JT Dispersion Research Articles

Repolarization dispersion in patients with systemic sclerosis.

Systemic sclerosis (SSc) is associated with increased cardiac morbidity and mortality. Whether some electrocardiographic markers of arrhythmias predispose to early cardiogenic death in SSc remains controversial. This study evaluated the occurrence of previously reported as well as unstudied markers of repolarization in patients with SSc and assessed their prognostic implications. A total of 21 patients with SSc and 31 unaffected controls were included in this prospective study. Electrocardiograms were conducted under strict standards. Repolarization and dispersion parameters and markers of late ventricular potentials were determined using designated computer software. Results of multiple beats were averaged. There were no significant differences between the SSc and control groups in average QT intervals, average corrected QT intervals, average QT interval dispersion (QTd), average QT corrected dispersion (QTcd), and QT dispersion ratio. However, average QT apex dispersion, average JT dispersion, average JT corrected dispersion, and Tpeak-Tend corrected were significantly higher in patients with SSc than in controls. Late ventricular potentials were not found in patients with SSc or in controls. Increased QTd and QTcd were recorded in 1 patient who experienced ventricular arrhythmia before inclusion in the study. None of the remaining patients with SSc or the controls developed arrhythmia during the 9-year follow-up. Abnormal repolarization parameters may be observed in patients with SSc. However, their prognostic significance with regard to increased risk for repolarization-associated ventricular arrhythmias and increased cardiac death could not be determined in this study. Our findings endorse additional studies on this matter.

Association of vitamin D deficiency with ventricular repolarization abnormalities.

Vitamin D is involved in cardiac contractility and myocardial calcium hemostasis, and vitamin D deficiencies are known to cause various cardiovascular disorders and have been linked with sudden cardiac death. The aim of the study was to evaluate repolarization distribution, represented by QT interval, corrected QT interval (QTc), QT dispersion, Tpeak‑to‑Tend (Tp‑e) interval, Tp‑e/QTc ratio, JT interval, JT dispersion, and Tp‑e/JTpeak ratio in children with vitamin D deficiency. Moreover, we aimed to determine the relationship between ventricular repolarization anomalies and vitamin D deficiency. The study included 50 adolescent patients with vitamin D deficiency (vitamin D <20 ng/ml), 50 adolescent patients with vitamin D insufficiency, and 50 age‑matched controls (vitamin D level >30 ng/ml). QTc duration, QT dispersion, JTpeak duration, JT dispersion, Tp‑e, Tp‑e/JTpeak ratio, and Tp‑e/QTc ratio were recorded on electrocardiogram. Patients with vitamin D deficiency or insufficiency had longer Tp‑e interval (P <0.001), while Tp‑e/QTc and Tp‑e/JTpeak ratios were found to be increased in the same group of patients (P = 0.005 and P <0.001, respectively). QT dispersion and JT dispersion were higher in the deficient group when compared with the other groups (P = 0.045 and P = 0.02, respectively). The present study, conducted in a pediatric population, is the first in the current literature to assess the relationship between ventricular repolarization anomalies and vitamin D deficiency.

Is sofosbuvir/ledipasvir safe for the hearts of children with hepatitis C virus?

BackgroundSymptomatic bradycardia has been reported in adults treated for chronic hepatitis C using sofosbuvir based regimens. AimWe studied the cardiac safety of sofosbuvir/ledipasvir in Egyptian children, treated for chronic hepatitis C. MethodsThe study included 40 hepatitis C virus infected children and adolescents 12–17 years old, using the combination of sofosbuvir (400 mg)/ledipasvir (90 mg) in a single oral tablet (Harvoni) taken daily for 12 weeks. All subjects underwent a baseline standard 12-lead surface Electrocardiography that was repeated at 4 and 12 weeks of therapy. Electrocardiography parameters (Heart Rate, RR interval, PR interval, QRS, QT interval, corrected QT interval, QT dispersion, JT interval, corrected JT interval, JT dispersion, Tpeak-Tend interval) were compared at the 3 different time points during antiviral therapy. ResultsNo symptoms related to the cardiovascular system were reported during treatment. There were no cases of symptomatic bradycardia/syncope. Heart rate was noted to be significantly lower and RR and QT intervals were significantly longer in the baseline electrocardiography. Heart rate was significantly lower and RR interval was significantly longer in patients with higher viral load. ConclusionNo adverse cardiovascular events were observed in this group of HCV infected children and adolescents treated with sofosbuvir/ledipasvir. None of the patients developed bradyarrhythmias during treatment.

