scholarly journals The effect of different stressors on the QT interval and the T wave

2009 ◽  
Vol 150 (10) ◽  
pp. 447-457 ◽  
Author(s):  
Gábor Andrássy
Keyword(s):  
Cardiovascular Reactivity ◽  
Qt Interval ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
Qt Prolongation ◽  
New Methods ◽  
Life Threatening ◽  
Prolonged Qt Interval ◽  
The Relationship ◽  
T Waves

Prolonged QT interval is associated with the generation of life-threatening arrhythmias and sudden death. However, neither the relation between QT duration and heart rate, nor the association between mental stress and QT time has been clarified. Aim: The relationship between QT duration and smoking, cardiovascular reactivity, and mental stress as well as newer methods of QT correction were studied. Methods: In six laboratory experiments 166 volunteers were studied. Smoking, treadmill exercise, mental arithmetic and videogame were applied as stressors. Besides fixed formulae, study and subject-specific QT correction methods were also used. Results: 1. Bazett formula is not appropriate to compare QT durations. 2. Acute smoking has no effect on QT time. 3. QT changes are related to cardiovascular reactivity. 4. Mental stress may induce QT prolongation. 5. Bifid T waves often develop during mental and isometric stress. Conclusions: New methods for QT correction are more reliable than preformed formulae. QT prolongation and bifid T waves may be the links between mental stress and life threatening arrhythmias.

scholarly journals Fluconazole-associated QT interval prolongation and Torsades de Pointes in a paediatric patient

2021 ◽  
pp. 1-3
Author(s):  
Ayşe Ünal Yüksekgönül ◽  
İlker Ertuğrul ◽  
Tevfik Karagöz
Keyword(s):  
Qt Interval ◽  
Torsades De Pointes ◽  
Qt Prolongation ◽  
Polymorphic Ventricular Tachycardia ◽  
Interval Prolongation ◽  
Qt Interval Prolongation ◽  
Life Threatening ◽  
Prolonged Qt Interval ◽  
Rhythm Disorder ◽  
Anti Fungal

Abstract “Torsades de pointes”, a life-threatening rhythm disorder, is a polymorphic ventricular tachycardia that usually develops in association with a prolonged QT interval. Fluconazole, an anti-fungal drug, may also induce QT prolongation, in some cases subsequent torsades de pointes. Herein, we report a 16-year-old female presenting “torsades de pointes” after administration of fluconazole and rapidly improved upon cessation of the drug.

scholarly journals Managing drug-induced QT prolongation in clinical practice

2020 ◽  
pp. postgradmedj-2020-138661
Author(s):  
Rani Khatib ◽  
Fatima R N Sabir ◽  
Caroline Omari ◽  
Chris Pepper ◽  
Muzahir Hassan Tayebjee
Keyword(s):  
Qt Interval ◽  
Simple Algorithm ◽  
Torsades De Pointes ◽  
Daily Practice ◽  
Qt Prolongation ◽  
Key Factors ◽  
Drug Induced ◽  
Electrolyte Disturbances ◽  
Related Risk ◽  
Life Threatening

Many drug therapies are associated with prolongation of the QT interval. This may increase the risk of Torsades de Pointes (TdP), a potentially life-threatening cardiac arrhythmia. As the QT interval varies with a change in heart rate, various formulae can adjust for this, producing a ‘corrected QT’ (QTc) value. Normal QTc intervals are typically <450 ms for men and <460 ms for women. For every 10 ms increase, there is a ~5% increase in the risk of arrhythmic events. When prescribing drugs associated with QT prolongation, three key factors should be considered: patient-related risk factors (eg, female sex, age >65 years, uncorrected electrolyte disturbances); the potential risk and degree of QT prolongation associated with the proposed drug; and co-prescribed medicines that could increase the risk of QT prolongation. To support clinicians, who are likely to prescribe such medicines in their daily practice, we developed a simple algorithm to help guide clinical management in patients who are at risk of QT prolongation/TdP, those exposed to QT-prolonging medication or have QT prolongation.

scholarly journals Prolonged QT Interval in a Patient With Coronavirus Disease-2019: Beyond Hydroxychloroquine and Azithromycin

