Endocardial repolarization dispersion in BrS: A novel automatic algorithm for mapping activation recovery interval

INTRODUCTION

Repolarization dispersion in the right ventricular outflow tract (RVOT) contributes to the type-1 electrocardiographic (ECG) phenotype of Brugada syndrome (BrS), while data on the significance and feasibility of mapping repolarization dispersion in BrS patients are scarce. Moreover, the role of endocardial repolarization dispersion in BrS is poorly investigated. We aimed to assess endocardial repolarization patterns through an automated calculation of activation recovery interval (ARI) estimated on unipolar electrograms (UEGs) in spontaneous type-1 BrS patients and controls; we also investigated the relation between ARI and right ventricle activation time (RVAT), and T-wave peak-to-end interval (Tpe) in BrS patients.

METHODS

Patients underwent endocardial high-density electroanatomical mapping (HDEAM); BrS showing an overt type-1 ECG were defined as OType1, while those without (latent type-1 ECG and LType1) received ajmaline infusion. BrS patients only underwent programmed ventricular stimulation (PVS). Data were elaborated to obtain ARI corrected with the Bazett formula (ARIc), while RVAT was derived from activation maps.

RESULTS

39 BrS subjects (24 OType1 and 15 LTtype1) and 4 controls were enrolled. OType1 and post-ajmaline LType1 showed longer mean ARIc than controls (306 ± 27.3 ms and 333.3 ± 16.3 ms vs. 281.7 ± 10.3 ms, p = .05 and p < .001, respectively). Ajmaline induced a significant prolongation of ARIc compared to pre-ajmaline LTtype1 (333.3 ± 16.3 vs. 303.4 ± 20.7 ms, p < .001) and OType1 (306 ± 27.3 ms, p < .001). In patients with type-1 ECG (OTtype1 and post-ajmaline LType1) ARIc correlated with RVAT (r = .34, p = .04) and Tpec (r = .60, p < .001), especially in OType1 subjects (r = .55, p = .008 and r = .65 p < .001, respectively).

CONCLUSION

ARIc mapping demonstrates increased endocardial repolarization dispersion in RVOT in BrS. Endocardial ARIc positively correlates with RVAT and Tpec, especially in OType1.

A proposed index of myocardial staining for vein of Marshall ethanol infusion: an Italian single-center experience

BACKGROUND

Mitral isthmus (MI) conduction block is a fundamental step in anatomical approach treatment for persistent atrial fibrillation (PeAF). However, MI block is hardly achievable with endocardial ablation only. Retrograde ethanol infusion (EI) into the vein of Marshall (VOM) facilitates MI block. Fluorographic myocardial staining (MS) during VOM-EI could be helpful in predicting procedural alcoholization outcome even if its role is qualitatively assessed in the routine. The aim was to quantitatively assess MS during VOM-EI and to evaluate its association with MI block achievement.

METHODS

Consecutive patients undergoing catheter ablation for PeAF at Fondazione Toscana Gabriele Monasterio (Pisa, Italy) from February 2022 to May 2023 were considered. Patients with identifiable VOM were included. A proposed index of MS (MSI) was retrospectively calculated in each included patient. Correlation of MSI with low-voltage zones (LVZ) extension after VOM-EI and its association with MI block achievement were assessed.

RESULTS

In total, 42 patients out of 49 (85.8%) had an identifiable VOM. MI block was successfully achieved in 35 patients out of 42 (83.3%). MSI was significantly associated with the occurrence of MI block (OR 1.24 (1.03-1.48); p = 0.022). A higher MSI resulted in reduced ablation time (p = 0.014) and reduced radiofrequency applications (p = 0.002) to obtain MI block. MSI was also associated with MI block obtained by endocardial ablation only (OR 1.07 (1.02-1.13); p = 0.002). MSI was highly correlated with newly formed LVZ extension (r = 0.776; p = 0.001).

CONCLUSIONS

In our study cohort, optimal MSI predicts MI block and facilitates its achievement with endocardial ablation only.

Impact of Vein of Marshall Ethanol Infusion Combined with Anatomical Ablation for the Treatment of Persistent Atrial Fibrillation: A Long-Term Follow-Up Based on Implantable Loop Recorders

BACKGROUND

The best ablation treatment for persistent atrial fibrillation (PeAF) patients is still debated. The vein of Marshall (VOM) seems to be a promising target for ablation and could be combined with a linear set of ablation lesions. The aim of our study is to evaluate the incidence of AF recurrences in a PeAF population treated with a comprehensive ablation approach consisting of VOM ethanol infusion (EI), pulmonary vein isolation (PVI), a left atrial (LA) roofline, a mitral line (guided by the newly formed lesion after alcohol infusion into the VOM and validated by pacing), and a cavotricuspid isthmus line.

METHODS

Consecutive patients undergoing the first ablation procedure of catheter ablation (CA) for PeAF were enrolled. All patients underwent VOM-EI, PVI, and ablation lines along the roof of the LA, mitral, and cavotricuspid isthmus. LA voltage mapping before and after VOM-EI was also performed. An implantable loop recorder (ILR) was implanted at the end of the ablation in each patient.

RESULTS

Thirty-one consecutive patients (66 ± 8 years and 71% male) affected by PeAF were included in this study. The VOM-EI procedural phase lasted 21.4 ± 10.1 min. PV isolation and lines were validated in all subjects. The ML block was achieved within 10.8 ± 8.7 min. At a mean follow-up of 12 ± 7 months, 27 out of 31 (87%) patients remained free from AT/AF recurrences. Among the patients with recurrences, two (50%) had incomplete ablation lesions and three (75%) had "suboptimal" VOM-EI. In 23/31 patients (74%), antiarrhythmic drugs (AADs) were discontinued after 1 month of follow-up. No significant complications were reported during the follow-up.

CONCLUSIONS

this single-center experience demonstrates that VOM-EI systematically combined with an anatomical ablation set in patients with PeAF resulted in feasible, safe, and effective freedom from AF/AT recurrences in 87% of the population after a 1-year follow-up period according to an ILR.

[Management of postoperative arrhythmias in the tetralogy of Fallot: a literature review]

Tetralogy of Fallot (ToF) occurs in about 4 births/1000/year and represents about one tenth of all congenital heart diseases. Nowadays 86% of patients reach adulthood with corrective surgery. Before the 1980s, these patients were treated only with "surgical palliation", which consisted in the creation of a systemic to pulmonary artery shunt or a pulmonary valvulotomy, whereas after the introduction of extracorporeal circulation, corrective surgery is performed electively between 3 and 6 months of life. After repair patients during their life may develop hemodynamic lesions, including right ventricular outflow tract dysfunction, and arrhythmias which can occur in over 30% of cases. It is estimated that these patients present a risk of sudden death of 0.2%/year. Therefore, for the prevention and treatment of arrhythmic events, a periodic follow-up in specialized centres for adult congenital heart disease is mandatory, because most often arrhythmias are triggered by the presence of hemodynamic lesions, first of all pulmonary regurgitation.

