Ventricular interdependence in pulmonary arterial hypertension: providing small pieces of a complex puzzle

Biventricular Dysfunction and Ventricular Interdependence in Patients With Pulmonary Hypertension: A 3.0-T Cardiac MRI Feature Tracking Study

BACKGROUND

Pulmonary hypertension (PH) results in right ventricular (RV) dysfunction, subsequently leading to left ventricular (LV) impairment. The mechanism underlying ventricular interdependence is largely uninvestigated.

PURPOSE

To explore the biventricular dysfunction and the ventricular interdependence in PH patients.

STUDY TYPE

Retrospective.

POPULATION

One hundred and seven PH patients (mean pulmonary artery pressure >20 mmHg) and 72 age- and sex-matched controls with cardiac magnetic resonance imaging (MRI) studies.

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession sequence.

ASSESSMENT

LV and RV ejection fractions (EF) and RV and LV radial, circumferential, and longitudinal strains were assessed using commercial software. Strains were compared between controls, PH patients with preserved RVEF (RVEF ≥40%, N = 48), and PH patients with reduced RVEF (RVEF <40%, N = 59).

STATISTICAL TESTS

Chi-squared tests or Fisher's exact test, t tests or Mann-Whitney U test, one-way ANOVA with Bonferroni's post hoc correction or Kruskal-Wallis test, Pearson or Spearman correlation, and multivariable linear regression analysis. A two-tailed P < 0.05 was deemed statistically significant.

RESULTS

RV strain decreased sequentially from controls, through PH with preserved RVEF, to PH with reduced RVEF. PH patients with reduced RVEF had significantly lower LV strain, especially septal strain, and LV peak diastolic strain rate compared with both controls and PH patients with preserved RVEF. Multivariable analyses showed that RVEF was independently correlated with LV strain; furthermore, independent of RVEF, RV strain was significantly correlated with LV strain (LVGRS: β = 0.416; LVGCS: β = -0.371; LVGLS: β = 0.283).

DATA CONCLUSION

Subclinical impairment of RV function was found in PH with preserved RVEF. LV strain was impaired when RV was dysfunctional, which was associated with worsening RV strain. Therefore, while focusing on improving RV function, LV dysfunction in PH patients should also be monitored and treated early in order to slow the progression of the disease.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 3.

Non-invasive imaging techniques for early diagnosis of bilateral cardiac dysfunction in pulmonary hypertension: current crests, future peaks

Pulmonary arterial hypertension (PAH) is a chronic and progressive disease that eventually leads to heart failure (HF) and subsequent fatality if left untreated. Right ventricular (RV) function has proven prognostic values in patients with a variety of heart diseases including PAH. PAH is predominantly a right heart disease; however, given the nature of the continuous circulatory system and the presence of shared septum and pericardial constraints, the interdependence of the right and left ventricles is a factor that requires consideration. Accurate and timely assessment of ventricular function is very important in the management of patients with PAH for disease outcomes and prognosis. Non-invasive modalities such as cardiac magnetic resonance (CMR) and echocardiography (two-dimensional and three-dimensional), and nuclear medicine, positron emission tomography (PET) play a crucial role in the assessment of ventricular function and disease prognosis. Each modality has its own strengths and limitations, hence this review article sheds light on (i) ventricular dysfunction in patients with PAH and RV-LV interdependence in such patients, (ii) the strengths and limitations of all available modalities and parameters for the early assessment of ventricular function, as well as their prognostic value, and (iii) lastly, the challenges faced and the potential future advancement in these modalities for accurate and early diagnosis of ventricular function in PAH.

Right to left ventricular volume ratio is associated with mortality in congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is associated with high neonatal mortality. We performed this study to test the hypothesis that left ventricular (LV) and right ventricular (RV) volumes assessed by three-dimensional echocardiography may be associated with mortality in CDH.

METHODS

This study was a single-center retrospective cohort study involving 35 infants with CDH. RV and LV end-diastolic volume (RVEDV and LVEDV, respectively) were measured by three-dimensional echocardiography and were corrected by birth body weight (BBW) on day 1. RVEDV/BBW, LVEDV/BBW, and LVEDV/RVEDV were compared between CDH survivors and non-survivors. Receiver-operating characteristic curve analysis was performed to assess the predictive ability for mortality of the echocardiographic parameters.

