Measuring the QT/QTc Interval in the Presence of Wide QRS Complexes

2022 ◽  
Vol 31 (1) ◽  
pp. 83-84
Author(s):  
Sukardi Suba ◽  
Dillon J. Dzikowicz ◽  
Teri M. Kozik ◽  
Michele M. Pelter
Keyword(s):  
Qtc Interval

Effect of Handgrip Exercise on QTc Interval During Different Phases of Menstrual Cycle

2006 ◽  
Vol 3 (2) ◽  
pp. 83-86
Author(s):  
V. P. Varshney ◽  
Mona Bedi ◽  
Bharti Bhandari ◽  
Jyotsna Bhatnagar
Keyword(s):  
Menstrual Cycle ◽  
Qtc Interval ◽  
Handgrip Exercise

Changes of QT interval in the acute phase after pulmonary vein isolation for paroxysmal atrial fibrillation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Chikata ◽  
T Kato ◽  
K Ududa ◽  
S Fujita ◽  
K Otowa ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Pulmonary Vein ◽  
Female Patient ◽  
Pulmonary Vein Isolation ◽  
Acute Phase ◽  
Paroxysmal Atrial Fibrillation ◽  
Qt Interval ◽  
Qt Prolongation ◽  
Qtc Interval ◽  
The Impact

Abstract Introduction Pulmonary vein isolation (PVI) affects ganglionated plexi (GP) around the atrium, leading to a modification of the intrinsic cardiac autonomic system (ANS). In animal models, GP ablation has a potential risk of QT prolongation and ventricular arrhythmias. However, the impact of PVI on QT intervals in humans remains unclear. Purpose This study aims to evaluate the Impact of PVI on QT interval in patients with paroxysmal atrial fibrillation. Methods We analyzed consecutive 117 PAF patients for their first PVI procedures. 12-lead ECG was evaluated at baseline, 4 hr, day 1, 1 month, and 3 months after ablation. Only patients with sinus rhythm on 12-lead ECG at each evaluation point without antiarrhythmic drugs were included. Results Heart rate significantly increased at 4 hr, day 1, and 1 month. Raw QT interval prolonged at 4 hr (417.1±41.6 ms, P<0.001) but shortened at day 1 (376.4±34.1 ms, P<0.001), 1 month (382.2±31.5 ms, P<0.001), and 3 months (385.1±32.8 ms, P<0.001) compared to baseline (391.6±31.4 ms). Bazett- and Fridericia- corrected QTc intervals significantly prolonged at 4hr (Bazett: 430.8±27.9 ms, P<0.001; Fridericia: 425.8±27.4 ms, P<0.001), day1 (Bazett: 434.8±22.3 ms, P<0.001; Fridericia: 414.1±23.7 ms, P<0.001), 1M (Bazett: 434.8±22.3 ms, P<0.001; Fridericia: 408.2±21.0 ms, P<0.05), and 3M (Bazett: 420.1±21.8 ms, P<0.001; Fridericia: 407.8±21.1 ms, P<0.05) compared to baseline (Bazett: 404.9±25.2 ms; Fridericia: 400.0±22.6 ms). On the other hand, Framingham- and Hodges- corrected QTc interval significantly prolonged only at 4hr (Framingham: 424.1±26.6 ms, P<0.001; Hodges: 426.8±28.4 ms, P<0.001) and at day1 (Framingham: 412.3±29.3 ms, P<0.01; Hodges: 410.6±40.2 ms, P<0.05) compared to baseline (Framingham: 399.2±22.7 ms; Hodges: 400.7±22.8 ms). At 4 hr after ablation, raw QT and QTc of all formulas significantly prolonged than baseline. Raw QT and QTc prolongation at 4hr after ablation were more frequently observed in female patients. Multiple regression analysis revealed that female patient is a significant predictor of raw QT and QTc interval prolongation of all formulas 4hr after PVI. Conclusions Raw QT and QTc prolonged after PVI, especially in the acute phase. Female patient is a risk factor for QT prolongation in the acute phase after PVI. Funding Acknowledgement Type of funding source: None

The Assessment of Ventricular Arrhythmia Indicators Based on Electrocardiography in Patients With Differentiated Thyroid Cancer Followed Up With Levothyroxine Suppression

Angiology ◽  
2021 ◽  
pp. 000331972199334
Author(s):  
Sema Hepsen ◽  
Davut Sakiz ◽  
Hilal Erken Pamukcu ◽  
Ismail Emre Arslan ◽  
Hakan Duger ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Thyroid Cancer ◽  
Ventricular Arrhythmia ◽  
Differentiated Thyroid Cancer ◽  
Linear Regression Analysis ◽  
Male Gender ◽  
Qtc Interval ◽  
Inclusion Criteria ◽  
Raising Awareness ◽  
Number Of Patients

Levothyroxine suppression therapy (LST) can cause some unfavorable effects on the cardiovascular system in patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate ventricular arrhythmia predictors based on electrocardiography (ECG) in patients with DTC with LST. The ECG parameters including QT, corrected QT (QTc), Tp-e intervals, Tp-e/QT, and Tp-e/QTC ratios of 265 patients with DTC who met the inclusion criteria were compared with 100 controls. No difference was observed in the number of patients with DTC and controls with prolonged and borderline QTc interval ( P = .273). Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were significantly higher in patients ( P = .002, P = .02, P = .003; respectively). Linear regression analysis suggested that male gender was a predictor of higher Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios (β = 4.322, R 2 = 0.024, P = .042; β = 0.016, R 2 = 0.048, P = .005; β = 0.015, R 2 = 0.044, P = .006, respectively). A higher serum fT4 level was found to be associated with a higher Tp-e/QT ratio (β = 0.018, R 2 = 0.089, P = .007). Ventricular arrhythmia indicators were found to be higher in patients with DTC with LST. Defining ventricular arrhythmia predictors through ECG, an easily accessible cardiac diagnostic tool, can be potentially useful in raising awareness of the possible cardiac harm of LST.