The Subcutaneous Implantable Cardioverter-Defibrillator: A Patient Perspective

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is a new technology for the management of ICD patients. But what is the patients' perspective? Previous studies on the transvenous ICD (TV-ICD) showed that device implantation is related not only to anxiety and depression because of the fear of ICD shocks, but also to many biopsychosocial factors like body image changes, perceived reduction of socialization and limitation in professional and sports activities. Anxiety and distress are more evident in younger women because of aesthetic reasons. The scar size and the position of the S-ICD can help these patients and positively influence their social relationships. Moreover, the position of the S-ICD reduces possible complications from catheters due to stress injury and can improve patients' professional life by avoiding some work activity limitations. An S-ICD can be also a good option for athletes in avoiding subclavian crash and reducing inappropriate shocks. However, some questions remain unsolved because an S-ICD is not suitable for patients with indications for pacing, cardiac resynchronization therapy or anti-tachycardia pacing. In conclusion, the use of an S-ICD can assist physicians in reducing the negative impact of implantation on the well-being of some groups of patients by helping them to avoid depression and anxiety as well as improving their noncompliance with their medical treatment.

Overcoming Underpowering in the Outcome Analysis of Repaired-Tetralogy of Fallot: A Multicenter Database from the CMR/CT Working Group of the Italian Pediatric Cardiology Society (SICPed)

Background: Managing repaired tetralogy of Fallot (TOF) patients is still challenging despite the fact that published studies identified prognostic clinical or imaging data with rather good negative predictive accuracy but weak positive predictive accuracy. Heterogeneity of the initial anatomy, the surgical approach, and the complexity of the mechanism leading to dilation and ventricular dysfunction explain the challenge of predicting the adverse event in this population. Therefore, risk stratification and management of this population remain poorly standardized. Design: The CMR/CT WG of the Italian Pediatric Cardiology Society set up a multicenter observational clinical database of repaired TOF evaluations. This registry will enroll patients retrospectively and prospectively assessed by CMR for clinical indication in many congenital heart diseases (CHD) Italian centers. Data collection in a dedicated platform will include surgical history, clinical data, imaging data, and adverse cardiac events at 6 years of follow-up. Summary: The multicenter repaired TOF clinical database will collect data on patients evaluated by CMR in many CHD centers in Italy. The registry has been set up to allow future research studies in this population to improve clinical/surgical management and risk stratification of this population.

Mid-Term Electrical Remodeling after Percutaneous Atrial Septal Defect Closure with GCO Device in a Pediatric Population

BACKGROUND AND AIM

The GORE® CARDIOFORM (GCO) septal occluder is an atrial septal defect/patent foramen ovale closure device with theoretical advantages over other commercialized devices thanks to its softness and anatomical compliance. Our aim was to evaluate the short- and medium-term electrocardiographic changes after percutaneous ASD closure with GCO in a pediatric population.

METHODS

We enrolled 39 patients with isolated ASD submitted to trans-catheter closure from January 2020 to June 2021. ECG was performed before, at 24 h and 6 months after the procedure. P wave dispersion, QTc and QTc dispersion were calculated. ECG Holter was recorded at 6 months after implantation.

RESULTS

Patients' age and body surface area (BSA) were 8.2 ± 4.2 years and 1.0 ± 0.3 m2 respectively. At the baseline, mean P wave dispersion was 40 ± 15 msec and decreased at 24 h (p < 0.002), without any further change at 6 months. At 24 h, PR conduction and QTc dispersion significantly improved (p = 0.018 and p < 0.02 respectively), while the absolute QTc value considerably improved after 6 months. During mid-term follow-up, QTc dispersion remained stable without a significant change in PR conduction. The baseline cardiac frequency was 88.6 ± 12.6 bpm, followed by a slight reduction at 24 h, with a further amelioration at 6 months after the procedure (87.3 ± 14.2, p = 0.9 and 81.0 ± 12.7, p = 0.009, respectively). After device deployment, two patients developed transient, self-limited junctional rhythm. One of them needed a short course of Flecainide for atrial ectopic tachycardia. No tachy/brady-arrhythmias were recorded at the 6-month follow-up. ASD closure resulted in a marked decrease in right heart volumes and diameters at 6 months after percutaneous closure.

CONCLUSIONS

Percutaneous ASD closure with the GCO device results in significant, sudden improvement of intra-atrial, atrio-ventricular and intraventricular electrical homogeneity. This benefit persists unaltered over a medium-term follow-up. These electrical changes are associated with a documented positive right heart volumetric remodeling at mid-term follow-up.

Antiplatelet and Anti-Coagulation Therapy for Left-Sided Catheter Ablations: What Is beyond Atrial Fibrillation?

Aim: International guidelines on the use of anti-thrombotic therapies in left-sided ablations other than atrial fibrillation (AF) are lacking. The data regarding antiplatelet or anticoagulation strategies after catheter ablation (CA) procedures mainly derive from AF, whereas for the other arrhythmic substrates, the anti-thrombotic approach remains unclear. This survey aims to explore the current practices regarding antithrombotic management before, during, and after left-sided endocardial ablation, not including atrial fibrillation (AF), in patients without other indications for anti-thrombotic therapy. Material and Methods: Electrophysiologists were asked to answer a questionnaire containing questions on antiplatelet (APT) and anticoagulation therapy for the following left-sided procedures: accessory pathway (AP), atrial (AT), and ventricular tachycardia (VT) with and without structural heart disease (SHD). Results: We obtained 41 answers from 41 centers in 15 countries. For AP, before ablation, only four respondents (9.7%) used antiplatelets and two (4.9%) used anticoagulants. At discharge, APT therapy was prescribed by 22 respondents (53.7%), and oral anticoagulant therapy (OAC) only by one (2.4%). In patients with atrial tachycardia (AT), before ablation, APT prophylaxis was prescribed by only four respondents (9.7%) and OAC by eleven (26.8%). At discharge, APT was recommended by 12 respondents (29.3%) and OAC by 24 (58.5%). For VT without SHD, before CA, only six respondents (14.6%) suggested APT and three (7.3%) suggested OAC prophylaxis. At discharge, APT was recommended by fifteen respondents (36.6%) and OAC by five (12.2%). Regarding VT in SHD, before the procedure, eight respondents (19.5%) prescribed APT and five (12.2%) prescribed OAC prophylaxis. At discharge, the administration of anti-thrombotic therapy depended on the LV ejection fraction for eleven respondents (26.8%), on the procedure time for ten (24.4%), and on the radiofrequency time for four (9.8%), with a cut-off value from 1 to 30 min. Conclusions: Our survey indicates that the management of anti-thrombotic therapy surrounding left-sided endocardial ablation of patients without other indications for anti-thrombotic therapy is highly variable. Further studies are necessary to evaluate the safest approach to these procedures.

