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QTc Dispersion (qtc + dispersion)
Selected AbstractsNew parameters in the interpretation of exercise testing in women: QTC dispersion and QT dispersion ratio differenceCLINICAL CARDIOLOGY, Issue 4 2002Kurtulu, Özdemr M.D. Abstract Background: It has been reported that the increase of QT dispersion (QTD) that occurs due to increased inhomogeneity of the ventricular repolarization because of transient ischemia obtained by standard 12-lead electrocardiogram (ECG), the changes during exercise, and the differences between exercise and rest increase the accuracy of exercise test in the diagnosis of coronary artery disease (CAD). Hypothesis: This study was designed to investigate the value of QTD parameters, which are reported to increase the diagnostic accuracy of exercise test in women. Methods: Ninety-seven women who had undergone coronary angiography and exercise test were evaluated for diagnosis of chest pain. QT dispersion was calculated using the measurements of the highest and lowest values of QT interval obtained by ECG during peak exercise. The QTc using Bazett's equation, and the QTD ratio (QTDR) using QT/RR were calculated, and QTcD and QTD ratios were obtained. The difference between QTcD and QTDR was determined by extracting the rest values from the exercise values. Results: The groups with normal coronaries (n = 48), single-vessel CAD (n= 24), and multivessel CAD (n= 25) were compared. The obtained QTD parameters at peak exercise and their differences between exercise and rest were found to be significantly increased in patients with CAD (p<0.001). Furthermore, these parameters were found to be higher in the patients with multivessel CAD than in those with single-vessel disease (p < 0.05). With the parameters QTcD > 60 ms and QTDR > 10%, greater sensitivity and specificity were obtained compared with ST-segment depression. The highest diagnostic accuracy was obtained with the QTD parameters calculated from the differences between rest and exercise values. The diagnostic accuracy of the difference of QTcD > 15 ms and the difference of QTDR > 5% was relatively higher than the other parameters (sensitivity, specificity, and negative and positive predictor values are 84,88,84, 87% and 84, 96, 85, 95%, respectively). Conclusion: The use of QTD parameters as variables of ECG, which is easily obtainable in the evaluation of exercise ECG in women, increases the diagnostic accuracy of the exercise test. In addition, the evaluation of QTD variables may provide information about the incidence of CAD. [source] The effect of sertindole on QTD and TPTEACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2010J. Nielsen Nielsen J, Andersen MP, Graff C, Kanters JK, Hardahl T, Dybbro J, Struijk JJ, Meyer JM, Toft E. The effect of sertindole on QTD and TPTE. Objective:, Recent research suggests that other surrogate markers than QTc, including QTc dispersion and Tpeak-Tend, may better correlate with cardiac arrhythmia risk. While sertindole significantly prolongs the QTc interval, the effects on other markers of arrhythmia risk, such as QTc dispersion and Tpeak-Tend are unknown. Method:, Digital 12-lead ECG was recorded at baseline and at steady-state in 37 patients switched to sertindole. ECG was analysed for Fridericia-corrected QT duration (QTcF), QT dispersion and Tpeak-Tend. Results:, From a baseline QTcF of 407 ± 22 ms, mean QTcF prolongation during sertindole treatment was 20 ± 23 ms, P < 0.01. No effect on QTc dispersion was found (,1 ± 11 ms; P = 0.41). No increased duration of the Tpeak-Tend interval from baseline was found (+7 ± 21 ms; P = 0.05). Conclusion:, These findings might be related to the absence of confirmed Torsade de Pointes (TdP) cases related to sertindole exposure, despite sertindole's QTc prolonging effects. [source] Low prevalence of cardiac autonomic neuropathy in Type 1 diabetic patients without nephropathyDIABETIC MEDICINE, Issue 8 2001J. A. Meinhold Abstract Aim To assess the prevalence of cardiac autonomic neuropathy (CAN) in Type 1 diabetic patients with and without nephropathy. Methods Sixty-six consecutive patients without nephropathy (n = 24), with incipient (n = 26) or overt nephropathy (n = 16) and a diabetes