Corrected QT interval (QTc) prolongation and syncope associated with pseudohypoparathyroidism and hypocalcemia

2000 ◽  
Vol 136 (3) ◽  
pp. 404-407 ◽  
Author(s):  
Ta Cheng Huang ◽  
Frank C. Cecchin ◽  
Patrick Mahoney ◽  
Michael A. Portman
Keyword(s):  
Qt Interval ◽  
Qtc Prolongation ◽  
Corrected Qt Interval

Corrected QT Interval Is Related to Markers of Hemolysis and Tricuspid Regurgitant Jet Velocity in a Young Cohort with Sickle Cell Disease.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2258-2258
Author(s):  
Robert I. Liem ◽  
Luciana T. Young ◽  
Alexis A. Thompson
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Qt Interval ◽  
Acute Chest Syndrome ◽  
Cell Disease ◽  
Qtc Prolongation ◽  
Corrected Qt Interval ◽  
Conduction Abnormalities ◽  
History Of ◽  
Tricuspid Regurgitant Jet Velocity

Abstract Recent evidence suggests that prolongation in QT interval may be a frequent finding in patients with sickle cell disease (SCD). Few studies, however, have examined the relationship between conduction abnormalities and other cardiac complications, such as left ventricular hypertrophy (LVH) and tricuspid regurgitant jet velocity (TRJV) elevation, in this population. Moreover, long QT may be a marker of increased mortality in conditions, other than SCD, associated with LVH. We therefore sought to evaluate QT interval and its relationship to echocardiographic findings, laboratory parameters and disease severity in a cohort of children and young adults with SCD. Methods We prospectively evaluated the corrected QT interval (QTc) on standard 12-lead ECG in a cross-sectional, convenience sample of 73 subjects (41 males, mean age 14.2±3 years, range 10 to 24) with Hb SS, SC and S-β0 thalassemia undergoing screening for TRJV elevation. Subjects on chronic transfusions were excluded and all studies were performed at baseline on the same day. A review of available medical records was also performed. Results In our cohort, QTc (mean 436±24 ms, range 387 to 531) was prolonged > 440 ms in 30/73 (41%) of subjects at steady state. We also found TRJV elevation ≥ 2.5 m/s in 24/73 (33%) and LVH by ECG or echocardiographic criteria in 32/73 (44%) subjects. Using Pearson’s correlation coefficient, we observed significant correlations between QTc and TRJV (r=0.38, p=0.002), WBC (r=0.37, p=0.001) and several markers of hemolysis, including LDH (r=0.46, p=0001), Hb (r=-0.32, p=0.005), retic (r=0.29, p=0.013), plasma Hb (r=0.27, p=0.03) and AST (r=0.38, p=0.001). Using Student’s t-test for independent samples, only TRJV (2.55±0.33 vs. 2.34±0.26 m/s, p=0.006), LDH (450±166 vs. 329±143 U/L, p=0.001), WBC (10.6±4.7 vs. 8.6±3.3×109/L, p=0.048), retic (14.4±9.2 vs. 10.6±6.1%, p=0.039) and AST (50±22 vs. 38±15 U/L, p=0.009) were significantly higher and Hb (9.1±1.3 vs. 9.9±1.7 g/dL, p=0.04) lower in subjects with QTc > 440 ms compared to those with QTc ≤ 440 ms. We found no significant relationship between QTc and age, LV mass, platelet count or fetal Hb. By χ2 analysis, a larger proportion of subjects with QTc > 440 ms also had a history of acute chest syndrome (p=0.007), gallstones (p=0.047), exchange transfusion (p=0.04) and to a less significant degree, TRJV elevation (p=0.112). Prolonged QTc was not affected by sex, hydroxyurea use or a history of LVH, frequent pain, asthma, splenectomy, priapism and tonsilloadenoidectomy. Given sample size limitations and data reduction methods, we found by logistic regression analysis that the combination of TRJV and history of acute chest syndrome best predicted QTc prolongation, correctly identifying 80% of cases and resulting in positive and negative predictive values of 76% and 81%, respectively. Conclusions We conclude that QTc prolongation is common in a prospectively screened cohort of young sickle cell patients at baseline and is associated with evidence of hemolysis and to a lesser degree, TRJV elevation. Our results contrast with findings in other conditions that link QTc prolongation primarily to LVH. Future studies will be critical to further define QTc variability, pathophysiologic determinants as well as the clinical consequences of conduction abnormalities, which may or may not relate to TRJV elevation, in the sickle cell population.

scholarly journals Artificial Intelligence-Enabled Assessment of the Heart Rate Corrected QT Interval Using a Mobile Electrocardiogram Device

