Severity of arterial and chronic thromboembolic pulmonary hypertension is associated with impairment of heart rate turbulence

Heart Rate Variability Impairment Is Associated with Right Ventricular Overload and Early Mortality Risk in Patients with Acute Pulmonary Embolism

The association between heart rate variability (HRV) and mortality risk of acute pulmonary embolism (APE), as well as its association with right ventricular (RV) overload is not well established. We performed an observational study on consecutive patients with confirmed APE. In the first 48 h after admission, 24 h Holter monitoring with assessment of time-domain HRV, echocardiography and NT-proBNP (N-terminal pro-B-type natriuretic peptide) measurement were performed in all participants. We pre-examined 166 patients: 32 (20%) with low risk of early mortality, 65 (40%) with intermediate-low, 65 (40%) with intermediate-high, and 4 (0.02%) in the high risk category. The last group was excluded from further analysis due to sample size, and finally, 162 patients aged 56.3 ± 18.5 years were examined. We observed significant correlations between HRV parameters and echocardiographic signs of RV overload. SDNN (standard deviation of intervals of all normal beats) correlated with echocardiography-derived RVSP (right ventricular systolic pressure; r = -0.31, p = 0.001), TAPSE (tricuspid annulus plane systolic excursion; r = 0.21, p = 0.033), IVC (inferior vena cava diameter; r = -0.27, p = 0.002) and also with NT-proBNP concentration (r = -0.30, p = 0.004). HRV indices were also associated with APE risk stratification, especially in the low-risk category (r = 0.30, p = 0.004 for SDNN). Univariate and multivariate analyses confirmed that SDNN values were associated with signs of RV overload. In conclusion, we observed a significant association between time-domain HRV parameters and echocardiographic and biochemical signs of RV overload. Impaired HRV parameters were also associated with worse a clinical risk status of APE.

The Value of Heart Rhythm Complexity in Identifying High-Risk Pulmonary Hypertension Patients

Pulmonary hypertension (PH) is a fatal disease—even with state-of-the-art medical treatment. Non-invasive clinical tools for risk stratification are still lacking. The aim of this study was to investigate the clinical utility of heart rhythm complexity in risk stratification for PH patients. We prospectively enrolled 54 PH patients, including 20 high-risk patients (group A; defined as WHO functional class IV or class III with severely compromised hemodynamics), and 34 low-risk patients (group B). Both linear and non-linear heart rate variability (HRV) variables, including detrended fluctuation analysis (DFA) and multiscale entropy (MSE), were analyzed. In linear and non-linear HRV analysis, low frequency and high frequency ratio, DFAα1, MSE slope 5, scale 5, and area 6–20 were significantly lower in group A. Among all HRV variables, MSE scale 5 (AUC: 0.758) had the best predictive power to discriminate the two groups. In multivariable analysis, MSE scale 5 (p = 0.010) was the only significantly predictor of severe PH in all HRV variables. In conclusion, the patients with severe PH had worse heart rhythm complexity. MSE parameters, especially scale 5, can help to identify high-risk PH patients.

HRT assessment reviewed: a systematic review of heart rate turbulence methodology

Heart rate turbulence (HRT) is a biphasic reaction to a ventricular premature contraction (VPC) mainly mediated by the baroreflex. It can be used for risk stratification in different disease patterns. Despite existing standards there is a lot of variation in terms of measuring and calculating HRT, which complicates research and application.

OBJECTIVE

This systematic review outlines and evaluates the methodological spectrum of HRT research, especially filtering criteria, parameter calculation and thresholds.

APPROACH

The analysis includes all research papers written in English that have been published before 12.10.2018, are listed on PubMed and involve calculation of HRT parameter values.

MAIN RESULTS

HRT assessment is still being performed in various ways and important specifications of the methodology are not given in many articles. Nevertheless, some suggestions regarding HRT methodology can be made: a normalised turbulence slope should be used to uncouple the parameter from heart rate and frequency of extrasystoles. Filtering criteria as formerly reviewed in the guidelines should be met and mentioned. The minimal number of VPC snippets (VPCSs) as well as new cut-off values for different risks need to be further evaluated. Most importantly, the exact and complete methodology must be described to ensure reproducibility and comparability.

SIGNIFICANCE

Methodical variation hinders comparability of research and medical application. Our continuing questions help to further standardise the measurement and calculation of HRT and increase its value for medical risk stratification.