RESULTS

Comparing CDH non-survivors (n = 6) with survivors (n = 29), respectively, RVEDV/BBW was significantly larger (2.54 ± 0.33 vs 1.86 ± 0.35 ml/kg; P < 0.01), LVEDV/BBW was significantly smaller (0.86 ± 0.21 vs 1.22 ± 0.33 ml/kg; P < 0.001), and LVEDV/RVEDV was significantly lower (0.34 ± 0.06 vs 0.66 ± 0.18; P < 0.001). The area under the curve for LVEDV/RVEDV was the largest (0.98).

CONCLUSIONS

Three-dimensional echocardiographic volume imbalance between the RV and LV was remarkable in CDH non-survivors. The LVEDV/RVEDV ratio may be associated with mortality in CDH.

IMPACT

Mortality with congenital diaphragmatic hernia (CDH) is high, and evaluating left and right ventricular structures and functions may be helpful in assessing the prognosis. Three-dimensional (3D) echocardiography indicated that the left ventricular end-diastolic volume/right ventricular end-diastolic volume ratio within 24 h after birth was associated with mortality in CDH infants. The usefulness of this ratio should be validated in prospective multicenter studies involving larger numbers of patients.

Early diagnosis and targeted approaches to pulmonary vascular disease in bronchopulmonary dysplasia

Pulmonary hypertension has emerged as a life-threatening disease in preterm infants suffering from bronchopulmonary dysplasia (BPD). Its development is closely linked to respiratory disease, as vasculogenesis and alveologenesis are closely interconnected. Once clinically significant, BPD-associated pulmonary hypertension (BPD-PH) can be challenging to manage, due to poor reversibility and multiple comorbidities frequently associated. The pulmonary vascular disease process underlying BPD-PH is the result of multiple innate and acquired factors, and emerging evidence suggests that it progressively develops since birth and, in certain instances, may begin as early as fetal life. Therefore, early recognition and intervention are of great importance in order to improve long-term outcomes. Based on the most recent knowledge of BPD-PH pathophysiology, we review state-of-the-art screening and diagnostic imaging techniques currently available, their utility for clinicians, and their applicability and limitations in this specific population. We also discuss some biochemical markers studied in humans as a possible complement to imaging for the detection of pulmonary vascular disease at its early stages and the monitoring of its progression. In the second part, we review pharmacological agents currently available for BPD-PH treatment or under preclinical investigation, and discuss their applicability, as well as possible approaches for early-stage interventions in fetuses and neonates. IMPACT: BPD-associated PH is a complex disease involving genetic and epigenetic factors, as well as environmental exposures starting from fetal life. The value of combining multiple imaging and biochemical biomarkers is emerging, but requires larger, multicenter studies for validation and diffusion. Since "single-bullet" approaches have proven elusive so far, combined pharmacological regimen and cell-based therapies may represent important avenues for research leading to future cure and prevention.

Echocardiography in Pulmonary Arterial Hypertension: Is It Time to Reconsider Its Prognostic Utility?

Pulmonary arterial hypertension (PAH) is characterized by an insult in the pulmonary vasculature, with subsequent right ventricular (RV) adaptation to the increased afterload that ultimately leads to RV failure. The awareness of the importance of RV function in PAH has increased considerably because right heart failure is the predominant cause of death in PAH patients. Given its wide availability and reduced cost, echocardiography is of paramount importance in the evaluation of the right heart in PAH. Several echocardiographic parameters have been shown to have prognostic implications in PAH; however, the role of echocardiography in the risk assessment of the PAH patient is limited under the current guidelines. This review discusses the echocardiographic evaluation of the RV in PAH and during therapy, and its prognostic implications, as well as the potential significant role of repeated echocardiographic assessment in the follow-up of patients with PAH.

Impact of Right Ventricular Function on Left Ventricular Torsion and Ventricular Deformations in Pulmonary Artery Hypertension Patients

INTRODUCTION

Ventricular interdependence in pulmonary arterial hypertension (PAH) by the use of most recent echocardiographic techniques is still rare. The current case-controlled study aims to assess left ventricular (LV) torsion in patients with PAH.

METHODS

The study included 42 cases of moderate to severe PAH and 42 age and gender-matched healthy controls between March 2016 and January 2018. All the patients and controls undergo routine practice echocardiography using the Vivid 7-echocardiography (2.5MHz transducer) system.