Circulation ◽  
2021 ◽  
Author(s):  
John R. Giudicessi ◽  
Matthew Schram ◽  
J. Martijn Bos ◽  
Connor D. Galloway ◽  
Jacqueline B. Shreibati ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Heart Rate ◽  
Qt Interval ◽  
Effective Means ◽  
Area Under The Curve ◽  
Cost Effective ◽  
Qtc Prolongation ◽  
Corrected Qt Interval ◽  
The Difference ◽  
Congenital Lqts

Background: Heart rate-corrected QT interval (QTc) prolongation, whether secondary to drugs, genetics including congenital long QT syndrome (LQTS), and/or systemic diseases including SARS-CoV-2-mediated COVID19, can predispose to ventricular arrhythmias and sudden cardiac death. Currently, QTc assessment and monitoring relies largely on 12-lead electrocardiography. As such, we sought to train and validate an artificial intelligence (AI)-enabled 12-lead electrocardiogram (ECG) algorithm to determine the QTc, and then prospectively test this algorithm on tracings acquired from a mobile ECG (mECG) device in a population enriched for repolarization abnormalities. Methods: Using over 1.6 million 12-lead ECGs from 538,200 patients, a deep neural network (DNN) was derived (n = 250,767 patients for training and n = 107,920 patients for testing) and validated (n = 179,513 patients) to predict the QTc using cardiologist over-read QTc values as the gold standard. The ability of this DNN to detect clinically-relevant QTc prolongation (e.g. QTc ≥ 500 ms) was then tested prospectively on 686 genetic heart disease (GHD) patients (50% with LQTS) with QTc values obtained from both a 12-lead ECG and a prototype mECG device equivalent to the commercially-available AliveCor KardiaMobile 6L. Results: In the validation sample, strong agreement was observed between human over-read and DNN-predicted QTc values (-1.76 ± 23.14 ms). Similarly, within the prospective, GHD-enriched dataset, the difference between DNN-predicted QTc values derived from mECG tracings and those annotated from 12-lead ECGs by a QT expert (-0.45 ± 24.73 ms) and a commercial core ECG laboratory [+10.52 ms ± 25.64 ms] was nominal. When applied to mECG tracings, the DNN's ability to detect a QTc value ≥ 500 ms yielded an area under the curve, sensitivity, and specificity of 0.97, 80.0%, and 94.4%, respectively. Conclusions: Using smartphone-enabled electrodes, an AI-DNN can predict accurately the QTc of a standard 12-lead ECG. QTc estimation from an AI-enabled mECG device may provide a cost-effective means of screening for both acquired and congenital LQTS in a variety of clinical settings where standard 12-lead electrocardiography is not accessible or cost-effective.

Torsades-de-Pointes associated with Taku-Tsubo cardiomyopathy following greatly reduced oxycodone use in an elderly woman

2018 ◽  
Vol 7 (2) ◽  
pp. 155-159 ◽  
Author(s):  
Harry W. Daniell, MD
Keyword(s):  
Qt Interval ◽  
Elderly Woman ◽  
Torsades De Pointes ◽  
Gene Activity ◽  
Related Gene ◽  
Qtc Prolongation ◽  
Standard Measurement ◽  
Corrected Qt Interval ◽  
Elderly Female

This article reports an elderly female oxycodone consumer who developed Torsades-de-Pointes soon after her opioid-associated rate-corrected QT interval (QTC; a standard measurement on electrocardiograms) prolongation had been augmented by the development of Taku-Tsubo cardiomyopathy (TC), a sequence that followed greatly reduced oxycodone ingestion. Factors that likely contributed to this sequence are discussed, including direct opioid-induced inhibition of human ether-a-go-go-related gene activity and of androgen formation plus QTc prolongation induced by the presence of TC.

scholarly journals P037: The impact of fever on corrected QT interval in a general emergency department population

CJEM ◽  
2016 ◽  
Vol 18 (S1) ◽  
pp. S90-S91
Author(s):  
D. Drew ◽  
A. Baranchuk ◽  
R.J. Brison
Keyword(s):  
Emergency Department ◽  
Qt Interval ◽  
Chart Review ◽  
Torsades De Pointes ◽  
Community Acquired Pneumonia ◽  
Qtc Prolongation ◽  
Corrected Qt Interval ◽  
Single Center Study ◽  
Electronic Chart ◽  
The Impact

