Malfunction of the Automatic Slope Adjustment of the QT Sensor in Patients with Normal QT Intervals

2004 ◽  
Vol 27 (3) ◽  
pp. 405-407 ◽  
Author(s):  
JACOB H. RUITER ◽  
MICHAEL J. BARRETT ◽  
LOES WETELING ◽  
RIK JANSEN
Keyword(s):  
Qt Intervals ◽  
Slope Adjustment

Comparison of wavelet continuous transform and signal averaged ECG for high frequency content and late potential detection in healthy individuals

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
D Garcia Iglesias ◽  
J.M Rubin Lopez ◽  
D Perez Diez ◽  
C Moris De La Tassa ◽  
F.J De Cos Juez ◽  
...  
Keyword(s):  
High Frequency ◽  
Classical Method ◽  
Total Power ◽  
Frequency Content ◽  
Healthy Individuals ◽  
Time Frequency ◽  
Qt Intervals ◽  
Long Time ◽  
Power Content ◽  
High Frequency Content

Abstract Introduction The Signal Averaged ECG (SAECG) is a classical method forSudden Cardiac Death (SCD) risk assessment, by means of Late Potentials (LP) in the filtered QRS (fQRS)[1]. But it is highly dependent on noise and require long time records, which make it tedious to use. Wavelet Continuous Transform (WCT) meanwhile is easier to use, and may let us to measure the High Frequency Content (HFC) of the QRS and QT intervals, which also correlates with the risk of SCD [2,3]. Whether the HFC of the QRS and QT measured with the WCT is a possible subrogate of LP, has never been demonstrated. Objective To demonstrate if there is any relationship between the HFC measured with the WCT and the LP analyzed with the SAECG. Methods Data from 50 consecutive healthy individuals. The standard ECG was digitally collected for 3 consecutive minutes. For the WCT Analysis 8 consecutive QT complexes were used and for the SAECG Analysis all available QRS were used. The time-frequency data of each QT complex were collected using the WCT as previously described [3] and the Total, QRS and QT power were obtained from each patient. For the SAECG, bipolar X, Y and Z leads were used with a bidirectional filter at 40 to 250 Hz [1]. LP were defined as less than 0.05 z in the terminal part of the filtered QRS and the duration (SAECG LP duration) and root mean square (SAECG LP Content) of this LP were calculated. Pearson's test was used to correlate the Power content with WCT analysis and the LP in the SAECG. Results There is a strong correlation between Total Power and the SAECG LP content (r=0.621, p<0.001). Both ST Power (r=0.567, p<0.001) and QRS Power (r=0.404, p=0.004) are related with the SAECG LP content. No correlation were found between the Power content (Total, QRS or ST Power) and the SAECG LP duration. Also no correlation was found between de SAECG LP content and duration. Conclusions Total, QRS and ST Power measured with the WCT are good surrogates of SAECG LP content. No correlation were found between WCT analysis and the SAECG LP duration. Also no correlation was found between the SAECG LP content and duration. This can be of high interest, since WCT is an easier technique, not needing long recordings and being less affected by noise. Funding Acknowledgement Type of funding source: None

scholarly journals Changes in Evoked QT Intervals According to Variations in Atrioventricular Delay and Cardiac Function in Patients With Implanted QT-Driven DDDR Pacemakers

2003 ◽  
Vol 67 (6) ◽  
pp. 515-518 ◽  
Author(s):  
Toshiyuki Ishikawa ◽  
Teruyasu Sugano ◽  
Shinichi Sumita ◽  
Masami Kosuge ◽  
Izumi Kobayashi ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Atrioventricular Delay ◽  
Qt Intervals

Poisoning severity score, Glasgow coma scale, corrected QT interval in acute organophosphate poisoning

2010 ◽  
Vol 29 (5) ◽  
pp. 419-425 ◽  
Author(s):  
Okhan Akdur ◽  
Polat Durukan ◽  
Seda Ozkan ◽  
Levent Avsarogullari ◽  
Alper Vardar ◽  
...  
Keyword(s):  
Glasgow Coma Scale ◽  
Severity Score ◽  
Initial Assessment ◽  
Organophosphate Poisoning ◽  
Qtc Interval ◽  
Coma Scale ◽  
Qt Intervals ◽  
Grade 3 ◽  
Poisoning Severity Score ◽  
Cardiac Manifestations