2020 ◽  
Vol 8 ◽  
pp. 232470962094840
Author(s):  
B K Anupama ◽  
Soumya Adhikari ◽  
Debanik Chaudhuri
Keyword(s):  
Qt Interval ◽  
Ventricular Arrhythmias ◽  
Torsade De Pointes ◽  
Cardiac Pacing ◽  
Qt Prolongation ◽  
Medication Effects ◽  
Increased Risk ◽  
Repolarization Reserve ◽  
Prolonged Qt Interval ◽  
Prolonged Qt

Recent reports have suggested an increased risk of QT prolongation and subsequent life-threatening ventricular arrhythmias, particularly torsade de pointes, in patients with coronavirus disease-2019 (COVID-19) treated with hydroxychloroquine and azithromycin. In this article, we report the case of a 75-year-old female with a baseline prolonged QT interval in whom the COVID-19 illness resulted in further remarkable QT prolongation (>700 ms), precipitating recurrent self-terminating episodes of torsade de pointes that necessitated temporary cardiac pacing. Despite the correction of hypoxemia and the absence of reversible factors, such as adverse medication effects, electrolyte derangements, and usage of hydroxychloroquine/azithromycin, the QT interval remained persistently prolonged compared with the baseline with subsequent degeneration into ventricular tachycardia and death. Thus, we highlight that COVID-19 illness itself can potentially lead to further prolongation of QT interval and unmask fatal ventricular arrhythmias in patients who have a prolonged QT and low repolarization reserve at baseline.

scholarly journals The relationship between J wave and ventricular tachycardia during Takotsubo cardiomyopathy

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Seong Huan Choi ◽  
Oh-Hyun Lee ◽  
Gwang-Seok Yoon ◽  
Sung Woo Kwon ◽  
Sung-Hee Shin ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Ventricular Arrhythmia ◽  
Takotsubo Cardiomyopathy ◽  
Qt Interval ◽  
Independent Predictor ◽  
Cardiac Events ◽  
Idiopathic Ventricular Fibrillation ◽  
Life Threatening ◽  
The Relationship ◽  
J Wave

Abstract Background and objectives Takotsubo cardiomyopathy (TTC) occasionally causes life-threatening ventricular arrhythmia. J wave on surface electrocardiography (sECG) has also been associated with idiopathic ventricular fibrillation and cardiac events; therefore, we investigated whether the presence of J wave on sECG is a potential risk factor for ventricular arrhythmia in patients with TTC. Subjects and methods We performed a retrospective study in 79 patients who were diagnosed with TTC from 2010 to 2014. Among them, 20 (25.3%) were diagnosed with ventricular tachycardia (VT). The J wave on the sECG was defined as J point elevation manifested through QRS notching or slurring at least 1 mm above the baseline in at least two leads. Results A higher prevalence of ventricular tachycardia was observed in patients with J wave. The corrected QT interval (QTc) was significantly longer in the VT group than in the non-VT group. In a multivariate analysis, the presence of J wave appeared to be the only independent predictors of VT [Hazard Ratio (HR) 3.5, p = 0.019]. Conclusion Our results suggest that the presence of J wave on the sECG is significantly associated with VT, and appear to indicate that the presence of J wave is a strong and independent predictor of VT in patients with TTC.

scholarly journals Compound heterozygote KCNQ1 mutation causing Jervell Lange Neilson syndrome: a case report of genotype-phenotype correlation

2021 ◽  
Vol 8 (7) ◽  
pp. 1307
Author(s):  
Khushboo Agarwal ◽  
Guruprasad H. Shankar ◽  
Bhakti Sarangi ◽  
Ajay Walimbe
Keyword(s):  
Qt Interval ◽  
Ventricular Arrhythmias ◽  
Monogenic Disease ◽  
Compound Heterozygous ◽  
Genetic Associations ◽  
Significant Family History ◽  
Cardiac Assessment ◽  
Life Threatening ◽  
Prolonged Qt Interval ◽  
Work Up

Congenital sensorineural hearing loss (SNHL) is a common phenomenon with several genetic and non-genetic associations that require early diagnosis and work-up to prompt appropriate interventions. Of the genetic associations, Jervell and Lange-Nielsen syndrome (JLNS) remains a rare monogenic disease that is characterized by SNHL, prolongation of QT interval, syncopal attacks due to ventricular arrhythmias and sudden cardiac death from very early in life. We hereby report a 5 years old girl with SNHL and recurrent blackout episodes in early childhood with significant family history, admitted for cochlear implant who developed ventricular arrhythmias requiring multiple interventions with further investigations revealing a prolonged QT interval on electrocardiography (ECG) with metabolic abnormalities (hypomagnesemia and hypokalemia). Her clinical exome study showed a compound heterozygous KCNQ1 mutation, a more sporadic form of JLNS managed using oral beta-blocker. This experience illustrates the relevance of a detailed systemic evaluation with an elaborate cardiac assessment in children with SNHL, more so in the presence of frequent unexplained acute life-threatening episodes.     