RESULTS

The LV twisting parameters, peak basal rotation, peak apical rotation, and twist were similar among both cases and controls, however, LV torsion was significantly (p=0.04) impacted. Right ventricular (RV) longitudinal deformation was clinically significant in the cases compared to controls: RV systolic strain imaging (p=0.001, 95% CI-9.75 to -2.65), RV systolic strain rate (p=0.01, 95% CI-0.99 to -0.09), and RV late diastolic strain rate (p=0.01, 95% CI-0.64 to -0.85). Although PAH did not impact longitudinal LV deformations significantly. At basal level circumferential strain and strain rate were significantly impacted (p=0.005, 95% CI-4.38 to -0.70; p=0.004, 95% CI-0.35 to -0.07) in the PAH group, while the radial strain was preserved. All RV echocardiographic parameters and LV end-diastolic dimension, LV end-systolic volume in the PAH were affected significantly (p=0.002, 95% CI-19.91 to -4.46; p=0.01, 95% CI-8.44 to -2.77). However, only a weak correlation (p=0.05, r =-0.20) was found between tricuspid annular plane systolic excursion and LV Tei index.

CONCLUSION

RV pressure overload directly affects RV longitudinal systolic deformation further influences the interventricular septal and LV geometry, which impaired LV torsion.

How to diagnose heart failure with preserved ejection fraction: the HFA-PEFF diagnostic algorithm: a consensus recommendation from the Heart Failure Association (HFA) of the European Society of Cardiology (ESC)

Making a firm diagnosis of chronic heart failure with preserved ejection fraction (HFpEF) remains a challenge. We recommend a new stepwise diagnostic process, the 'HFA-PEFF diagnostic algorithm'. Step 1 (P=Pre-test assessment) is typically performed in the ambulatory setting and includes assessment for HF symptoms and signs, typical clinical demographics (obesity, hypertension, diabetes mellitus, elderly, atrial fibrillation), and diagnostic laboratory tests, electrocardiogram, and echocardiography. In the absence of overt non-cardiac causes of breathlessness, HFpEF can be suspected if there is a normal left ventricular ejection fraction, no significant heart valve disease or cardiac ischaemia, and at least one typical risk factor. Elevated natriuretic peptides support, but normal levels do not exclude a diagnosis of HFpEF. The second step (E: Echocardiography and Natriuretic Peptide Score) requires comprehensive echocardiography and is typically performed by a cardiologist. Measures include mitral annular early diastolic velocity (e'), left ventricular (LV) filling pressure estimated using E/e', left atrial volume index, LV mass index, LV relative wall thickness, tricuspid regurgitation velocity, LV global longitudinal systolic strain, and serum natriuretic peptide levels. Major (2 points) and Minor (1 point) criteria were defined from these measures. A score ≥5 points implies definite HFpEF; ≤1 point makes HFpEF unlikely. An intermediate score (2-4 points) implies diagnostic uncertainty, in which case Step 3 (F1: Functional testing) is recommended with echocardiographic or invasive haemodynamic exercise stress tests. Step 4 (F2: Final aetiology) is recommended to establish a possible specific cause of HFpEF or alternative explanations. Further research is needed for a better classification of HFpEF.

Three-dimensional biventricular strains in pulmonary arterial hypertension patients using hyperelastic warping

BACKGROUND AND OBJECTIVE

Evaluation of biventricular function is an essential component of clinical management in pulmonary arterial hypertension (PAH). This study aims to examine the utility of biventricular strains derived from a model-to-image registration technique in PAH patients in comparison to age- and gender-matched normal controls.

METHODS

A three-dimensional (3D) model was reconstructed from cine short- and long-axis cardiac magnetic resonance (CMR) images and subsequently partitioned into right ventricle (RV), left ventricle (LV) and septum. The hyperelastic warping method was used to register the meshed biventricular finite element model throughout the cardiac cycle and obtain the corresponding biventricular circumferential, longitudinal and radial strains.

RESULTS

Intra- and inter-observer reproducibility of biventricular strains was excellent with all intra-class correlation coefficients > 0.84. 3D biventricular longitudinal, circumferential and radial strains for RV, LV and septum were significantly decreased in PAH patients compared with controls. Receiver operating characteristic (ROC) analysis showed that the 3D biventricular strains were better early markers (Area under the ROC curve = 0.96 for RV longitudinal strain) of ventricular dysfunction than conventional parameters such as two-dimensional strains and ejection fraction.

CONCLUSIONS

Our highly reproducible methodology holds potential for extending CMR imaging to characterize 3D biventricular strains, eventually leading to deeper understanding of biventricular mechanics in PAH.

