Fractal scaling properties of heart rate dynamics and myocardial efficiency in dilated cardiomyopathy

Heart rate variability (HRV) has been conventionally analysed with time- and frequency-domain methods, which measure the overall magnitude of RR interval fluctuations around its mean value or the magnitude of fluctuations in some predetermined frequencies. Analysis of heart rate dynamics by novel methods, such as heart rate turbulence after ventricular premature beats, deceleration capacity of heart rate and methods based on chaos theory and nonlinear system theory, have gained recent interest. Recent observational studies have suggested that some indices describing nonlinear heart rate dynamics, such as fractal scaling exponents, heart rate turbulence and deceleration capacity, may provide useful prognostic information in various clinical settings and their reproducibility may be better than that of traditional indices. For example, the short-term fractal scaling exponent measured by the detrended fluctuation analysis method has been shown to predict fatal cardiovascular events in various populations. Similarly, heart rate turbulence and deceleration capacity have performed better than traditional HRV measures in predicting mortality in post-infarction patients. Approximate entropy, a nonlinear index of heart rate dynamics, which describes the complexity of RR interval behaviour, has provided information on the vulnerability to atrial fibrillation. There are many other nonlinear indices which also give information on the characteristics of heart rate dynamics, but their clinical usefulness is not as well established. Although the concepts of nonlinear dynamics, fractal mathematics and complexity measures of heart rate behaviour, heart rate turbulence, deceleration capacity in relation to cardiovascular physiology or various cardiovascular events are still far away from clinical medicine, they are a fruitful area for research to expand our knowledge concerning the behaviour of cardiovascular oscillations in normal healthy conditions as well as in disease states.

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185 Effect of carvedilol versus metoprolol immediate release on 24-hour heart rate in patients with idiopathic dilated cardiomyopathy. A 1-year cross-over study

European Journal of Heart Failure Supplements ◽

10.1016/s1567-4215(04)90115-4 ◽

2004 ◽

Vol 3 (1) ◽

pp. 39

Author(s):

A DILENARDA

Keyword(s):

Heart Rate ◽

Dilated Cardiomyopathy ◽

Immediate Release ◽

Idiopathic Dilated Cardiomyopathy

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Assessment of Nonlinear Heart Rate Dynamics after Beating-Heart Revascularization

The Heart Surgery Forum ◽

10.1532/hsf98.20081116 ◽

2009 ◽

Vol 12 (1) ◽

pp. E10-E16 ◽

Cited By ~ 10

Author(s):

Jus Ksela ◽

Piotr Suwalski ◽

Jurij Matija Kalisnik ◽

Viktor Avbelj ◽

Grzegorz Suwalski ◽

...

Keyword(s):

Heart Rate ◽

Beating Heart ◽

Nonlinear Heart Rate Dynamics ◽

Heart Rate Dynamics

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Heart Rate Dynamics After Acute Cocaine Administration

Journal of Cardiovascular Pharmacology ◽

10.1097/00005344-199203000-00024 ◽

1992 ◽

Vol 19 (3) ◽

pp. 453-459 ◽

Cited By ~ 4

Author(s):

Alan Garfinkel ◽

Sheryl L. Raetz ◽

Ronald M. Harper

Keyword(s):

Heart Rate ◽

Cocaine Administration ◽

Heart Rate Dynamics

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Heart Rate Reduction Strategy Improves Survival in Children with Severe Dilated Cardiomyopathy

The Journal of Heart and Lung Transplantation ◽

10.1016/j.healun.2021.01.384 ◽

2021 ◽

Vol 40 (4) ◽

pp. S122

Author(s):

R. Adorisio ◽

E. Mencarelli ◽

N. Cantarutti ◽

L. Amato ◽

M. Ciabattini ◽

...

Keyword(s):

Heart Rate ◽

Dilated Cardiomyopathy ◽

Heart Rate Reduction ◽

Rate Reduction ◽

Reduction Strategy

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PR interval as a predictor of syncope in tilt-up testing in adolescents and young adults

The Egyptian Heart Journal ◽

10.1186/s43044-021-00149-6 ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Juraj Jug ◽

Lada Bradić ◽

Rea Levicki ◽

Martina Lovrić Benčić

Keyword(s):