[Tachycardia and pulmonary arterial hypertension]

Pulmonary hypertension is newly defined as an elevation of the mean pulmonary arterial pressure >20 mmHg and a pulmonary vascular resistance ≥3 Wood units. Arrhythmias are an increasing problem in patients with pulmonary hypertension. Pathophysiological aspects leading to supraventricular arrhythmias are atrial fibrosis caused by increased right atrial pressure and dilation. An increased sympathetic tone leads to prolongation of action potential and delayed polarisations causing arrhythmias. Therapy of arrhythmias includes drugs (preferred amiodarone) and electrophysiological therapy like electric cardioversion and ablation, which is safe in patients with pulmonary hypertension.

Heart Rhythm Complexity Impairment in Patients with Pulmonary Hypertension

Pulmonary hypertension is a fatal disease, however reliable prognostic tools are lacking. Heart rhythm complexity analysis is derived from non-linear heart rate variability (HRV) analysis and has shown excellent performance in predicting clinical outcomes in several cardiovascular diseases. However, heart rhythm complexity has not previously been studied in pulmonary hypertension patients. We prospectively analyzed 57 patients with pulmonary hypertension (31 with pulmonary arterial hypertension and 26 with chronic thromboembolic pulmonary hypertension) and compared them to 57 age- and sex-matched control subjects. Heart rhythm complexity including detrended fluctuation analysis (DFA) and multiscale entropy (MSE) and linear HRV parameters were analyzed. The patients with pulmonary hypertension had significantly lower mean RR, SDRR, pNN₂₀, VLF, LF, LF/HF ratio, DFAα1, MSE slope 5, scale 5, area 1-5 and area 6-20 compared to the controls. Receiver operating characteristic curve analysis showed that heart rhythm complexity parameters were better than traditional HRV parameters to predict pulmonary hypertension. Among all parameters, scale 5 had the greatest power to differentiate the pulmonary hypertension patients from controls (AUC: 0.845, P < 0.001). Furthermore, adding heart rhythm complexity parameters significantly improved the discriminatory power of the traditional HRV parameters in both net reclassification improvement and integrated discrimination improvement models. In conclusion, the patients with pulmonary hypertension had worse heart rhythm complexity. MSE parameters, especially scale 5, had excellent single discriminatory power to predict whether or not patients had pulmonary hypertension.

Ventricular tachycardias in patients with pulmonary hypertension: an underestimated prevalence? A prospective clinical study

BACKGROUND

Sudden cardiac death (SCD) accounts for approximately 30 % in patients with pulmonary arterial hypertension (PAH). The exact circumference for SCD in this patient population is still unclear. Malignant cardiac arrhythmias are reported to be rarely present. There are no systematic data concerning long-term electrocardiographic (ECG) recording in patients with PAH.

OBJECTIVES

We sought to investigate the rate of potentially relevant arrhythmias in patients with pulmonary hypertension (PH).

METHODS

Consecutive patients without diagnosis of known cardiac arrhythmias followed in our outpatient clinic for PH were enrolled in the study. All patients underwent a 72-h Holter ECG. Clinical data, 6-min walk distance, laboratory values, and echocardiography were collected/performed.

RESULTS

Ninety-two consecutive patients (New York Heart Association class (NYHA) III/IV: 65.2 %/5.4 %, PH Group 1: 35.9 %, Group 3: 10.9 %, Group 4: 28.3 %, Group 5: 2.2 %) were investigated. Relevant arrhythmias were newly detected in 17 patients: non-sustained ventricular tachycardia (n = 12), intermittent second-degree heart block (n = 1), intermittent third-degree heart block (n= 3), and atrial flutter (n = 1). Echocardiographic systolic pulmonary pressure and diameter of the right heart were elevated in patients with relevant arrhythmias. Right heart catheterization revealed higher pulmonary vascular resistance (672 vs. 542 dyn · s · cm(-5), p = 0.247) and lower cardiac index (2.46 vs. 2.82 l/min/m(2), p = 0.184).

CONCLUSIONS

Ventricular tachycardias occur more often in PH patients than previously reported. However, the prognostic relevance of non-sustained ventricular tachycardias in this cohort remains unclear. As a large number of PH patients die from SCD, closer monitoring, e.g., using implantable event recorders, might be useful to identify patients at high risk.