Gender gap in study inclusion: Insights from the STAR-FIB cohort study

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation Swiss Heart Foundation

Background

The underrepresentation of women in cardiovascular clinical trials is well described but cannot be fully explained by sex-specific differences in the prevalence of cardiovascular diseases. Data on potential sex- and gender-related differences in study exclusion reasons are scarce.

The STAR-FIB cohort study aimed to estimate the age and sex-specific prevalence of screening-detected atrial fibrillation (AF) in 800 hospitalized patients aged 65-84 years using serial seven-day ECGs. Recruitment for study inclusion was stratified by sex (female/male, as stated in the patient’s records) and age (four age bands, ≥65 to <70, ≥70 to <75, ≥75 to <80, and ≥80 to <85 years), and was truncated for each subgroup after the inclusion of 100 participants.

Purpose

To assess sex and gender differences in patient recruitment for inclusion in the STAR-FIB cohort study.

Methods

A screening log containing sex-category, age, and reasons for exclusion was maintained. Exclusion criteria are shown in the figure. For the purpose of the present study, an explorative analysis of all exclusion criteria with respect to sex category was done.

Results

Overall, 11’470 patients were identified for eligibility, 795 patients (49% women; mean age 75 years) were enrolled, and 10’675 patients (52% women vs. 48% men, p =0.13) were not enrolled. The two major exclusion reasons were unwillingness to participate, which was more frequent in women (27.9% of women vs. 18.4% of men, p < 0.01), and the presence of clinical AF, which was more prevalent in men (27.1% of men vs. 20.5 % of women, p < 0.01). A detailed analysis of all exclusion criteria analysed by sex category is provided in the figure.

Conclusions

Clinical AF was more frequent in men, in accordance with the well described sex-driven (biological) higher prevalence of AF in men. In contrast, we found a higher percentage of women unwilling to participate in this study, which may represent a more gender-based (sociocultural) phenomenon. A further exploration of these findings should be performed and may help to identify and potentially overcome modifiable obstacles for study participation.

Multipolar pulsed-field ablation for the treatment of left atrial reentry tachycardia

Funding Acknowledgements

Type of funding sources: None.

Background

A multipolar pulsed field ablation (PFA) catheter was recently introduced for pulmonary vein isolation and combines the benefits of high procedural efficacy and safety. It may also be used to treat left atrial (LA) reentry tachycardia.

Purpose

To describe our initial experience using a multipolar PFA catheter for the treatment of LA reentry tachycardia.

Methods

We included all patients with LA reentry tachycardia treated with a multipolar PFA catheter at our institution. Using 3D electro-anatomical mapping (3D-EAM), we identified the tachycardia mechanism and applied linear lesions either at the left atrial roof, mitral isthmus or on the anterior wall, as appropriate. Positioning of the PFA catheter was verified by integration into 3D-EAM. Applications were performed using 2.0kV with the catheter in basket or flower configuration, depending on ablation site. Bidirectional block across linear lesions was verified using standard criteria. Additional focal radiofrequency ablation (RFA) was used to achieve bidirectional block if necessary.

Results

We treated 17 LA reentry tachycardia with a multipolar PFA catheter in 13 patients (median age 69 (59-73) years; 5 females). The tachycardia mechanism was identified as roof-dependent in five, peri-mitral in eight and anterior scar-related in four cases. PFA lesion sets consisted of 12 posterior wall isolations (i.e. roof lines), four mitral isthmus lines (MIL) and eight anterior lines. For ablation of the mitral side of the anterior line, we always used the PFA catheter in basket configuration, while we targeted the posterior wall and the superior side of the anterior line exclusively with the catheter in flower configuration. To ablate the MIL we used both flower and basket configurations. Three roof-dependent, six peri-mitral, and four anterior scar-related tachycardias were successfully terminated by PFA (76%). Additional RFA was necessary for two MIL, two anterior lines and no roof line (17%). Finally, we achieved bidirectional block across all lines. PFA triggered, vagal-mediated and reversible AV block was observed in one case. Otherwise, there were no acute procedural complications.