Evaluation of ventricular repolarization features with Tp-e, Tp-e/QTc, JTc and JTd during electroconvulsive therapy

ObjectiveThe purpose of this study was to investigate the influence of electrical stimulation transmitted through the body during electroconvulsive therapy on traditional and relatively new ventricular repolarization parameters (Rate corrected QT interval (QTc), QT dispersion (QTd), rate corrected JT interval (JTc), JT dispersion (JTd), T-peak to T-end interval (Tp-e) and Tp-e/QTc ratio) under propofol anaesthesia. MethodsTwenty-two patients (aged 18–50 years) who were each scheduled for ECT for major depression, bipolar disorder or schizophrenia enrolled to the study. Electrocardiography (ECG) recordings were obtained before anaesthesia and within 3–5 min after electrical stimulus of ECT for measurements. QTc, QTd, JTc, JTd, Tp-e and Tp-e/QTc were measured as repolarization indices. ResultsThe study included twenty-two patients, 9(40.9%) females and 13(59.1%) males, and the mean age accounted for 33.57 ± 9.95 years. The comparison of the measured parameters before and after ECT, which were not statistically different, were as follows: QTc (416.52 ± 46.64 vs 430.00 ± 34.00msn; p = 0.18), JTc (308.09 ± 25.09 vs 315.47 ± 26.89msn; p = 0.30), QTd (22.27 ± 11.51 vs 20.45 ± 9.9msn; p = 0.52) and JTd (22.72 ± 11.2 vs 17.72 ± 10.20msn; p = 0.06). Also, no significant difference was detected at the following parameters Tp-e (80.0 ± 13.45 vs 78.63 ± 15.21msn; p = 0.65) and Tp-e/QTc ratio (0.19 ± 0.03 vs 0.18 ± 0.07; p = 0.08). On the other hand, HR showed a significant increase after ECT at 88.13 ± 13.74 vs 93.0 ± 15.2 bpm; p = 0.03. ConclusionQTc, QTd, JTc, JTd, Tp-e interval and Tp-e/QTc ratio, which are thought to be potential repolarisation markers for ventricular arrhythmias, did not demonstrate significant change within 3–5 min of electrical stimulation during ECT.

Changes in electrocardiographic parameters in children with complete left bundle branch block early after transcatheter closure of ventricular septal defect

To observe the changes in electrocardiographic parameters in children with complete left bundle branch block (CLBBB) after the transcatheter closure of simple ventricular septal defect (VSD). A total of 21 children with CLBBB early after transcatheter closure of perimembranous VSD were recruited. Another 21 children without any type of arrhythmia after transcatheter closure of perimembranous VSD were enrolled as the control group. The sex, age, and the size of occluder were matched between the two groups. The changes in the following indices were compared between the two groups: left ventricular voltage, QT interval, corrected QT interval (QTc), QT dispersion (QTd), corrected QT dispersion (QTcd), JT dispersion (JTd), and corrected JT dispersion (JTcd) on the electrocardiogram before transcatheter closure and at 1, 3, 5, 30 days after transcatheter closure. Left ventricular voltage and JTcd changed with operation time in the CLBBB and control groups (P<0.05). There were interaction effects between time and grouping in the changes in left ventricular voltage and QTd (P<0.05). There was a significant difference in JTcd between the CLBBB and control groups (P<0.05). There was also a significant difference in left ventricular voltage between the CLBBB and control groups at 3 and 5 days after the transcatheter closure (P<0.05). There are significant differences in electrocardiographic left ventricular voltage and JTcd between VSD children with and without CLBBB early after transcatheter closure. JTcd might be useful in predicting the development of CLBBB early after transcatheter closure of VSD.