Association between digoxin use and sudden cardiac death in individuals with the rs10494366 variant of the NOS1AP gene

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Soroush ◽  
A Aarnoudse ◽  
F Shokri ◽  
M Van Den Berg ◽  
F Ahmadizar ◽  
...  
Keyword(s):  
Sudden Cardiac Death ◽  
Cardiac Death ◽  
Smoking Status ◽  
Adaptor Protein ◽  
Therapeutic Window ◽  
P Value ◽  
Qtc Interval ◽  
Total Study Population ◽  
Increased Risk

Abstract Background Digoxin is one of the oldest cardiovascular medications still used to treat heart failure and atrial fibrillation. Due to its narrow therapeutic window, it is associated with life threatening intoxication and arrhythmias, and with QTc-shortening. Common genetic variation in the nitric oxide synthase-1 adaptor protein (NOS1AP) has been associated with QTc interval prolongation. Purpose We investigated whether the rs10494366 variant of the NOS1AP gene modified the risk of SCD in patients using digoxin. Methods In a prospective population-based cohort study, we included data of the three cohorts, started as of January 1st, 1991 until January 1st 2014. Digoxin current use on the date of cardiac death in cases and the same day of follow-up in the remainder of the cohort was a time-dependent exposure. The main outcome was SCD defined as sudden and unexpected death as a result of cardiac causes, according to international criteria. Identification and adjudication of SCD was performed independently, before the start of this study. We used Cox proportional hazard regression analysis to investigate the associations between NOS1AP rs10494366 variant and incident SCD among digoxin users compared to non-users. Associations were adjusted for age, sex (model 1) in addition to BMI, prevalent diabetes, myocardial infarction, baseline hypertension and smoking status (past, current, never) (model 2). Results We included 14,594 individuals, with a mean age of 65.3 (SD 10.3) years. Almost 59% were female. The cumulative incidence of SCD was 9.5% (609 cases) by the end of follow up. Among them, 98 (16%) individuals were exposed to digoxin at the time of death. In model 1, NOS1AP rs10494366 variant was not associated with SCD in the total study population. However, an interaction term of the gene with the daily dose of digoxin was significantly associated with increased risk of SCD (p-value 0.0001). In model 2, the risk of SCD in current users of digoxin was 4.2 [95% CI 1.3–13.8] for the GG genotype; 2.1 [95% CI 1.1–4.2] for the GT genotype, and 1.5 [95% CI 0.7–3.2] for the TT genotype. Conclusion NOS1AP rs10494366 variant modified the risk of sudden cardiac death in users of digoxin. Our study suggests that individuals with the homozygous minor GG allele have a fourfold increased risk of sudden cardiac death. Funding Acknowledgement Type of funding source: None

scholarly journals Antipsychotics in routine treatment are minor contributors to QT prolongation compared to genetics and age

2021 ◽  
pp. 026988112110034
Author(s):  
Leif Hommers ◽  
Maike Scherf-Clavel ◽  
Roberta Stempel ◽  
Julian Roth ◽  
Matthias Falter ◽  
...  
Keyword(s):  
Qt Interval ◽  
Multivariate Regression Analysis ◽  
Cardiac Repolarization ◽  
Qtc Interval ◽  
Serum Concentrations ◽  
Drug Induced ◽  
Individual Level ◽  
Main Determinants ◽  
The Individual ◽  
Polygenic Variation

Background: Drug-induced prolongation of cardiac repolarization limits the treatment with many psychotropic drugs. Recently, the contribution of polygenic variation to the individual duration of the QT interval was identified. Aims: To explore the interaction between antipsychotic drugs and the individual polygenic influence on the QT interval. Methods: Retrospective analysis of clinical and genotype data of 804 psychiatric inpatients diagnosed with a psychotic disorder. The individual polygenic influence on the QT interval was calculated according to the method of Arking et al. Results: Linear regression modelling showed a significant association of the individual polygenic QT interval score (ßstd = 0.176, p < 0.001) and age (ßstd = 0.139, p < 0.001) with the QTc interval corrected according to Fridericia’s formula. Sex showed a nominal trend towards significance (ßstd = 0.064, p = 0.064). No association was observed for the number of QT prolonging drugs according to AZCERT taken. Subsample analysis ( n = 588) showed a significant association of potassium serum concentrations with the QTc interval (ßstd = −0.104, p = 0.010). Haloperidol serum concentrations were associated with the QTc interval only in single medication analysis ( n = 26, ßstd = 0.101, p = 0.004), but not in multivariate regression analysis. No association was observed for aripiprazole, clozapine, quetiapine and perazine, while olanzapine and the sum of risperidone and its metabolite showed a negative association. Conclusions: Individual genetic factors and age are main determinants of the QT interval. Antipsychotic drug serum concentrations within the therapeutic range contribute to QTc prolongation on an individual level.

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