duration between 21 and 31 years were examined. Heart rate variability (HRV) as measure for CAN was investigated with short-term spectral analysis in the low-frequency (LF) band (0.06,0.15 Hz), reflecting sympathetic and vagal activity, and high-frequency (HF) band (0.15,0.50 Hz), reflecting vagal activity. HRV was expressed as spectral power (ms2, log-transformed). Normal, age-corresponding reference values were established in 184 controls. QTc intervals and dispersion were measured. Results After adjustment for age, there was no significant difference between healthy controls and patients without nephropathy. After further adjustment for diabetes duration, HbA1c, hypertension and treatment with ,-blockers, HRV in both frequency bands decreased with evidence of nephropathy. LF band (supine): patients without nephropathy 5.56 (4.89,6.21) (least squares means and 95% confidence interval (CI)), incipient nephropathy 5.72 (5.15,6.29) and overt nephropathy 4.11 (3.27,4.96). HF band (supine): without nephropathy 5.93 (5.26,6.60), incipient nephropathy 5.99 (5.41,6.57) and overt nephropathy 4.84 (4.00,5.68). Significant differences were found for patients without and with incipient nephropathy compared with those with overt nephropathy in the LF band and between patients with incipient nephropathy compared with those with overt nephropathy in the HF band. QTc intervals and QTc dispersion increased significantly with increasing nephropathy. Conclusions Long-term Type 1 diabetes without nephropathy was not associated with impaired cardiac autonomic function in our study. However, in those with nephropathy, a loss of both vagal and sympathetic activity was present, and the severity of CAN correlated positively with more advanced nephropathy. Diabet. Med. 18, 607,613 (2001) [source] QTc interval and QTc dispersion during haemodiafiltrationNEPHROLOGY, Issue 6 2004FULVIO FLOCCARI SUMMARY: Background and Aim: Our aim was to evaluate QTc interval and QTc dispersion in 27 end-stage renal disease (ESRD) patients undergoing Acetate Free Biofiltration (AFB) in order to ascertain any correlations between the electrrocardiographic (ECG) parameters, serum Na+, K+, Ca++, Mg++ and intraerythrocytic Mg++ (Mg++e) concentrations. All measures were made at t0 (session beginning), t1 (first hour), t2 (second hour), t3 (third hour), and t4 (session end). Results: Blood pressure, heart rate, bodyweight and total ultrafiltration in the three dialysis sessions were constant. A significant progressive increase occurred in serum Ca++ during the sessions, while there was a significant diminution in serum K+. The pattern for Mg++ concentrations in serum and erythrocytes differed: in serum it decreased, whereas Mg++e increased. At t4, the QTc interval was reduced to a significant extent with respect to the baseline value. QTc dispersion significantly increased at t1 without there being significant variations at other times with respect to t0. At t2, t3 and t4, values promptly returned to baseline levels. QTc had a negative correlation with serum Ca++ levels at t4. In contrast, an inverse correlation was found between QTc dispersion and serum K+ at t1. No other correlations could be found between any other electrolytes, QTc interval or QTc dispersion. Conclusion: In conclusion, the decrease observed in the QTc interval at the end of an AFB session was inversely related to serum Ca++ concentrations. Moreover, an increase in QTc dispersion occurred during the first hour of the session, and was negatively correlated with serum K+. [source] Exercise Does Not Increase QTcmax and QTcd in Diabetic Patients with Autonomic NeuropathyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2007MEHMET YAZICI M.D. Background:The purpose of this study was to examine the effects of exercise on maximum QTc interval (QTcmax) and QTc dispersion (QTcd) in diabetic patients without clinically evident heart disease. Methods: Seventy-six diabetic patients who had no coronary artery disease or hypertension (group I; mean age 48 ± 9 years old) and 40 healthy volunteers (group II; mean age 46 ± 13 years old) were enrolled in the study. Cases with clinically evident heart disease were excluded from the study. Resting 12-lead electrocardiogram (ECG) and