Electrophysiological Adverse Effects of Direct Acting Antivirals in Patients With Chronic Hepatitis C.

Recently, several cases of symptomatic, sometimes fatal bradycardia during the first days of direct-acting antiviral (DAA) (eg, sofosbuvir [SOF]) administration have been reported. We analyzed in detail electrocardiographic (ECG) changes during SOF- or non-SOF-based chronic hepatitis C (CHC) treatment, specifically focusing on bradyarrhythmias. All 39 consecutive patients treated at our center with any interferon-free regimen between June and December 2015 were included in this study (26 SOF-based therapy vs 13 no-SOF interferon-free regimens). ECG tracings were obtained from all patients the first day of treatment and after 7, 14, and 28 days. ECG parameters (P-wave, QRS, QT interval, JT interval, Tapex -Tend interval duration) were compared between the 2 groups at baseline and at the 3 different time points during antiviral therapy. There were no cases of symptomatic bradycardia/syncope. In the SOF group, QTc duration rose after 1 week (from 424.3 to 431.2 milliseconds; P = .013) and returned to baseline during therapy. QT dispersion dropped since week 1 (from 85.6 to 67.2 milliseconds) and remained significantly reduced until the end of the observation period (72.9 msec) (P = .003). JT dispersion reduced up to week 2 (P = .010) and returned to baseline at week 4; in the no-SOF group, QRS dispersion transiently reduced (from 41 to 34.5 milliseconds, day 7). No other significant changes were observed in the remaining parameters. In CHC patients treated with SOF and other DAAs, ECG parameter changes were mild and/or transient and did not translate into clinically significant electrophysiological effects in the absence of amiodarone coadministration.

QT Interval Derived Measurements in Patients with Cardiac Syndrome X Compared to Coronary Artery Disease.

Previous studies assessing effect of ischemia on ventricular repolarization are mostly directed toward patients with coronary artery disease (CAD); however, similar reports on cardiac syndrome X (CSX) are scarce. Whether microvascular dysfunction of CSX and ischemia induced by CAD produce comparable effect on ventricular repolarization is unclear and deserve further studies. In the present study, ECG measures of ventricular repolarization were compared between CAD and CSX patients (40 subjects in each group). Following evaluation of sociodemographic characteristics, medical and past medical history, a resting ECG was used to assess measurements of ventricular repolarization in each patient, namely, QT interval (QT), corrected QT interval (QTc), QT dispersion (QTd), corrected QT dispersion (QTcd), adjacent QT dispersion (AdQTd), QT dispersion ratio (QTdR), JT dispersion (JTd), and Corrected JT dispersion (JTcd). Results showed comparable QT intervals and QTd in CAD and CSX patients even after adjustment for the possible variations in gender, age and body mass index of the studied groups. Although JTd was increased in CSX subjects (26.6 ± 7.2 ms) compared with CAD patients (22.7 ± 6.5 ms, p = 0.019), statistical significance disappeared after correcting JT for variations in heart rate. QT and QTc were significantly below 440 ms in CAD as well as CSX patients (p < 0.001). In contrast, maximum QTd, maximum QTcd and AdQTd of CAD and CSX patients were significantly above 440 ms (p < 0.001). The means of JTd and JTcd were significantly above 22 ms and 24 ms respectively (p < 0.001, p = 0.001) in CSX but not CAD patients (p = 0.529, p = 0.281). The present findings clearly demonstrate comparable measures of ventricular repolarization in CAD and CSX patients and consequently an equal risk of cardiac events in both groups.