How to diagnose heart failure with preserved ejection fraction: the HFA-PEFF diagnostic algorithm: a consensus recommendation from the Heart Failure Association (HFA) of the European Society of Cardiology (ESC)

Making a firm diagnosis of chronic heart failure with preserved ejection fraction (HFpEF) remains a challenge. We recommend a new stepwise diagnostic process, the 'HFA-PEFF diagnostic algorithm'. Step 1 (P=Pre-test assessment) is typically performed in the ambulatory setting and includes assessment for heart failure symptoms and signs, typical clinical demographics (obesity, hypertension, diabetes mellitus, elderly, atrial fibrillation), and diagnostic laboratory tests, electrocardiogram, and echocardiography. In the absence of overt non-cardiac causes of breathlessness, HFpEF can be suspected if there is a normal left ventricular (LV) ejection fraction, no significant heart valve disease or cardiac ischaemia, and at least one typical risk factor. Elevated natriuretic peptides support, but normal levels do not exclude a diagnosis of HFpEF. The second step (E: Echocardiography and Natriuretic Peptide Score) requires comprehensive echocardiography and is typically performed by a cardiologist. Measures include mitral annular early diastolic velocity (e'), LV filling pressure estimated using E/e', left atrial volume index, LV mass index, LV relative wall thickness, tricuspid regurgitation velocity, LV global longitudinal systolic strain, and serum natriuretic peptide levels. Major (2 points) and Minor (1 point) criteria were defined from these measures. A score ≥5 points implies definite HFpEF; ≤1 point makes HFpEF unlikely. An intermediate score (2-4 points) implies diagnostic uncertainty, in which case Step 3 (F₁ : Functional testing) is recommended with echocardiographic or invasive haemodynamic exercise stress tests. Step 4 (F₂ : Final aetiology) is recommended to establish a possible specific cause of HFpEF or alternative explanations. Further research is needed for a better classification of HFpEF.

Congenital diaphragmatic hernia-associated cardiac dysfunction

There is increasing evidence that cardiac dysfunction is a key contributor to CDH pathophysiology. Dysfunction in both right and left ventricles is common in the early neonatal period, contributes to clinical disease severity, and is associated with adverse outcomes including death and ECMO use. Early and routine assessment of ventricular function and pulmonary artery pressure may guide individualized clinical decision-making, including use of pulmonary vasodilators, cardiotropes, ECMO, and timing of surgical repair. Minimizing cardiac dysfunction, whether by prenatal, postnatal or perinatal treatment strategies, may lead to improved outcome in CDH.

In-silico assessment of the effects of right ventricular assist device on pulmonary arterial hypertension using an image based biventricular modeling framework

Pulmonary arterial hypertension (PAH) is a heart disease that is characterized by an abnormally high pressure in the pulmonary artery (PA). While right ventricular assist device (RVAD) has been considered recently as a treatment option for the end-stage PAH patients, its effects on biventricular mechanics are, however, largely unknown. To address this issue, we developed an image-based modeling framework consisting of a biventricular finite element (FE) model that is coupled to a lumped model describing the pulmonary and systemic circulations in a closed-loop system. The biventricular geometry was reconstructed from the magnetic resonance images of two PAH patients showing different degree of RV remodeling and a normal subject. The framework was calibrated to match patient-specific measurements of the left ventricular (LV) and RV volume and pressure waveforms. An RVAD model was incorporated into the calibrated framework and simulations were performed with different pump speeds. Results showed that RVAD unloads the RV, improves cardiac output and increases septum curvature, which are more pronounced in the PAH patient with severe RV remodeling. These improvements, however, are also accompanied by an adverse increase in the PA pressure. These results suggest that the RVAD implantation may need to be optimized depending on disease progression.

Echocardiographic evaluation of diastolic function in the setting of pulmonary hypertension

Heart failure due to diastolic dysfunction and pulmonary hypertension are frequent comorbid conditions with significant morbidity and mortality. Identifying the presence and etiology of diastolic dysfunction in the setting of pulmonary hypertension remains challenging despite profound therapeutic and prognostic implications. Additionally, there is little guidance in identifying and parsing etiology of diastolic dysfunction in patients found to have pulmonary hypertension. This review discusses the complex interplay between left ventricular diastolic dysfunction and pulmonary hypertension. With an explicit focus on the use of echocardiography for determination of diastolic dysfunction and etiology of pulmonary hypertension, this review also provides a comprehensive review of the literature and provides a framework by which to assess diastolic dysfunction echocardiographically in the setting of pulmonary hypertension.

