Assessment of QT and JT intervals in patients with left bundle branch block

Tabatabaei, Peyman; Keikhavani, Ala; Haghjoo, Majid; Fazelifar, Amirfarjam; Emkanjoo, Zahra; Zeighami, Mahbobeh; Bakhshandeh, Hooman; Ghadrdoost, Behshid; Alizadeh, Abolfath

doi:10.5812/cardiovascmed.31528

Cited by 11 publications

(13 citation statements)

References 11 publications

(19 reference statements)

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“…Alizadeh et al also reported improvement in 65% of patients with use of hand grip, and 75% with use of squatting (compared to 43% with the control treatment of increased hydration and salt consumption). While this study was not identified in our original search, it does align with the findings of our meta-analysis (88). During activities of daily living, while many patients do appear to experience relief from CPM use, the current findings are limited by a lack of control or placebo condition (55,65,67,72,89), and a small sample size (57,58,65).…”

Section: Treatment Efficacysupporting

confidence: 68%

Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis

Williams

Khan

Claydon

2022

Front. Cardiovasc. Med.

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Physical counter pressure maneuvers (CPM) are movements that are recommended to delay or prevent syncope (fainting) by recruiting the skeletal muscle pump to augment cardiovascular control. However, these recommendations are largely based on theoretical benefit, with limited data evaluating the efficacy of CPM to prevent syncope in the real-world setting. We conducted a semi-systematic literature review and meta-analysis to assess CPM efficacy, identify literature gaps, and highlight future research needs. Articles were identified through a literature search (PubMed, April 2022) of peer-reviewed publications evaluating the use of counter pressure or other lower body maneuvers to prevent syncope. Two team members independently screened records for inclusion and extracted data. From 476 unique records identified by the search, 45 met inclusion criteria. Articles considered various syncopal conditions (vasovagal = 12, orthostatic hypotension = 8, postural orthostatic tachycardia syndrome = 1, familial dysautonomia = 2, spinal cord injury = 1, blood donation = 10, healthy controls = 11). Maneuvers assessed included hand gripping, leg fidgeting, stepping, tiptoeing, marching, calf raises, postural sway, tensing (upper, lower, whole body), leg crossing, squatting, “crash” position, and bending foreword. CPM were assessed in laboratory-based studies (N = 28), the community setting (N = 4), both laboratory and community settings (N = 3), and during blood donation (N = 10). CPM improved standing systolic blood pressure (+ 14.8 ± 0.6 mmHg, p < 0.001) and heart rate (+ 1.4 ± 0.5 bpm, p = 0.006), however, responses of total peripheral resistance, stroke volume, or cerebral blood flow were not widely documented. Most patients experienced symptom improvement following CPM use (laboratory: 60 ± 4%, community: 72 ± 9%). The most prominent barrier to employing CPM in daily living was the inability to recognize an impending faint. Patterns of postural sway may also recruit the skeletal muscle pump to enhance cardiovascular control, and its potential as a discrete, proactive CPM needs further evaluation. Physical CPM were successful in improving syncopal symptoms and producing cardiovascular responses that may bolster against syncope; however, practical limitations may restrict applicability for use in daily living.

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Section: Treatment Efficacysupporting

confidence: 68%

Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis

Williams

Khan

Claydon

2022

Front. Cardiovasc. Med.

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“…Besides the suggestion to evaluate the JT interval in patients with LBBB as an alternative risk-stratification method in the presence of LBBB [1] , several formulas were developed the last years for avertable estimation of the QT interval [14] , [15] , [16] , [17] , [18] , [19] , [20] ( Table 1 ). A different approach in pacemaker recipients is the subtraction of 50 ms of the QTc LBBB as a rule of thumb.…”

Section: Assessing Qt-interval In the Presence Of Bundle-branch Blockmentioning

confidence: 99%

“…Subsequently, several additional formulas followed and were used in a similar way to the prior assessment methods. Like for the development of the Bogossian-formula in 2014, Tabatabaei et al (2016) and Wang et al (2017) used also the method of artificial LBBB during right ventricular pacing in patients who underwent electrophysiological studies [17] , [18] . Finally, Yankelson et al (2018) and Tang et al (2019) used the second assessment-method of the Bogossian-formula and analyzed patients with intermittent LBBB or with LBBB after trans -aortic valve replacement (TAVR) [19] , [20] , [22] .…”