AN INDIVIDUALIZED RISK ASSESSMENT OF SUDDEN CARDIAC DEATH IN DILATION CARDIOMYOPATHY PATIENTS

Search for effective methods of risk stratification in patients with higher risk of lifethreatening ventricular tachyarrhythmias (VTA) and sudden cardiac death is important task for applied healthcare and a priority scientific field. Aim. To invent a mathematic model and algorithm of individualized risk assessment for sudden cardiac death (SCD) in dilation cardiomyopathy patients (DCMP). Material and methods . Totally, 165 patients included, with verified DCMP (mean age 49,2±11,5 y; 135/81,8% males; NYHA class 2,67±0,45; LV ejection fraction 26,7±10,1%; follow-up 46,7±12,5 months). With an original software “Intecard 7”, with the data of 7-minute ECG-12 registration, we evaluated markers of electrical instability of myocardium — microvoltage alternans of T-waves (mATW), turbulence of cardiac rhythm (TCR), intervals QT and JT dispersion, acceleration and deceleration of cardiac rhythm. As primary endpoints for multifactorial Cox-analysis we used sustained ventricular tachicardia (VT) or ventricular fibrillation, shocks of implanted devices and documented SCD. We analyzed clinical, electrocardiographic, echocardiographic data and results of molecular-genetic study of lamin A/C gene (LMNA). Results. As result of multifactor regression analysis we found 2 cumulative independent predictors (HR 5,23; 95% CI 1,45-16,9; р=0,013) of life-threatening VTA events in DCMP patients: paroxysms of non-sustained VT (≥5 ventricular complexes with HR ≥150 bpm) and changes in LMNA gene (missense mutations and polymorhpism of 10 exon of rs4641). With binary logit-regression analysis of independent risk factors (VES, sVT, mATW, TCR, JTd and GLS LV) we built-up a model of binary regression (F=31,2; χ2=143,2; p=0,0000) and developed an algorithm of SCD risk evaluation that make it to classify with high prediction power up to 93,9%, cases of DCMP (OR 470; sensitivity 80,8%, specificity 99,1%). Conclusion. The invented algorithm of SCD risk is non-ivasive, individualized, easily applicable and interpretable technology that makes it to stratify patients with higher risk of life-threatening VTA with standard clinical and instrumental methods of investigation (ECG, EchoCG, Holter ECG). Implementation of the oroginal riskstratification model makes it to optimize tactics of DCMP patients treatment and strategy of selection of potential candidates for cardioverter-defibrillator implanting for primary SCD prevention.

QT and JT Dispersion in Children With Familial Mediterranean Fever

Objectives: This study aims to determine QT dispersion and JT dispersion, and their relationship with conventional echocardiography values in a group of children with familial Mediterranean fever (FMF). Patients and methods: The study included 48 FMF patients (26 males, 22 females, mean age 11.10±3.42 years; range 5 to 18 years) as the FMF patients and 31 healthy children (17 males, 14 females, mean age 9.61±2.83 years; range 5 to 17 years) as the healthy controls. Electrocardiography and conventional echocardiography were performed on the FMF patients and healthy controls. Both groups were evaluated with a standard 12-lead electrocardiography. QT, JT and RR distances were measured in both groups. The corrected QT (QTc) and corrected JT (JTc) were calculated. QTcd and corrected JT dispersion (JTcd) were detected. Results: There was no statistically significant difference between the FMF patients and healthy controls in terms of RR, QT, QTd, QTcd, JT, JTc, JTd, and JTcd measurements and echocardiography parameters. QTc value was higher in the FMF patients than the healthy controls. Conclusion: QTc value indicates increased ventricular sensitivity and is an important marker of cardiovascular mortality. It has an important effect on sudden cardiac death and arrhythmia. Our study results suggest that electrocardiographic monitoring may be useful in patients with FMF.

Relationship between Neurocardiogenic Syncope and Ventricular Repolarization.

