Comparison of Formulae for Heart Rate Correction of QT Interval in Exercise Electrocardiograms

Aytemir, Kudret; Maarouf, N.; Gallagher, Mark M.; Yap, Yee Guan; Waktare, Johan; Malík, Marek

doi:10.1111/j.1540-8159.1999.tb00635.x

Cited by 75 publications

(57 citation statements)

References 8 publications

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“…Many workers have investigated the relationship of the QT/RR relationship during exercise [4,6,[13][14][15]. As with all of these studies, we have also shown a linear relationship between the QT and RR interval, even though different mathematical models across the studies have been used.…”

Section: Figuresupporting

confidence: 54%

Lack of correlation between exercise and sibenadet‐induced changes in heart rate corrected measurement of the QT interval

Newbold¹,

Sanders

Reele

2006

Brit J Clinical Pharma

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What is already known about this subject• When this study was conducted it was already known that the 'standard' methods of correcting the QT interval for hear t rate were not optimal and that bias could result in their use in certain circumstances, in particular when drugs or conditions also induced wide fluctuations in heart rate.• The use of subject specific correction methods had been advocated and whilst these had been shown to apparently correct QT interval over usual physiological heart rates, they had not been tested under conditions where drugs could potentially increase heart rate and 'standard' correction methods gave apparent increases in QT interval. Furthermore, subject specific correction methods had usually been generated over a normal physiological heart rate range and made the assumption that the relationship remained linear outside of this usual range. What this study adds• A subject specific correction factor for QT correction can be calculated from a wide range of heart rates using exercise testing and the relationships between QT and RR are unique for a given individual.• The generation of subject specific correction factors from ECGs collected under resting conditions is not a robust method.• That subject specific correction factors derived from exercise testing are not appropriate to apply to drugs (with no evidence to suggest effects on the QT interval) that induce increases in heart rate and that the relationship between the QT and RR interval during exercise is clearly different to the QT/RR relationship of a drug that increases heart rate. AimsWe sought to investigate subject specific QT interval correction factors (SSCF) determined at rest and after exercise and to determine the validity of these factors after the administration of a probe drug known to increase hear t rate without directly affecting cardiac repolarization. MethodsThirty-two healthy volunteers underwent graded exercise, multiple recordings of electrocardiogram during rest over a day and a treatment phase administering inhaled placebo or sibenadet (a β 2 -adrenoceptor/dopamine D 2 -receptor agonist) at 250, 500 or one of 750 or 1000 µ g. SSCF were determined from linear regression of plots of log RR interval vs. log QT after exercise (QTcX), rest (QTcR), and combined data (QTcC). The SSCFs along with Bazett & Fridericia corrections were applied to the ECGs after inhalation of sibenadet. ResultsSSCFs obtained from the combination of the exercise and resting day (mean QTcC = 0.41) and exercise alone (mean QTcX = 0.40) were similar with a good fit to the data (mean r 2 = 0.92 and 0.93, respectively) while data at rest resulted in a less pronounced slope (mean QTcR = 0.27) and poorer fit (mean r 2 = 0.52). After the administration of sibenadet, none of the SSCFs, Bazett or Fridericia corrections adequately corrected QT for heart rate induced changes. ConclusionsNeither a SSCF from exercise, Bazett's or Fridericia's correction factors, adequately corrected the QT interval after the administration of a sympathomimetic agoni...

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Section: Figuresupporting

confidence: 54%

Lack of correlation between exercise and sibenadet‐induced changes in heart rate corrected measurement of the QT interval

Newbold¹,

Sanders

Reele

2006

Brit J Clinical Pharma

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“…[13][14][15] This alteration of the repolarization period could be documented in all available ECGs recorded at different time points and ages, with a QT interval always Ͻ300 ms, without significant dynamic changes during heart rate variations or on exertion. QT interval constantly Յ300 was regarded as short QT.…”

Section: Discussionmentioning

confidence: 99%

Short QT Syndrome

Gaïta¹,

Giustetto²,

Bianchi³

et al. 2003

Circulation

621

144

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Background-A prolonged QT interval is associated with a risk for life-threatening events. However, little is known about prognostic implications of the reverse-a short QT interval. Several members of 2 different families were referred for syncope, palpitations, and resuscitated cardiac arrest in the presence of a positive family history for sudden cardiac death. Autopsy did not reveal any structural heart disease. All patients had a constantly and uniformly short QT interval at ECG. Methods and Results-Six patients from both families were submitted to extensive noninvasive and invasive work-up, including serial resting ECGs, echocardiogram, cardiac MRI, exercise testing, Holter ECG, and signal-averaged ECG. Four of 6 patients underwent electrophysiological evaluation including programmed ventricular stimulation. In all subjects, a structural heart disease was excluded. At baseline ECG, all patients exhibited a QT interval Յ280 ms (QTc Յ300 ms). During electrophysiological study, short atrial and ventricular refractory periods were documented in all and increased ventricular vulnerability to fibrillation in 3 of 4 patients. Conclusions-The short QT syndrome is characterized by familial sudden death, short refractory periods, and inducible ventricular fibrillation. It is important to recognize this ECG pattern because it is related to a high risk of sudden death in young, otherwise healthy subjects.

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“…That is met using adapted derivation leads and a matched window. A refinement to a fixed window definition would be to adapt its position using the Bazett correction or any Q-T predictor [32], [33].…”

Section: Discussionmentioning

confidence: 99%

Quantifying the PR Interval Pattern During Dynamic Exercise and Recovery

Cabasson

Meste

Blain

et al. 2009

IEEE Trans. Biomed. Eng.

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Abstract-We present a novel analysis tool for time delay estimation in electrocardiographic signal processing. This tool enhances PR interval estimation (index of the atrioventricular conduction time) by limiting the distortion effect of the T wave overlapping the P wave at high heart rates. Our approach consists of modeling the T wave, canceling its influence, and finally estimating the PR intervals during exercise and recovery with the proposed generalized Woody method. Different models of the T wave are presented and compared in a statistical summary that quantitatively justifies the improvements introduced by this study. Among the different models tested, we found that a piecewise linear function significantly reduces the T wave-induced bias in the estimation process. Combining this modeling with the proposed time delay estimation method leads to accurate PR interval estimation. Using this method on real ECGs recorded during exercise and its recovery, we found: 1) that the slopes of PR interval series in the early recovery phase are dependent on the subjects' training status (average of the slopes for sedentary men = 0.11 ms/s, and for athlete men = 0.28 ms/s), and 2) an hysteresis phenomenon exists in the relation PR/RR intervals when data from exercise and recovery are compared.

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Comparison of Formulae for Heart Rate Correction of QT Interval in Exercise Electrocardiograms

Cited by 75 publications

References 8 publications

Lack of correlation between exercise and sibenadet‐induced changes in heart rate corrected measurement of the QT interval

Lack of correlation between exercise and sibenadet‐induced changes in heart rate corrected measurement of the QT interval

Short QT Syndrome

Quantifying the PR Interval Pattern During Dynamic Exercise and Recovery

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