Ventricular Dysfunction, Interdependence, and Mechanical Dispersion in Newborn Infants with Congenital Diaphragmatic Hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is an important cause of mortality and morbidity in the neonatal period. Pulmonary hypertension and pulmonary hypoplasia are key pathological findings. Cardiac function may also be an important determinant of disease severity, prognostic indicator, and therapeutic target in CDH.

OBJECTIVE

The aim of this study was to assess ventricular mechanics and synchrony in infants with CDH and controls using speckle tracking echocardiography (STE).

METHODS

Retrospective analysis was performed of echocardiograms obtained in the first 48 h of life in 27 infants with CDH and 20 controls. STE-derived longitudinal strain (LS) was measured in the right and left ventricles (RV, LV). Circumferential strain (CS) and radial strain (RS) were additionally measured in the LV. Mechanical dispersion (MD), a measure of synchrony, was assessed by calculation of the standard deviation of time to peak systolic strain in six ventricular segments.

RESULTS

RV LS and LV LS, LV CS, and LV RS were significantly reduced in CDH compared to controls. In the LV free wall, LS and RS were significantly reduced in CDH. LV LS correlated significantly with RV LS in CDH cases (r2 = 0.37, p = 0.002), but not controls (r2 = 0.19, p = 0.06). LV LS also correlated with LV MD in CDH (r2 = 0.25, p = 0.01) but not controls (r2 = 0.02, p = 0.54).

CONCLUSIONS

Global impairment of RV and LV systolic function are present in newborn infants with CDH and are associated with primary left ventricular dysfunction, ventricular interdependence, and MD.

MRI assessment of aortic flow in patients with pulmonary arterial hypertension in response to exercise

Background

While primarily a right heart disease, pulmonary arterial hypertension (PAH) can impact left heart function and aortic flow through a shifted interventricular septum from right ventricular pressure overload and reduced left ventricular preload, among other mechanisms. In this study, we used phase contrast (PC) MRI and a modest exercise challenge to examine the effects of PAH on systemic circulation. While exercise challenges are typically performed with ultrasound in the clinic, MRI exercise studies allow for more reproducible image alignment, more accurate flow quantification, and improved tissue contrast.

Methods

Six PAH patients and fifteen healthy controls (8 older age-matched, 7 younger) exercised in the magnet bore with an MRI-compatible exercise device that allowed for scanning immediately following cessation of exercise. PC scans were performed in the ascending aorta during a breath hold immediately after modest exercise to non-invasively measure stroke volume (SV), cardiac output (CO), aortic peak systolic flow (PSF), and aortic wall stiffness via relative area change (RAC).

Results

Images following exercise showed mild blurring, but were high enough quality to allow for segmentation of the aorta. While SV was approximately 30% lower in PAH patients (SV_PAH,rest = 67 ± 16 mL; SV_PAH,stress = 90 ± 42 mL) than age-matched controls (SV_,older,rest = 93 ± 16 mL; SV_older,stress = 133 ± 40 mL) at both rest and following exercise, CO was similar for both groups following exercise (CO_PAH,stress = 10.8 ± 5.7 L/min; CO_older,stress = 11.8 ± 5.0 L/min). This was achieved through a compensatory increase in heart rate in the PAH subjects (74% increase as compared to 29% in age-matched controls). The PAH subjects also demonstrated reduced aortic peak systolic flow relative to the healthy controls (PSF_PAH,_rest = 309 ± 52 mL/s; PSF_older,_rest = 416 ± 114 mL/s; PSF_PAH,_stress = 388 ± 113 mL/s; PSF_older,_stress = 462 ± 176 mL/s). PAH patients and older controls demonstrated stiffer aortic walls when compared to younger controls (RAC_PAH,rest = 0.15 ± 0.05; RAC_older,rest = 0.17 ± 0.05; RAC_young,rest = 0.28 ± 0.08).

Conclusions

PC MRI following a modest exercise challenge was capable of detecting differences in left heart dynamics likely induced from PAH. These results demonstrated that PAH can have a significant influence on systemic flow, even when the patient has no prior left heart disease. Image quantification following exercise could likely be improved in future studies through the implementation of free-breathing or real-time MRI acquisitions.

Trial registration

Retrospectively registered on 02/26/2018 (TRN:NCT03523910).

Increased Pulmonary-Systemic Pulse Pressure Ratio Is Associated With Increased Mortality in Group 1 Pulmonary Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterised by remodelling of the pulmonary vasculature leading to right ventricular (RV) failure. The failing RV, through interventricular uncoupling, deleteriously impacts the left ventricle and overall cardiac efficiency. We hypothesised that the ratio of the pulmonary artery pulse pressure to the systemic pulse pressure ("pulmonary-systemic pulse pressure ratio", or PS-PPR) would be associated with mortality in PAH.

