Is less always more? A prospective two-centre study addressing clinical outcomes in leadless versus transvenous single-chamber pacemaker recipients

Background

Transvenous (TV) pacemakers are a well established treatment of bradyarrhythmias yet their complications, namely bleeding, infection and pneumothorax, still pose challenges to modern cardiology. This applies particularly to the older patient subgroup requiring single-chamber pacing due to comorbid atrial fibrillation (AF). Furthermore, conditions such as superior venous access issues, high infectious, or bleeding risk may complicate or preclude transvenous lead implantation. While VVIR leadless (LL) pacemakers aim to tackle these shortcomings, a comparison with contemporary single-chamber TV cohorts is currently lacking thus hindering a clear definition of the scope of LL pacing in clinical practice.

Purpose

To prospectively analyse survival and complication rates in leadless versus transvenous single-chamber pacemaker recipients.

Methods

This is a prospective analysis of 344 consecutive patients who received single-chamber TV or LL pacemakers between June 2015 and May 2021 in two tertiary cardiology centres. Indications for single-chamber pacing were “slow” AF, atrio-ventricular block with comorbid AF (either permanent or accepted as “destination rhythm”) or with sinus rhythm in bedridden cognitively impaired patients. LL indications were ongoing or expected chronic haemodialysis (6.9%), superior venous access issues such as occlusion (11.1%) or need for its preservation (9.7%), active lifestyle with low amount of pacing expected (22.2%), frailty causing high bleeding and infectious risk (23.6%), as well as recent valvular endocarditis (2.8%) or implantable electronic device infection requiring extraction (5.6%).

Results

72 patients (20.9%) received LL and 272 (79.1%) TV single-chamber pacemakers. In keeping with LL indications, diabetes and ongoing haemodialysis were more prevalent in the LL population. No significant difference in overall complication rate was observed between LL and TV patients (5.6% vs. 5.1%, p=0.33) apart from haematomas, which occurred more frequently in the LL population. Only 1 haematoma in the TV group required surgical reintervention. TV recipients survival was lower with greater cardiovascular mortality, likely due to selection of significantly older patients.

Conclusions

Given the limited complication rate observed in this contemporary single-chamber TV cohort and low life expectancy of this particular population, extending LL indications to all VVIR candidates is unlikely to provide a clearcut survival advantage. Considering the higher costs of LL technology, these data prompt a careful selection of those cases where LL approach does indeed provide an advantage. In addition to the setting of vascular access issues and high bleeding or infectious risk, these may include patients with sufficient life expectancy where lead-related risks may indeed adversely affect prognosis. Based on our patient selection criteria, LL might account for approximately 20% of VVIR pacing recipients.

Funding Acknowledgement

Type of funding sources: None.

Early experience with the second generation of leadless pacemakers and correlation with ecg parameters

Funding Acknowledgements

Type of funding sources: None.

Background

Leadless pacing has evolved as a safe and effective treatment option in selected patients. With the updated generation that allows sensing of atrial contraction, atrioventricular synchronized pacing is now possible in a VDD mode. Previous retrospective analyses have demonstrated that echocardiographic parameters may be helpful in selecting patients with a higher chance of good atrioventricular synchronous pacing behaviour.

Purpose

Analysis of the early experience with the second generation of leadless pacemaker and the role of ECG parameters to predict a good atrial contraction signal (so-called A4 amplitude) in patients who underwent leadless pacemaker implantation in four tertiary centres.

Methods and Results

In this retrospective analysis, a total of 136 patients were included. Mean age was 78.0 (64.7 - 84.2 years) years with 48.9 % being male. Coronary artery disease was the leading underlying heart disease with 27.1 % affected patients. 61.7 % of the population suffered from sinus rhythm with complete or intermittent atrioventricular block. The majority of devices were implanted at the mid-septal (61.2 %) or high-septal (25.6 %) right ventricle, respectively. Electrical parameters were optimal at implant (Table 1) and remained stable over time (Table 1). In addition, A4 signal amplitude remained stable too during follow-up compared to the value early after implantation (Table 1). From this entire cohort, patients with an ECG available at implant and those in which the device was working predominantly in the VDD mode were selected for further analyses (62 patients). PR interval measured from the ECG prior to implantation did not correlate with the A4 signal amplitude (Figure 1A; P = NS). Next, P wave amplitudes were measured in all 12 ECG leads. There was a correlation between P wave amplitude from lead V2 with the A4 amplitude (Figure 1B; P = 0.034, R2 = 0.09), whereas the other right-sided ECG leads (V1/aVR), either alone or in combination, did not correlate with the A4 signal amplitude (P = NS).

Conclusions

In our cohort of patients with the second generation of leadless pacemakers, offering VDD pacing, good electrical parameters can be achieved as it has been observed with the first generation. Also the A4 signal amplitude as a marker for atrial contraction remains stable over time. In regard to ECG parameters measured prior to device implantation, only the P wave amplitude in lead V2 correlated with a amplitude of the A4 signal.