Section: Assessing Qt-interval In the Presence Of Bundle-branch Blockmentioning

confidence: 99%

QTc evaluation in patients with bundle branch block

Bogossian

Linz

Heijman

et al. 2020

IJC Heart & Vasculature

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Proper measurement of the QT interval on the 12-lead body-surface ECG is challenging in daily practice. Even more difficult is its correct estimation in the presence of repolarization abnormalities, arrhythmias or bundle-branch blocks (BBB). The QT interval results from two parts of the ECG: (1) the QRS complex, describing the excitation of the ventricles and (2) the JT interval, describing the repolarisation of the ventricles. Prolongation of the QRS width – like in the presence of BBB – entails prolongation of the QT interval, making the estimation of the true repolarisation time challenging. The US recommendations for the standardization and interpretation of the ECG suggest focusing on the JT interval in presence of BBB. However, in clinical practice physicians have become more familiar with the interpretation of QT-interval measurements than with the interpretation of the JT Interval. In the last decade, a simple formula for the estimation of the “modified QT interval” in the presence of left or right BBB has been developed and evaluated. In this formula, the modified QT interval is calculated by subtracting 50% of the length of the BBB-QRS from the measured QT interval (QT m = QT BBB − 50% QRS BBB ). Subsequently, rate-correction formula should be applied as usual. In this review, we discuss the determination of the QT-interval in the presence of BBB and summarize the origin and application of the modified QT-interval formula.

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“… 40 Obviously, the QTc measurement does not make any sense in the presence of complete left bundle branch block and, in such a case, the use of the JTc interval is more appropriate. 20 , 21 , 41 The QRS duration, the transition QRS zone, the electrical left ventricular hypertrophy, and the frontal QRS-T angle are influenced by myocardial mass and fibrosis. Particularly, the QRS duration, a marker of intraventricular conduction, was independently related to all-cause mortality, 42 especially in patients with severe AS and low flow, low gradient and reduced ejection fraction.…”

Section: Discussionmentioning

confidence: 99%

Possible predictive role of electrical risk score on transcatheter aortic valve replacement outcomes in older patients: preliminary data

Piccirillo¹,

Moscucci²,

Mastropietri³

et al. 2018

CIA

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ObjectivesTo evaluate the predicative power of the electrical risk score (ERS), a noninvasive and inexpensive test obtained by means of a standard 12-lead electrocardiogram (ECG), in a cohort of elderly patients who had undergone transcatheter aortic valve replacement (TAVR).MethodsSurvivors and non-survivors after TAVR at 1-year follow-up were compared in respect to the pre-procedural ERS as well as a number of other clinical and instrumental variables. ERS is composed of seven simple ECG markers: heart rate (>75 bpm); QRS duration (>110 ms); left ventricular hypertrophy (Sokolow–Lyon criteria); delayed QRS transition zone (≥ V4); frontal QRS-T angle (>90°); long QTBazett (>450 ms for men and >460 in women) or JTBazett (330 ms for men and >340 ms for women); and long Tpeak to Tend interval (Tp-e) (>89 ms). The trial was registered in ClinicalTrials.gov as NCT03145376.ResultsA total of 40 patients were evaluated. During the follow-up, the all-cause mortality rate was 25% (ten patients) with 15% of cardiovascular death (six patients). The ERS was the strongest predictor of all-cause (odds ratio 3.73, 95% CI: 1.44–9.66, P<0.05) or cardiovascular (odds ratio 3.95, 95% CI: 1.09–14.27, P<0.05) mortality. Receiver operating characteristic curves showed that ERS had the widest significant sensitivity-specificity area under the curve (AUC) predicting all-cause (AUC: 0.855, P<0.05) or cardiovascular mortality (AUC: 0.908, P<0.05).ConclusionERS seems to be a useful noninvasive tool able to stratify the risk of mortality in 1-year follow-up of TAVR patients. These findings, however, require larger trials to be confirmed.

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Assessment of QT and JT intervals in patients with left bundle branch block

Cited by 11 publications

References 11 publications

Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis

Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis

QTc evaluation in patients with bundle branch block

Possible predictive role of electrical risk score on transcatheter aortic valve replacement outcomes in older patients: preliminary data

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