Estimation of the second ventilatory threshold through ventricular repolarization profile analysis

Milagro, Javier; Hernández-Vicente, Adrián; Hernando, David; Garatachea, Nuria; Bailón, Raquel; Pueyo, Esther

doi:10.1111/sms.13849

Cited by 6 publications

(14 citation statements)

References 38 publications

(58 reference statements)

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“…It is thus valid and reproducible in both athletes who are only able to perform exercise until lower maximal workloads and in athletes capable to continue exercise tests up to very high maximum workloads. This determination of AT is similar to results previously published by Milagro et al who also found changes in the profile of ventricular repolarization instability as well as of oscillations in the low frequency spectrum once reaching the anaerobic threshold [ 21 ]. It is noteworthy that these changes in repolarization instability cannot be provoked by increased heart rate or by fixed atrial pacing [ 11 , 15 ].…”

Section: Discussionsupporting

confidence: 90%

“…The change in autonomic cardiac modulation during increasing workload subsequently results in altered HRV-derived parameters and this has been used to assess AT in athletes [ 24 , 25 ]. Our present study, studies assessing AT via HRV-derived parameters [ 24 , 25 ] and previous studies investigating the connection of changes in repolarization instability and AT [ 15 , 21 ] thus suggest that the autonomic control of the electrical activity of the myocardium, especially on the level of the ventricular myocardium seems to change once reaching the anaerobic threshold.…”

Section: Discussionsupporting

confidence: 73%

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Estimation of anaerobic threshold by cardiac repolarization instability: a prospective validation study

Schüttler

Krammer

Stülpnagel

et al. 2021

BMC Sports Sci Med Rehabil

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Background Assessing lactate (LT) or anaerobic thresholds (AT) in athletes is an important tool to control training intensities and to estimate individual performance levels. Previously we demonstrated that ECG-based assessment of cardiac repolarization instability during exercise testing allows non-invasive estimation of AT in recreational athletes. Here, we validate this method in professional and amateur team sports athletes. Methods We included 65 team sports athletes (32 professionals and 33 amateur athletes; 51 men, 14 women, mean age 22.3 ± 5.2 years) undergoing a standardized incremental cycle exercise test. During exercise testing a high-resolution ECG (1000 Hz) was recorded in Frank-leads configuration and beat-to-beat vector changes of cardiac repolarization (dT°) were assessed by previously established technologies. Repolarization-based AT (ATdT°) was estimated by its typical dT°-signal pattern. Additionally, LT was detected in accordance to methods established by Mader (LTMader) and Dickhuth (LTDickhuth). Results All athletes performed exercise testing until exhaustion with a mean maximum workload of 262.3 ± 60.8 W (241.8 ± 64.4 W for amateur athletes and 283.4 ± 49.5 W for professional athletes). Athletes showed ATdT° at 187.6 ± 44.4 W, LTDickhuth at 181.1 ± 45.6 W and LTMader at 184.3 ± 52.4 W. ATdT° correlated highly significantly with LTDickhuth (r = 0.96, p < 0.001) and LTMader (r = 0.98, p < 0.001) in the entire cohort of athletes as well as in the subgroups of professional and amateur athletes (p < 0.001 for all). Conclusions ATdT°, defined by the maximal discordance between dT° and heart rate, can be assessed reliably and non-invasively via the use of a high-resolution ECG in professional and amateur athletes.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionsupporting

confidence: 73%

Estimation of anaerobic threshold by cardiac repolarization instability: a prospective validation study

Schüttler

Krammer

Stülpnagel

et al. 2021

BMC Sports Sci Med Rehabil

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“…To the best of our knowledge, this study is the first one using time-frequency methods to evaluate the frequency components of dTV and RRV during rest, exercise and recovery. The results of our ECG analysis corroborate that dT oscillations are mainly contained in the LF band and their magnitude is enhanced in response to exercise-induced sympathetic stimulation [ 10 , 16 , 18 ]. These results agree well with previous reports showing enhancement of PRD, which represents the same concept as P dTV , subsequent to tilt table test and to mild exercise as well as decrease following β-adrenergic blockade [ 10 ].…”

Section: Discussionsupporting

confidence: 79%

“…Moreover, PRD has been confirmed not to be an epiphenomenon of HR and HRV, as substantiated by the fact that fixed atrial pacing exerts modest effects on PRD despite fully abolishing HRV and despite varying HR at fixed values in a large range [ 10 , 18 ]. This has been later supported by studies using an incremental exercise test, which have described low correlation between PRD and HR or HRV [ 16 ]. Nevertheless, there is yet limited information on how PRD varies continuously with time so that a full characterization of its temporal profile following physiological sympathoexcitatory interventions can be established.…”