Heart Rate ◽

Vasovagal Syncope ◽

True Positive ◽

Ecg Monitoring ◽

Interval Prolongation ◽

Patient History ◽

Pr Interval ◽

Heart Rate Dynamics ◽

Testing Data ◽

Consciousness Disorder

Abstract Background Syncope, as the most frequent consciousness disorder, is very common in young individuals. The aim of this study was to analyze ECG parameters and clinical properties obtained during tilt-up testing in 12 to 30-year-old subjects. We enrolled a total of 142 patients from our outpatient clinic (39 males, 103 females) with a true positive tilt-up test and analyzed ECG records obtained during tilt-testing. Data were stratified according to the age, gender, and type of syncope. Results PR interval shortening preceding syncope was found in all syncope types, irrespective of the gender. All types of syncope were more frequent in women (72.5%). Mixed syncope type was found to be the most common (47.18%). Male and female subjects differed in initial heart rate (71.56 vs 76.23/min, p=0.05), as well as heart rate dynamics during tilt-up testing. A gender difference was also found in systolic blood pressure (116.92 vs 110.44 mmHg, p<0.01), time to syncope onset (20.77 vs. 16.44 min, p=0.03), and the total number of syncopal episodes in patient history (2.79 vs. 4.62, p<0.05). Subjects with cardioinhibitory syncope had the longest PR interval (average 154.3 ms). PR interval prolongation and loss of variability during tilt-up testing positively correlated with aging (r=0.22, p<0.05). Nodal rhythm was found in 8 patients. Conclusion PR interval shortening on ECG tracings during a tilt-up test can be found in all subtypes of vasovagal syncope, thereby contrasting previous reports that these changes are a hallmark of the cardioinhibitory type of syncope. PR shortening, if observed during ECG monitoring, could be a potential predictor of syncope.

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Heart rate as a marker of relapse during withdrawal of heart failure therapy in patients with recovered dilated cardiomyopathy: an analysis from TRED-HF

European Heart Journal ◽

10.1093/ehjci/ehaa946.1057 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

B Halliday ◽

A Vazir ◽

R Owen ◽

J Gregson ◽

R Wassall ◽

...

Keyword(s):

Heart Rate ◽

Cardiac Function ◽

Dilated Cardiomyopathy ◽

Funding Source ◽

End Point ◽

Therapy Withdrawal ◽

The Mean ◽

Withdrawal Of Therapy ◽

Continue Therapy

Abstract Introduction In TRED-HF, 40% of patients with recovered dilated cardiomyopathy (DCM) relapsed in the short-term during phased withdrawal of drug therapy. Non-invasive markers of relapse may be used to monitor patients who wish a trial of therapy withdrawal and provide insights into the pathophysiological drivers of relapse. Purpose To investigate the relationship between changes in heart rate (HR) and relapse amongst patients with recovered DCM undergoing therapy withdrawal in TRED-HF. Methods Patients with recovered DCM were randomised to phased withdrawal of therapy or to continue therapy for 6 months. After 6 months of continued therapy, those in the control arm underwent withdrawal of therapy in a single arm crossover phase. HR was measured at each study visit. Mean HR and 95% confidence intervals (CI) were calculated at baseline, 45 days after baseline, 45 days prior to the end of the study or relapse and at the end of the study or relapse. Patients were stratified by treatment arm and the occurrence of the primary relapse end-point. Heart rate at follow-up was compared amongst patients who had therapy withdrawn and relapsed versus those who had therapy withdrawn and did not. ANCOVA was used to adjust for differences in HR at baseline between the two groups. Results Of 51 patients randomised, 26 were assigned to continue therapy and 25 to withdraw therapy. In the randomised and cross-over phases, 20 patients met the primary relapse end-point; one patient withdrew from the study and one patient completed follow-up in the control arm but did not enter the cross-over phase. Mean HR (standard deviation) at baseline and follow-up for (i) patients in the control arm was 69.9 (9.8) & 65.9 (9.1) respectively; (ii) for those who had therapy withdrawn and did not relapse was 64.6 (10.7) & 74.7 (10.4) respectively; and (iii) for those who had therapy withdrawn and relapsed was 68.3 (11.3) & 86.1 (11.8) respectively [all beats per minute]. The mean change in HR between the penultimate visit and the final visit for those who had therapy withdrawn and did not relapse was −2.4 (9.7) compared to 3.1 (15.5) for those who relapsed. After adjusting for differences in HR at baseline, the mean difference in HR measured at follow-up between patients who underwent therapy withdrawal and did, and did not relapse was 10.4bpm (95% CI 4.0–16.8; p=0.002) (Figure 1 & Table 1). Conclusion(s) A larger increase in HR may be a simple and effective marker of relapse for patients with recovered DCM who have insisted on a trial of therapy withdrawal. Whether HR control is crucial to the maintenance of remission amongst patients with improved cardiac function, or is simply a marker of deteriorating cardiac function, warrants further investigation. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation

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