Predicting long-term mortality following transvenous lead extraction using the lead extraction difficulty (LED) index score

Funding Acknowledgements

Type of funding sources: None.

Background

Transvenous Lead Extraction (TLE) scoring systems have proven to be a reliable method to predict TLE difficulty, thus improving procedure safety and efficacy. Nevertheless, TLE has shown a significant mortality rate during the subsequent follow-up, up to 33% at 10 years, with historical data showing several procedural and clinical characteristics associate with this poor outcome.

Purpose

We aimed to investigate the association between difficult TLE procedures and long-term mortality, using a specific scoring system [Lead Extraction Difficulty (LED)] to identify difficult/simple procedures.

Methods

Consecutive patients underwent TLE procedures between January 2014 and January 2016 at Spedali Civili Hospital, Brescia, Italy, were prospectively considered to receive a follow-up during 2021. TLE difficulty was retrospectively assessed in all patients using the LED index score (number of leads to extract + years from implant of the oldest lead to remove + 1 [for a dual-coil implantable cardioverter defibrillator lead] – 1 [in case of confirmed vegetations along the lead]). According to the score, "high-difficult" procedures were defined for a LED >10. Patient long-term follow-up was obtained by review of medical records from patient surveys or from the referring institution/family practitioner. Univariate analysis and multivariate logistic regression were used to identify factors associated with long-term mortality. Kaplan-Meier estimates were used to investigate survival during the follow-up. Two-sided P<.05 was considered significant.

Results

A total of 466 permanent leads were removed in 249 patients with a clinical success rate of 99.1%, and without major acute complications. The mean time follow-up was 6.7 (5.9-7.1) years, with a cumulative all-cause mortality rate of 17.7%. Clinical characteristics, indication for TLE, and mortality during follow-up are reported in the Table. Among all variable associated with mortality at univariate analysis, only LED index >10 independently predicted the mortality during the follow-up at logistic regression (OR 2.98; 95% CI: 0.081-1.4; p=0.028). Survival plots for individuals underwent high/low difficult TLE are shown in the Figure. Mortality at 1, 3, and 5 years following TLE was highest among patients with LED index >10 (1.1%, 12.6%, and 26.3%, respectively).

Conclusions

Cumulative long-term mortality following TLE was confirmed to be high. Of interest it resulted highest among patients following high-difficult TLE procedure. LED index score resulted a useful tool to predict long-term mortality after procedure. This finding should be considered when approaching TLE procedures in order to estimate the risk/benefit ratio over the time.

The subcutaneous defibrillator in patients with low BMI - insights from a large European multicenter registry

Funding Acknowledgements

Type of funding sources: None.

Background

The subcutaneous implantable cardioverter defibrillator (S-ICD) has become an alternative to transvenous ICDs (tv-ICD), especially in young patients without a need for pacing. One of the current limitations of the S-ICD is the relatively large size of the generator compared to tv-ICDs. There is little evidence whether the size of the current S-ICD generator is associated with an elevated risk of device-related complications in patients with a low body mass index (BMI).

Purpose

To compare the device-related complications and long-term outcomes in a large real world cohort of S-ICD recipients in patients with a BMI <18 kg/m2 compared to patients with a BMI >18 kg/m2.

Methods

The iSuSI registry is a European, multi-center, open-label, independent, and physician-initiated observational registry. A total of twenty-two Public and Private Healthcare Institutions from 4 different countries in Europe were involved in the registry. All consecutive patients meeting current guideline indications for ICD implantation and undergoing implantation of a S-ICD device (Boston Scientific, Marlborough, Massachusetts, USA) at 21 European institutions enrolled in the registry were used for the current analysis. Patients were classified into two cohorts, depending on the BMI at the time of device implantations: BMI < 18 kg/m2 versus > 18 kg/m2.

Results

Out of a total of 1497 pts, 58 pts (3.9%) had a BMI < 18 kg/m2. Patients with BMI <18 kg/m2 were younger (44.6±2.4 vs 50.8±0.4; p=0.004) and more frequently female (58.6% vs 22.3%, p<0.001). No differences in any of the other baseline characteristic were observed. Implantation techniques resulted comparable between the groups (Rates of 2-incision technique: 87.8% vs 91.9%; p=0.256; inter-muscular placement: 89.7% vs 83.3%; p=0.198). Of note, the mean PRAETORIAN score at implantation of patients with BMI <18 kg/m2 was significantly lower (33.8±9.1 vs 54.1±47.3; p=0.035), although the vast majority of pts in both cohorts qualify as at low risk of conversion failure (100% vs 91.4%; p=0.436).