[Arrhythmias in adult congenital heart disease at the emergency department: ANMCO Tuscany clinical pathway]

Arrhythmias are a common complication in the adult population with congenital heart disease (ACHD). Arrhythmias often lead to hemodynamic instability and, on the other hand, may be a marker of hemodynamic impairment in ACHD patients, both in natural history and after cardiac surgery. Treatment requires knowledge of basic anatomy and any previous cardiac surgery; the availability of patient's health records, if possible, is therefore crucial for therapeutic choices. In the emergency setting, the first target is represented by the patient's hemodynamic stabilization; mainly in moderate or high complexity ACHD, the connection with the referral center is recommended, to which patients should be entrusted for follow-up. A regional epidemiological observatory, aiming to assess the number, type and outcomes of emergency admissions of ACHD patients could be a useful tool for analyzing the effectiveness of the collaboration network between the different structures involved and for implementing organizational pathways.

Prognostic value of right ventricular refractory period heterogeneity in Type-1 Brugada electrocardiographic pattern

AIMS

To investigate the prognostic significance of heterogeneity in the refractoriness of right ventricular (RV) outflow tract (RVOT) and RV apex at the electrophysiological study (EPS) in Brugada syndrome (BrS).

METHODS AND RESULTS

A cohort of BrS patients (primary prevention) from five Italian centres was retrospectively analysed. Patients with spontaneous or drug-induced Type-1 electrocardiogram (ECG) + symptoms were offered an EPS for prognostic stratification. The primary endpoint was a composite of sudden cardiac death (SCD), resuscitated cardiac arrest, or appropriate intervention by the implantable cardioverter-defibrillator (ICD). Three hundred and seventy-two patients with BrS were evaluated (44 ± 15 years, 69% males, 23% with ICD): 4 SCDs and 17 ICD interventions occurred at follow-up (median 48, interquartile range: 36-60 months). Family history of SCD, syncope, and a spontaneous Type-1 ECG pattern were univariate predictors of the primary endpoint in the whole population. In patients undergoing EPS (n = 198, 53%, 44 ± 12 years, 71% males, 39% with ICD), 3 SCD and 15 ICD interventions occurred at follow-up. In this subset, the primary endpoint was not only predicted by ventricular tachycardia/fibrillation inducibility but also by a difference in the refractory period between RVOT and RV apex (ΔRPRVOT-apex) >60 ms. ΔRPRVOT-apex > 60 ms remained an independent predictor of SCD/ICD shock at bivariate analysis, even when adjusted for the other univariate predictors, showing the highest predictive power at C-statistic analysis (0.75, 95% confidence interval 0.63-0.86).

CONCLUSIONS

Heterogeneity of RV refractory periods is a strong, independent predictor of life-threatening arrhythmias in BrS patients, beyond VT/VF inducibility at EPS and common clinical predictors.

Transmural voltage gradient dispersion and heterogeneity in brugada syndrome phenotype - a novel workflow for advanced mapping using endocardial unipolar electrograms J-point elevation

Funding Acknowledgements

Type of funding sources: None.

Background

Differential action potential duration shortening across the right ventricular (RV) myocardial wall is primarily responsible for the Brugada Syndrome (BrS) phenotype [1]. To date, data on electrical substrate characterization in humans with BrS phenotype is limited and risk evaluation is still controversial.

Purpose

We hypothesized that Uni-JEl mapping could be used as a marker of transmural voltage gradient dispersion resulting. Our aim was to evaluate Uni-JEl mapping in defining arrhythmogenic substrates in patients with BrS phenotype.

Methods

12 patients were included in our analysis. 2 normal patients provided control data and 10 asymptomatic subjects with spontaneous type-1 BrS underwent 3D RV mapping (CARTO3 System, Biosense Webster). Among BrS patients we had 3 patients with arrhythmic events (aborted sudden death or appropriate ICD therapies) during follow-up (median 56, interquartile range: 46-74 months) and 7 patients without arrhythmic events. In the former group we had 1 patient with inducibility of VT/VF during EPS (EPS+) and 2 patients non-inducibles during EPS (EPS-), in the latter group we had 3 patients with EPS+ and 4 patients with EPS-. Electrophysiological data and signals were exported and OpenEP [2] was used to convert Carto proprietary data formats into Matlab format (Fig.1). Uni-JEl was calculated for each point map as the unipolar value at J point on surface electrocardiogram. Uni-JEl values were then interpolated in Paraview to create Uni-JEl maps, interpolating data points on the mesh cell (Fig.1). Finally, a region of interest (ROI) was selected and the calculation of mean Uni-JEI (MUni-JEI, as a measure of voltage gradient dispersion), interquartile range and range (intrqUni-JEI and ∆Uni-JEI, as markers of heterogeneity of dispersion) was performed. Results are shown as mean ± standard deviation for the group of BrS patients and the actual values for the two controls.

Results

BrS patients showed Muni-JEl, intrqUni-JEl and ∆Uni-JEI higher than controls (2.03 mV ± 0.31 mV vs 0,82 mV and 1,1 mV, 1.90 mV ± 0.82 mV vs 1,04 mV and 1,18 mV 6.26 mV ± 1.98 mV vs 3,54 mV and 4,01 mV, respectively). BrS patients with arrhythmic events during the follow-up showed higher intrqUni-JEl and the ∆Uni-JEI respect to BrS with EPS+ and without arrhythmic events during follow-up (2.31 mV ± 0.44 mV vs 0.78 mV ± 0.11 mV and 6.69 mV ± 2.27 mV vs 3.98 mV ± 0.31 mV). Figure 2 shows some examples of calculated Uni-JEl maps for each group under study.

Conclusions

In this work we introduced a novel workflow for the electrical substrate characterization of subjects with BrS phenotype. The results from our preliminary analysis indicate that a higher transmural voltage gradient dispersion and heterogeneity can be found in type-1 BrS with respect to normal subjects. Voltage gradient dispersion heterogeneity could be used to better recognize high risk BrS patients regardless of VT/VF inducibility during EPS.

Short-term electrocardiographic atrial remodelling after asd closure with the gco device in a pediatric population

Funding Acknowledgements

Type of funding sources: None.

Background and Aim

The GORE® CARDIOFORM septal occluder (GCO) is an atrial septal defect/patent foramen ovale (ASD/PFO) closure device with theoretical advantages over other commercialized devices thanks to its softness and anatomical compliance.

Our aim was to evaluate the short and medium-term electrocardiographic changes after percutaneous ASD closure with GCO in a pediatric population.

Methods

We enrolled 39 patients with isolated ASD submitted to trans-catheter closure with GCO from January 2020 to June 2021. EKG was performed before (T0), at 24 hours (T1) and 6 months (T2) after ASD transcatheter closure. P wave dispersion was calculated as the difference between maximum and minimum P- wave duration, PR interval as the interval between beginning of the P wave and beginning of the QRS complex and QT dispersion as the difference between maximun and minimun of QTc intervals. At 6-months from device implantation, the patients were submitted to ambulatory EKG Holter recording.

