Clustering analysis based on automated electrocardiographic measurements to identify prognostically distinct phenotypes in patients hospitalized for heart failure: a retrospective cohort study

Funding Acknowledgements

Type of funding sources: None.

Background

Heart failure (HF) is a heterogeneous disease with complex structural and electrophysiological derangements of the heart. Attempts to classify HF from the electrophysiological perspective are lacking.

Purpose

To use electrocardiographic (ECG) data for phenotypic classification of patients with HF.

Methods

In this retrospective cohort study, all adult patients hospitalized for HF during 2010-2016 at a tertiary center were included. Automated measurements of the first ECG obtained during the index admission were recorded. K-means clustering using premorbid conditions and selected ECG measurements were used to classify the cohort into four mutually exclusive clusters. The primary (all-cause and cardiovascular mortality) and secondary (ventricular arrhythmia (VA)) outcomes were compared between clusters using Cox regression analysis.

Results

In total, 2849 patients (1363 males, age 75.1 ± 13.4 years) were included. Over a mean follow-up period of 5.37 ± 4.10 years, all-cause and cardiovascular mortality occurred in 2071 (72.7%) and 600 (21.1%) patients respectively, while VA occurred in 110 patients (3.9%). Cluster 1 was characterised by a low heart rate and low ventricular activation time (VAT). Cluster 2 was characterised by old age, low absolute QRS area, and high QTc and QT dispersion. Cluster 3 was characterised by young age, and left ventricular hypertrophy (LVH), and few had history of VA. Cluster 4 was characterised by wide QRS, hypertension, ischaemic heart disease, high VAT, and high absolute T wave area. Cluster 4 had the highest and cluster 1 the lowest risks of all-cause (hazard ratio (HR) 2.96 [1.09, 1.50], p = 0.003; Figure A) and cardiovascular mortality (HR 2.90 [1.15, 2.11], p = 0.004; Figure B). Meanwhile, cluster 2 had the highest risk of VA (HR 2.23 [1.09, 3.85], p = 0.025; Figure C) while clusters 1 and 3 similarly had the lowest risks.

Conclusion

HF presents with clinically and electrophysiologically distinct phenotypes. Clustering analysis is useful in identifying HF phenotypes which are prognostically significant. Abstract Figures A, B, and C

Safety of catheter ablation of AF without pre- or periprocedural imaging for the detection of LA thrombus

Funding Acknowledgements

Type of funding sources: None.

Background

The need for pre- or peri-procedural imaging to rule out the presence of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation (AF) is unclear in the era of uninterrupted direct oral anticoagulant (DOAC) regimen. We sought to examine the safety of catheter ablation in appropriately selected patients with paroxysmal AF without performing screening for left atrial thrombus.

Methods

Consecutive patients planned for radiofrequency AF catheter ablation between January 2016 and June 2020 were enrolled, and prospectively studied. All subjects were receiving uninterrupted anticoagulation with DOACs for at least 4 weeks before the procedure. All subjects were in sinus rhythm the day of the procedure. The primary outcome of the study was ischemic stroke or transient ischemic attack (TIA) during at 30 days.

Results

A total of 451 patients (age 59.7 ± 10.2 years, 289 males) with paroxysmal AF were included in the study. The mean CHA2DS2-VASc score was 1.4 ± 1.2. The mean left ventricular ejection fraction and left atrial diameter were 60 ± 5% and 39.3 ± 4 mm, respectively. Regarding the anticoagulation regimen, apixaban was used in 197 (43.6%) patients, rivaroxaban in 148 (32.8%) patients, and dabigatran in 106 (23.5%) patients. None of the patients developed clinical ischemic stroke or TIA during the 30-day post-discharged period.

Conclusions

Catheter ablation can be safely performed in low-risk patients with paroxysmal AF without imaging for the detection of left atrial thrombus in the era of uninterrupted DOAC anticoagulation.

414 Ventricular-arterial interaction predicts response to cardiac resynchronization therapy: a link with improvement of endothelial function and arterial elastic properties

Background

Endothelial dysfunction (ED) is a hall mark of chronic heart failure and has been linked to disease progression, hospitalizations and mortality.

Purpose

to evaluate the impact of cardiac resynchronization therapy (CRT) in ED and to determine predictors of response to CRT

Methods

CRT recipients from 19/07/2016 until 19/10/2018 were studied at baseline and 3 months after. In each visit we evaluated a 12 lead ECG, carotid to femoral pulse wave velocity (cfPWV), flow-mediated dilatation of the brachial artery (FMD), left ventricle ejection fraction (LVEF) and left ventricle (LV) global longitudinal strain (GLS). We evaluated arterial elastance (Ea) to ventricular elastance (Ees) ratio (Ea/Ees) by echocardiography and the ratio of cfPWV to GLS, as valid markers of ventricular-arterial interaction. We also assessed the layer of endothelial glycocalyx by measurement of Perfused Boundary Region (PBR) of the sublingual microvessel range:5-25 microns.

