Therefore, the best performing QT correction formula has a slope value and R2 closest to zero, indicating the least remaining influence by the RR interval. In a recent study published in the Journal of the American Heart Association, authors compared previously listed methods of QT correction and concluded that Framingham and Fridericia equations provided the best rate correction and mortality prediction. 2022 Oct 1;18(4):299-305. doi: 10.4274/ejbh.galenos.2022.2021-9-8. Applicability of a Novel Formula (Bogossian formula) for Evaluation of the QT-Interval in Heart Failure and Left Bundle Branch Block Due to Right Ventricular Pacing. In combination with the Hodge formula, the Boggosian formula delivered the best results in comparing the true QTc interval in narrow QRS with the QTmc interval in the presence of a bifascicular block. 2021 Aug 24;4(1):109-111. doi: 10.1016/j.cjco.2021.08.005. J. Keywords: 2. Please remember that this QTc calculator should NOT be considered as a substitute for any medical professional service. qtc correction for rbbb calculator - distrada.net Since the QT-interval prolongs in ventricular conduction defects, an adjustment for QRS duration becomes necessary. Remember, this calculator is not 100% reliable, and it is not a substitute for traditional methods of corrected QT interval calculation, nor electrocardiogram evaluation made by a doctor or competent professional. Application of the Bogossian formula for evaluation of the QT interval in pacemaker patients with stimulated left bundle branch block. This content does not have an Arabic version. Finally, very little is known about how the JTc in the presence of bundle branch block correlates with the QTc in the presence of a narrow QRS. New formula for evaluation of the QT interval in patients with left bundle branch block. Heart rate correction was performed using different heart rate formulas in comparison to each other. The probability for LQTS is based on the QTc-interval percentiles of controls and LQTS-patients. Based on the correction formula you wish to use the calculator will provide you the probability of LQTS for this specific patient with this specific measured QT-interval. However, when repolarization is happening longer than physiologically (as in QT prolongation), or a premature depolarization develops, the depolarization wave may reach cardiomyocytes before they can fully repolarize. Methods In patients with intrinsic QRS duration <120 ms, artificial RBBB with either left posterior (LPFB) or left anterior fascicular block (LAFB), created by left ventricular pacing maneuvers,. 2008;5:1015-1018. Epub 2017 Mar 3. How do you calculate QTc in LBBB? - Studybuff A mean QTc interval was calculated from all QTc intervals measured. Unauthorized use of these marks is strictly prohibited. 6. Therefore, it is common practice to measure the QT-interval instead of the QU-interval as a measure of the duration of cardiac repolarization. Previous formulae to determine the QT interval in LBBB showed significant HR dependency except for one proposed by Rautaharju et al. The hypothesis of the present study was to evaluate the feasibility of a simple formula for RBBB and bifascicular block correction, thereby making it easier to determine the QTc interval. Rautaharju P.M. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: endorsed by the International Society for Computerized Electrocardiology. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. 4. Framingham formula: QTC = QT + 0.154 (1 RR) Hodges formula: QTC = QT + 1.75 (heart rate 60). Would you like email updates of new search results? Background Heart rate-corrected QT interval (QTc) is the traditional method of assessing the duration of repolarization. 