Results

Patients’ age and BSA were 8.2±4.2 years (IQR 4.2-8.3, median 7.0) and 1.0±0.3 m2 (IQR 0.7-1.7, median 0.9), respectively. The strectched ASD diameter was 16.3±4.5 mm (median 16), resulting in QP/QS of 1.7±0.6 (median 1.5). At the baseline mean P wave dispersion was 40±15 msec and decreased to 30±13 msec (p&lt;0.002) at 24h, without any further change at 6 months (30±13 msec, p&lt;0.002). PR conduction significantly improved at 24 h from device implantation (from 175.0±20.8 to 144.0±22.7 msec, p=0.018) and did not significantly change at 6 months (164.0±19.5 msec, p=NS). QTc dispersion decreased at 24 hours (31.7±.20.3, p&lt;0.02) and at 6 months (28.0±18.1, p&lt;0.002) from device implantation. After device deployment, 2 pts (5%) developed transient, self-limited junctional rhythm and one of them needed a short course of anti-arrhythmic therapy for supra-ventricular tachycardia. No tachy/brady-arrhythmias were recorded at the 6-months follow-up EKG Holter monitoring.

Conclusions

Percutaneous ASD closure with the GCO device results in significant, sudden improvement of intra-atrial, atrio-ventricular and intraventricular electrical homogeneity. This benefit persists unaltered over a medium term follow-up. It might be due to a favourable volumetric remodelling that was not hindered by mechanical impact of the occluding prosthesis and could explain the low rate of arrhythmias found at the mid-term EKG evaluation.

Heterogeneity of right ventricular refractory period: a novel prognostic predictor in type-1 Brugada

Funding Acknowledgements

Type of funding sources: None.

Risk stratification in Brugada syndrome (BrS) is needed especially for the choice of an Implantable Cardiac Defibrillator (ICD). To date the predictive value of either clinical or conventional electrophysiological indexes in type 1 electrocardiographic pattern BrS is rather low.

We aimed to evaluate the eventual prognostic significance of refractoriness heterogeneity of right ventricular outflow tract, an emergent relevant pathophysiological substrate, at electrophysiological study (EPS) in patients with BrS.

From 5 centers 348 patients were retrospectively selected (age 44 ± 15 years, males 68%). Eighty-five (24%) patients had an ICD. EPS was proposed in patients with spontaneous type-1 ECG pattern regardless of symptoms, or in patients with drug-induced type-1 ECG pattern with symptoms (n = 174). The difference in the refractory period between the right ventricular outflow tract and the apex (ΔRPRVOT-apex) at EPS was evaluated as a prognostic factor. The optimal ΔRPRVOT-apex cutpoint for prognosis prediction was calculated through a P-spline hazard ratio analysis. Thus, ΔRPRVOT-apex  was compared through different statistical analyses to other other clinical or conventional electrophysiological prognostic indexes previosly described in literature. 

During a 36-month median follow-up (range 6-228) 3 SCD and 10 appropriate ICD shocks (aborted SCD, aSCD) occurred. Fifty patients (29%) had a positive EPS (induction of sustained ventricular tachycardia, VT, or ventricular fibrillation, VF, during the procedure). At multivariable logistic analysis, only ΔRPRVOT-apex  and late potentials remained independent predictors of a positive EPS. At Cox Proportional Hazard analysis, family history of SCD, history of syncope, VT/VF inducibility and a ΔRPRVOT-apex &gt;60 ms were all univariate predictors of SCD/aSCD. At bivariate analysis, a ΔRPRVOT-apex &gt;60 ms remained an independent predictor of SCD/aSCD even when adjusted the other univariate predictors. At C-Statistic analysis, the strongest predictive model was the one using ΔRPRVOT-apex &gt;60 ms as covariate with a C-statistics (95% CI) of 0.72 (0.51-0.93). At Kaplan-Meyer curves, ΔRPRVOT-apex &gt;60 ms was confirmed a strong predictor of SCD/aSCD and another very interesting observation was possible: patients with positive EPS, but a ΔRPRVOT-apex &lt; 60 ms, had a similar risk to SCD/aSCD compared to patients with a negative EPS, while those with a positive EPS and a ΔRPRVOT-apex &gt; 60 ms were found to be at a higher risk of events.

Refractory period heterogeneity of the right ventricle defined as ΔRPRVOT-apex &gt; 60 ms at EPS is a strong and independent predictor of SCD/aSCD in patients with BrS, beyond VT/VF inducibility at EPS and common clinical predictors. Abstract Figure.

Central and obstructive apneas prevalence in heart failure with reduced, mid-range and preserved ejection fraction

Background

Central apneas (CA) and obstructive apneas (OA) are highly prevalent in heart failure (HF) both with reduced and preserved systolic function. However, a comprehensive evaluation of apnea prevalence across HF according to ejection fraction (i.e HF with patients with reduced, mid-range and preserved ejection fraction- HFrEf, HFmrEF and HFpEF, respectively) throughout the 24 hours has never been done before.

Materials and methods

700 HF patients were prospectively enrolled and then divided according to left ventricular EF (408 HFrEF, 117 HFmrEF, 175 HFpEF). All patients underwent a thorough evaluation including: 2D echocardiography; 24-h Holter-ECG monitoring; cardiopulmonary exercise testing; neuro-hormonal assessment and 24-h cardiorespiratory monitoring.

Results

In the whole population, prevalence of normal breathing (NB), CA and OA at daytime was 40%, 51%, and 9%, respectively, while at nighttime 15%, 55%, and 30%, respectively.

When stratified according to left ventricular EF, CA prevalence decreased from HFrEF to HFmrEF and HFpEF: (daytime CA: 57% vs. 43% vs. 42%, respectively, p=0.001; nighttime CA: 66% vs. 48% vs. 34%, respectively, p&lt;0.0001), while OA prevalence increased (daytime OA: 5% vs. 8% vs. 18%, respectively, p&lt;0.0001; nighttime OA: 20 vs. 29 vs. 53%, respectively, p&lt;0.0001).

When assessing moderte-severe apneas, defined with an apnea/hypopnea index &gt;15 events/hour, prevalence of CA was again higher in HFrEF than HFmrEF and HFpEF both at daytime (daytime moderate-severe CA: 28% vs. 19% and 23%, respectively, p&lt;0.05) and at nighttime (nighttime moderate-severe CA: 50% vs. 39% and 28%, respectively, p&lt;0.05). Conversely, moderate-severe OA decreased from HFrEF to HFmrEF to HFpEF both at daytime (daytime moderate-severe OA: 1% vs. 3% and 8%, respectively, p&lt;0.05) and nighttime (noghttime moderate-severe OA: 10% vs. 11% and 30%, respectively, p&lt;0.05).

Conclusions

Daytime and nighttime apneas, both central and obstructive in nature, are highly prevalent in HF regardless of EF. Across the whole spectrum of HF, CA prevalence increases and OA decreases as left ventricular systolic dysfunction progresses, both during daytime and nighttime.

