.2, p < 0.001) significantly increased after HD compared to predialysis values. There was significant correlation between the QT dispersion increase and serum electrolyte changes (K+, Ca++, and pH levels) (p < 0.05). The association between serum electrolyte changes, acid-base status and QT measurements might provide new insights into the evaluation of the ionic bases involved in inhomogeneous ventricular repolarization.

Diurnal variation of QT dispersion in patients with and without coronary artery disease.

QT dispersion defined as interlead QT variability in a 12-lead electrocardiogram was proposed by Day and associates as a simple method to evaluate the repolarization heterogenicity of the ventricular myocardium. The frequency of onset of myocardial infarction and sudden death has been reported to have a circadian variation, with a peak incidence in the early morning hours. The authors investigated whether there is diurnal variation of QT interval and QT interval dispersion in healthy subjects and in patients with coronary artery disease. The study population consisted of two groups. Group I consisted of 62 subjects without coronary artery disease and group II consisted of 82 patients with coronary artery disease. Twelve-lead ECG was recorded for each patient in the morning (between 7 AM and 8 AM), afternoon (between 3 PM and 5 PM) and at night (between 11 PM and 1 AM), on the day after performance of coronary angiography. QTc dispersion was significantly higher in patients with coronary artery disease than in healthy subjects in the morning hours and afternoon (p<0.001). Although the differences were much prominent in group I than group II, both QTc dispersion of morning and afternoon were significantly greater than those at night. There were no statistically significant differences between group I and group II at nighttime with respect to maximum QTc, minimum QTc intervals, and QTc dispersion (p>0.05). In conclusion, QT dispersion shows diurnal variation with an increase in the morning hours in both patients with coronary artery disease and subjects without coronary artery disease. The mechanism of diurnal variation of QT dispersion in patients with coronary artery disease is quite different from that of healthy subjects.

Increased levels of soluble adhesion molecules, E-selectin and P-selectin, in patients with infective endocarditis and embolic events.

AIMS: Inflammation-induced procoagulant changes and endothelial cell activation appear to play an important role in thromboembolic complications of infective endocarditis. Hence, the aim of this study was to compare the plasma levels of soluble adhesion molecules E- and P-selectin in infective endocarditis patients with and without embolic events, and healthy subjects. METHODS AND RESULTS: The study group consisted of 76 consecutive patients (mean age=26 years old, range from 8 to 64 years) with definite infective endocarditis according to the Duke criteria. Thirteen of the patients (17.1%) had embolic events. Transoesophageal echocardiographic examinations were performed on all patients within 3 days of initiation of antimicrobial therapy. Although there was a trend towards a higher rate of vegetations detected in those with embolic events than in those without, this did not reach statistical significance (84.6% vs 80.9%, P>0.05). Significantly larger vegetations were observed in patients with embolic events as compared to those without embolic events (1.4 cm vs 1.0 cm, P=0.03). The mean plasma concentrations of P-selectin were elevated in patients with embolic events as compared to both patients without embolic events and control subjects (58.69+/-7.49 ng x ml(-1)vs 29.65+/-5.69 ng x ml(-1), P=<0.001 and 58.69+/- 7.49 ng x ml(-1) vs 25.82+/-5.38 ng x ml(-1), P<0.001). Similarly, the patients with embolic events had increased plasma levels of E-selectin compared to those without embolic events and the control group (73.15+/-11.47 ng x ml(-1) vs 42.84+/-8.77 ng x ml(-1), P<0.001 and 73.15+/- 11.47 ng x ml(-1) vs 34.23+/-5.92 ng x ml(-1), P<0.001). CONCLUSION: Determination of these membrane activation molecules may provide useful markers with which to identify patients at high thromboembolic risk from infective endocarditis.

The clinical significance of QTc dispersion measurement for risk of syncope in patients with aortic stenosis.

OBJECTIVES: (1) To evaluate the clinical usefulness of QTc dispersion determination in aortic stenosis and (2) to compare the effects of QTc dispersion on the occurrence risk of syncope in aortic stenosis. BACKGROUND: QT interval dispersion has long been known to be a marker of dispersion of ventricular repolarization and, hence, electrical instability. Additionally, it has been shown that these patients have a propensity to ventricular tachyarrhythmic syncope. METHODS: The study included 86 patients with aortic stenosis who underwent left-heart catheterization and coronary angiography during investigation of syncope, as well as 30 control subjects. The patients were characterized with regards to the presence or absence of a history of syncope and the severity of aortic stenosis (the degree of peak transvalvular gradient). In addition, QT dispersion measurements were corrected for heart rate according to Bazett's formula and both were measured. RESULTS: QTc dispersion was greater in patients with aortic stenosis than in the control subjects (60 +/- 13 msec vs 38 +/- 12 msec, P < 0.001). Similarly, QTc dispersion was greater in the patients with a history of syncope than in the patients with no history of syncope (68 +/- 12 msec vs 53 +/- 10 msec, P < 0.001). In addition, QTc dispersion values were greater in the patients with a high transvalvular gradient than in the patients with a low transvalvular gradient (65 +/- 12 msec vs 50 +/- 9 msec, P < 0.001). Multivariate logistic regression analysis showed that only an increased QTc dispersion had significant value for the risk of syncope in aortic stenosis. CONCLUSIONS: An increased QTc dispersion increases the occurrence risk for syncope in aortic stenosis. These results suggest that high values of QTc dispersion are a sensitive noninvasive marker for determining the risk for syncope in aortic stenosis.