2009;119:e241e250. The Bogossian formula showed a significant deviation from the actual QTc interval with both the Bazett and the Fridericia formulas. qtc correction for rbbb calculator - findthatlostphone.com Front Cardiovasc Med. There are also some individuals that have QT intervals longer but dont develop serious arrhythmia while others experience moments in which their heart suddenly beats faster for no particular reason and this disruption of rhythm leads to the brain not being oxygenated properly and then fainting. This QTc calculator is designed to show the QT corrected interval for heart rate extremes because it returns the estimations by 4 different equations as presented below: QT corrected interval: by Bazett's formula: QTc = QT/ (RR in seconds) by Fridericia's formula: QTc = QT/ (RR^0.33) by Framingham's formula: QTc = QT + 0.154 (1-RR) Garca-Izquierdo E, Garca-Gmez S, Aguilera-Agudo C, De Castro-Campos D, Garca-Rodrguez D, Fajardo-Simn L, Veloza-Urrea D, Segura-Domnguez M, Jimnez-Snchez D, Castro-Urda V, Toquero-Ramos J, Fernndez-Lozano I. J Electrocardiol. It can be performed with, Bazetts formula. Ann Noninvasive Electrocardiol. Figure from the first Publication in patients with artificial LBBB. Make a donation. Corrected QT interval (QTc) Fridericia formula: QTC = QT / RR. Priori SG, BlomstrmLundqvist C, Mazzanti A, et al. Bogossian H, Frommeyer G, Ninios I, Hasan F, Nguyen QS, Karosiene Z, Mijic D, Kloppe A, Suleiman H, Bandorski D, Seyfarth M, Lemke B, Eckardt L, Zarse M. Heart Rhythm. 2017;22:e12393 10.1111/anec.12393. Bookshelf Inclusion of an HR correction factor in existing formulae blunted HR dependency but not if . Account. This site needs JavaScript to work properly. Bazetts formula looks like this: Although very popular, Bazetts formula has its limitations it is known for overcorrecting at high heart rates and undercorrecting at low heart rates. 1992;70:797801. In atrial fibrillation, the QT-interval is difficult to determine and the irregular RR-intervals/heart rate also effects the QTc-interval. Unauthorized use of these marks is strictly prohibited. What enzyme makes PRPP from ribose 5-phosphate? Formula for easy correction of QT interval in presence of LBBB and the, Figure from the first Publication in patients with artificial LBBB. Recommendations for the standardization and interpretation of the electrocardiogram: part II: electrocardiography diagnostic statement list a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society Endorsed by the International Society for Computerized Electrocardiology. 2016; 17;5(6). doi: 10.5812/cardiovascmed.31528. Prolonged QT syndrome is also indicative of an arrhythmia type and is characteristic by moments in which the heart suddenly beats faster for no particular reason. New formula for evaluation of the QT interval in patients with left bundle branch block. qtc correction for rbbb calculator. Heart Rhythm, 2014. Their account also has more than 160,000 followers. Careers. Am. Clin Cardiol, 2020; Erkapic D et al.). Author Simon W Rabkin 1 Affiliation 1 Department of Medicine, Division of Cardiology, University of British Columbia, Vancouver, Canada. Endorsed by the International Society for Computerized Electrocardiology. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part V: electrocardiogram changes associated with cardiac chamber hypertrophy: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Prolonged QT-intervals in individuals with wide QRS-complex can be associated with normal repolarization or prolonged repolarization times and can therefore be non-specific. 3. -, Wagner G.S. This therapy utilizes psychedelic , Stylish Face Masks to Check Out in Toronto, Street Style Influencers in Canada That You Should Follow on Instagram, Cherry Blossom Street Style Inspirations from High Park, Rose-Shape Candles by Toronto Sisters Sell Out After TikTok Fame, What You Need to Know About Adult Ballet Classes and Where to Attend One in Toronto. Then the heart rate (HR) is determined (HR = 1500/RR). In sinus arrhythmia, especially apparent in (young) children, the varying RR-intervals result in so much variation in the QTc-interval that the probability for an erroneous diagnosis of a prolonged QT-interval is increased. 2007;115:2613-2620. Considering the absence of included individuals from the general population in this study, the probability for LQTS given by the calculator is most relevant in a setting where your patient has a high (e.g. You can further save the PDF or print it. The .gov means its official. Muneer K, Jose B, Dubey G, T A, Cg S, Mn K. Eur J Breast Health. Corrected QT Interval (QTc) Calculate Click on "Calculate" button Long QTc: greater than 460 ms in children under the age of 15, 450 ms in men, and 470 ms in women 1. 7. Heart Rhythm. On the other hand there are people, generally healthy that have shortened QT but dont display any symptoms. Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with SunAgri and INRAE in Avignon between 2019 and 2022. QTc: how long is too long? We can diagnose QT prolongation with QTc of over 450 ms for the adult male and 470 ms for the adult female. We have many other calculators that you may want to see. The QT interval is a cardiologic term used for the time in the hearts electrical cycle between the start of the Q wave and the end of the T wave. 6. This is a relatively new discovery of the 21st century medicine and there havent been numerous cases documented. Lower heart rates also result in a longer QT interval. There are many drugs with prolongation of QT as one of their side effects. -, Kligfield P. Recommendations for the standardization and interpretation of the electrocardiogram: part I: The electrocardiogram and its technology: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: endorsed by the International Society for Computerized Electrocardiology. baptist ordination service. mechanicsburg accident yesterday; lee chamberlin cause of death; why do geordies call cigarettes tabs; tui management style; duggar couples ranked. This site needs JavaScript to work properly. The QT-interval you use to enter in the calculator should preferably be determined from the average of 3 consecutive beats. The efficacy and safety of MDMA-assisted therapy are still being explored. (Reprinted from Publication, MeSH Specify which method you used to measure the QT-interval. You can use a ruler or a caliper. The QT-interval can then be corrected for the RR-interval/heart rate with several correction formulas as shown in the QTcalculator. Developed in 2014 to minimize rate-dependent bias of QTc in the upper normal limits, the Rautaharju formula was derived from 57,595 cases of 46% males and 54% females ranging in age from 5 to 89 years (17). Hence, the data used to build the calculator provides the possibility to assess the likelihood that your individual patient has LQTS. The QT lengthens at slower heart rates; this calculatorcorrects the QT to the QT at a heart rate of 60. Moreover it returns the QT corrected interval expressed in both seconds and milliseconds. government site. Assessment of QTc and Risk of Torsades de Pointes in Ventricular Conduction Delay and Pacing: A Review of the Literature and Call to Action. 2020 Sep 19;30:100636. doi: 10.1016/j.ijcha.2020.100636. eCollection 2022. Before The normal value for QTc is: below 450ms for men and below 460ms for women as agreed upon by the ACC / HRS. Careers. Department of Medicine I, University Hospital Munich, Ludwig-Maximilians University, Munich, Germany, 4. Heart rhythm. We use Framingham corrections2 in this calculator because it has more uniform correction over a wide range of heart rate3. 3. Assessment of the QT interval in right bundle branch block Acta Cardiol. A, RBBB+LAFB ECG pattern during pacing (on the left side) and narrow QRS complexes during intrinsic rhythm (on the right side). How does alkaline phosphatase affect P-nitrophenol? QTc evaluation in patients with bundle branch block - PubMed With our QTc calculator, you will be able to perform a correction of QT interval for your patients heart rate. QTc Interval as a Guide to Select Those Patients With Congestive Heart It is discussed that there is an inheritance pattern for this anomaly and that there are higher chances for it to appear to individuals that have cases of heart disease in the family. qtc correction for rbbb calculator. Postema PG, De Jong JS, Van der Bilt IA and Wilde AA. B, RBBB+LPFB ECG pattern during pacing (on the left side) and narrow QRS complexes during intrinsic rhythm (on the right side). 2009;6:711-715. The Toronto location of the company has been selected as one of the sites for the trial study. Before However, in clinical practice physicians have become more familiar with the interpretation of QT-interval measurements than with the interpretation of the JT Interval. -, Mason J.W. Application of the Bogossian formula for evaluation of the QT - PubMed PMID: 35582918 DOI: 10.1080/00015385.2022.2066778 Keywords: MDCalc loves calculator creators researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. government site. Sagie, A., Larson, M. G., Goldberg, R. J., Bengtson, J. R., Levy, D. Rautaharju, P. M., Mason, J. W., Akiyama, T. Vandenberk B, Vandael E, Robyns T, Vandenberghe J, Garweg C, Foulon V, Ector J, Willems R. Check out 37 similar cardiovascular system calculators . qtc correction for rbbb calculator - fairplay4ncaa.com Epub 2021 Feb 13. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. What is the structural formula of ethyl p Nitrobenzoate? Genotype-Specific ECG-Based Risk Stratification Approaches in Patients With Long-QT Syndrome. qtc correction for rbbb calculator - comedoresyahualica.com 2022 Sep-Oct;74:26-31. doi: 10.1016/j.jelectrocard.2022.07.006. Clipboard, Search History, and several other advanced features are temporarily unavailable. Steps on how to print your input & results: 1. Mayo Clinic is a not-for-profit organization. As a consequence of the above-mentioned reasons, the reference values are also determined for lead II. A New Formula for Estimating the True QT Interval in Left Bundle Branch Endorsed by the International Society for Computerized Electrocardiology. After one comparison study, it was concluded that Fridericia and Framingham correction formulas have the best rate correction and significantly improved prediction while Bazetts formula overestimated QTC prolongation. To perform optimal risk stratification, this rate correction has to be reliable. 8600 Rockville Pike and transmitted securely. By using this form you agree with the storage and handling of your data by this website. Please enable it to take advantage of the complete set of features! How to handle the U-wave is shown in the figure. Factors such as medical history and the health care providers experience, knowledge, and training must also be considered. When to Use Why Use Formula Bazett Fridericia Framingham Hodges Rautaharju Heart rate/pulse beats/min Paper speed, mm/sec 25 50 QT interval In 1973, Tablot et al. Even more difficult is its correct estimation in the presence of repolarization abnormalities, arrhythmias or bundle-branch blocks (BBB). Coll Cardiol. Despite the importance of the degree of QT-interval prolongation, no standard method for its measurement and correction for heart rate (QTc-interval) has been unequivocally established. The QT interval represents the duration of ventricular electrical systole, it is measured from the beginning of the QRScomplex to the end of the Twave. Corrected QT Interval (QTc) Corrects the QT interval for heart rate extremes (choose from Bazett, Fridericia, Framingham, Hodges, or Rautaharju formulas). Close Search. sharing sensitive information, make sure youre on a federal Heart rhythm. 2022 Sep 7;9:912474. doi: 10.3389/fcvm.2022.912474. Transform the length of the QT interval from millimeters or boxes to milliseconds. Corrects the QT interval for heart rate extremes (choose from Bazett, Fridericia, Framingham, Hodges, or Rautaharju formulas). Coll. Download : Download high-res image (371KB) Download : Download full-size image; Fig. The Bogossian formula is a reliable tool for QTc interval evaluation in pacemaker patients with LBBB due to apical or non-apical RV pacing. Although the QT-interval can be assessed automatically, LQTS-experts advocate manual measurements using either the tangent or threshold method (See How to measure the QT-interval). The calculator gives you the percentile of the entered QT-interval for a control individual and for a LQTS-patient. ), Figure from the last Publication in patients with artificial RBBB. In 2 cases ofleft bundle-branch block the QTc was measured before and after the onset of left bundle . Please check if your browser is up to date! The QTc calculator is aimed at determining the corrected QT interval. Department of Clinical and Experimental Cardiology, Heart Center, Academic Medical Center, Amsterdam, The Netherlands, 2. Assessment of the QT interval in right bundle branch block Simple guide to reading and reporting an EKG step by step. 1. The QT-interval is different in different leads (as all ECG parameters are). PMC Privacy Policy. Short QTc interval: less than 340 ms is accepted as pathological. qtc correction for rbbb calculator - mitocopper.com The long QT syndrome isan uncommon condition, also put under arrhythmias and can pose a serious threat as the electrical activity of the heart is disrupted. In some situations, the results have to be corrected see our corrected calcium calculator and corrected magnesium calculator. Such an event may cause serious electrical disturbances resulting in previously mentioned tachyarrhythmias. CJC Open. This can lead to severe arrhythmias: Usually, cardiomyocytes manage to repolarize entirely before the next wave of depolarization reaches them through the heart's electrical conduction system and other cardiomyocytes. In this formula, the modified QT interval is calculated by subtracting 50% of the length of the BBB-QRS from the measured QT interval (QTm = QTBBB 50% QRSBBB). 