Funding Acknowledgement

Type of funding source: None

Central apneas and Ticagrelor related dyspnea in patients with acute coronary syndrome

Background

Patients treated with ticagrelor often develop dyspnea of unknown origin. We aim to explore the contribution of central apneas to ticagrelor-related dyspnea in patients with acute coronary syndrome (ACS).

Methods

We consecutively enrolled patients with ACS, preserved left ventricular ejection fraction and no history of obstructive sleep apnea, treated either with ticagrelor 90 mg bid (n=30) or prasugrel 10 mg od (n=24). One week after ACS onset, all patients underwent, beyond thorough cardiovascular and respiratory assessment, 24-hour cardiorespiratory monitoring and assessment of chemosensitivity to hypercapnia.

Results

Patients treated with ticagrelor reported more frequently dyspnea than patients treated with prasugrel (43% versus 4%, p=0.001), despite no difference in demographic, clinical, echocardiographic and pulmonary data. Patients with dyspnea induced by ticagrelor showed higher apnea-hypopnea and central apnea index both at daytime and at nighttime compared to patients treated with ticagrelor but without dyspnea and patients treated with prasugrel (daytime AHI: 26 [7–34] vs 6 [4–14] and 6 [0–11] events/hour; nighttime AHI: 65 [17–72] vs 22 [8–37] and vs 11 [4–23] events/hour; daytime CAI: 5 [1–15] vs 1 [0–6] and 0 [0–1) events/hour; nighttime CAI 34 [2–55] vs 3 [0–9] and 0 [0–1], all p&lt;0.05). Likewise, they also presented with higher hypercapnic ventilatory response (2.4 [1.9–2.7] vs 1.3 [1.1–1.9] and 0.9 [0.5–2.1] L/min/mmHg, all p&lt;0.05).

Conclusions

Central apneas should be considered a likely mechanism of dyspnea in ACS patients treated with ticagrelor. A drug-related sensitization of the chemoreflex may be the cause of ventilatory instability in this setting.

Funding Acknowledgement

Type of funding source: None

Central apnoeas and ticagrelor-related dyspnoea in patients with acute coronary syndrome

AIMS

Dyspnoea often occurs in patients with acute coronary syndrome (ACS) treated with ticagrelor compared with other anti-platelet agents and is a cause of drug discontinuation. We aimed to explore the contribution of central apnoeas (CA) and chemoreflex sensitization to ticagrelor-related dyspnoea in patients with ACS.

METHODS AND RESULTS

Sixty consecutive patients with ACS, preserved left ventricular ejection fraction, and no history of obstructive sleep apnoea, treated either with ticagrelor 90 mg b.i.d. (n = 30) or prasugrel 10 mg o.d. (n = 30) were consecutively enrolled. One week after ACS, all patients underwent two-dimensional Doppler echocardiography, pulmonary static/dynamic testing, carbon monoxide diffusion capacity assessment, 24-h cardiorespiratory monitoring for hypopnoea-apnoea detection, and evaluation of the chemosensitivity to hypercapnia by rebreathing technique. No differences were found in baseline demographic and clinical characteristics, echocardiographic, and pulmonary data between the two groups. Patients on ticagrelor, when compared with those on prasugrel, reported more frequently dyspnoea (43.3% vs. 6.7%, P = 0.001; severe dyspnoea 23.3% vs. 0%, P = 0.005), and showed higher apnoea-hypopnoea index (AHI) and central apnoea index (CAI) during the day, the night and the entire 24-h period (all P < 0.001). Similarly, they showed a higher chemosensitivity to hypercapnia (P = 0.001). Among patients treated with ticagrelor, those referring dyspnoea had the highest AHI, CAI, and chemosensitivity to hypercapnia (all P < 0.05).

CONCLUSION

Central apnoeas are a likely mechanism of dyspnoea and should be screened for in patients treated with ticagrelor. A drug-related sensitization of the chemoreflex may be the cause of ventilatory instability and breathlessness in this setting.

Benefit of buspirone on chemoreflex and central apnoeas in heart failure: a randomized controlled crossover trial

AIMS

Increased chemosensitivity to carbon dioxide (CO₂ ) is an important trigger of central apnoeas (CA) in heart failure (HF), with negative impact on outcome. We hypothesized that buspirone, a 5HT_1A receptor agonist that inhibits serotonergic chemoreceptor neuron firing in animals, can decrease CO₂ chemosensitivity and CA in HF.

METHODS AND RESULTS

The BREATH study was a randomized, double-blind, placebo-controlled, crossover study (EudraCT-code 2015-005383-42). Outpatients with systolic HF (left ventricular ejection fraction <50%) and moderate-severe CA [nocturnal apnoea-hypopnoea index (AHI) ≥15 events/h] were randomly assigned to either oral buspirone (15 mg thrice daily) or placebo for 1 week, with a crossover design (1 week of wash-out). The primary effectiveness endpoint was a decrease in CO₂ chemosensitivity >0.5 L/min/mmHg. The primary safety endpoint was freedom from serious adverse events. Sixteen patients (age 71.3 ± 5.8 years, all males, left ventricular ejection fraction 29.8 ± 7.8%) were enrolled. In the intention-to-treat analysis, more patients treated with buspirone (8/16, 50%) had a CO₂ chemosensitivity reduction >0.5 L/min/mmHg from baseline than those treated with placebo (1/16, 6.7%) (difference between groups 43%, 95% confidence interval 14-73%, P = 0.016). Buspirone compared to baseline led to a 41% reduction in CO₂ chemosensitivity (P = 0.001) and to a reduction in the AHI, central apnoea index and oxygen desaturation index of 42%, 79%, 77% at nighttime and 50%, 78%, 86% at daytime (all P < 0.01); no difference was observed after placebo administration (all P > 0.05). No patient reported buspirone-related serious adverse events.

CONCLUSIONS

Buspirone reduces CO₂ chemosensitivity and improves CA and oxygen saturation across the 24 h in patients with HF.

Catheter cryoablation of ventricular ectopy originating from his region

Careful mapping, early detection of AV conduction damage and cryothermal energy availability are essential in dealing with ablation procedures at the parahisian region.

The extent and location of late gadolinium enhancement predict defibrillator shock and cardiac mortality in patients with non-ischaemic dilated cardiomyopathy

BACKGROUND

In non-ischaemic dilated cardiomyopathy (NIDCM), it is uncertain which late gadolinium enhancement (LGE) pattern, extent and location predict ventricular arrhythmias.

METHODS

We analysed 183 NIDCM patients (73% men, median age 66 years) receiving an implantable cardioverter defibrillator (ICD) for primary prevention, undergoing cardiac magnetic resonance within 1 month before implantation. The primary endpoint was appropriate ICD shock, the secondary endpoint was a composite of appropriate ICD shock and cardiac death.