Section: Introductionmentioning

confidence: 80%

“…The importance of LF oscillations in providing information potentially related to sympathetic neural activity has been described through different markers obtained from the T-wave vector, sympathetic nerve activity recordings, HRV, action potentials or systolic arterial blood pressure [ 9 ]. Specifically regarding PRD, clinical and experimental studies have so far provided evidence that it is enhanced by sympathetic activation, induced by either tilt table test or exercise, and suppressed by pharmacological β-adrenergic blockade [ 10 , 16 ]. PRD has been verified to occur independently of respiratory activity in volume-controlled ventilated swine [ 10 ] and in humans when comparing respiratory rates of 10 and 20/min with constant minute ventilation [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

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ECG Ventricular Repolarization Dynamics during Exercise: Temporal Profile, Relation to Heart Rate Variability and Effects of Age and Physical Health

Hernández-Vicente

Hernando

Vicente-Rodríguez

et al. 2021

IJERPH

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Periodic repolarization dynamics (PRD) is a novel electrocardiographic marker of cardiac repolarization instability with powerful risk stratification capacity for total mortality and sudden cardiac death. Here, we use a time-frequency analysis approach to continuously quantify PRD at rest and during exercise, assess its dependence on heart rate variability (HRV) and characterize the effects of age (young adults/middle-aged adults/older adults), body mass index (non-overweight/overweight) and cardiorespiratory fitness level (fit/unfit). Sixty-six male volunteers performed an exercise test. RR and dT variabilities (RRV, dTV), as well as the fraction of dT variability unrelated to RR variability, were computed based on time-frequency representations. The instantaneous LF power of dT (PdTV), representing the same concept as PRD, and of its RRV-unrelated component (PdTVuRRV) were quantified. dT angle was found to mostly oscillate in the LF band. Overall, 50–70% of PdTV was linearly unrelated to RRV. The onset of exercise caused a sudden increase in PdTV and PdTVuRRV, which returned to pre-exercise levels during recovery. Clustering analysis identified a group of overweight and unfit individuals with significantly higher PdTV and PdTVuRRV values at rest than the rest of the population. Our findings shed new light on the temporal profile of PRD during exercise, its relationship to HRV and the differences in PRD between subjects according to phenotypic characteristics.

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Periodic repolarization dynamics as predictor of risk for sudden cardiac death in chronic heart failure patients

Palacios

Cygankiewicz

Luna

et al. 2021

Sci Rep

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The two most common modes of death among chronic heart failure (CHF) patients are sudden cardiac death (SCD) and pump failure death (PFD). Periodic repolarization dynamics (PRD) quantifies low-frequency oscillations in the T wave vector of the electrocardiogram (ECG) and has been postulated to reflect sympathetic modulation of ventricular repolarization. This study aims to evaluate the prognostic value of PRD to predict SCD and PFD in a population of CHF patients. 20-min high-resolution (1000 Hz) ECG recordings from 569 CHF patients were analyzed. Patients were divided into two groups, $$\hbox {PRD}^+$$ PRD + and $$\hbox {PRD}^-$$ PRD - , corresponding to PRD values above and below the optimum cutoff point of PRD in the study population. Univariate Cox regression analysis showed that SCD risk in the $$\hbox {PRD}^+$$ PRD + group was double the risk in the $$\hbox {PRD}^-$$ PRD - group [hazard ratio (95% CI) 2.001 (1.127–3.554), $$\hbox {p}<0.05$$ p < 0.05 ]. The combination of PRD with other Holter-based ECG indices, such as turbulence slope (TS) and index of average alternans (IAA), improved SCD prediction by identifying groups of patients at high SCD risk. PFD could be predicted by PRD only when combined with TS [hazard ratio 2.758 (1.572–4.838), $$\hbox {p}<0.001$$ p < 0.001 ]. In conclusion, the combination of PRD with IAA and TS can be used to stratify the risk for SCD and PFD, respectively, in CHF patients.

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Estimation of the second ventilatory threshold through ventricular repolarization profile analysis

Cited by 6 publications

References 38 publications

Estimation of anaerobic threshold by cardiac repolarization instability: a prospective validation study

Estimation of anaerobic threshold by cardiac repolarization instability: a prospective validation study

ECG Ventricular Repolarization Dynamics during Exercise: Temporal Profile, Relation to Heart Rate Variability and Effects of Age and Physical Health

Periodic repolarization dynamics as predictor of risk for sudden cardiac death in chronic heart failure patients

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