Results

32 patients with a mean age 65.5 (±10.9) years and severe LV systolic dysfunction were enrolled. During follow-up, LVEF, GLS, LVESV and all ED markers exhibited significant improvement (table 1). 23 patients were responders. Among the baseline vascular function markers, only the ratio cfPWV/GLS predicted response to CRT (OR: 0.245, 95%CI: 0.042-0.759, p = 0.044).Threshold analysis showed that the best threshold of cfPWV/GLS for response to CRT was 2.75 (specificity: 0.67%, sensitivity: 0.94%).

Conclusions

After 3 months of CRT, endothelial function, arterial elasticity and ventricular arterial interaction are improved. The baseline ratio cfPWV/GLS, a novel marker of ventricular arterial interaction, can be applied to predict response to CRT.

table 1 Baseline Follow-up Change Measurement mean (sd) mean (sd) mean (sd) p-value SBP (mmHg) 126 (19) 128 (16) 2.18 (11.98) 0,465 DBP (mmHg) 79 (9) 80 (9) 1.06 (8.58) 0,618 LVEF (%) 27 (7) 35 (9) 7.50 (4.77) <0.001 LVESV (mL) 151 (42) 120 (46) -26.91 (17.20) <0.001 GLS (%) 6.47 (2.89) 9.33 (4.18) 2.85 (2.28) <0.001 FMD (%) 5.88 (2.79) 10.25 (3.67) 4.37 (3.34) <0.001 Ea/Ees 2.81 (1.10) 2.04 (0.99) -0.77 (0.47) <0.001 cfPWV 11.11 (2.61) 10.01 (2.45) -1.10 (1.56) 0,003 PBR 5-25(microns) 2.26 (0.20) 2.14 (0.24) -0.13 (0.25) 0,028 cfPWV/GLS 2.18 (1.46) 1.45 (1.11) -0.73 (0.55) <0.001 Measurements at baseline, follow-up and their change during study

Abstract 414 Figure. picture 1

P709Improvement in endothelial function and arterial elastic properties facilitates response to cardiac resynchronization therapy

Background

Cardiac resynchronization therapy (CRT) is a well-established therapy in heart failure (HF) patients with prolonged QRS. In HF patients, reduced nitric oxide availability and increased oxidative stress promote endothelial dysfunction (ED) and arterial stiffness.

Purpose

To investigate the pathophysiologic changes in endothelium and arterial elastic properties in CRT patients and their correlation to therapy.

Methods

We studied 32 HF patients before and 3 months after CRT implantation. In each visit we performed a 12-lead ECG and assessed markers of endothelial function. Specifically, we examined flow-mediated dilatation of the brachial artery (FMD), carotid to femoral pulse wave velocity (cfPWV), as well as the layer of endothelial glycocalyx using the Perfused Boundary Region (PBR) of the sublingual microvessel range: 5–25 microns. We also evaluated left ventricle ejection fraction (LVEF), left ventricle (LV) global longitudinal strain (GLS) and arterial elastance (Ea) to ventricular elastance (Ees) ratio (Ea/Ees) by echocardiography.

Results

32 HF CRT patients, at age 65.5 (±10.9) years, with reduced LVEF (baseline LVEF: 27±7%, LVESV: 151±42 ml, GLS: 6.47±2.89%) were followed-up for a median of 115 days (IQR: 36). During follow up, all markers of ED demonstrated significant change: FMD was increased by 4.37±3.34% (p<0.001), cfPWV and PBR 5–25 were reduced by 1.10±1.56 (p=0.003) and 0.13±0.25 microns (p=0.028) respectively. LVEF was significantly increased (mean change: 7.50±4.77%) and LVESV was significantly reduced (mean change: −26.91±17.20 ml). 16 of 32 patients were responders (LVESV change ≥15% compared to baseline). Among the changes of the examined markers during follow-up, response to CRT correlated with the change of FMD (OR: 3.10, 95% CI: 1.47–15.51, p=0.039) and change of Ea/Ees (OR: 0.000, 95% CI: 0.000–0.061, p=0,0239).

Effect of change in measurements during follow-up on response to CRT Measurement OR (95% CI) Main effect p-value FMD change 3.100 (1.470–15.513) 0.0397 cfPWV change 0.669 (0.295–1.354) 0.0622 PBR 5–25 change 1.773 (0.008–455.458) 0.828 Ea/Ees change 0.000 (0.000–0.061) 0.0239

Conclusion

Improvement in endothelial function and arterial elastic properties evaluated by FMD and Ea/Ees respectively are related with effective CRT.