Evaluation of Five QT Correction Formulas Using a Software-Assisted Method of Continuous QT Measurement from 24-Hour Holter Recordings

Molnár, J.; Weiss, Jerry; Zhang, Feng; Rosenthal, James E.

doi:10.1016/s0002-9149(96)00468-7

Cited by 76 publications

(53 citation statements)

References 27 publications

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“…To evaluate and compare QTc formulae in 21 healthy subjects, MOLNAR et al [26] used 24-h Holter monitoring, as it allows the assessment of QT intervals over a large range of rates. QT-RR relationships for individuals and the group were fitted by regression analysis to five QT prediction formulas: simple Bazett's, modified Bazett's, linear (Framingham), modified Fridericia's and exponential (Sarma's).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

QT interval dispersion in obstructive sleep apnoea syndrome patients without hypertension

Dursunoğlu

Dursunoğlu²,

Evrengül³

et al. 2005

Eur Respir J

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QT interval dispersion (QTd) reflects inhomogeneity of repolarisation. Delayed cardiac repolarisation leading to the prolongation of the QT interval is a well-characterised precursor of arrhythmias. Obstructive sleep apnoea syndrome (OSAS) can cause cardiovascular complications, such as arrhythmias, myocardial infarction, and systemic and pulmonary hypertension. The aim of this study was to assess QTd in OSAS patients without hypertension.A total of 49 subjects without hypertension, diabetes mellitus, any cardiac or pulmonary diseases, or any hormonal, hepatic, renal or electrolyte disorders were referred for evaluation of OSAS. An overnight polysomnography and a standard 12-lead ECG were performed in each subject. According to the apnoea-hypopnoea index (AHI), subjects were divided into control subjects (AHI ,5, n520) and moderate-severe OSAS patients (AHI o15, n529). QTd (defined as the difference between the maximum and minimum QT interval) and QT-corrected interval dispersion (QTcd) were calculated using Bazzet's formula.In conclusion, the QTcd was significantly higher in OSAS patients (56.1¡9.3 ms) than in controls (36.3¡4.5 ms). A strong positive correlation was shown between QTcd and AHI. In addition, a significantly positive correlation was shown between QTcd and the desaturation index (DI). The AHI and DI were significantly related to QTcd as an independent variable using stepwise regression analysis.The QT-corrected interval dispersion is increased in obstructive sleep apnoea syndrome patients without hypertension, and it may reflect obstructive sleep apnoea syndrome severity.

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Section: Discussionmentioning

confidence: 99%

“…For comparison with other studies, the QT interval was corrected for heart rate. It is well known that Bazett's formula is inaccurate at higher heart rates [26]. It overcorrects at faster heart rates and undercorrects at lower heart rates.…”

Section: Study Limitationmentioning

confidence: 99%

QT interval dispersion in obstructive sleep apnoea syndrome patients without hypertension

Dursunoğlu

Dursunoğlu²,

Evrengül³

et al. 2005

Eur Respir J

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show abstract

“…A number of correction methods exists that attempt to normalize QT intervals to an RR interval of 1000 ms, corresponding to a heart rate of 60 beats per minute. [52][53][54][55] While ECG measurements directly evaluate the effect of a particular test compound on the QT interval, they may not be the best choice to evaluate the potential off-target activity of a class of compounds on hERG channels since other factors may affect the QT interval and either obscure an effect on I Kr or complicate the interpretation of the results. 56 …”

Section: Evaluation Of Cardiac Riskmentioning

confidence: 99%

Role of hERG potassium channel assays in drug development

Priest¹,

Bell²,

García³

2008

Channels

118

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“…The QT intervals obtained were modified according to heart rate using Bazett's formula (QTc = QT/RR 1/2 ). 16,17) QT dispersion (QTd) was found by subtracting the shortest QT interval from the longest QT interval calculated on the 12-lead ECG (QTd = QT max -QT min ). Corrected QTd (QTdc) was obtained by subtracting the minimum QTc from the maximum QTc (QTdc = QTc max -QTc min ).…”

Section: Vol 44 Nomentioning

confidence: 99%

“…Corrected QTd (QTdc) was obtained by subtracting the minimum QTc from the maximum QTc (QTdc = QTc max -QTc min ). 16,17) Echocardiographic investigations: Echocardiographic investigations were conducted before the conventional treatment, after standardization of that treatment (values obtained after the conventional treatment were regarded as baseline data), and at the end of the 12-week period during which the spironolactone-metoprolol treatment was continued. Echocardiographic studies were conducted using an Acuson Sequa 515 (Minnesota, USA) from the standard angle and windows.…”

Section: Vol 44 Nomentioning

confidence: 99%

Effects of Spironolactone and Metoprolol on QT Dispersion in Heart Failere

et al. 2003

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SUMMARYThe effects of spironolactone or metoprolol added to a conventional treatment protocol on QT dispersion, which is accepted as a sudden cardiac death predictor, were evaluated in heart failure patients.?A total of 105 New York Heart Association class III patients were included in this study. The conventional treatment protocol was standardized by giving ramipril, furosemide, and digoxin to all patients for 3 weeks at the same doses. At the end of this period, the patients were divided into three groups. Conventional treatment was continued in group 1, 25 mg spironolactone was added in group 2, and 12.5 mg metoprolol was added in group 3. Patients were followed for 12 weeks and clinical and laboratory tests were conducted at 3 week intervals.No significant change in corrected QT dispersion was observed in group1 at the end of 12 weeks (corrected QT dispersion: 80 ± 2 msc to 79 ± 2 msc, P: 0.22). However, corrected QT dispersion in group 2 was reduced by 32.5% (83 ± 2 msc to 56 ± 1 msc; P: 0.01). A 32.9% reduction in corrected QT dispersion (79 ± 2 msc to 53 ± 2 msc; P: 0.01) was observed in group 3.In conclusion, the addition of spironolactone or metoprolol to a conventional treatment in heart failure patients resulted in improved clinical conditions and the significant decrease in sudden death predictors corrected QT dispersion. The effects of spironolactone and metoprolol on corrected QT dispersion were similar. (Jpn Heart J 2003; 44: 681-692)

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Evaluation of Five QT Correction Formulas Using a Software-Assisted Method of Continuous QT Measurement from 24-Hour Holter Recordings

Cited by 76 publications

References 27 publications

QT interval dispersion in obstructive sleep apnoea syndrome patients without hypertension

QT interval dispersion in obstructive sleep apnoea syndrome patients without hypertension

Role of hERG potassium channel assays in drug development

Effects of Spironolactone and Metoprolol on QT Dispersion in Heart Failere

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