P280 Concomitant use of ivabradine and cyp3a4 inhibitors in critical cardiac patients

2020 ◽  
Vol 41 (Supplement_1) ◽  
Author(s):  
A Mohamed Ariff ◽  
H Abd Hadi ◽  
T W Nay ◽  
M I Thoulath ◽  
A T Jauhari Aktifanus ◽  
...  
Keyword(s):  
Critical Care ◽  
Drug Interactions ◽  
Cardiac Disease ◽  
Qt Interval ◽  
Qt Prolongation ◽  
Left Ventricular Ejection ◽  
Drug Event ◽  
Cyp3a4 Inhibitor ◽  
Life Threatening ◽  
Cyp3a4 Inhibitors

Abstract Background In recent years there have been warnings concerning drug-induced life-threatening arrhythmias. Drug interactions can increase the risk of QT interval prolongation via interaction of pharmacokinetic mechanism. Some drugs such as Ivabradine does not affect the repolarization or affect the QT interval themselves. However, it can increase the risk of QT prolongation when taken with drugs that block the metabolic breakdown which inhibit the CYP3A4 enzyme particularly. Predisposing factors of QT prolongation include female sex, age over 65 years, brady-arrhythmia, electrolyte disturbances (hypokalemia, hypomagnesaemia), cardiac disease (congestive heart failure, ventricular hypertrophy, myocardial infarction, atrial fibrillation), impaired hepatic/renal function and hypothyroidism.  Purpose To assess potential Ivabradine – CYP3A4 inhibitor interactions in a Cardiac Critical Care Unit (CCCU).  Method We prospectively observed patients admitted at CCCU received Ivabradine and CYP3A4 inhibitor (QTprolonging agent) concomitantlyfrom Feb 2018 to July 2018 at National Heart Institute, Malaysia. We use a clinical drug decision support system (CDDSS) to identify the potential drug-drug interactions (PDDI) and assessed the likelihood of drug - drug interactions (DDI) using Drug Interaction Probability Scale (DIPS).  Results Patients admitted at CCCU co-administered with Ivabradine and CYP3A4 inhibitors (amiodarone/azithromycin) were analyzed. The severity level for both potential Ivabradine – Azithromycin and Ivabradine – Amiodarone interactions were alerted by the CDDSS as Major. Total 10 (M = 70%) patients were screened. The mean age was ± 57 years old. They had no previous exposure to both or one of the medications before. All patients had underlying cardiac disease. The left ventricular ejection fractions (LVEF) ranged from 15% - 65%. Adverse drug event (ADE) occurred in 7 (70%) patients [Male = 5 (71%), Female = 2 (67%)]. 70% of patients had prolonged QT interval induced by Ivabradine – Amiodarone and Ivabradine – Azithromycin All patients had QTc interval &lt; 500 ms before co-administration and had a change of ± 100 ms after coadministration. The onset of ADE ranged from day 2 to day 5 in all patients. One had life threatening arrhythmia; ventricular fibrillation and require defibrillator and another one patient had non-sustained ventricular tachycardia. The most common precipitating factor was underlying cardiac disease. All suspected precipitating drug was discontinued. DIPS revealed; 57% patients scored 9 points (highly probable DDI) and the rest scored between 5-7 points (probable DDI). Conclusion Ivabradine potentially associated to fatal arrhythmia when it is co-administered with CYP3A4 inhibitor. Hence, the physician should reconsider such combination within the correct clinical context to avoid cardiovascular deterioration especially in a critical care setting.