RESULTS

LGE was found in 116 patients (63%), accounting for 9% of LV mass (5-13%). Over a 30-month follow-up (10-65), 20 patients (11%) experienced the primary and 30 patients (16%) the secondary endpoint. LGE presence, inferior wall LGE, diffuse (≥2 wall) LGE, the number of segments with LGE, the number of segments with 50-75% transmural LGE, and percent LGE mass were univariate predictors of both endpoints. Also septal LGE predicted the primary, and lateral LGE predicted the secondary endpoint. LGE limited to right ventricular insertion points did not predict any endpoint. Percent LGE mass had an area under the curve of 0.734 for the primary endpoint, with 13% as the best cut-off (55% sensitivity, 86% specificity, 32% PPV, 94% NPV), conferring a 7-fold higher risk compared to patients with no LGE or LGE <13%. Survival free from both endpoints was significantly worse for patients with LGE ≥13%.

CONCLUSIONS

In patients with NIDCM receiving a defibrillator for primary prevention, LGE presence and extent predicted appropriate ICD shock and cardiac mortality; also specific LGE patterns and locations predicted a worse prognosis.

P995The extent of late gadolinium enhancement predicts defibrillator shocks in patients with non-ischaemic heart failure

Background

Implantable cardioverter defibrillator (ICD) is recommended for patients with non-ischaemic heart failure (HF) and left ventricular ejection fraction (LVEF) ≤35%, although most patients will not experience any appropriate ICD intervention. We assessed if cardiovascular magnetic resonance (CMR) findings may predict benefit from ICD implantation.

Methods and results

We retrieved the data of all patients (n=183) with non-ischaemic HF receiving an ICD for primary prevention at our Institution, and undergoing CMR within 1 month before implantation. 183 patients were evaluated (men 73%, median age 66 years, LVEF 24%, N-terminal fraction of pro-B-type natriuretic peptide 1217 ng/L, atrial fibrillation, flutter or atrial ectopic rhythm 21%). They received single-chamber (n=21, 12%), dual-chamber (n=34, 19%), or cardiac resynchronization therapy devices (n=127, 69%); 1 patient (1%) received a subcutaneous defibrillator. Twenty patients (11%) experienced a shock for ventricular tachycardia or fibrillation (VT/VF) over 2.5 years (0.8–5.4), and 13 (7%) had an inappropriate shock over 2.7 years (0.9–5.4). Late gadolinium enhancement (LGE) was present in 146 patients (80%), but on average accounted for limited percentage of LV mass (4% [2–11%]). LGE mass independently predicted shocks for VT/VF (HR 2.13, 95% CI 1.02–4.47; p=0.045). LGE mass ≥14% (the best cut-off at receiver operating characteristics analysis) independently predicted shocks for VT/VF (HR 3.82, 95% CI 1.51–9.68; p=0.005). LGE mass <4% was the only univariate predictor of inappropriate shocks (HR 4.82, 95% CI 1.07–21.76; p=0.041).

Conclusions

Patients with non-ischaemic HF and LGE mass ≥14% benefit most from ICD, while those with LGE mass <4% display mainly inappropriate shocks.

P3525Buspirone effect on chemoreflex and central apneas in heart failure

Background

Increased chemosensitivity to carbon dioxide (CO2) is an important trigger of central apneas in heart failure (HF), contributing to HF progression and mortality. We hypothesized that buspirone, a 5HT1A receptor agonist that inhibits serotonergic chemoreceptor neuron firing in animals, can decrease CO2 chemosensitivity, thus preventing CA in patients with HF.

Methods

Sixteen patients with systolic HF (age 71.3±5.8 years, left ventricular ejection fraction 29.8±7.8%) and moderate-severe central apneas (nighttime apnea/hypopnea index AHI≥15 events/hour) underwent a double-blind, placebo-controlled, cross over, randomized study of oral buspirone administration (45 mg/day for 1 week).

Results

Buspirone reduced CO2 chemosensitivity compared to placebo (1.2 IR [1.1–1.5] vs. 2.0 [1.6–2.2] L/min/mmHg, p=0.008). Furthermore, buspirone improved: the AHI at nighttime (16.5 [8.5–24.7] vs. 27.5 [23.0–37.3] events/hour, p=0.002), and daytime (8.0 [2.3–11.5] vs. 11.5 [6.3–18.8] events/hour, p=0.006); the central apnea index at nighttime (4.0 [1.0–19.0] vs. 12.5 [8.3–27.3] events/hour, p=0.01) and daytime (1.0 [0.0–3.0] vs. 4.0 [1.3–6.0] events/hour, p=0.009); and the oxygen desaturation index at nighttime (4.7 [1.0–11.0] vs. 20.0 [8.7–26.5] events/hour, p=0.004) and daytime (0.2 [0.1–0.7] vs. 1.2 [0.3–4.8] events/hour, p=0.005). Buspirone showed a good safety profile and had no effect on neurohormones, arrhythmias, exercise capacity and mood/daytime sleepiness.

Conclusion

Buspirone reduces CO2 chemosensitivity and inhibits central apneas both during the day and the night in patients with systolic HF.

Central and Obstructive Apneas in Heart Failure With Reduced, Mid-Range and Preserved Ejection Fraction

Background: Although central apneas (CA) and obstructive apneas (OA) are highly prevalent in heart failure (HF), a comparison of apnea prevalence, predictors and clinical correlates in the whole HF spectrum, including HF with reduced ejection fraction (HFrEF), mid-range EF (HFmrEF) and preserved EF (HFpEF) has never been carried out so far.

Materials and methods: 700 HF patients were prospectively enrolled and then divided according to left ventricular EF (408 HFrEF, 117 HFmrEF, 175 HFpEF). All patients underwent a thorough evaluation including: 2D echocardiography; 24-h Holter-ECG monitoring; cardiopulmonary exercise testing; neuro-hormonal assessment and 24-h cardiorespiratory monitoring.

Results: In the whole population, prevalence of normal breathing (NB), CA and OA at daytime was 40, 51, and 9%, respectively, while at nighttime 15, 55, and 30%, respectively. When stratified according to left ventricular EF, CA prevalence decreased (daytime: 57 vs. 43 vs. 42%, p = 0.001; nighttime: 66 vs. 48 vs. 34%, p < 0.0001) from HFrEF to HFmrEF and HFpEF, while OA prevalence increased (daytime: 5 vs. 8 vs. 18%, p < 0.0001; nighttime 20 vs. 29 vs. 53%, p < 0.0001).

In HFrEF, male gender and body mass index (BMI) were independent predictors of both CA and OA at nighttime, while age, New York Heart Association functional class and diastolic dysfunction of daytime CA. In HFmrEF and HFpEF male gender and systolic pulmonary artery pressure were independent predictors of CA at daytime, while hypertension predicted nighttime OA in HFpEF patients; no predictor of nighttime CA was identified. When compared to patients with NB, those with CA had higher neuro-hormonal activation in all HF subgroups. Moreover, in the HFrEF subgroup, patients with CA were older, more comorbid and with greater hemodynamic impairment while, in the HFmrEF and HFpEF subgroups, they had higher left atrial volumes and more severe diastolic dysfunction, respectively. When compared to patients with NB, those with OA were older and more comorbid independently from background EF.