We aimed to analyze ventricular repolarization in neurocardiogenic syncope (NCS) patients by using T-peak-T-end interval, T-peak-T-end/QT ratio, T-peak-T-end/QTc ratio and corrected QT interval (QTc), QT dispersion (QTd), QT index (QTI) and corrected QT interval index (QTcI) comparing with the corrected JT dispersion (JTcd), and corrected JT (JTc) and the corrected JT interval index (JTcI), by inspecting ventricular activation until termination of repolarization. These parameters are used as an index of potential ventricular arrhythmogenesis. We have studied patients with head-up tilt table test (HUTT) (+) (33 patients; mean age: 28 ± 11 years) and HUTT (-) as control group (33 patients; mean age: 30 ± 11 years). In all patients, T-peak-T-end interval, T-peak-T-end/QT ratio, T-peak-T-end/QTc ratio, QT, QTd, QTI, QTc, QTcI, JTd, JTc, and JTcI were measured on electrocardiogram. The following parameters were statistically significant between groups: QTd (22.72 ± 17.54 msn; 11.21 ± 13.40 msn; P = 0.004), QTc (424.27 ± 33.75 msn; 403.66 ± 38.08 msn; P = 0.023), QTcI (114.09 ± 14, 29%; 106.71 ± 15.33%, P = 0.047), and QTI (100.72 ± 7.19%; 97.14 ± 7.13%, P = 0.046). Furthermore, T-peak-T-end interval was significantly prolonged in the study group (93.78 ± 20.27 msn; 81.21 ± 11.66 msn; P = 0.003). T-peak-T-end/QT ratio was significantly higher in the study group (0.24 ± 0.04 msn; 0.22 ± 0.04 msn; P = 0.030). T-peak-T-end/QTc ratio was significantly higher in the study group (0.22 ± 0.04 msn; 0.20 ± 0.03 msn; P = 0.015). The JTc and JTd were also significantly higher in the study group ([103.00 ± 9, 72%; 95.44 ± 10.26%, P = 0.003], [27.57 ± 16.01 msn; 10.45 ± 16.08 msn; P < 0.001], respectively). Electrocardiographic ventricular repolarization parameters including T-peak-T-end interval, T-peak-T-end/QT ratio, T-peak-T-end/QTc ratio, QTc, QTd, QTI, QTcI, JTc, JTd, and JTI are prolonged in NCS.

PReS-FINAL-2227: QT and JT dispersion in children with FMF

Familial Mediterranean Fever (FMF) is an autoimmune, autosomal recessive inherited disorder, and characterized by recurrent episodes of peritonitis, ploritis and arthritis. Patients with inflammatory disease are at increased risk of cardiovascular complications due to rhythm disorders. QT and JT dispersions are simple and non-invasive arrhythmogenic markers and can be used to assess the homogeneity of cardiac repolarization.

P01-038 – QT and JT dispersion in children with FMF

Familial Mediterranean Fever (FMF) is an autoimmune, autosomal recessive inherited disorder, and characterized by recurrent episodes of peritonitis, ploritis and arthritis. Patients with inflammatory disease are at increased risk of cardiovascular complications due to rhythm disorders. QT and JT dispersions are simple and non-invasive arrhythmogenic markers and can be used to assess the homogeneity of cardiac repolarization.

QT and JT dispersion and cardiac performance in children with neonatal Bartter syndrome: a pilot study

QT dispersion and JT dispersion are simple noninvasive arrhythmogenic markers that can be used to assess the homogeneity of cardiac repolarization. The aim of this study was to assess QT and JT dispersion and their relation with left ventricular systolic and diastolic functions in children with Bartter syndrome (BS). Nine neonatal patients with BS (median age 9.7 years) and 20 controls (median age 8 years) were investigated at rest. Both study and control subjects underwent electrocardiography (ECG) in which the interval between two R waves and QT intervals, corrected QT, QT dispersion, corrected QT dispersion, JT, corrected JT, JT dispersion and corrected JT dispersion were measured with 12-lead ECG. Two-dimensional, Doppler echocardiographic examinations were performed. Patients and controls did not differ for gender and for serum levels of potassium, magnesium, and calcium (p > 0.05). Both study and control subjects had normal echocardiographic examination and baseline myocardial performance indexes. The QT dispersion and JT dispersion were significantly prolonged in patients with BS compared to those of the controls {37.5 ms [interquartile range (IQR) 32.5-40] vs. 25.5 ms (IQR 20-30), respectively, p = 0.014 and 37.5 ms (IQR 27.5-40) vs. 22.5 ms (IQR 20-30), respectively, p = 0.003}. Elevated QT and JT dispersion during asymptomatic and normokalemic periods may be risk factors for the development of cardiac complications and arrhythmias in children with BS. In these patients the need for systematic cardiac screening and management protocol is extremely important for effective prevention.