Cardiovascular reactivity in isometric exercise and mental arithmetic in children

1994 ◽  
Vol 76 (1) ◽  
pp. 146-150 ◽  
Author(s):  
H. A. Verhaaren ◽  
R. M. Schieken ◽  
P. Schwartz ◽  
M. Mosteller ◽  
D. Matthys ◽  
...  
Keyword(s):  
Cardiovascular Reactivity ◽  
Stress Responses ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
Isometric Exercise ◽  
Left Ventricular ◽  
Stress Tests ◽  
Isometric Handgrip ◽  
Cardiovascular Stress ◽  
Changes Over Time

In children, we studied noninvasively the cardiovascular stress responses, including changes over time of systolic blood pressure (SBP), heart rate (HR), and stroke volume (SV) in isometric handgrip (IHG) and mental arithmetic. Specifically, we asked whether 1) these cardiovascular stress responses were different for the two stress conditions in children, 2) these responses differed in boys and girls, and 3) the anthropometric variables related to these stress responses. SV differed significantly between IHG and mental arithmetic over the entire stress period. This may reflect higher systemic vascular resistance during IHG. HR in boys was lower than in girls over the entire period of stress in both stress tests. This observation cannot be attributed to differences in conditioning, because this should not influence responses to isometric or mental stress. A larger left ventricular mass was related to higher SVs. A marked relationship was found between HR and SBP and between HR and SV. No relationship was found between SBP and SV.

scholarly journals The QT long syndrome: clinical and diagnostic aspect

2021 ◽  
Vol 69 (1) ◽  
Author(s):  
Constantin Martiniuc ◽  
◽  
Serghei Pisarenco ◽  
Iurie Simionica ◽  
◽  
...  
Keyword(s):  
Qt Interval ◽  
Torsade De Pointes ◽  
Qt Prolongation ◽  
Current Data ◽  
Polymorphic Ventricular Tachycardia ◽  
Interval Prolongation ◽  
Qt Interval Prolongation ◽  
Increased Risk ◽  
Wide Range ◽  
Life Threatening

QT interval prolongation is a predictor of the life-threatening cardiac arrhythmias — polymorphic ventricular tachycardia (torsade de pointes). Long QT syndrome may be congenital or acquired. It is known that a wide range of both antiarrhythmic and non-cardiac medications might lead to QT interval prolongation. List of drugs that cause QT prolongation is constantly growing and being updated. The review contains current data on the clinical significance of the control of QT interval duration within drug therapy. Clinical conditions associated with an increased risk of QT interval prolongation are described. Drugs that can induce QT prolongation are also discussed.

scholarly journals Risk of QT Prolongation through Drug-drug Interactions between Hydroxychloroquine and Concomitant Drugs Prescribed in Real-world Practice

2020 ◽  
Author(s):  
Byung Jin Choi ◽  
Yeryung Koo ◽  
Tae Young Kim ◽  
Wou Young Chung ◽  
Yun Jung Jung ◽  
...  
Keyword(s):  
Drug Interactions ◽  
Real World ◽  
Qt Interval ◽  
Qt Prolongation ◽  
Qtc Interval ◽  
Interval Prolongation ◽  
Qt Interval Prolongation ◽  
Life Threatening ◽  
Alternative Drugs

Abstract Background: Hydroxychloroquine has recently received attention as a treatment for COVID-19. However, hydroxychloroquine may prolong the QTc interval, thus increasing the risk of life-threatening arrhythmia. Many patients with COVID-19 have comorbidities, necessitating the use of several drugs simultaneously with hydroxychloroquine. However, the risk of QT prolongation due to drug-drug interactions (DDIs) between hydroxychloroquine and these co-medications has not been identified. Therefore, it is necessary to investigate the risk of QT interval prolongation due to DDIs between hydroxychloroquine and frequently used concurrent drugs.Methods and Results: Using 447,632 patients and 1,040,752 electrocardiograms, we investigated the risk of QT prolongation due to DDIs between hydroxychloroquine and 118 concurrent drugs frequently used in real-world practice. In the analysis, we observed that 11 drugs (trimebutine, tacrolimus, tramadol, rosuvastatin, ciclosporin, sulfasalazine, rofecoxib, diltiazem, piperacillin/tazobactam, and isoniazid) show DDIs with hydroxychloroquine in the direction of QT prolongation.Conclusions: We found 11 drugs that show significant (p <0.05) DDIs with hydroxychloroquine, thereby increasing the risk of QT prolongation in patients. It is necessary to consider prescribing alternative drugs that have less DDI when these drugs are concurrently administered with hydroxychloroquine. Further investigation is needed to assess more profoundly the risk of QT prolongation due to DDI with hydroxychloroquine of each drug that we found in this analysis.

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