Over a median follow up time of 22.4 [11.6–36.8] months, both overall device-related complications (5.2% vs 7.4%) and rates of inappropriate shocks (12.0% vs 8.8%) resulted comparable between the two groups (p =0.517 and p=0.385, respectively). Figure1 reports Kaplan-Meier curves reporting the combined incidence of device-related complications and inappropriate shocks in the two groups (log-rank p = 0.576).

Conclusion

No difference in device-related complications and long-term outcomes after S-ICD implantation were observed in patients with BMI <18 kg/m2 compared to the remaining recipients from a large, multi-centered S-ICD registry.

Figure 1: Kaplan-Meier-survival curve for the combined endpoint of inappropriate shocks (IAS) and device-related complications (DRC)

S-ICD in heart failure patients: real-world data from a multicenter, european analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Data on patients with heart failure (HF) and subcutaneous implantable cardioverter defibrillator (S-ICD) are very scarce and limited to a single prospective analysis from the UNTOUCHED trial.

Purpose

Aim of this study was to assess clinical outcomes of the S-ICD in HF patients, comparing them with a no-HF population, in a real-world analysis from the largest European retrospective S-ICD registry (ELISIR registry).

Methods

All consecutive patients undergoing S-ICD implantation at 20 European institutions enrolled in the ELISIR registry were used for the current analysis. According to European Guidelines, the registry population was classified into two groups: the HF cohort (further classified as HF with reduced and mid-range ejection fraction – HFrEF and HFmrEF) vs the no-HF group. The primary outcome of the study was the inappropriate shock (IS) rate across the two cohorts. As secondary outcomes, appropriate shocks, cardiovascular mortality and device-related complications during follow-up were assessed.

Results

A total of 1409 patients from the ELISIR registry were included in this analysis; HF patients represented 57.3% of the entire cohort (n=701, 86.9% HFrEF; n=106,13.1% HFmrEF). As expected, the HF cohort showed significantly higher rates of cardiovascular risk factors and comorbidities when compared to the no-HF cohort. Over a median follow-up of approximately 2 years, a total of 133 inappropriate shocks were observed in the entire cohort, without significant differences among the two groups (9.2% vs 9.8%, p=0.689). 133 complex ventricular arrhythmias were adequately recognized and treated in the overall cohort, showing similar rates of appropriate shocks (9.2% vs 9.8%, p=0.689). Inappropriate and effective shocks-free survival has been represented in Figure 1, showing Kaplan-Meier estimates comparing HF vs no-HF patients, also stratified by left ventricular ejection fraction (LVEF). The impact of baseline and procedural characteristics on the primary outcome was tested through univariable and multivariable Cox regression analysis in HF patients; at multivariate analysis, only age (HR=0.974 [0.955–0.992], p=0.005), LVEF (HR=0.954 [0.926-0.984], p=0.003), ARVC (HR=3.364 [1.206-9.384], p=0.020) and smart pass algorithm "on" (HR=0.321 [0.184-0.560], p<0.001) remained associated with inappropriate shocks (Figure 2). A low number of patients (n=76) experienced device-related complications, more frequently in the HF cohort (6.2% vs 3.8%, p=0.031) with no significant differences regarding any specific outcome of interest: lead infection (1.1% vs 0.7%, p=0.381), pocket infection (1.9% vs 0.8%, p=0.107), pocket hematoma (3.2% vs 2.8%, p=0.668).

Conclusion

The rate of inappropriate shocks seems to be comparable in both HF and non-HF patients implanted with S-ICD. However, the rate of device-related complications was slightly more frequent in HF patients.

Age-related differences and associated outcomes of S-ICD: insights from a large, european, multicenter, real-world registry

Funding Acknowledgements

Type of funding sources: None.

Background

Young patients often represent the most suitable candidates for an entirely subcutaenous implantable cardioverter defibrillator (S-ICD) system, since they have to face a lifetime of device therapy and they rarely have a pre-existing or concurrent pacing or cardiac resynchronization therapy (CRT) indication. Moreover, S-ICD offers lower rate and a safer management of lead and major procedure-related complications. To date, a few limited case series and experiences with S-ICD in teenagers and young adults have shown that the S-ICD system is safe and feasible in this population, with a rate of inappropriate shocks (IS) comparable to transvenous (TV) ICD, but focused analysis on a large scale are currently lacking in this setting.

Purpose

The aim of the current study was to compare the age-related differences observed in patient selection, baseline characteristics, and device long-term associated outcomes in a large real world cohort of S-ICD recipients. The primary outcome of the study was defined as the comparisons of the IS rate observed during the entirety of follow up in the teenagers/young adult vs the adult populations. Rate of complications, freedom from sustained ventricular arrhythmic events, overall and cardiovascular mortality were also assessed in the two cohorts and assessed as secondary outcomes.