Repolarização ventricular em pacientes diabéticos: caracterização e implicações clínicas

Diabetes mellitus is a chronic and very common condition, and there has been lately a considerable increase in its prevalence and incidence. Diabetic patients have increased cardiovascular mortality, in which malignant ventricular arrhythmias seem to be implicated. To study the effects of diabetes on ventricular repolarization parameters responsible for an increased susceptibility to malignant ventricular arrhythmias and/or sudden death. We selected a group of 110 diabetic patients and a group of 110 controls with the same distribution of age, gender and race. We evaluated the following parameters of ventricular repolarization: QT(max), QT(mean), QT(min), QTc(max), QTc(mean), QTc(min), QT and QTc dispersions, T(peak)-T(end) and jT(peak)-jT(end) intervals (D(II), V(2) and V(5)), T(peak)-T(end) and jT(peak)-jT(end) dispersions. The electrocardiograms (ECG) were performed by the same operator and reviewed by the same observers. QT intervals were corrected according to Bazzet's formula. We found significantly higher values of QTc(max) (p < 0.001), QTc(mean) (p < 0.001), QT dispersion (p < 0.001), QTc dispersion (p < 0.001), T(peak)-T(end) dispersion ( p < 0.001), and jT(peak)-jT(end) dispersion (p < 0.001) in diabetic patients than in controls. In diabetic patients, we observed prolonged values of QTc interval (5.5%), QT dispersion (0.9%), QTc dispersion (0%), T(peak)-T(end) interval (7.3%), jT(peak)-jT(end) interval (6.4%), T(peak)-T(end) dispersion (16.4%), and jT(peak)-jT(end) dispersion (12.7%). In the controls there were no prolonged values of any of the parameters. We concluded that diabetes causes prolongation and spatial dispersion of repolarization, and it may contribute to a greater ventricular electrical instability, whose expected clinical expression may be malignant ventricular arrhythmias.

Normal QT dispersion in colchicine-resistant familial Mediterranean fever (FMF)

The association between familial Mediterranean fever (FMF) and subclinical cardiac disease remains controversial. The aim of the current study was to evaluate whether FMF patients, who do not respond to colchicine treatment, and thereby endure persistent inflammation, have increased QT dispersion (QTd) values. Twenty-two FMF patients and 22 age- and sex-matched control subjects were included in the study. Repolarization and QT dispersion parameters were computed from 12-lead ECG recording using designated computer software, and results of five beats were subsequently averaged. Both FMF patients and controls had similar comorbidities, similar values of average QT, average corrected QT interval length, average QTd interval, average QT corrected dispersion, QT dispersion ratio, JT dispersion (JTd), and JT corrected dispersion. In conclusion, FMF patients who were unresponsive to colchicine treatment and did not develop amyloidosis had normal QTd and JTd parameters, indicating a non-increased risk for repolarization-associated ventricular arrhythmias.