METHODS

We conducted a retrospective analysis of 262 patients in the National Institute of Health Primary Pulmonary Hypertension Registry (NIH-PPH). We evaluated the association between the PS-PPR and mortality after adjustment for the Pulmonary Hypertension Connection (PHC) risk equation.

RESULTS

Among 262 patients (mean age 37.5±15.8years, 62.2% female), median PS-PPR was 1.04 (IQR 0.79-1.30). In the Cox proportional hazards regression model, each one unit increase in the PS-PPR was associated with more than a two-fold increase in mortality during follow-up (HR 2.06, 95% CI 1.40-3.02, p=0.0002), and this association of PS-PPR with mortality remained significant in the multivariable Cox model adjusted for the PHC risk equation, mean pulmonary artery pressure, and body mass index (BMI) (adjusted HR 1.81, 95% CI 1.13-2.88, p=0.01). Furthermore, PS-PPR in the upper quartile (>1.30) versus quartiles 1-3 was associated with a 68% increase in mortality after adjustment for these same covariates (adjusted HR 1.68, 95% CI 1.13-2.50, p=0.01).

CONCLUSIONS

Pulmonary-systemic pulse pressure ratio, a marker of biventricular efficiency, is associated with survival in PAH even after adjustment for the PHC risk equation. Further studies are needed on the wider applications of PS-PPR in PAH patients.

SHOCKABLE VERSUS NONSHOCKABLE LIFE-THREATENING VENTRICULAR ARRHYTHMIAS USING DWT AND NONLINEAR FEATURES OF ECG SIGNALS

Shockable ventricular arrhythmias (VAs) such as ventricular tachycardia (VT) and ventricular fibrillation (VFib) are the life-threatening conditions requiring immediate attention. Cardiopulmonary resuscitation (CPR) and defibrillation are the significant immediate recommended treatments for these shockable arrhythmias to obtain the return of spontaneous circulation. However, accurate classification of these shockable VAs from nonshockable ones is the key step during defibrillation by automated external defibrillator (AED). Therefore, in this work, we have proposed a novel algorithm for an automated differentiation of shockable and nonshockable VAs from electrocardiogram (ECG) signal. The ECG signals are segmented into 5, 8 and 10[Formula: see text]s. These segmented ECGs are subjected to four levels of discrete wavelet transformation (DWT). Various nonlinear features such as approximate entropy ([Formula: see text], signal energy ([Formula: see text]), Fuzzy entropy ([Formula: see text]), Kolmogorov Sinai entropy ([Formula: see text], permutation entropy ([Formula: see text]), Renyi entropy ([Formula: see text]), sample entropy ([Formula: see text]), Shannon entropy ([Formula: see text]), Tsallis entropy ([Formula: see text]), wavelet entropy ([Formula: see text]), fractal dimension ([Formula: see text]), Kolmogorov complexity ([Formula: see text]), largest Lyapunov exponent ([Formula: see text]), recurrence quantification analysis (RQA) parameters ([Formula: see text]), Hurst exponent ([Formula: see text]), activity entropy ([Formula: see text]), Hjorth complexity ([Formula: see text]), Hjorth mobility ([Formula: see text]), modified multi scale entropy ([Formula: see text]) and higher order statistics (HOS) bispectrum ([Formula: see text]) are obtained from the DWT coefficients. Later, these features are subjected to sequential forward feature selection (SFS) method and selected features are then ranked using seven ranking methods namely, Bhattacharyya distance, entropy, Fuzzy maximum relevancy and minimum redundancy (mRMR), receiver operating characteristic (ROC), Student’s [Formula: see text]-test, Wilcoxon and ReliefF. These ranked features are supplied independently into the [Formula: see text]-Nearest Neighbor (kNN) classifier. Our proposed system achieved maximum accuracy, sensitivity and specificity of (i) 97.72%, 94.79% and 98.74% for 5[Formula: see text]s, (ii) 98.34%, 95.49% and 99.14% for 8[Formula: see text]s and (iii) 98.32%, 95.16% and 99.20% for 10[Formula: see text]s of ECG segments using only ten features. The integration of the proposed algorithm with ECG acquisition systems in the intensive care units (ICUs) can help the clinicians to decipher the shockable and nonshockable life-threatening arrhythmias accurately. Hence, doctors can use the CPR or AED immediately and increase the chance of survival during shockable life-threatening arrhythmia intervals.