Methods

All S-ICD recipients in the ELISIR project were enrolled in the current study. Patients were classified into teenagers + young adults (≤ 30 years old) vs adults (> 30 years old), depending from patient age at device implantation (Figure 1). Rates of device-related complications and IS were compared between the cohorts.

Results

A total of 1349 patients were extracted from the ELISIR project. Teenagers and young adults represented 12.4% of the registry (n=56 teenagers; n=112 young adults). Patients were followed-up for a median of 23.1 [12.6–37.9] months. Overall, 117 (8.7%) patients experienced inappropriate S-ICD shocks and 100 (7.4%) device related complications were observed, with no age-related differences. IS resulted more frequent in the teenager and young adult cohort (14.3% vs 7.9%; p=0.006). Figure 2 reports Kaplan Meier curves for the occurrence of IS. At univariate analysis, young age was associated with IS, but after correcting for differences in arrhythmic substrate, this association resulted non-significant (aHR: 1.428 [0.883–2.331]; p=0.146). The use of SMART pass algorithm was instead associated to a strong reduction in IS (aHR 0.367 [0.245–0.548]; p<0.001).

Conclusion

The use of S-ICD in teenagers/young adults resulted safe and effective. Indeed, the rate of complications between teenagers/young adults and adults was not significantly different. Although a higher rate of IS was observed in the teenagers/young adults, when accounting for differences in baseline substrate and comorbidities, young age did not result associated with an increased risk of IS.

P94 LOWER RATE OF MAJOR BLEEDING IN HIGH–RISK PATIENTS UNDERGOING LEFT ATRIAL APPENDAGE OCCLUSION: A PROPENSITY MATCHED COMPARISON WITH DIRECT ORAL ANTICOAGULATION

Background

Stroke prophylaxis in very high risk (CHA2DS2–VASc ≥ 5) patients with atrial fibrillation (AF) is one of the major challenges faced by physicians. Specifically, initiating direct oral anticoagulants (DOACs) in these patients poses a therapeutic conundrum due to the concomitant high risk of bleeding. Left atrial appendage occlusion (LAAO) might be a potential alternative for thromboembolic (TE) prevention; however, there are no studies comparing these two strategies in very high–risk patients.

Objective

To evaluate the efficacy of LAAO versus DOACs in AF patients at very high TE risk.

Methods

Data were extracted from two prospective databases including 1053 Watchman and 1328 DOAC patients. Watchman patients with a CHA2DS2–VASc ≥ 5 accounted for 26.3% (n = 277). In order to attenuate the imbalance in covariates, a 1:1 propensity score matching technique was used (co–variates: age, sex, CHA2DS2–VASc and HAS–BLED scores). This method resulted in 554 matched patients (277 patients per group; mean age: 79±7y; 57.4% F; CHA2DS2–VASc: 5.8±0.9). The primary endpoint was a composite of cardiovascular (CV) death, TE events (Stroke/TIA/peripheral embolism) and clinically significant bleeding. The annual TE and major bleeding risks were estimated based on the CHA2DS2–VASc score and compared with the annualized observed risk.

Results

After a mean follow–up of 26±7 months, total events were 55 (9.4 event rates per 100 patient–years) in LAAO group vs. 78 (14.9 event rates per 100 patient–years) in DOAC group. DOACs had a significantly higher risk of the primary endpoint (hazard ratio [HR]: 1.30; 95% confidence interval [CI]: 1.08 to 1.56; p = 0.03). TE events (HR: 1.15; 95% CI: 0.84 to 1.57; p = 0.63) and CV death (HR: 1.13; 95% CI: 0.84 to 1.54; p = 0.63) did not differ between groups. Major bleeding events were significantly lower in LAAO patients (HR: 0.75; 95% CI: 0.51 to 0.82; p = 0.04). The unadjusted estimated risk of TE events was 12.3% with LAAO and 12.4% with DOACs. The annualized incidence of TE was 3.2% with LAAO and 4.1% with DOACs, which led to a risk reduction of 74% and 67%, respectively.

Conclusion

In a large cohort of AF patients at very high TE risk (CHA2DS2–VASc ≥ 5), LAAO showed similar stroke prevention but a significantly lower risk of major bleeding than DOACs during a > 2year follow–up.

C9 SUBCUTANEOUS IMPLANTABLE CARDIOVERTER DEFIBRILLATOR IN PATIENTS WITH LOW BMI: REAL–WORLD DATA FROM A EUROPEAN MULTICENTER ANALYSIS

Background

One of the current limitations of the S–ICD is the relatively large size of the generator compared to the TV (transvenous) ICD. There is little evidence whether the size of the current S–ICD generator is associated with an elevated risk of device–related complications in patients with a low body mass index (BMI).

Purpose

Aim of this study was to compare the device–related complications and long–term outcomes in a large real world cohort of S–ICD recipients in patients with a BMI <18 kg/m2 compared to patients with a BMI >18 kg/m2.