Effect of Pranayama (Breathing Exercise) on Arrhythmias in the Human Heart

Cardiac arrhythmias, especially ventricular tachyarrhythmias are an important public health problem. QT dispersion (QTd), defined as the difference between maximal and minimal QT intervals, reflects the regional inhomogeneity of ventricular repolarization dispersion and may mark the presence of malignant ventricular arrhythmias. To determine the effects of Pranayama (breathing exercise) on QTd in patients with arrhythmia. Fifteen patients with arrhythmia and ejection fractions <40% (mean = 28 ± 9%) who were on a stable medical regimen. Standardized 12-lead surface ECGs were obtained at the beginning and end of the Pranayama session, and QT and JT intervals were measured manually and corrected for heart rate by using Bazett's formula. QTd, heart rate-corrected QTd (QTc-d), JT dispersion (JTd), and heart ratecorrected JTd (JTc-d) were measured in at least eight ECG leads in each patient. Following the Pranayama session, patients with arrhythmia had only slight improvements in exercise capacity (results were not significant). However, these patients had marked improvements in QTd (71 ± 11 to 59 ± 17 ms; P < .02), QTc-d (82 ± 28 to 63 ± 17 ms; P < .01), JTd (76 ± 19 to 57 ± 18 ms; P < .002), and JTc-d (84 ± 23 to 61 ± 18 ms; P < .001) following the Pranayama session. These data indicate that Pranayama significantly reduces the indices of ventricular repolarization dispersion in patients with arrhythmia. Further studies are needed to evaluate how effectively this reduction in ventricular repolarization dispersion decreases the risk of malignant ventricular arrhythmias and sudden death in patients with arrhythmia.

QT dispersion in amyloidosis due to familial Mediterranean fever

Cardiac amyloid deposition in FMF may cause increased QT dispersion (QTd), a marker for cardiac arrhythmias. The aim of this study was to further evaluate repolarization dispersion in familial Mediterranean fever (FMF) with amyloidosis. Findings on 12-lead electrocardiography were compared between 18 patients with FMF-amyloidosis and 18 age- and sex-matched control subjects. Repolarization and dispersion parameters were computed with designated computer software, and results of the 5 beats were subsequently averaged. There were no statistically significant differences between the groups as to average corrected QT interval length, average QTd interval, average QT corrected dispersion, or QT dispersion ratio. JT dispersion and JT corrected dispersion were also similar in both groups. In conclusion, patients with FMF-amyloidosis seem to have QT and JT dispersion parameters similar to those of healthy subjects. Future research and longer follow-ups should be conducted in order to evaluate the prognostic importance of repolarization dispersion parameters in amyloidosis of FMF.

Dispersion of repolarization and beta-thalassemia major: the prognostic role of QT and JT dispersion for identifying the high-risk patients for sudden death

Patients with beta-thalassemia major (β-TM) are at increased risk for sudden cardiac death (SCD). Heterogeneity of ventricular repolarization is considered to provide an electrophysiological substrate for malignant arrhythmias. QT dispersion (QTc-D) and JT dispersion (JTc-D) are electrocardiographic parameters indicative of heterogeneity of ventricular repolarization. The aim of our study was to evaluate the heterogeneity of ventricular repolarization in patients with beta-thalassemia and to test the hypothesis that an abnormal QTc and JTc dispersion may predict SCD in this population. The study involved 51 patients with β-TM (age 33.9±8.4; 33M) and 51 healthy subjects used as controls, matched for age, gender, and body mass index (BMI). Among the β-TM group, 14 patients with β-TM (age 27±6.64; 11M) died from SCD during follow-up. For each patient, QTD and JTD intervals were calculated. Compared to the healthy control group, β-TM group presented increased values of the QTc-D (65.36±33.95 vs. 37, 62±17.65; P<0.003) and JTc-D (74.64±33.27 vs. 40.32±12.45; P<0.001). In the β-TM sudden death group, QTc-D and JTc-D were significantly greater than in survived β-TM group (92.70±44.24 vs. 56.14±23.80, P=0.0001; 101.54±47.93 vs. 64.47±17.90, P=0.0001). A cutoff value of 70ms for QTc-D had a sensitivity and specificity of 77% in identifying patients at risk for SCD. A cutoff value of 100ms for JTc-D had a sensitivity of 65% and a specificity of 94% in identifying this category of patients. β-TM is associated with significant changes in heterogeneity of ventricular repolarization. QTc and JTc dispersion are useful markers of risk of SCD in patients with β-TM.

