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QT interval

Itsuro Kazama
By simply adding a high concentration of calcium solution to the surface of the bullfrog heart, we reproduced electrocardiogram (ECG) abnormalities representing those observed in hypercalcemia, such as Osborn waves and shortening of the QT interval. The rise in extracellular calcium concentration may have activated the outward potassium currents during phase 3 of the action potential, and thus decreased its duration. In addition to the known decrease in the duration of phase 2, such changes in phase 3 were also likely to contribute to the shortening of the QT interval...
October 22, 2016: Journal of Veterinary Medical Science
Seon Ah Cha, Jae Seung Yun, Tae Seok Lim, Yoon Goo Kang, Kang Min Lee, Ki Ho Song, Ki Dong Yoo, Yong Moon Park, Seung Hyun Ko, Yu Bae Ahn
BACKGROUND: We investigated an association between baseline heart rate-corrected QT (QTc) interval before severe hypoglycemia (SH) and prolongation of QTc interval during SH in patients with type 2 diabetes mellitus (T2DM). METHODS: Between January 2004 and June 2014, 208 patients with T2DM, who visited the emergency department because of SH and underwent standard 12-lead electrocardiography within the 6-month period before SH were consecutively enrolled. The QTc interval was analyzed during the incidence of SH, and 6 months before and after SH...
October 5, 2016: Diabetes & Metabolism Journal
Abdunoor M Kabanywanyi, Rita Baiden, Ali M Ali, Muhidin K Mahende, Bernhards R Ogutu, Abraham Oduro, Halidou Tinto, Margaret Gyapong, Ali Sie, Esperanca Sevene, Eusebio Macete, Seth Owusu-Agyei, Alex Adjei, Guillaume Compaoré, Innocent Valea, Isaac Osei, Abena Yawson, Martin Adjuik, Raymond Akparibo, Mwaka A Kakolwa, Salim Abdulla, Fred Binka
The antimalarial drug piperaquine is associated with delayed ventricular depolarization, causing prolonged QT interval (time taken for ventricular de-polarisation and re-polarisation). There is a lack of safety data regarding dihydroartemisinin/piperaquine (DHA/PPQ) for the treatment of uncomplicated malaria, which has limited its use. We created a platform where electrocardiograms (ECG) were performed in public hospitals for the safety assessment of DHA/PPQ, at baseline before the use of dihydroartemisinin/piperaquine (Eurartesim®), and on day 3 (before and after administration of the final dose) and day 7 post-administration...
2016: PloS One
Jie Wu, Wei-Guang Ding, Minoru Horie
Long QT syndrome type 1 (LQT1) is a subtype of a congenital cardiac syndrome caused by mutation in the KCNQ1 gene, which encodes the α-subunit of the slow component of delayed rectifier K(+) current (IKs) channel. Arrhythmias in LQT1 are characterized by prolongation of the QT interval on ECG, as well as the occurrence of life-threatening cardiac events, frequently triggered by adrenergic stimuli (e.g., physical or emotional stress). During the past two decades, much advancement has been made in understanding the molecular pathogenesis underlying LQT1...
October 2016: Journal of Arrhythmia
Ali Eshraghi, Reyhaneh Takalloo Ebdali, Seyed Sajed Sajjadi, Reza Golnezhad
INTRODUCTION: It is believed that an exaggerated blood pressure response (EBPR) to exercise stress test is associated with a higher risk of cardiovascular events. It is also assumed that QT dispersion (QT-d), which was originally proposed to measure the spatial dispersion of ventricular recovery times, may have a relationship to cardiovascular events. The objective of this study was to examine the difference of changes in QT-d, Maxi-QT, Mini-QT, and QT-c (corrected QT interval) of the electrocardiogram in two groups of patients with exaggerated blood pressure responses (EBPR group) and normal responses (control group) to exercise testing...
August 2016: Electronic Physician
Tomomichi Ishizaka, Yu Yoshimatsu, Yu Maeda, Wataru Takasaki, Katsuyoshi Chiba, Kazuhiko Mori
INTRODUCTION: Load-independent cardiac parameters obtained from the ventricular pressure-volume relationship are recognized as gold standard indexes for evaluating cardiac inotropy.In this study, for better analyses of cardiac risks, load-independent pressure-volume loop parameters were assessed in addition to load-dependent inotropic, hemodynamic and electrocardiographic changes in isoflurane-anesthetized monkeys. METHODS: The animals were given milrinone (a PDE 3 inhibitor), metoprolol (a β-blocker), or dl-sotalol (a β+IKr blocker) intravenously over 10min at two dose levels including clinically relevant doses (n=5/drug)...