Methods

All consecutive patients meeting current guideline indications for ICD implantation and undergoing implantation of a S–ICD device (Boston Scientific, Marlborough, Massachusetts, USA) at 21 European institutions enrolled in the extended ELISIR registry were used for the current analysis. Patients were classified into two cohorts, depending on the BMI at the time of device implantations: BMI < 18 kg/m2 versus > 18 kg/m2.

Results

Out of a total of 1497 pts, 58 pts (3.9%) had a BMI < 18 kg/m2. Patients with BMI <18 kg/m2 were younger (44.6±2.4 vs 50.8±0.4; p = 0.004) and more frequently female (58.6% vs 22.3%, p < 0.001). No differences in any of the other baseline characteristic were observed. Implantation techniques resulted comparable between the groups (rates of 2–incision technique: 87.8% vs 91.9%; p = 0.256; inter–muscular placement: 89.7% vs 83.3%; p = 0.198). Of note, the mean PRAETORIAN score at implantation of patients with BMI <18 kg/m2 was significantly lower (33.8±9.1 vs 54.1±47.3; p = 0.035), although the vast majority of patients in both cohorts qualified as at low risk of conversion failure (100% vs 91.4%; p = 0.436). Over a median follow up time of 22.4 [11.6–36.8] months, both overall device–related complications (5.2% vs 7.4%) and rates of inappropriate shocks (12.0% vs 8.8%) resulted comparable between the two groups (p = 0.517 and p = 0.385, respectively). Figure 1 reports Kaplan–Meier curves showing the combined incidence of device–related complications and inappropriate shocks in the two groups (log–rank p = 0.576).

Conclusion

No differences in device–related complications and long–term outcomes after S–ICD implantation were observed in patients with BMI <18 kg/m2 compared to the remaining recipients in a large multicentered real–world analysis.

P21 AGE–RELATED DIFFERENCES AND ASSOCIATED OUTCOMES OF S–ICD: INSIGHTS FROM A LARGE, EUROPEAN, MULTICENTER REGISTRY

Background

The subcutaneous implantable cardioverter defibrillator (S–ICD) has become an alternative to transvenous ICDs (TV–ICD) in patients who do not need pacing. To date, there is little evidence directly comparing the rates of inappropriate shocks (IAS) in young vs old S–ICD recipients.

Purpose

Aim of our study was to assess differences in device–related complications and inappropriate shocks (IS) between teenagers/young adults and adult recipients of a subcutabeous implantable cardioverter defibrillator (S–ICD) device.

Methods

Two propensity–matched cohorts of teenagers + young adults (≤ 30–year–old) and adults (> 30–year–old) were retrieved from the ELISIR registry. The primary outcome was the comparison of the inappropriate shock (IAS) rate; complications, freedom from sustained ventricular arrhythmic events, overall and cardiovascular mortality were deemed secondary outcomes.

Results

A total of 1491 patients were extracted from the ELISIR project. Teenagers + young adults represented 11.0% of the entire cohort. Two propensity–matched groups of 161 patients each were used for the analysis (Figure 1); median follow–up was 23.1 [13.2–40.5] months. 15.2% patients experienced inappropriate S–ICD shocks and 9.3% device related complications were observed with no age–related differences in IAS (16.1% vs 14.3%; p = 0.642) and complication rates (9.9% vs 8.7%; p = 0.701); Figure 2 shows a survival analysis from inappropriate shocks in the teen–ager/young adult cohort (red) and in the adult cohort (blue). At univariate analysis, young age was not associated with increased rates of IAS (HR 1.204 [0.675–2.148]: p = 0.529). At multivariate analysis (Figure 3), the use of SMART pass algorithm was associated to a strong reduction in IAS (aHR 0.292 [0.161–0.525]; p < 0.001), while ARVC was associated with higher rates of IAS (aHR 2.380 [1.205–4.697]; p = 0.012).

Conclusion

In a large multicentered European registry of patients with S–ICD, 11.0% of all recipients were teenagers or young adults. The use of S–ICD in teenagers/young adults resulted safe and effective, and the rates of complications and IAS between teenagers/young adults and adults were not significantly different. The only predictor of increased IAS was a diagnosis of ARVC.

P25 SUBCUTANEOUS–ICD IN PATIENTS WITH HEART FAILURE: RESULTS FROM A MULTICENTER, EUROPEAN ANALYSIS

Background

Data on patients with heart failure (HF) with a subcutaneous implantable cardioverter defibrillator (S–ICD) are scarce.

Objective

Aim of this study was to assess clinical outcomes of the S–ICD in HF patients in a real–world analysis from the largest European retrospective S–ICD registry (ELISIR).

