P605Correlation of left atrial phasic transport function and arrhythmogenic substrate in patients with atrial fibrillation: cardiac magnetic resonance feature tracking and bipolar voltage mapping

Background

Bipolar voltage mapping is a widely accepted approach to identify areas of arrhythmogenic substrate in patients presenting for atrial fibrillation (AF) ablation.

However, until now little is known about the correlation of left atrial (LA) bipolar voltage distribution and LA transport function.

Purpose

To study the impact of LA low voltage zones (LVZ) on LA transport function.

Methods

107 consecutive patients presenting for ablation of symptomatic AF (34 paroxysmal AF, 73 persistent AF) were prospectively enrolled. Each patient underwent cardiac magnetic resonance imaging (CMR) within 24 hours prior to the ablation procedure. 59 patients were in sinus rhythm (SR) and 48 in AF. LA phasic indexed volumes (LAVi) and ejection fractions were calculated using biplane area length formula. In addition LA phasic strains and strain rates were analyzed using dedicated software (Figure 1A & B).

LA bipolar voltage mapping was performed prior to beginning of ablation in sinus rhythm using a 3-dimensional mapping system and LVZ were defined as areas of bipolar voltage <0.5mV.

Results

LVZ were present in 47 patients (23 in SR). The area of LVZ was 14.6cm2 (5.3–34.0). For patients in AF at the time of CMR only elevated minimal and maximal LAVi (p=0.001 and p=0.002 respectively) but no LA functional parameter was predictive for the occurrence of LVZ. In contrast for patients in SR all LA phasic volumes (endsystolic, pre atrial contraction and enddiastolic LAVi) and LA function parameters (passive, active and total ejection fraction (EF), reservoir, conduit and booster pump strains and strain rates) were predictive for the occurrence of LVZ. After clustered and pooled multivariate logistic regression only impaired booster pump strain rate was still predictive for occurrence of LVZ (OR 0.974, 95% CI 0.950–0.998, p=0.036).

In addition Pearson correlation analysis revealed a strong link between LA booster pump functional parameters and cm2 expansion of LVZ areas: LA active EF, LA booster pump strain and SR (r=−0.42, p=0.044; r=−0.47, p=0.024; r=−0.65, p=0.001 [Figure 1C] respectively).

Conclusion

For patients in SR LA transport function is closely linked to the occurrence of LA LVZ and outperforms LA volumetric measurements for the prediction of LA LVZ.

Furthermore LA booster pump function parameters show robust correlation to the extension of LA LVZ.

P5573Disproportionate functional mitral regurgitation: advancing a conceptual framework from bench to bedside

Introduction

A recently proposed conceptual framework seeks to rearrange the effective regurgitant orifice area (EROA) and regurgitant volume (RegVol) cut-offs according to left ventricular end-diastolic volume (LVEDV) and left ventricular ejection fraction (LVEF) in functional mitral regurgitation introducing “disproportionate FMR” to describe clinically meaningful FMR. The conceptual framework, however, remains hypothetical.

Purpose

To test the significance of disproportionate FMR.

Methods

Data of 291 heart failure patients with reduced ejection fraction (HFrEF) under guideline directed therapy were embedded into this conceptual framework (Figure 1A). The black line represents the relationship when the degree of FMR is proportionate to LVEDV with a regurgitant fraction of (RegFrac) of 50%. The dashed lines represent the degree of uncertainty determined by the imprecision inherent to the measurement of RegFrac defined as 2SD for inter- and intraobserver variability by Bland-Altmann analysis (equals ±6.6%). Cox-regression and Kaplan-Meier analysis were applied to assess the association between FMR proportionality and mortality.