October 15, 2016: Journal of Pharmacological and Toxicological Methods
Kaylin T Nguyen, Rachel A Gladstone, Jonathan W Dukes, Babak Nazer, Eric Vittinghoff, Nitish Badhwar, Vasanth Vedantham, Edward P Gerstenfeld, Byron K Lee, Randall J Lee, Zian H Tseng, Jeffrey E Olgin, Melvin M Scheinman, Gregory M Marcus
INTRODUCTION: Atrial refractoriness may be an important determinant of atrial fibrillation (AF) risk, but its measurement is not clinically accessible. Because the QT interval predicts incident AF and the atrium and ventricle share repolarizing ion currents, we investigated the association between an individual's QT interval and atrial effective refractory period (AERP). METHODS: In paroxysmal AF patients presenting for catheter ablation, the QT interval was measured from the surface 12-lead ECG...
October 18, 2016: Pacing and Clinical Electrophysiology: PACE
Ning Ma, Xiao-Yan Wu, Chang-Sheng Ma, Nian Liu, Rong Bai, Xin Du, Yan-Fei Ruan, Jian-Zeng Dong
Catheter ablation has been recommended as a treatment option for paroxysmal atrial fibrillation (PAF) patients complicated with type 2 diabetes mellitus (T2DM). PAF patients with T2DM have a higher recurrence rate after catheter ablation. Prolongation of corrected QT (QTc) interval has been linked to poor outcomes in T2DM patients. Whether the abnormal QTc interval is associated with the ablation outcome in the PAF patients with T2DM remains unknown. In this study, 134 PAF patients with T2DM undergoing primary catheter ablation were retrospectively enrolled...
October 2016: Journal of Huazhong University of Science and Technology. Medical Sciences
Shegu Gilbert, Devender Singh, M Lawrance Jesuraj
Severe QT interval prolongation >500ms occurs in one quarter of cardiac surgical patients in the perioperative period while moderate prolongation occurs in most of them. Prolonged QT interval may be associated with torsades de pointes and lead to sudden cardiac death. Because of the high incidence of prolonged QT in cardiac surgery patients and its perioperative adverse outcomes, it is vital to identify it early and take necessary precautions. We report and discuss the catastrophic events and management of two patients with long QT syndrome complicating mitral valve replacement...
September 2016: Indian Heart Journal
Steven P Sears, Trevor W Getz, Christopher O Austin, William C Palmer, Evelyn A Boyd, Fernando F Stancampiano
BACKGROUND: Azithromycin has been associated with abnormalities of cardiac repolarization and development of torsades de pointes. Observational data suggest that the risk of death from cardiovascular causes is increased in patients taking azithromycin. Little is known regarding the risk of ventricular arrhythmia in patients with prolongation of the corrected QT interval who receive azithromycin. OBJECTIVE: The purpose of this study was to determine the incidence of sustained ventricular tachycardia in patients with prolonged corrected QT (QTc) who subsequently received azithromycin...
March 2016: Drugs—Real World Outcomes
Frank F Vincenzi, Philippe Lunetta
While SCUBA diving, a 44-year-old Caucasian patient had an abnormal cardiac rhythm, presumably Torsade de Pointes (TdP), during the initial descent to depth. Upon surfacing, she developed ventricular fibrillation and died. The patient had been treated for mild depression for nearly a year with citalopram 60 mg per day, a drug known to cause prolonged QT interval. She had also been treated with two potentially hepatotoxic drugs. Liver impairment causes selective loss of cytochrome P450 (CYP) 2C19 activity, the major pathway for metabolism of citalopram...
December 2015: Drug Saf Case Rep
S Gibiino, A Trappoli, B Balzarro, A R Atti, D De Ronchi
A 71-year-old man developed coma with severe respiratory failure, hypotension, and tachycardia induced by the intentional ingestion of quetiapine fumarate extended release (XR) 20 g. At the time, he had been treated for bipolar depression with venlafaxine 75 mg/day, lamotrigine 100 mg/day, pregabalin 75 mg/day, and quetiapine XR 400 mg/day for approximately 1 year. Comorbidities were hypertension treated with metoprolol, diabetes mellitus type 2 treated with metformin, and benign prostatic hyperplasia treated with silodosin...
December 2015: Drug Saf Case Rep
Akira Fujiki, Masao Sakabe
Objective Detecting paroxysmal atrial fibrillation in patients with ischemic stroke presenting in sinus rhythm is difficult because such episodes are often short, and they are also frequently asymptomatic. It is possible that the ventricular repolarization dynamics may reflect atrial vulnerability and cardioembolic stroke. Hence, we compared the QT-RR relation between cardioembolic stroke and atherosclerotic stroke during sinus rhythm. Methods The subjects comprised 62 consecutive ischemic stroke patients including 31 with cardioembolic strokes (71...