Methods

All consecutive patients undergoing S–ICD implantation at several European institutions were used for the current analysis. The population was classified into two groups: the HF (classified as HF with reduced and mid–range ejection fraction – HFrEF and HFmrEF) vs the no–HF cohort. The primary outcome of the study was the inappropriate shock (IS) rate across the two cohorts. As secondary outcomes, appropriate shocks, cardiovascular mortality and device–related complications during follow–up were assessed

Results

A total of 1409 patients from the ELISIR registry were included; HF patients represented 57.3% of the entire cohort (n = 701, 86.9% HFrEF; n = 106,13.1% HFmrEF). Over a median follow–up of approximately 2 years, a total of 133 inappropriate shocks were observed in the entire cohort, without significant differences among the two groups (9.2% vs 9.8%, p = 0.689). 133 complex ventricular arrhythmias were adequately recognized and treated, with similar rates of appropriate shocks (9.2% vs 9.8%, p = 0.689). Inappropriate and effective shocks–free survival has been represented in Figure 1 (Kaplan–Meier estimates). At multivariate analysis (Figure 2), age (HR = 0.974 [0.955–0.992], p = 0.005), LVEF (HR = 0.954 [0.926–0.984], p = 0.003), arrhythmogenic right ventricular cardiomyopathy – ARVC (HR = 3.364 [1.206–9.384], p = 0.020) and smart pass + (HR = 0.321 [0.184–0.560], p < 0.001) remained associated with inappropriate shocks. Moreover, a low number of patients (n = 76) experienced device–related complications, more frequently in the HF cohort (6.2% vs 3.8%, p = 0.031) with no significant differences regarding any specific outcome of interest: lead infection (1.1% vs 0.7%, p = 0.381), pocket infection (1.9% vs 0.8%, p = 0.107), pocket hematoma (3.2% vs 2.8%, p = 0.668).

Conclusion

The use of S–ICD in HF patients did not result in a higher rate of inappropriate shocks when compared to no–HF patients, even when stratifying for LVEF. Only age, LVEF, ARVC e Smart Pass algorithm were predictors of the primary outcome at multivariate analysis. Despite a lower overall rate of complications in the entire cohort, HF patients experienced device–related complications more frequently.

P529Efficacy and safety of S-ICD implantation without use of defibrillation threshold testing: a retrospective multicentric observational study

Introduction

The subcutaneous ICD (S-ICD) is a valid alternative to transvenous systems (TV-ICD) for the treatment of life-threatening arrhythmias, and the extravascular position of the lead allows a significant reduction of the risk of infection. Current guidelines recommend defibrillation threshold testing (DFT) at the time of S-ICD implantation (class I). Although randomised trials have proven the safety of TV-ICD implantation with no DFT, it is unclear whether such an approach could be adopted for S-ICD as well. The PRAETORIAN score, based on post-implantation chest X-ray, can accurately predict a high defibrillation threshold after S-ICD implantation. The aim of this retrospective multicentre study was to evaluate the efficacy and safety of S-ICD implantation with no DFT.

Methods

We enrolled 203 consecutive patients undergoing S-ICD implantation in six different centres between October 2012 and January 2019. It was left at discretion of the operator whether performing or not DFT at the time of the procedure. Baseline device settings were collected, and the PRAETORIAN score was retrospectively calculated whenever chest X-ray was available. Both remote or in-clinic device interrogation reports were systemically analysed, and all the shocks and arrhythmia episodes identified. All the patients provided consent form and ethical approval was obtained.

Results

The population (mean age 57.6 ± 14.2) was divided in two groups, based on whether DFT was performed at the time of the S-ICD implantation: 72 patients (35.4%) underwent DFT (DFT+ group), while 131 patients (64.5%) did not (DFT- group). In the DFT- group, mean LVEF was lower (32 ± 8% vs 42 ± 17%, p < 0.0001) and prevalence of diabetes mellitus and atrial fibrillation higher compared to the DFT+ group (27.5% vs 13.9%, p = 0.04 and 38.9% vs 19.44%, p = 0.007; respectively). In addition, the indication for S-ICD was more frequently primary prevention in the DFT- vs DFT+ group (70.8% vs 90.8%, p = 0.0004; respectively). No differences in terms of device programming were identified between the two cohorts. The PRAETORIAN score was significantly higher in the DFT- vs DFT+ patients (50 ± 26 vs 36 ± 18, p = 0.032; respectively). After a median follow-up of … months, we observed 5 appropriate shocks in 3 patients from the DFT+ group vs. 15 shocks in 8 patients from the DFT- group (p = 0.81). All the life-threatening arrhythmias were successfully recognised and treated by the device. DFT was complicated by pulseless electrical activity in one patient. One patient in the DFT- group suffered from an episode of ventricular tachycardia requiring a total of 4 shocks for being terminated. Six patients in the DFT- group died for non-arrhythmic causes. On the Kaplan-Meier analysis, cumulative survival was comparable between the two groups (log rank p value = 0.13).