Introduction: Fever is one of the most common reasons for presentation to the emergency department (ED). Interestingly, a number of small studies suggest that fever may function as a modulator of the QT interval in healthy individuals and an arrhythmogenic trigger in patients with occult congenital QT abnormalities. The objective of this study was to explore whether presence of fever adversely affects the QT interval, and whether medications known to prolong this interval affect any association found. Methods: We performed a retrospective, single center study identifying patients (age > 18 years) presenting to the ED with fever (temperature > 38.0 °C) between January 1st, 2012 and December 31st, 2013 via electronic chart review. The subset for analysis were those who had an ECG both at time of fever and while afebrile (within 30 days of initial ECG). Temperature measurement was within 30 minutes of ECG. Actively paced patients were excluded. Univariate and multiple regression analysis were used to determine risk factors for QT derangement in patients with fever. Results: 2018 febrile visits occurred during the reviewed period, 181 of these patients went on to be included in the study. 54.1% of study subjects were female, and the average age was 68.9 years old. The etiology of fever was predominately infectious (69.6%), with community acquired pneumonia being the most frequent cause (24.3%). We found the median corrected QT interval to be significantly shorter in febrile as compared to afebrile patients [QTc = 388.7ms, (371.5-407.5) vs 406.7, (386.7-434.4); p < 0.001]. This difference was observed in both sexes. Males were found to be more likely to experience medication induced QTc prolongation [OR 5.35, 95% CI = 1.46 - 19.68; P < 0.05]. Two instances of Torsades de pointes were identified in our study, both occurring in males on QT prolonging medications. Conclusion: In an ED patient population, fever generally shortens the QT interval independent of sex. Prolongation of the QT interval during fever should thus increase clinical suspicion of congenital or acquired QT disorders. Additionally, males appear to be more susceptible to medication-induced derangements in the QT interval and may require more vigilant monitoring when treated with multiple QT prolonging medications.

Corrected QT interval prolongation in anthracycline-treated survivors of childhood cancer.

1993 ◽  
Vol 11 (10) ◽  
pp. 1906-1910 ◽  
Author(s):  
C L Schwartz ◽  
W L Hobbie ◽  
S Truesdell ◽  
L C Constine ◽  
E B Clark
Keyword(s):  
Childhood Cancer ◽  
Qt Interval ◽  
Myocardial Damage ◽  
Qtc Prolongation ◽  
Corrected Qt Interval ◽  
Cardiac Decompensation ◽  
Qt Interval Prolongation ◽  
Increased Risk ◽  
Primary Caretakers ◽  
Survivors Of Childhood Cancer

PURPOSE Comprehensive cardiac evaluations are currently recommended for all anthracycline-treated patients to detect subclinical cardiac failure. A screening test is needed that would easily and inexpensively identify patients who are at risk for late cardiac decompensation. METHODS We routinely reviewed the ECG and echocardiogram (ECHO) results of 52 of 56 anthracycline-treated long-term survivors of childhood cancer who had received > or = 100 mg/m2 of ANTH (ANTH = 1 mg/m2 of doxorubicin), and who were not in clinical heart failure. Exercise testing was performed in eight patients with a corrected QT interval (QTc) of > or = 0.43. RESULTS Zero of 15 patients (without chest radiation) who received less than 300 mg/m2 of ANTH versus six of 22 who received > or = 300 mg/m2 of ANTH had a QTc > or = 0.43 (P = .03). Three of 15 patients (with chest radiation) who received less than 300 mg/m2 of ANTH versus 12 of 22 who received > or = 300 mg/m2 of ANTH had a QTc > or = 0.43 (P = .03). For all patients (including those with chest radiotherapy), zero of 19 who received less than 300 mg/m2 of ANTH versus eight of 33 who received > or = 300 mg/m2 of ANTH had a QTc of > or = 0.45 (P = .025). Three of 19 who received less than 300 mg/m2 of ANTH versus 19 of 33 who received > or = 300 mg/m2 of ANTH had a QTc of > or = 0.43 (P = .003). One patient had decreased fractional shortening (FS) and QTc prolongation. Cardiac decompensation (with a FS of 24%) occurred with propranolol in a patient with previously normal FS but prolonged QTc. With exercise, the QTc became further prolonged in all four patients with a QTc of 0.44 to 0.46 and in two of four patients with a QTc of 0.43. CONCLUSION Prolongation of the QTc, a measure of myocardial repolarization, may reflect injury to myocardial cells. QTc prolongation may be predictive of an increased risk of late cardiac decompensation. If the utility of the QTc measure is confirmed, screening for evidence of myocardial damage can be easily and inexpensively performed by oncologists and primary caretakers.

scholarly journals Can indicators of myocardial damage predict carbon monoxide poisoning outcomes?