Conclusions: Across the whole spectrum of HF, CA prevalence increases and OA decreases as left ventricular systolic dysfunction progresses. Different predictors and specific clinical characteristics might help to identify patients at risk of developing CA or OA in different HF phenotypes.

Contribution of the Lung to the Genesis of Cheyne-Stokes Respiration in Heart Failure: Plant Gain Beyond Chemoreflex Gain and Circulation Time

Background

The contribution of the lung or the plant gain (PG; ie, change in blood gases per unit change in ventilation) to Cheyne‐Stokes respiration (CSR) in heart failure has only been hypothesized by mathematical models, but never been directly evaluated.

Methods and Results

Twenty patients with systolic heart failure (age, 72.4±6.4 years; left ventricular ejection fraction, 31.5±5.8%), 10 with relevant CSR (24‐hour apnea‐hypopnea index [AHI] ≥10 events/h) and 10 without (AHI <10 events/h) at 24‐hour cardiorespiratory monitoring underwent evaluation of chemoreflex gain (CG) to hypoxia (CGO2) and hypercapnia (CGCO2) by rebreathing technique, lung‐to‐finger circulation time, and PG assessment through a visual system. PG test was feasible and reproducible (intraclass correlation coefficient, 0.98; 95% CI, 0.91–0.99); the best‐fitting curve to express the PG was a hyperbola (R²≥0.98). Patients with CSR showed increased PG, CGCO2 (but not CGO2), and lung‐to‐finger circulation time, compared with patients without CSR (all P<0.05). PG was the only predictor of the daytime AHI (R=0.56, P=0.01) and together with the CGCO2 also predicted the nighttime AHI (R=0.81, P=0.0003) and the 24‐hour AHI (R=0.71, P=0.001). Lung‐to‐finger circulation time was the only predictor of CSR cycle length (R=0.82, P=0.00006).

Conclusions

PG is a powerful contributor of CSR and should be evaluated together with the CG and circulation time to individualize treatments aimed at stabilizing breathing in heart failure.

Targeting Mitochondrial Dysfunction in Chronic Heart Failure: Current Evidence and Potential Approaches

BACKGROUND

Mitochondria are cellular organelles responsible for energy production, calcium handling, controlled synthesis of reactive oxygen species (ROS), and regulation of apoptosis. All these functions are crucial for cardiac homeostasis, and may be impaired in chronic heart failure (CHF). Therefore, mitochondrial dysfunction might represent a crucial element in the onset and progression of CHF and, as such, a promising therapeutic target.

METHODS

Original articles and review on the treatment of mitochondrial dysfunction in CHF were searched on Medline and Scopus.

RESULTS

The present review summarizes the current knowledge about mitochondrial modulation as a therapeutic strategy for CHF, and proposes some perspectives for future studies. Mitochondrial dysfunction can be ascribed to neuro-humoral activation and cardiac remodeling associated with CHF. Conceptually, the correction of mitochondrial dysfunction could provide an additive benefit to optimal CHF treatment. Increasing glucose metabolism and reducing oxidative stress within mitochondria are the two most promising approaches, even though further studies are required before implementing new treatments in the setting of CHF. On the other hand, inhibition of apoptosis, and normalization of calcium and mitochondrial dynamics have been assessed almost exclusively in ex vivo models, and mostly in settings other than CHF.

CONCLUSION

Mitochondrial modulation in CHF is an intriguing example of translational research and a potentially rewarding field.

Prognostic Significance of Central Apneas Throughout a 24-Hour Period in Patients With Heart Failure

BACKGROUND

Large trials using noninvasive mechanical ventilation to treat central apnea (CA) occurring at night ("sleep apnea") in patients with systolic heart failure (HF) have failed to improve prognosis. The prevalence and prognostic value of CA during daytime and over an entire 24-h period are not well described.

OBJECTIVES

This study evaluated the occurrence and prognostic significance of nighttime, daytime, and 24-h CA episodes in a large cohort of patients with systolic HF.

METHODS

Consecutive patients receiving guideline-recommended treatment for HF (n = 525; left ventricular ejection fraction [LVEF] of 33 ± 9%; 66 ± 12 years of age; 77% males) underwent prospective evaluation, including 24-h respiratory recording, and were followed-up using cardiac mortality as an endpoint.

RESULTS

The 24-h prevalence of predominant CAs (apnea/hypopnea index [AHI] ≥5 events/h, with CA of >50%) was 64.8% (nighttime: 69.1%; daytime: 57.0%), whereas the prevalence of predominant obstructive apneas (OA) was 12.8% (AHI ≥5 events/h with OAs >50%; nighttime: 14.7%; daytime: 5.9%). Episodes of CA were associated with neurohormonal activation, ventricular arrhythmic burden, and systolic/diastolic dysfunction (all p < 0.05). During a median 34-month follow-up (interquartile range [IQR]: 17 to 36 months), 50 cardiac deaths occurred. Nighttime, daytime, and 24-h moderate-to-severe CAs were associated with increased cardiac mortality (AHI of </≥15 events/h; log-rank: 6.6, 8.7, and 5.3, respectively; all p < 0.05; central apnea index [CAI] of </≥10 events/h; log-rank 8.9, 11.2, and 10.9, respectively; all p < 0.001). Age, B-type natriuretic peptide level, renal dysfunction, 24-h AHI, CAI, and time with oxygen saturation of <90% were independent predictors of outcome.

CONCLUSIONS

In systolic HF patients, CAs occurred throughout a 24-h period and were associated with a neurohormonal activation, ventricular arrhythmic burden, and worse prognosis.

How to take arms against central apneas in heart failure

Introduction Despite being a risk mediator in several observational studies, central apneas are currently orphan of treatment in heart failure. After the neutral effects on survival of two randomized controlled trials (RCTs) based on the use of positive airway pressure (the CANPAP and SERVE-HF trials), two alternative hypotheses have been formulated: 1) Periodic breathing/Cheyne-Stokes respiration (PB/CSR) in HF is protective. Indeed, the Naughton's hypothesis assumes that hyperventilation leads to increased cardiac output, lung volume, oxygen storage and reduced muscle sympathetic nerve activity, while central apnea to respiratory muscle rest and hypoxia-induced erythropoiesis. 2) The use of positive airway pressure is just a wrong treatment for PB/CSR. If this is the case, the search for novel potential alternative treatment approaches is mandatory in HF. Areas covered This review will focus on the crucial issue of whether PB/CSR should be treated or not in HF, first by outlining the ideal design of pathophysiological studies to test the Naughton's hypothesis and second by summarizing the treatment strategies so far proposed for PB/CSR in HF and identifying the most promising options to be tested in future RCTs. Expert commentary It is likely that PB/CSR may be compensatory in some cases, but after a certain threshold (to be defined) it becomes maladaptive with negative prognostic meaning in HF. The development of a pathophysiologically based treatment targeting feedback resetting and neurohormonal activation underlying PB/CSR is likely to be the best option to obtain survival benefits in HF.