Conclusions

This study suggests that implantation of S-ICD with no DFT might be reasonable. These results should be confirmed in prospective randomised trials.

P538Single- and Multi-Site Pacing Strategies for Optimal Cardiac Resynchronization Therapy: Impact on Device Longevity and Therapy Cost

Funding Acknowledgements

No funding

Introduction

Multiple left ventricular pacing strategies have been suggested for improving response to cardiac resynchronization therapy (CRT). However, these programming strategies can be obtained by accepting configurations with high pacing threshold and accelerated battery drain. We assessed the feasibility of predefined pacing programming protocols and we evaluated their impact on device longevity and their cost-impact.

Methods

We estimated battery longevity in 167 CRT-D (RESONATE, Boston Scientific) patients based on measured pacing parameters and according to multiple programming strategies: single-site pacing associated with lowest threshold, non-apical location, longest interventricular delay, pacing from two electrodes. To determine the economic impact of each programming strategy, we applied the results of a published model-based cost analysis to a 15-year time-horizon.

Results

Selecting the electrode with the lowest threshold resulted in a median device longevity of 11.5 years. Non-apical pacing and interventricular delay maximization were feasible in most patients (99% non-apical pacing, 65% RV-to-LV interval >80ms), and were obtained at the price of a few months of battery life. Device longevity of >10 years was preserved in 87% of cases of non-apical pacing and in 77% on pacing at the longest interventricular delay. The mean reduction in battery life when the second electrode was activated was 1.5 years. Single-site pacing strategies increased the therapy cost by 4-6%, and multi-site pacing by 12-13%, in comparison with the best-case scenario.

Conclusions

Modern CRT-D systems ensure effective pacing and allow multiple optimization strategies for maximizing service life or for enhancing effectiveness. Single- or multi-site pacing strategies can be implemented without compromising device service life and at an acceptable increase in therapy cost.

Abstract Figure. Image1

Non-invasive hemodynamic analysis in cardiac resynchronization therapy patients wearing quadripolar left ventricular leads: the importance of pacing electrode selection

AIM

Quadripolar left ventricular (LV) leads offer multiple choices for LV pacing increasing programming flexibility. Aim of this study is to assess the influence of LV pacing vector selection on hemodynamic parameters for patients who underwent cardiac resynchronization therapy (CRT) using quadripolar LV lead chronically evaluated with a non-invasive approach by Nexfin(®) system provided analysis (BMEYE B.V., Amsterdam, The Netherlands).

METHODS AND RESULTS

In 16 CRT patients implanted with a quadripolar LV lead (mean follow-up 8,8 ±13,4 months after implantation), we measured Cardiac Output (CO), Mean Blood Pressure (MBP), Total Peripheral Resistance (TPR), LV dP/dt max and Stroke volume (SV) from each one of the ten available bipolar pacing configurations. All the recorded parameters showed marked differences among the ten pacing configurations, but dP/dt max, SV and TPR were those showing the wider range, depending of the selected pacing vector. The average delta for the whole group of subjects between the maximum and minimum hemodynamic values for each pacing configuration were 15.9% for SV, 21.1% for dP/dt max and 20.3% for TPR. Inter-individual analysis of data failed to identify a link between a specific pacing vector and the hemodynamic response.

CONCLUSION

Our study demonstrates that different bipolar pacing configurations, even if arising from a single CS branch, substantially modify the hemodynamic effect of LV pacing in CRT patients. Moreover, the non-invasive hemodynamic analysis suggests the better pacing configuration should be established individually and could represent an important issue in optimizing CRT during follow-up.

Gut hormones and endothelial dysfunction in patients with obesity and diabetes

Overweight and obesity are the fifth leading risk for global deaths and its prevalence has doubled since 1980. At least 2.8 million adults, worldwide, die each year as a result of being overweight or obese. The deleterious effects of obesity are tightly related to diabetes, as they are often clinically present in combination to confer increased cardiovascular mortality. Thus, patients with diabetes and obesity are known to develop accelerated atherosclerosis characterized by a dysfunctional endothelium and decreased nitric oxide bioavailability. Recent clinical studies support, indeed, the use of incretin-based antidiabetic therapies for vascular protection. Thus, attention has been focusing on gut hormones and their role, not only in the regulation of appetite but also in vascular health. Intervention directed at modulating these molecules has the potential to decrease mortality of patients with diabetes and obesity. This review will cover part of the ongoing research to understand the role of gut hormones on endothelial function and vascular health.