The aim of this study was to investigate effectiveness of the poisoning severity score (PSS), Glasgow coma scale (GCS), and corrected QT (QTc) interval in predicting outcomes in acute organophosphates (OP) poisoning. Over a period of 2 years, 62 patients with OP poisoning were admitted to emergency department (ED) of Erciyes University Medical School Hospital. The age, sex, cause of contact, compound involved, time elapsed between exposure and admission to the ED, duration of hospital stay, and cardiac manifestations at the time of presentation were recorded. GCS and poisoning severity score (PSS) was calculated for each patient. Electrocardiogram (ECG) analysis included the rate, rhythm, ST-T abnormalities, conduction defects, and measurement of PR and QT intervals. Sixty-two patients with OP poisoning presented to our ED from January 2007 to December 2008 from which 54 patients were included in the study. The mean age was 34.1 ± 14.8 years. Of the cases, 53.7% were female. Twenty-six patients had a prolonged QTc interval. Mean PSS of men and women was 1.8 ± 1.0. No statistically significant correlation was found between the PSS and QTc intervals of the cases. A significant correlation was determined between the GCS and PSS of grade 3 and grade 4 cases. GCS is a parameter that helps clinician to identify advanced grade OP poisoning patients in the initial assessment in the ED. However, ECG findings, such as prolonged QTc interval, are not effective in determination of short-term prognosis and show no relationship with PSS.

Empagliflozin significantly attenuates QTc prolongation in rats due to sotalol

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
V.O Baris ◽  
B Dincsoy ◽  
E Gedikli ◽  
A Erdem
Keyword(s):  
Qt Prolongation ◽  
Control Group ◽  
Diabetic Patients ◽  
Protective Effects ◽  
Qtc Prolongation ◽  
Positive Effects ◽  
T Wave ◽  
Qt Intervals ◽  
Electrocardiogram Ecg

Abstract Introduction Sotalol (SOT) is a Class 3 antiarrhythmic drug and commonly used for various arrhythmia treatments. However; it can prolong QT interval and lead to malignant arrhythmias. Empagliflozin is a selective SGLT-2 inhibitor used in the treatment of Type 2 diabetes and has been shown to have positive effects on cardiovascular outcomes. Since the effect of empagliflozin (EMPA) on potassium channel activation is not yet known, there is no recommendation for the concomitant use of these drugs. Purpose In this study, we aimed to evaluate possible protective effects of empagliflozin in sotalol induced QT prolongation. Materials and methods Twenty-four male Wistar Alba rats were randomized into four groups. The first (control) group (n: 6) received only serum physiologic (1ml) via orogastric gavage (OG). The second (EMPA) group (n: 6) received EMPA (10 mg/kg) via OG. The third (SOT) group (n: 6) received SOT (80 mg/kg) via OG. The fourth (EMPA+SOT) group (n: 6) received EMPA (10 mg/kg) and SOT (80 mg/kg) via OG. Under anesthesia; PR, QT intervals and heart rate (HR) were measured and QTc value was also calculated at second hour on lead II using electrocardiogram (ECG). Results In the SOT group; QT intervals, T wave durations and QTc values were found to be statistically longer than the control group, whereas HR was found to be lower than the control group (p<0.01). In the EMPA+SOT group; QT intervals, T wave durations and QTc values were significantly lower and HR was significantly higher compared to the SOT group (p<0.001, p<0.01, p<0.001, p<0.001 respectively) (Table) Conclusion In the present study, we detected that EMPA significantly ameliorates SOT induced QT prolongation. In addition to this, we have also shown that EMPA can be used safely with SOT in clinical practice. With more clinical trials, the routine use of EMPA may be suggested to prevent QTc prolongation in diabetic patients receiving SOT. Finally; our study indicates that EMPA can effect on potassium channels. Funding Acknowledgement Type of funding source: None

A comprehensive formula for computing corrected QT intervals in patients with wide QRS

2021 ◽  
Author(s):  
Santiago Colunga ◽  
Valeria Rolle ◽  
Cesar Moris ◽  
David Calvo
Keyword(s):  
Qt Intervals

Abstract 14358: Treadmill Exercise Testing Improves Diagnostic Accuracy in Children With Concealed Congenital Long QT Syndrome

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Trisha Patel ◽  
Stanley Kamande ◽  
Elizabeth Jarosz ◽  
James Bost ◽  
Sridhar hanumanthaiah ◽  
...  
Keyword(s):  
Exercise Testing ◽  
Long Qt Syndrome ◽  
Stress Testing ◽  
Normal Population ◽  
Recovery Phase ◽  
Exercise Stress ◽  
Long Qt ◽  
Qt Intervals ◽  
Prolonged Qt ◽  
Qt Syndrome