maximal treadmill exercise test (according to Bruce protocol) were performed in all cases. The QTcmax interval was determined at rest (RQTcmax) and during peak exercise (PQTcmax). Also, the QTcd was measured at rest (RQTcd) and during peak exercise (PQTcd). Autonomic neuropathy was assessed by measuring the heart rate variability (HRV). Results: There was no significant difference between clinical characteristics of two groups. In group I, HRV parameters were significantly lower than group II. RQTcd, PQTcd, RQTcmax, and PQTcmax were significantly longer in group I (56 ± 16 vs 34 ± 11; P< 0.001, 62 ± 22 vs 40 ± 15; P < 0.001, respectively). In diabetic patients, there was no significant difference between RQTcmax and PQTcmax (428 ± 19 vs 420 ± 31; P > 0.05), and no significant difference was present between RQTcd and PQTcd (56 ± 16 vs 62 ± 22; P > 0.05, respectively). Conclusion: Exercise does not affect QTcd in patients with diabetes mellitus and without clinically evident heart disease. [source] QT Dispersion and Mortality in the ElderlyANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2001Juha S. Perkiömäki M.D. Background: The prognostic value of QT interval dispersion measured from a standard 12-lead electrocardiogram (ECG) in the general population is not well established. The purpose of the present study was primarily to assess the value of QT interval dispersion obtained from 12-lead ECG in the prediction of total, cardiac, stroke, and cancer mortality in the elderly. Methods: A random population sample of community-living elderly people (n = 330, age ,; 65 years, mean 74 ±; 6 years) underwent a comprehensive clinical evaluation, laboratory tests, and 12-lead ECG recordings. Results: By the end of the 10-year follow-up, 180 subjects (55%) had died and 150 (45%) were still alive. Heart rate corrected QT (QTc) dispersion had been longer in those who had died than in the survivors (75 ±; 32 ms vs 63 ±; 35 ms, P = 0.01). After adjustment for age and sex in the Cox proportional hazards model, prolonged QTc dispersion (,; 70 msec) predicted all-cause mortality (relative risk [RR] 1.38, 95% confidence interval [Cl] 1.02,1.86) and particularly stroke mortality (RR 2.7, 95% Cl 1.29,5.73), but not cardiac (RR 1.38, 95% Cl 0.87,2.18) or cancer (RR 1.51, 95% Cl 0.91,2.50) mortality. After adjustment for age, sex, body mass index, blood pressure, blood glucose and cholesterol concentrations, functional class, history of cerebrovascular disease, diabetes, smoking, previous myocardial infarction, angina pectoris, congestive heart failure, medication, left ventricular hypertrophy on ECG, presence of atrial fibrillation and R-R interval, increased QTc dispersion still predicted stroke mortality (RR 3.21, 95% Cl 1.09,9.47), but not total mortality or mortality from other causes. The combination of increased QTc dispersion and left ventricular hypertrophy on ECG was a powerful independent predictor of stroke mortality in the present elderly population (RR 16.52, 95% Cl 3.37,80.89). QTcmin (the shortest QTc interval among the 12 leads of ECG) independently predicted total mortality (RR 1.0082, 95% Cl 1.0028,1.0136, P = 0.003), cardiac mortality (RR 1.0191, 95% Cl 1.0102,1.0281, P < 0.0001) and cancer mortality (RR 1.0162, 95% Cl 1.0049,1.0277, P = 0.005). Conclusions: Increased QTc dispersion yields independent information on the risk of dying from stroke among the elderly and its component, QTcmin, from the other causes of death. A.N.E. 2001; 6(3):183,192 [source] Notable effects of angiotensin II receptor blocker, valsartan, on acute cardiotoxic changes after standard chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisoloneCANCER, Issue 11 2005Hirohisa Nakamae M.D. Abstract BACKGROUND There are three distinct types of doxorubicin-induced cardiotoxicity (acute, chronic, and late-onset). Although previous studies with animal models suggest that angiotensin II plays a key role in the process of the doxorubicin-induced cardiotoxicity, there has been no such observation in humans. This randomized study investigated whether valsartan, a new class of angiotensin II receptor blocker (ARB), can inhibit acute cardiotoxicity after doxorubicin-based chemotherapy. METHODS Forty consecutive patients with