Obesity, inflammation and endothelial dysfunction

Cardiovascular disease is the leading cause of morbidity and mortality in obese individuals. Obesity dramatically increases the risk of development of metabolic and cardiovascular disease. This risk appears to originate from disruption in adipose tissue function leading to a chronic inflammatory state and to dysregulation of the endocrine and paracrine actions of adipocyte-derived factors. These, in turn, impair vascular homeostasis and lead to endothelial dysfunction. An altered endothelial cell phenotype and endothelial dysfunction are common among all obesity-related complications. A crucial aspect of endothelial dysfunction is reduced nitric oxide (NO) bioavailability. A systemic pro-inflammatory state in combination with hyperglycemia, insulin resistance, oxidative stress and activation of the renin angiotensin system are systemic disturbances in obese individuals that contribute independently and synergistically to decreasing NO bioavailability. On the other hand, pro-inflammatory cytokines are locally produced by perivascular fat and act through a paracrine mechanism to independently contribute to endothelial dysfunction and smooth muscle cell dysfunction and to the pathogenesis of vascular disease in obese individuals. The promising discovery that obesity-induced vascular dysfunction is, at least in part, reversible, with weight loss strategies and drugs that promote vascular health, has not been sufficiently proved to prevent the cardiovascular complication of obesity on a large scale. In this review we discuss the pathophysiological mechanisms underlying inflammation and vascular damage in obese patients.

[Diabetes worsens the clinical manifestations and prognosis of concurrent cardiovascular and kidney disease]

Numerous studies have shown a marked increase in the incidence of diabetes mellitus worldwide. Diabetes mellitus is currently considered equivalent to coronary artery disease in terms of prognostic risk stratification, and its high prevalence makes this clinical condition the first cause of end-stage renal disease requiring chronic hemodialysis or kidney transplant. Even if chronic kidney disease remains the ''Cinderella of the cardiovascular profile'', the presence of microalbuminuria is closely related to a high risk of development of coronary artery disease. The same risk factors that impair heart function are also harmful to the kidney, and the common pathophysiological features of the two systems are at the origin of a new subspecialty, cardionephrology. A crucial task of cardiologists and nephrologists is the early identification of high risk patients with concurrent cardiovascular and kidney disease. The utilization of simple screening methods such as assessment of microalbuminuria and glomerular filtration rate by family doctors may help in establishing prevention strategies directed towards cardiovascular risk and progression of kidney disease. In conclusion, early stratification of cardiovascular risk, coupled with primary prevention strategies aimed at the general population, is warranted to obtain a significant reduction of kidney and cardiovascular disease and of the need for chronic hemodialysis treatment. This strategy is safe and cost-effective in comparison with the costs of chronic dialysis of patients affected by chronic kidney disease.

Oesophageal electrical cardioversion of atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia and the most frequent cause of hospitalization and utilization expense among all heart diseases. Taking into account persistent atrial fibrillation we know that, in order to cardiovert persistent atrial fibrillation, external direct current cardioversion is the method most frequently used to restore sinus rhythm. But external cardioversion has also some limitations: it requires high energy direct current shocks so that patients have to be anaesthetised, which means a dedicated apparatus and place to adequately assist the patients. The oesophageal cardioversion is an alternative method to restore sinus rhythm, which could obviate some of these limitations of external cardioversion. Compared to external cardioversion oesophageal one has lower defibrillation impedance and requires lower energies to restore sinus rhythm, increasing for the same energy level, success rate. Using low energy shocks, a mild sedation is sufficient to make the procedure well tolerated by most of patients. Other 2 important advantages coming from low energy shocks are the safety in patients with pacemaker or implantable cardioverter-defibrillator and the availability of a back up atrial pacing. Oesophageal cardioversion is not indeed a new technique. Looking at literature, studies in animals and in humans have been performed since the 60s, assessing feasibility, effectiveness and safety of such a procedure. The oesophageal-precordial cardioversion is usually performed on an outpatient regimen, resulting in a very cost-effective method to cardiovert patients with persistent atrial fibrillation, which may definitely represent a real alternative technique to external cardioversion.

Two novel mutations and a new STK11/LKB1 gene isoform in Peutz-Jeghers patients

Peutz-Jeghers syndrome (PJS) is a rare autosomal dominantly inherited disorder with variable expression and incomplete penetrance characterized by mucocutaneous pigmentation, predisposition to hamartomatous intestinal polyposis, and various other neoplasms. It occurs in approximately 1 in 8,300 to 29,000 live births. In nearly 50% of patients PJS is caused by germ line mutations in the STK11/LKB1 serine/threonine kinase gene, the only kinase gene currently known to act as a tumor suppressor. We have performed a mutation search in the STK11/LKB1 gene in 8 sporadic cases and 3 PJS families using a combination of different screening techniques. We have identified four mutations, two of which I177N and the IVS2+1A->G, were previously unreported. We have also evaluated the presence of cDNA alterations by means of RT-PCR analysis and direct cDNA sequencing and have found two aberrant transcripts in a single PJS case despite the lack of any apparent genomic alteration. Finally, we report the presence of a novel STK11/LKB1 cDNA isoform observed in all the normal subjects studied as well as in the majority of the PJS patients.