Prediction of the Chemoreflex Gain by Common Clinical Variables in Heart Failure

BACKGROUND

Peripheral and central chemoreflex sensitivity, assessed by the hypoxic or hypercapnic ventilatory response (HVR and HCVR, respectively), is enhanced in heart failure (HF) patients, is involved in the pathophysiology of the disease, and is under investigation as a potential therapeutic target. Chemoreflex sensitivity assessment is however demanding and, therefore, not easily applicable in the clinical setting. We aimed at evaluating whether common clinical variables, broadly obtained by routine clinical and instrumental evaluation, could predict increased HVR and HCVR.

METHODS AND RESULTS

191 patients with systolic HF (left ventricular ejection fraction--LVEF--<50%) underwent chemoreflex assessment by rebreathing technique to assess HVR and HCVR. All patients underwent clinical and neurohormonal evaluation, comprising: echocardiogram, cardiopulmonary exercise test (CPET), daytime cardiorespiratory monitoring for breathing pattern evaluation. Regarding HVR, multivariate penalized logistic regression, Bayesian Model Averaging (BMA) logistic regression and random forest analysis identified, as predictors, the presence of periodic breathing and increased slope of the relation between ventilation and carbon dioxide production (VE/VCO2) during exercise. Again, the above-mentioned statistical tools identified as HCVR predictors plasma levels of N-terminal fragment of proBNP and VE/VCO2 slope.

CONCLUSIONS

In HF patients, the simple assessment of breathing pattern, alongside with ventilatory efficiency during exercise and natriuretic peptides levels identifies a subset of patients presenting with increased chemoreflex sensitivity to either hypoxia or hypercapnia.

The search for efficient diagnostic and prognostic biomarkers of heart failure

Several biomarkers have been tested for screening, diagnosis and prognosis purposes, as well as to guide treatment in heart failure, but only the assay of circulating B-type natriuretic peptides has widely recognized applications for clinical decision-making. Natriuretic peptides are sensitive in detecting the clinically overt or subclinical myocardial damage, but their plasma levels are increased following every generic insult to the cardiovascular system. Novel biomarkers are required to identify specific pathways of disease progression, such as diverse neurohormonal axes activation, inflammation and fibrogenesis, and to act as a tool for therapeutic tailoring. In this view, Gal-3 and ST-2 assays seem very promising, given their involvement in mechanisms of cardiac fibrosis and their prognostic value.

Peripheral reflex feedbacks in chronic heart failure: Is it time for a direct treatment?

Despite repeated attempts to develop a unifying hypothesis that explains the clinical syndrome of heart failure (HF), no single conceptual paradigm for HF has withstood the test of time. The last model that has been developed, the neurohormonal model, has the great virtue of highlighting the role of the heart as an endocrine organ, as well as to shed some light on the key role on HF progression of neurohormones and peripheral organs and tissues beyond the heart itself. However, while survival in clinical trials based on neurohormonal antagonist drugs has improved, HF currently remains a lethal condition. At the borders of the neurohormonal model of HF, a partially unexplored path trough the maze of HF pathophysiology is represented by the feedback systems. There are several evidences, from both animal studies and humans reports, that the deregulation of baro-, ergo- and chemo-reflexes in HF patients elicits autonomic imbalance associated with parasympathetic withdrawal and increased adrenergic drive to the heart, thus fundamentally contributing to the evolution of the disease. Hence, on top of guideline-recommended medical therapy, mainly based on neurohormonal antagonisms, all visceral feedbacks have been recently considered in HF patients as additional potential therapeutic targets.

Cardioprotection by remote ischemic conditioning: Mechanisms and clinical evidences

In remote ischemic conditioning (RIC), several cycles of ischemia and reperfusion render distant organ and tissues more resistant to the ischemia-reperfusion injury. The intermittent ischemia can be applied before the ischemic insult in the target site (remote ischemic preconditioning), during the ischemic insult (remote ischemic perconditioning) or at the onset of reperfusion (remote ischemic postconditioning). The mechanisms of RIC have not been completely defined yet; however, these mechanisms must be represented by the release of humoral mediators and/or the activation of a neural reflex. RIC has been discovered in the heart, and has been arising great enthusiasm in the cardiovascular field. Its efficacy has been evaluated in many clinical trials, which provided controversial results. Our incomplete comprehension of the mechanisms underlying the RIC could be impairing the design of clinical trials and the interpretation of their results. In the present review we summarize current knowledge about RIC pathophysiology and the data about its cardioprotective efficacy.

Measurement of myocardial amyloid deposition in systemic amyloidosis: insights from cardiovascular magnetic resonance imaging

BACKGROUND

Cardiac involvement in systemic amyloidosis is caused by the extracellular deposition of misfolded proteins, mainly immunoglobulin light chains (AL) or transthyretin (ATTR), and may be detected by cardiovascular magnetic resonance (CMR). The aim of this study was to measure myocardial extracellular volume (ECV) in amyloid patients with a novel T1 mapping CMR technique and to determine the correlation between ECV and disease severity.

METHODS

Thirty-six patients with biopsy-proven systemic amyloidosis (mean age 70 ± 9 years, 31 men, 30 with AL and six with ATTR amyloidosis) and seven patients with possible amyloidosis (mean age 64 ± 10 years, six men) underwent comprehensive clinical and CMR assessment, with ECV estimation from pre- and postcontrast T1 mapping. Thirty healthy subjects (mean age 39 ± 17 years, 21 men) served as the control group.

RESULTS

Amyloid patients presented with left ventricular (LV) concentric hypertrophy with impaired biventricular systolic function. Cardiac ECV was higher in amyloid patients (definite amyloidosis, 0.43 ± 0.12; possible amyloidosis, 0.34 ± 0.11) than in control subjects (0.26 ± 0.04, P < 0.05); even in amyloid patients without late gadolinium enhancement (0.35 ± 0.10), ECV was significantly higher than in the control group (P < 0.01). A cut-off value of myocardial ECV >0.316, corresponding to the 95th percentile in normal subjects, showed a sensitivity of 79% and specificity of 97% for discriminating amyloid patients from control subjects (area under the curve of 0.884). Myocardial ECV was significantly correlated with LV ejection fraction (R(2)  = 0.16), LV mean wall thickness (R(2)  = 0.41), LV diastolic function (R(2)  = 0.21), right ventricular ejection fraction (R(2)  = 0.13), N-terminal fragment of the pro-brain natriuretic peptides (R(2)  = 0.23) and cardiac troponin (R(2)  = 0.33).

CONCLUSION

Myocardial ECV was increased in amyloid patients and correlated with disease severity. Thus, measurement of myocardial ECV represents a potential noninvasive index of amyloid burden for use in early diagnosis and disease monitoring.