Area weighted unipolar voltage to predict heart failure death in patients with ischemic cardiomyopathy and ventricular tachycardia

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with ischemic cardiomyopathy (ICM) referred for catheter ablation (CA) of ventricular tachycardia (VT) are at risk for end-stage heart failure (HF) due to adverse remodeling of the left ventricle (LV). Local unipolar voltages (UV) decrease with loss of viable myocardium. A UV mapping derived parameter that corrects for oversampling of the infarct area may reflect the total amount of remaining LV viable myocardium.

Objective

To evaluate if the newly proposed parameter, `area weighted unipolar voltage’ (awUV), can predict HF related death/LVAD/Heart transplant (HFD) in ICM.

Methods

Voltage maps from consecutive patients with ICM referred for CA of VT, were transferred to Paraview after valve area removal. AwUV was calculated by mathematically interpolating all mapping points weighted for relative distances divided by the LV endocardial surface. Unipolar low voltage areas (ULVA, UV<8.27mV) were measured as percentage of the total LV surface. Associations between clinical and mapping derived parameters and HFD (HF-related death/LVAD/heart transplant) were evaluated and validated in a second cohort of consecutive patients.

Results

Eighty-nine patients in the study group (age 68±8; LVEF 33% [IQR 24-40%]; ULVA 64% [IQR 46-86%]; awUV 7.01 [IQR 5.01-8.52]) and 69 patients in the validation group (age 68±9; LVEF 39% [IQR 29-44%]; ULVA 59% [IQR 43-77%]; awUV 7.60 [IQR 6.16-8.69]) were included. Follow-up was 32±17 months in the study group, 28±17 months in the validation group. HFD was 20% in the study group, 10% in the validation cohort. Patients with HFD had lower LVEF and awUV, and larger ULVA than patients without HFD (LVEF 23±10% vs. 35±11%; awUV: 5.12±1.92 vs. 7.75±2.64; LVA 86±21% vs. 60±23%, all P<0.001). Univariable analysis showed that LVEF, ULVA and awUV were associated with HFD (HR and 95% CI: LVEF 1.10 [1.05 – 1.16]; LVA 1.05 [1.02 – 1.08]; awUV 2.18 [1.58 – 3.40], all P<0.01). AwUV was superior to ULVA to predict HFD in likelihood ratio calculations (awUV: LR 5.66, P=0.02; LVA: 1.76 P=0.18) and ROC analysis (AUC awUV: 0.86; LVA 0.78). The optimal cut-off for awUV of<5.27 was highly accurate to predict HFD in the validation cohort (log-rank P<0.001).

Conclusion

The newly proposed parameter awUV, easily available from routine voltage mapping, may be useful at identifying ICM patients at risk for HFD.

675Non-sustained ventricular tachycardia in nonischemic dilated cardiomyopathy: results from a nonischemic cardiomyopathy study

Background

The underlying substrates and mechanisms of non-sustained ventricular tachycardia (NSVT) in nonischemic dilated cardiomyopathy (DCM) are unclear and may be different than those of sustained VT.

Purpose

To characterize NSVT in DCM and analyze its association with late gadolinium enhancement (LGE) on CMR, inducibility of sustained VT during EP study, and ventricular arrhythmias during follow-up.

Methods

In the prospective Leiden Nonischemic Cardiomyopathy Study (ClinicalTrials.gov Identifier: NCT01940081) patients with DCM underwent a comprehensive evaluation. For the present study, 24h-Holters were assessed for the presence of NSVT (defined as ≥3 consecutive beats arising below the atrioventricular node with a rate ≥120 bpm and lasting <30 s) and its features (number of episodes, rate, rate variability >10%, duration, coupling interval and morphology). CMRs were assessed for the presence of LGE and EP studies for inducibility of sustained monomorphic VT. Patients were followed and ICDs were programmed with therapy >188-200 bpm or adjusted to clinically documented VT.

Results

Of all 148 patients, 95 underwent a 24-hour Holter at the Leiden University Medical Center and were included in the present study (age 59 ± 13 years, 76% male, history of sustained VT in 26 [27%], out-of-hospital cardiac arrest in 7 [9%]). NSVT was observed during Holter in 52 patients (55%) and was typically short (median 4 beats, IQR 3-5 beats), relatively slow (median 144 bpm, IQR 134-156 bpm), irregular (median 67%, IQR 43-100% of all episodes per patient) and monomorphic (median 87%, IQR 12-100%). NSVT was not associated with LGE on CMR (p = 0.49) or VT inducibility during EP study (p = 0.96), nor were its features (all p > 0.05). During 4.0 ± 1.7 years follow-up, sustained VT occurred in 25 patients (26%), polymorphic VT/VF in 8 (8%), and any sustained ventricular arrhythmia in 30 (32%). NSVT was associated with a higher rate of sustained VT during follow-up (HR 5.45, p = 0.002) and any sustained ventricular arrhythmia (HR 4.17, p = 0.002), but not with polymorphic VT/VF (p = 0.69). Similarly, inducibility of sustained VT during EP study was also associated with sustained VT during follow-up (HR 5.78, p < 0.001) and any sustained ventricular arrhythmia (HR 4.88, p < 0.001), but not with polymorphic VT/VF (p = 0.13). The findings remained similar when only primary prevention patients were included. In multivariate analysis, NSVT on Holter and inducibility of sustained VT during EP study both remained independently associated with sustained VT and any sustained ventricular arrhythmia during follow-up (all p ≤ 0.001), but not with polymorphic VT/VF.

Conclusion

In DCM, NSVT on Holter and inducible sustained VT during EP study are not directly interrelated, but both predict the occurrence of sustained VT during follow-up. These data suggest that non-sustained and sustained VT may have different underlying mechanisms and provide complementary information in DCM.

Abstract Figure. Sustained VT during follow-up

Abdominal obesity reduction in indigenous men

OBJECTIVES

To assess the effectiveness of a men's 'waist loss' program over one year in Indigenous men.

DESIGN

Pre-and post-test measurements of 47 Indigenous men on four island groups in the Torres Strait region of Northern Australia involved in a version of the 'GutBuster' program, modified by and for Indigenous men.

RESULTS

Weight, waist and hip size of 47 men, and body fat estimated from electrical impedence measures of 27 men, were compared at baseline, after approx 2 months, approx 6 months and approx one year. Average weight loss was 3.3 kg (3.5%), and waist loss 4.0 cm (3.5%). The average percentage decrease in fat mass (FM) was 10.8%. An environmental audit technique highlighted modifications needed to the environment to assist behaviour change.

CONCLUSIONS

Education-behaviour change interventions of this kind may offer opportunities for health improvements in Indigenous men.