2016: Internal Medicine
Hyewon Chung, Anhye Kim, Kyoung Soo Lim, Sang-In Park, Kyung-Sang Yu, Seo Hyun Yoon, Joo-Youn Cho, Jae-Yong Chung
Escitalopram is the (S)-enantiomer of citalopram that has a potential QT prolonging effect. In this study, 12 healthy elderly individuals received a single oral dose of escitalopram (20 mg), and their pharmacokinetics and QT effect data were compared with data from 33 younger adults obtained in a previous study. Serial blood samples for pharmacokinetic analysis were collected and ECG was performed up to 48 h postdose. The elderly and younger adults showed similar pharmacokinetic profiles. The geometric mean ratios (90% confidence interval) of the elderly compared with the younger adults were 1...
October 12, 2016: International Clinical Psychopharmacology
Yuko Y Inoue, Bharath Ambale-Venkatesh, Nathan Mewton, Gustavo J Volpe, Yoshiaki Ohyama, Ravi K Sharma, Colin O Wu, Chia-Ying Liu, David A Bluemke, Elsayed Z Soliman, João A C Lima, Hiroshi Ashikaga
Purpose To examine the associations of myocardial diffuse fibrosis and scar with surface electrocardiographic (ECG) parameters in individuals free of prior coronary heart disease in four different ethnicities. Materials and Methods This prospective cross-sectional study was approved by the institutional review boards, and all participants gave informed consent. A total of 1669 participants in the Multi-Ethnic Study of Atherosclerosis, or MESA, who were free of prior myocardial infarction underwent both ECG and cardiac magnetic resonance imaging...
October 13, 2016: Radiology
C M Batra, Rajiv Agarwal
Hypocalcemic cardiomyopathy is a rare entity. We describe a patient with severe heart failure, decreased ejection fraction and global hypokinesia documented on echocardiogram, associated with severe hypocalcemia, very low vitamin D status, increased QT intervals, increased BNP (serum brain natriuretic peptide) levels and CPK (creatine phosphokinase) levels. All these defects reversed on treatment with vitamin D and calcium within a few days without any specific cardiac intervention.
June 2016: Journal of the Association of Physicians of India
Hiroko Izumi-Nakaseko, Yuji Nakamura, Xin Cao, Takeshi Wada, Kentaro Ando, Atsushi Sugiyama
Since an antipsychotic drug haloperidol has been clinically reported to induce QT interval prolongation and torsade de pointes, in this study its risk stratification for the onset of torsade de pointes was performed by using the chronic atrioventricular block canine model with a Holter electrocardiogram. Haloperidol in a dose of 3 mg kg(-1) p.o. prolonged the QT interval, but it did not induce torsade de pointes during the observation period of 21 h (n = 4), indicating that the dose would be safe. Meanwhile, haloperidol in a dose of 30 mg kg(-1) p...
October 13, 2016: Cardiovascular Toxicology
Ebru Yalın İmamoğlu, Ayşe Güler Eroğlu
AIM: To investigate ventricular arrhythmias in children with primary mitral valve prolapse and to evaluate its relation with QT length, QT dispersion, autonomic function tests and heart rate variability measurements. MATERIAL AND METHODS: Fourty two children with mitral valve prolapse and 32 healthy children were enrolled into the study. Twelve-lead electrocardiograms, autonomic function tests, echocardiography and 24-hour rhythm Holter tests were performed. Electrocardiograms were magnified digitally...
September 2016: Türk Pediatri Arşivi
Robert M Nevels, Samuel T Gontkovsky, Bryman E Williams
Paroxetine, also known by the trade names Aropax, Paxil, Pexeva, Seroxat, Sereupin and Brisdelle, was first marketed in the U.S. in 1992. Effective for major depression and various anxiety disorders, it quickly gained a sizable share of the antidepressant prescription market. By the late 1990s, paroxetine frequently was being associated with serious drug interactions and medication side effects. Most significantly, in a major Canadian epidemiological study examining the relationship between antidepressants and diseases, paroxetine was associated with a 620 percent increase in the rate of breast cancer in women who had taken it over a four-year period...
March 1, 2016: Psychopharmacology Bulletin
Dan M Roden, Jonathan D Mosley, Joshua C Denny
No abstract text is available yet for this article.
October 18, 2016: Journal of the American College of Cardiology
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