Electrical Remodeling Following Percutaneous Pulmonary Valve Implantation

Sudden cardiac death in congenital heart disease is related to increased right ventricular end-diastolic volume (RVEDV), abnormalities of QRS duration, and QRS, JT, and QT dispersions. Surgical pulmonary valve replacement and percutaneous pulmonary valve implantation (PPVI) decrease RVEDV, but the effects of PPVI on surface electrocardiographic parameters are unknown. PPVI represents a pure model of RV mechanical and electrophysiologic changes after replacement. This prospective study sought to determine the effects of PPVI on surface electrocardiographic parameters: Ninety-nine PPVI procedures in patients with congenital heart disease (23.1 ± 10 years of age) were studied before, after, and 1 year after PPVI with serial electrocardiograms and echocardiogram/magnetic resonance images. Forty-three percent had pulmonary stenosis, 27% pulmonary regurgitation (PR), and 29% mixed lesions. In those with predominantly PR (n = 26), QRS duration decreased significantly (135 ± 27 to 128 ± 29 ms, p = 0.007). However, in the total cohort no significant change in QRS duration at 1 year was observed (137 ± 29 to 134 ± 29 ms). Corrected QT interval and QRS, QT, and JT dispersions significantly decreased at 1 year (p ≤0.001). RVEDV correlated with preprocedure QRS duration (r = 0.34, p <0.002) but there was no correlation after PPVI. In conclusion, this is the first study reporting electrical remodeling after isolated PPVI and it confirms that decreases in QRS duration occur after PPVI in PR, as reported for equivalent surgical cohorts. Further, increased homogeneity of repolarization in combination with improved conduction may decrease arrhythmic events in congenital cardiac patients with pulmonary valvular disease.

Effect of L-carnitine on diabetic neuropathy and ventricular dispersion in patients with diabetes mellitus

Diabetes is a common cause of polyneuropathy. Cardiac arrhythmias and markedly increased mortality rate have been demonstrated in patients with diabetic neuropathy and also demonstrated that abnormally prolonged QT dispersion interval (QTd) is associated with a higher risk of ventricular arrhythmias and sudden death. We investigated the efficacy and tolerability of L-carnitine (LC) in the treatment of diabetic neuropathy and ventricular dispersion, mainly by evaluating the effects of treatment on electrophysiological parameters. Materials and methods: We recruited 30 patients with type I or type II diabetes (mean age: 60 ± 9 years, range: 36-75; 18 males, 12 females) meeting clinical and neurophysiological criteria for diabetic neuropathy. All of the patients were given LC 2 g/day for 10 months. Blood glucose regulation was maintained by diet, oral antidiabetic, or insulin. To determine the nerve functions electrophysiologically, superficial electrode distal latency, amplitude, nerve conduction velocity in median and ulnar nerves in the upper extremities and peroneal, tibial and sural nerves in the lower extremities and F response in motor nerves were studied. Resting 12-lead electrocardiograms were recorded for measurements of QTd, corrected QTd (QTcd), JT dispersion (JTd), and corrected JT dispersion (JTcd). Results: After 10 months of treatment, median, ulnar, and tibial nerves' motor nerve conduction velocities (P < 0.05) and M-wave amplitudes (P < 0.05) increased; distal latencies and the F-wave latencies (P < 0.05) decreased; ulnar, sural, and median sensory nerve action potential amplitude (P < 0.01) and nerve conduction velocities (P < 0.05) increased; distal latencies (P < 0.05) decreased; and , QTd, QTcd, JTd, and JTcd (P < 0.05) decreased significantly when compared to basal values. The greatest changes in sensory nerve action potential amplitude and ventricular dispersion parameters were observed in the sensory sural nerve and QTcd, respectively. LC was well tolerated over the study period. Conclusion: LC, well tolerated by diabetic patients, may improve peripheral neuropathy and ventricular dispersion and may be useful in preventing the increased incidence of arrhythmias and sudden death observed in such patients. Larger clinical trials are needed to confirm these data before changes to clinical practice can be advocated.