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hitoshi Koga ◽  
Hideki Tashiro ◽  
Kouta Mukasa ◽  
Tomohiro Inoue ◽  
Aya Okamoto ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Qt Interval ◽  
Troponin I ◽  
Morphological Changes ◽  
Carbon Monoxide Poisoning ◽  
Myocardial Damage ◽  
Qt Dispersion ◽  
Ecg Changes ◽  
Corrected Qt Interval ◽  
Logistic Analysis

Abstract Background Carbon monoxide causes electrical, functional, and morphological changes in the heart. It is unclear, however, whether the indicators of myocardial damage can predict the patient’s prognosis after carbon monoxide poisoning. This retrospective study aimed to investigate the relationship between the carboxyhemoglobin level and electrocardiographic (ECG) changes and whether the ECG changes and troponin I levels are related to the patient’s prognosis after carbon monoxide poisoning. Methods Carboxyhemoglobin, troponin I, and ECG parameters were measured in 70 patients with carbon monoxide poisoning. The QT and RR intervals were measured for each ECG lead in all patients, and the corrected QT interval and corrected QT dispersion were calculated. Results The correlation between the maximum corrected QT interval and the carboxyhemoglobin level was significant (P = 0.0072, R2 = 0.1017), as were the relationships between QT dispersion and carboxyhemoglobin (P < 0.001, R2 = 0.2358) and the corrected QT dispersion and carboxyhemoglobin (P < 0.001, R2 = 0.2613). The multivariate logistic analysis showed that the significant predictors of sequential disability were corrected QT dispersion (P = 0.0042), and troponin I level (P = 0.0021). Conclusions Patients’ prognosis following carbon monoxide poisoning can be predicted based on corrected QT dispersion and the troponin I level. Patients with myocardial damage should be monitored not only for their cardiovascular outcome but also for their neurological outcome and their prognosis.

Electrocardiographic characteristics and associated outcomes in patients with Takotsubo syndrome. Insights from the RETAKO registry

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I Martin-Demiguel ◽  
I Nunez-Gil ◽  
A Perez-Castellanos ◽  
O Vedia ◽  
A Uribarri ◽  
...  
Keyword(s):  
Heart Rate ◽  
Primary Endpoint ◽  
Qt Interval ◽  
Protective Factor ◽  
Independent Predictor ◽  
Prognostic Significance ◽  
Takotsubo Syndrome ◽  
St Segment Elevation ◽  
Corrected Qt Interval ◽  
St Segment

Abstract Background Our aim was to describe the prevalence and prognostic significance of electrocardiographic features in patients with Takotsubo syndrome (TTS). Methods Our data come from the Spanish Multicenter REgistry of TAKOtsubo syndrome (RETAKO). All patients with complete electrocardiogram were included. Results 246 patients were studied, mean age was 71.3±11.5 and 215 (87.4%) were women. ST-segment elevation was seen in 143 patients (59.1%) and was present in ≥2 wall leads in 97 (39.8%). Exclusive elevation in inferior leads was infrequent (5 - 2.0%). After 48 hours, 198 patients (88.0%) developed negative T-waves in a median of 8 leads with a mean amplitude of 0.7±0.5 mV. Mean corrected QT interval was 520±72 ms and it was independently associated with the primary endpoint of all-cause death and nonfatal cardiovascular events (p=0.002) and all-cause death (p=0.008). A higher heart rate at admission was also an independent predictor of the primary endpoint (p=0.001) and of developing acute pulmonary edema (p=0.04). ST-segment elevation with reciprocal depression was an independent predictor of all-cause death (p=0.04). Absence of ST-segment deviation was a protective factor (p=0.005) for the primary endpoint. Arrhythmias were independently associated with cardiogenic shock (p&lt;0.001). Conclusion Prolonged corrected QT interval, arrhythmia, heart rate at admission and broader repolarization alterations are associated with a poor outcome in TTS. Typical ECG at admission and after 48h. Funding Acknowledgement Type of funding source: None

The rate-corrected QT interval calculated from 24-hour Holter recordings may serve as a significant arrhythmia risk stratifier in heart failure patients

2011 ◽  
Vol 147 (2) ◽  
pp. 321-323 ◽  
Author(s):  
Petros Arsenos ◽  
Konstantinos A. Gatzoulis ◽  
Polychronis Dilaveris ◽  
Theodoros Gialernios ◽  
Skevos Sideris ◽  
...  
Keyword(s):  
Heart Failure ◽  
Qt Interval ◽  
Heart Failure Patients ◽  
Corrected Qt Interval ◽  
Holter Recordings
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