2017 Jun;28(6):684-689. doi: 10.1111/jce.13203. With a paper speed of 25 mm/s, one small box (1 mm) lasts 0.04 s, and one big box (5 mm) 0.2 s. Genetic disorders an inherited Long QT Syndrome, for example in Romano-Ward syndrome or Jervell and Lange-Nielsen syndrome; Insufficient function of the thyroid gland hypothyroidism. Epub 2020 May 19. Fill in the calculator/tool with your values and/or your answer choices and press Calculate. 2. This tool is a statistical model and is not a substitute for an individual treatment plan developed by a health care provider with personal knowledge of a specific patient. An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study). A new formula, QT-LBBB = QT LBBB - (0.86 * QRS LBBB - 71), which takes the net increase in QRS LBBB into account, best predicted the QT interval with heart rate corrected QTc in the test set of LBBB ECGs when compared to the baseline value and prior formulae. Please use some other web browser! The QT interval is one of the most important pieces of information provided by the ECG and represents the electrical depolarization and repolarization of the ventricles. This is not considered to have to do with any underlying structural anomaly of the heart and can appear at any age. However, an overestimation of 30 ms should be included in the calculation. -, Hancock E.W. Remember that the QTinterval is measured from the beginning of the QRScomplex to the end of the Twave. To enter the value of the QT Interval, you can either directly enter its duration in milliseconds or, if you wish, enter the number of small squares it comprises. 1) Bazett HC. This often results in easily recognizable P, QRS, T and U-waves in lead II, which promotes their measurement. Accurate electrocardiographic assessment of the QT interval: teach the tangent. 2021 Sep-Oct;62(5):501-510. doi: 10.1016/j.jaclp.2021.02.003. Given that optimal QTc correction should be independent of the RR interval, the slope of the linear regression (B) and R2 should be zero. Accessibility The site is secure. Subsequently, rate-correction formula should be applied as usual. To see the QTc calculated with these formulas, click on the advanced mode button. QTc = QT + 0.154 (1-RR) An equation by M Hodges: QTc = QT + 1.75 (Heart_Rate - 60) And by Pentti M Rautaharju: QTc = QT - 185 ( (60 / Heart_Rate) - 1) + sex_coefficient The sex coefficient equals 6 ms for men and 0 ms for women. Corrects the QT interval based on its duration on ECG test and the patients heart rate. Unable to load your collection due to an error, Unable to load your delegates due to an error, Utilization of the simplified Bogossian formula for bundle branch block correction and true QT interval evaluation. An official website of the United States government. Older versions of Internet Explorer are not suppoprted! Prolongation of the QT-interval corrected for heart rate (QTc-interval) is the hallmark of the clinical diagnosis of LQTS and it mirrors a prolonged repolarization caused by mutations in genes encoding key cardiac ion channels. salvador bernal masterpiece; homes 4 sale by owner mccormick, sc 0 Home. Princess Al-Jawhara Al-Brahim Center of Excellence in Research of Hereditary Disorders, Jeddah, Kingdom of Saudi Arabia. Funk MC, Cates KW, Rajagopalan A, Lane CE, Lou J. J Acad Consult Liaison Psychiatry. Enter also the value of the heart rate to make the correction, you also have the option to enter the length of the R-Rinterval if you wish. Accessibility Estimation of the QTc interval in the presence of right bundle branch block: A comparative study using validated formulae for left bundle branch block. But as the U-wave is often suppressed by standard ECG filtering or suppressed by the P-wave at faster heart rates, it is often not well recognized on a standard 10 second ECG. Extra systoles and the beat directly following an extra systole should preferably not be included in the measurement of the QT-interval but may provide a lot of information; those patients with decreased repolarization reserve will show aberrant QT-intervals or even giant T-U waves after the sudden change in heart rate initiated by the extra systole. J. 2014;10:287-294. 