untreated non-Hodgkin lymphoma who were scheduled to undergo standard chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) (mean age, 56 yrs; range, 24,70 yrs) were randomized with minimization methods to receive CHOP with or without 80 mg/day of valsartan. Acute cardiotoxicity was comprehensively evaluated with neurohumoral, echocardiographic, and electrocardiographic markers before and on Days 3, 5, and 7 after the initiation of CHOP. RESULTS CHOP induced transient increases in the left ventricular end-diastolic diameter in an echocardiogram, the QTc interval and QTc dispersion in an electrocardiogram, and in the plasma brain and atrial natriuretic peptides. All these changes returned to nearly normal levels within a week after CHOP (P < 0.001). Notably, valsartan significantly prevented all these changes except for the elevation in atrial natriuretic peptide (P < 0.05). No significant change was observed in blood pressure or heart rate between the valsartan and control groups. CONCLUSIONS The results indicate that angiotensin II may play an essential role in acute CHOP-induced cardiotoxicity in humans. Future long-term studies are necessary to judge whether ARBs have a potential to prevent the chronic or late-onset types of doxorubicin-induced cardiotoxicity. Cancer 2005. © 2005 American Cancer Society. [source] Coronary Slow Flow Phenomenon and Risk for Sudden Cardiac Death Due to Ventricular Arrhythmias: A Case Report and Review of LiteratureCLINICAL CARDIOLOGY, Issue 8 2008Dr. Shoaib Saya Abstract We report a case of coronary slow flow phenomenon (CSFP) in a patient who underwent coronary angiography due to anginal chest pain and recurrent syncope with complete normalization of flow after intracoronary adenosine. He was noted to have multiple episodes of nonsustained ventricular tachycardia on holter monitor and increased QTc dispersion on surface electrocardiogram (EKG). He responded very well to oral dipyridamole therapy with complete resolution of his symptoms and no episodes of ventricular tachycardia on the event recorder at 3 months. We review the diagnosis and clinical features of CSFP and its association with increased QTc dispersion and the role of oral dipyridamole therapy in this condition. Copyright © 2007 Wiley Periodicals, Inc. [source] Late potentials and QT dispersion after high-dose chemotherapy in patients with non-Hodgkin lymphomaCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 3 2010Taru Kuittinen Summary The most common cardiotoxic effects of high-dose cyclophosphamide (CY) are electrocardiographic changes and transient arrhythmias. Therefore, we prospectively assessed serial electrocardiogram (ECG) and signal-averaged electrocardiogram (SAECG) recordings in 30 adult patients with non-Hodgkin lymphoma (NHL) receiving high-dose CY as part of high-dose chemotherapy (HDT) regimen. All patients were treated with anthracyclines earlier. Heart-rate-corrected QT interval and QT dispersion (QTc and QTc dispersion) were measured from ECG. QRS duration and late potentials (LPs) were analysed from SAECG. Both ECG and SAECG were recorded 1 day (d) prior to HDT (d,7) at baseline, and 1 day (d,2), 7 days (d+7), 12 days (+12) and 3 months (m+3) after HDT. Stem cells were infused on day 0 (d0). Cardiac systolic and diastolic function were assessed on (d,7), (d+12) and (m+3) by radionuclide ventriculography. At baseline, four patients presented with LPs. Cardiac systolic function decreased significantly (53 ± 2; 49 ± 2%, P = 0·009 versus baseline), whilst no patient developed acute heart failure. QRS duration prolonged and RMS40 reduced significantly versus baseline (104 ± 3; 107 ± 3 ms, P = 0·003; 41 ± 4; 38 ± 3 ,V, P = 0·03), and six patients (21%) presented with LPs after CY treatment. Both QTc interval and QTc dispersion increased versus baseline (402 ± 5; 423 ± 5 ms, P<0·001; 32 ± 2; 44 ± 3 ms, P = 0·012), and six patients (20%) developed abnormal QT dispersion. In conclusion, high-dose CY causes subclinical and transient electrical instability reflected by occurrence of LPs as well as increased QTc interval and QT dispersion. Thus, longer follow-up is required to confirm the meaning of these adverse effects on cardiac function and quality of life. [source] | ||||||||||