Results

Median age was 68 years (IQR 61–75), 77% were male. Median LVEF was 25% (IQR 18–33) and LVEDV was 214ml (IQR 165–267). Disproportionate FMR was present in 71 patients (24%) (red dots Figure 1A) with a median EROA of 0.26cm2 (IQR 0.18–0.34) and a median RegVol of 42ml (IQR 28–52), proportionate FMR (yellow dots Figure 1 A) in 81 patients (28%) with a median EROA of 0.12cm2 (IQR 0.09–0.17) and a median RegVol of 18ml (IQR 14–27). During 7-years follow-up, 166 patients died. Disproportionate FMR was associated with excess mortality compared to patients with non-severe FMR (HR 1.97, 95% CI 1.04–0.71, P<0.001), whereas proportionate FMR was not associated with increased long-term mortality (HR 1.04, 95% CI −1.53–0.71, P=0.83, Figure 1B).

Figure 1. Panel A and B

Conclusion

Every fifth patient suffers from disproportionate FMR which conveys a two-fold increased risk of mortality. Disproprtionate FMR corresponds to an EROA of roughly 0.3cm2 and a RegVol of 45ml – the unifying intersection between ESC and ACC/AHA guidelines to define severe FMR. The RegFrac provides a measure proportionated to left ventricular size and function supporting its use to define clinically relevant FMR. However, RegFrac is subject to compound error due to imputation of multiple measurements limiting its use as the leading contender for FMR grading. Regardless of the term used to describe clinically significant FMR, the conceptual framework emphasizes the unmet clinical need for recalibrated cut-offs for FMR severity condensed to an algorithm that combines the strengths of several measurements of FMR severity in an integrated manner.

131Left atrial phasic function in heart failure with preserved ejection fraction: cardiac magnetic resonance myocardial feature tracking, invasive hemodynamics and outcome

Background

Global left atrial (LA) size and function have been shown to be associated with adverse events in heart failure with preserved ejection fraction (HFpEF). The machanism of coupling from left heart failure to pulmonary circulation is still controversially discussed.

Purpose

To study the prognostic most relevant determinant of LA size and function and its backward and forward interplay.

Methods

188 HFpEF patients were prospectively enrolled and underwent baseline clinical assessment, cardiac magnetic resonance imaging (CMR) and invasive hemodynamic assessment. Coronary artery disease was ruled out by coronary angiography. 92 patients were in atrial fibrillation (AF), 96 in sinus rhythm. LA size and function were assessed by CMR including LA strain imaging by myocardial feature tracking (Figure 1A & B).

Results

Patients in AF had more pronounced dilatation of all phasic LA volumes and reduction of all phasic LA functions when compared to sinus rhythm (each p<0.001 respectively).

After 31 (9–57) months 66 patients reached the combined endpoint defined as combination from hospitalization due to heart failure and cardiovascular death. In AF no atrial functional or volume parameter was correlated to outcome. In contrast in sinus rhythm several phasic LA volume and functional parameters were associated with outcome. After multivariate cox regression analysis only reduced total LA ejection fraction and conduit strain rate were still predictive for worse outcome (p=0.031 and <0.001 respectively). After adjustment for known risk factors in HFpEF like age, six minute walking distance (6MWD), systolic pulmonary artery pressure (sPAP) and right ventricular ejection fraction as derived by CMR only impaired LA conduit strain rate remained predicitve for cardiovascular events (p=0.001). In contrast to LA booster pump function LA conduit function parameters were significantly correlated to reduced 6MWD (Figure 1C) and coupled backwards to pulmonary vasculature via correlation to sPAP and pulmonary vascular resistance (PVR) but without coupling to CMR derived elevated LV extracellular volume and left ventricular end diastolic pressure.

Conclusion

Total LA ejection fraction plays a key role in the prognosis of HFpEF. This effect seems to be mainly related to its LA conduit function but not to LA booster pump function. LA conduit function correlates to impaired 6MWD, sPAP and PVR.

P4128The right heart in patients undergoing transcatheter aortic valve replacement: insights from cardiac magnetic resonance imaging

Background

Cardiac magnetic resonance (CMR) provides the gold standard for the assessment of ventricular volumes and mass. However, data on right ventricular systolic dysfunction (RVSD) and its prognostic significance on outcome in patients undergoing transcatheter aortic valve replacement (TAVR) are lacking.