7-2-1 complete right bundle-branch block (RBBB) was defined as QRS duration 120 ms in a majority of beats (of the same QRS pattern) in any of leads I . Circulation. Specify which correction formula you want to use to correct the QT-interval for heart rate. Calculates the QTc interval by entering QTinterval andHR, How not to overlook EKG changes in acute myocardial infarction, Detailed description of each of the EKG wave. The QTc calculator is based on heart rate (pulse rate) in beats per minute and QT interval, either in seconds or miliseconds. Corrected QT Interval (QTc) - MDCalc QTc interval evaluation in patients with right bundle branch block or FOIA For research purposes only; answer does NOT impact results. Samesima N, God EG, Kruse JCL, Leal MG, Pinho C, Frana FFAC, Pimenta J, Cardoso AF, Paixo A, Fonseca A, Prez-Riera AR, Ribeiro ALP, Madaloso BA, Luna Filho B, Oliveira CAR, Grupi CJ, Moreira DAR, Kaiser E, Paixo GMM, Feitosa Filho G, Pereira Filho HG, Grindler J, Aziz JL, Molina MS, Facin M, Tobias NMMO, Oliveira PA, Sanches PCR, Teixeira RA, Atanes SM, Pastore CA. Even more difficult is its correct estimation in the presence of repolarization abnormalities, arrhythmias or bundle-branch blocks (BBB). AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: endorsed by the International Society for Computerized Electrocardiology. The site is secure. Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Continuous Professional Development, Mayo Clinic School of Graduate Medical Education, Cardiovascular Diseases and Cardiac Surgery, Mayo Clinic corrected QT interval (QTc) calculator. Epub 2022 Jul 22. Epub 2017 Apr 18. Brazilian Society of Cardiology Guidelines on the Analysis and Issuance of Electrocardiographic Reports - 2022. (PDF) QTc interval evaluation in patients with right bundle branch 1. Bogossian H, Linz D, Heijman J, Bimpong-Buta NY, Bandorski D, Frommeyer G, Erkapic D, Seyfarth M, Zarse M, Crijns HJ. Disclaimer. Because of that, a correction of the QT interval for heart rate should be made. qtc correction for rbbb calculator - oilsnfoods.com The congenital long-QT syndrome (LQTS) is an inheritable cardiac arrhythmia disorder with a prevalence of about 1 per 2000 persons and is associated with sudden cardiac death due to malignant ventricular arrhythmias. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Therefore, the probability for LQTS in this patient is rather low since this specific QTc-interval calculated with Bazetts formula is seen more often in controls as compared to LQTS-patients. qtc correction for rbbb calculator - torontoverve.org This can lead to syncope, dizziness and even complicate to cardiac arrest and sudden death. The calculator will then provide you the QTc-intervals for five established correction formulas (i.e. Their rose-shaped candles, Blush Candles, are starting to get attention abroad. 2. -. QTc Calculator - MDApp 2015;36:27932867. mcdonalds garfield mugs worth 2020 The Authors. It starts at the beginning of the QRS complex (caused by the depolarization of ventricles) and ends at the end of the T wave (the repolarization of ventricles). Proper measurement of the QT interval on the 12-lead body-surface ECG is challenging in daily practice. Postema PG and Wilde AA. Based on the correction formula you wish to use the calculator will provide you the probability of LQTS for this specific patient with this specific measured QT-interval. Compared to intrinsic QTc interval, the mean QTmc interval by combination of the Bogossian and the Hodge formulas was -3 24 ms in RBBB + LPFB (P = .44) and -6 25 ms in RBBB + LAFB (P = .15). This QTc calculator is designed to show the QT corrected interval for heart rate extremes because it returns the estimations by 4 different equations as presented below: byBazetts formula: QTc = QT/(RR in seconds), by Fridericias formula: QTc = QT/(RR^0.33), by Framinghams formula: QTc = QT + 0.154(1-RR), by Hodgess formula: QTc = QT + 1.75(HR - 60). We also explain what a regular QT interval is, the risks of QT prolongation, and which QT-prolonging drugs you should avoid in treating patients with a prolonged QT interval.