Introduction: Resting electrocardiogram (ECG) identification of long QT syndrome (LQTS) has limitations. Uncertainty exists on how to classify patients with borderline prolonged QT intervals. We tested if exercise testing could help serve as a guide for which children with borderline prolonged QT intervals may be gene positive for LQTS. Methods: Pediatric patients (n=139) were divided into three groups: Controls (n=76), gene positive LQTS with borderline QTc (n=21), and gene negative patients with borderline QTc (n=42). Borderline QTc was defined between 440 to 470 (male) and 440 to 480 (female) msec. ECGs were recorded while supine, sitting, and standing. Patients then underwent treadmill stress testing using the Bruce protocol followed by a 9-minute recovery phase. Statistical analysis was completed to compare the QTc intervals amongst all three of the groups using t-test, ANOVA, and the Youden method to calculate sensitivity and specificity cut points. Results: Supine resting QTc, age, and Schwartz score for the three groups were: 1) Gene positive: 446 ± 23 msec, 12.4 ± 3.4 yo, 3.2 ± 1.8; 2) Gene negative: 445 ± 20 msec, 12.1 ± 2.8 yo, 2.0 ± 1.2; and 3) Control: 400 ± 24 msec, 15.0 ± 3 yo. The three groups could be differentiated by their QTc response at two time points: standing and recovery phase at six minutes. Standing QTc ≥ 460 msec differentiated borderline prolonged QTc patients (Gene positive and Gene negative) from controls with a specificity of 90% for gene positive versus control and 83% for gene negative versus control. A late recovery QTc ≥ 480 msec at minute six distinguished Gene positive from Gene negative patients with a specificity of >97%. Conclusions: Exercise stress testing can be useful to identify Gene positive borderline LQTS from a normal population and Gene negative borderline QTc patients, allowing for increased cost effectiveness by selectively gene testing a higher risk group of patients with borderline QTc intervals and intermediate Schwartz scores.

Abstract 202: Aging Alters the Electrical and Mechanical properties of LV Myocytes

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Andrea Sorrentino ◽  
Sergio Signore ◽  
Mark Sundman ◽  
Ramaswamy Kannappan ◽  
Chiara Mangiaracina ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Na Channel ◽  
Relaxation Phase ◽  
Qt Intervals ◽  
K Current ◽  
Electrocardiographic Parameters ◽  
Perfused Hearts ◽  
Old Mice ◽  
Ionic Basis

Aging results in delays in the electrical recovery of the heart, enhancing the risk of malignant ventricular arrhythmias and sudden death. But whether altered electrical properties affect myocardial mechanical performance remains unclear. The aim of this study was to establish the ionic basis for the protracted repolarization of the senescent heart, and to determine whether these electrical changes impact on myocardial contractility. For this purpose, electrophysiological analyses were conducted in vivo and in isolated LV myocyte preparations from mice ranging from 3 to 30 months of age. Electrocardiographic parameters were preserved from 3 to 12 months of age, whereas animals 2 years or older presented prolonged PR, QRS and QT intervals. These in vivo results were confirmed in the isolated organ, using Langendorff perfused hearts. Myocytes from 30 months old mice showed longer early and late repolarization phases of the action potential (AP), in comparison with cells from animals at 3 months. By voltage-clamp, the density of the transient outward K+ current (Ito) was significantly reduced in old, whereas the late Na+ current (INaL) was increased, changes consistent with the prolonged AP of old cells. Additionally, by Western blotting, the SCN1B subunit, involved in Na+ channel gating, was reduced with age. Using field stimulation, old myocytes presented slower Ca2+ transient decay and relaxation, in comparison to young. Blockade of INaL with mexiletine in old myocytes shortened the AP duration, and fastened the decay of Ca2+ transients and relaxation. To assess the functional impact of INaL on the myocardium, papillary muscles were studied in an isometric system. Using tension-length protocols, old muscles presented elevated diastolic tension with respect to young. Importantly, inhibition of INaL in old muscles reduced diastolic tension, and attenuated the active developed force. Conversely, increasing INaL in the myocardium of young mice with anemonetoxin had opposite effects. Overall, these data indicate that aging results in a prolongation of the AP mediated, at least in part, by enhanced INaL. The prolonged repolarization of the AP contributes to the slower clearance of diastolic Ca2+ from the cytoplasm, resulting in protracted relaxation phase.

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