Methods

We consecutively enrolled patients with severe aortic stenosis scheduled for TAVR who underwent preprocedural CMR. Kaplan-Meier estimates and multivariate Cox-regression analysis were used to identify factors associated with outcome, including RVSD. A composite of heart failure hospitalization and/or cardiovascular death was selected as primary study endpoint.

Results

145 consecutive patients (80.5±7.6 years; 51.7% female) were prospectively included, 25 (17.2%) of which had RVSD defined as RV ejection fraction (RVEF) <40%. RVSD was significantly associated with male sex, atrial fibrillation, reduced left ventricular (LV) EF (<50%) and RV endsystolic volume on CMR (all p<0.05). Serum NT-proBNP (14065±12042 vs. 3203±4615 ng/ml; p<0.001) and creatinine levels (1.59±0.96 vs. 1.29±1.03 mg/dl; p=0.201) were elevated in patients with RVSD. A total of 27 events occurred during follow-up (29±13 weeks). While LVSD was not significantly associated with outcome (p=0.654), RVSD showed a strong and independent association with event-free survival in the multivariate Cox-regression analysis [hazard ratio 3.836 (95% confidence interval 1.670–8.810); p=0.002], which included all relevant CMR parameters, cardiovascular risk factors and routine biomarkers.

Conclusions

RVSD rather than LVSD, as determined by CMR, is an important predictor of outcome in patients undergoing TAVR. RV function might thus add useful prognostic information on top of established risk factors.

Aortic valve stenosis awareness in Austria-results of a nationwide survey in 1001 subjects

Despite the prognostic significance of severe aortic valve stenosis, knowledge is limited in the general population. To document the status quo for Austria, knowledge about valvular heart disease/aortic valve stenosis was documented in 1001 participants >60 years of age. 6.7% of respondents were knowledgeable of aortic valve stenosis, with 1.6% being concerned about the condition (24.1% cancer, 18.8% Alzheimer’s disease, 15.1% stroke). 29.5% were familiar with valvular heart disease (76.7% heart attack, 36.9% stroke). Only 1/3 reported auscultation by their general practitioner (GP) at least every third visit. Typical symptoms of aortic valve stenosis were likely to be reported by 50%. After exposure to further information on aortic valve stenosis, only 20% reported to be more concerned and ready to obtain more disease-related information. Awareness of surgical and catheter-based treatment options was claimed by 77% of respondents. Awareness campaigns on valvular heart disease are warranted to improve patient care in Austria.

Native T1 time of right ventricular insertion points by cardiac magnetic resonance: relation with invasive haemodynamics and outcome in heart failure with preserved ejection fraction

Aims

Increased afterload to the right ventricle (RV) has been shown to induce myocardial fibrosis at the RV insertion points (RVIPs). Such changes can be discrete but potentially detected by cardiac magnetic resonance (CMR) T1-mapping. Whether RVIP fibrosis is associated with prognosis in heart failure with preserved ejection fraction (HFpEF) is unknown.

Methods and results

We prospectively investigated 167 consecutive HFpEF patients, a population frequently suffering from post-capillary pulmonary hypertension, who underwent CMR including T1-mapping. About 92.8% also underwent right heart catheterization for haemodynamic assessment.

Native T1 times were 995 ± 73 ms at the anterior and 1040 ± 90 ms at the inferior RVIP. By Spearman’s rank order testing, RVIP T1 times were significantly correlated with pulmonary artery pressure (mean PAP, r = 0.313 and 0.311 for anterior and inferior RVIP), pulmonary artery wedge pressure (r = 0.301 and 0.251) and right atrial pressure (r = 0.245 and 0.185; P for all &lt;0.05). During a mean follow-up of 43.2 ± 22.6 months, 30 (18.0%) subjects died. By multivariable Cox regression, NTproBNP [Hazard ratio (HR) 2.105, 95% confidence interval (CI) 1.332–3.328; P = 0.001], systolic PAP (HR 1.618, 95% CI 1.175–2.230; P = 0.003), and native T1 time of the anterior RVIP (HR 1.659, 95% CI 1.125–2.445; P = 0.011) were significantly associated with outcome. Also, by Kaplan–Meier analysis, T1 times at the anterior RVIPs had a significant effect on survival (log-rank, P = 0.002).

Conclusion

Interstitial expansion of the anterior RVIP as detected by CMR T1-mapping reflects haemodynamic alterations, and is independently related with prognosis in HFpEF.

Angs (Angiotensins) of the Alternative Renin-Angiotensin System Predict Outcome in Patients With Heart Failure and Preserved Ejection Fraction

The renin-angiotensin system plays an important role in the development and progression of heart failure (HF). In addition to the classical renin-angiotensin pathway, an alternative pathway produces Angs (angiotensins), which counteract the negative effects of Ang II. We hypothesized that Ang profiling could provide insights into the pathogenesis and prognosis of HF with preserved ejection fraction. We aimed to investigate the effects of Angs on outcome in HF with preserved ejection fraction. Consecutive patients were included into a prospective single-center registry. Clinical, laboratory, and imaging parameters were assessed and serum samples were taken at baseline and measured by mass spectroscopy. Serum equilibrium levels were analyzed in regard to the combined clinical end point of cardiovascular death or HF hospitalization. In total, 155 patients were included during a median follow-up time of 22.5 (interquartile range, 4.0-61.0) months, 52 individuals (34%) reached the combined end point. We identified higher levels of Ang 1-7 and Ang 1-5 as predictors for poor outcome. After adjusting for potential confounding factors, Ang 1-5 remained predictive for poor outcome. In addition to Ang 1-7 and Ang 1-5, the novel ACE (angiotensin-converting enzyme) independent Ang composite marker [Ang 1-7+Ang 1-5] was shown to predict adverse events. We conclude that Angs of the alternative renin-angiotensin system seem to play a role in HF with preserved ejection fraction and are linked to outcome in patients with HF and preserved ejection fraction. Ang 1-5 and the alternative renin-angiotensin system composite marker [Ang 1-7+Ang 1-5] are independent predictors of outcome.

EXPRESS: Riociguat for the treatment of transthyretin cardiac amyloidosis - Data from a named patient use program in Austria

Patients with transthyretin cardiac amyloidosis (TTR CA) suffer from impaired exercise capacity, have a poor quality of life (QoL), and approved treatments are lacking. Stimulators of the soluble guanylate cyclase are promising new pharmaceuticals in the treatment armamentarium of heart failure patients. The aim of the present study was to report on the safety and efficacy of riociguat administration in patients with TTR CA. TTR CA patients received riociguat for 4–6 months within the frames of a national named patient use (NPU) program. Parameters of interest included changes in submaximal exercise capacity, invasive hemodynamic parameters, and QoL. Between March 2012 and June 2017, 86 CA patients were screened for the NPU program, of whom 13 TTR CA patients were eligible for participation. In our study cohort, riociguat had an acceptable tolerability profile. At follow-up, we could detect slight improvements in median 6-min walk distance (396 m [interquartile range (IQR) = 340–518] vs. 400 m [IQR = 350–570], P  = 0.045), New York Heart Association class ≥ III (n = 7 [53.9%] vs. n = 0 [0.0%], P  = 0.031), cardiac output (4.3 L/min [IQR = 3.9–5.1] vs. 4.5 L/min [IQR = 4.2–5.1], P  = 0.022), diastolic pressure gradient (1.0 mmHg [IQR = −1.5–3.0) vs. −1.0 mmHg [IQR = −3.0–1.0], P  = 0.049), and QoL (50.0% [IQR = 40.0–58.0] vs. 60.0% [IQR = 50.0–75.0], P  = 0.021). Pulmonary arterial pressures were not altered. The present case series of TTR CA patients indicates that riociguat administration was safe and associated with minor clinical as well as hemodynamic improvements.