Conclusion

Linear lesion sets are feasible and safe using a multipolar PFA catheter. Posterior wall isolation by PFA for the treatment of roof-dependent LA reentry tachycardia is highly efficient while anterior lines and MIL remain challenging and may need complementary RFA or a PFA catheter designed for focal or linear ablations.

Pulsed field ablation of atrial fibrillation: recurrence rate after first pulmonary vein isolation and first insights into durability at redo procedures

Funding Acknowledgements

Type of funding sources: None.

Background

Pulsed field ablation (PFA) is newly available for pulmonary vein isolation (PVI) and combines the benefits of high procedural efficacy and safety. Independent data on the recurrence-rate of atrial fibrillation (AF) after PVI and on PVI durability during redo procedures are scarce.

Purpose

We report data on the recurrence rate of AF after first PVI using PFA and first insights into findings of PVI durability during redo procedures.

Methods

Consecutive AF patients undergoing a first PFA PVI at our center between May 2021 and August 2021 were included. PVI was verified by 3D-electroanatomical mapping (3D-EAM), and additional PFA lesions were applied when necessary until all PV were isolated. Seven-day Holter ECGs were performed at 3 and 6 months after ablation. After a blanking period of 3 months, episodes of AF/AT lasting more than 30 seconds were considered as AF-recurrence.

Results

41 Patients, median age 69 (interquartile range 62-73) years, 24% female, 56% persistent AF, underwent first PVI by PFA. All PVs were successfully isolated using a multipolar PFA catheter. Median total procedure time including 3D-EAM was 104 (85-121) min. Total fluoroscopy time and dose were 26 (19-30) min and 671 (323-1248) Gym2. Acute complications occurred in 1 (2.4%) patient (cardiac tamponade requiring drainage). Early recurrence of AF during the blanking period occurred in 1 (2.4%) patient. Median follow-up time was 107 (91-152) days. Recurrence of AF after the blanking period was detected in 5 (12%) patients, 1 (6%) in paroxysmal AF and 4 (17%) in persistent AF patients, respectively. Redo procedures in 3 (7.3%) patients with AF recurrence confirmed durable isolation of 12/12 (100%) pulmonary veins and showed no evidence of PFA lesion regression.

Conclusion

AF recurrence rates after PVI by means of PFA are low. Durable isolation of 12/12 pulmonary veins (100%) and no evidence of PFA lesion regression was observed during redo procedures in patients with AF recurrence.

Nurse-led compared to physician-led implant of cardiac monitors

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Implantation of an implantable cardiac monitor (ICM) is a simple and straightforward procedure. However, with a growing demand for such implants, workload significantly increases. In January 2020, we established a completely nurse-led ICM implantation service (N-IMPLANT) with a standard operating procedure.

Purpose

The present study aimed to analyze the safety, efficacy, and patient satisfaction of N-IMPLANT compared to implantation of ICMs by a physician (P-IMPLANT).

Method

Consenting patients implanted with an ICM were included in a prospective registry, which collects patient characteristics, procedural and remote monitoring data. All patients were followed-up by phone interview four weeks after ICM implantation and a standardized questionnaire was completed.

Results

Of 321 patients implanted with an ICM (median age 67 years; 33% women), 189 (59%) were N-IMPLANT. Significantly more N-IMPLANT were performed in the outpatient clinic compared to P-IMPLANT (94% vs. 10%; p<0.001). For wound closure, N-IMPLANT used wound glue in 65 (34%) and a single subcutaneous stitch in 124 patients (66%). Two N-IMPLANT patients experienced vaso-vagal reaction during implantation, whereas no adverse events occurred during P-IMPLANT (p=0.51). Two-hundred and fifty-two patients (79%) completed the questionnaire. We found no difference between N-IMPLANT and P-IMPLANT regarding pain after implant, analgesic use, wound closure after 2 weeks and presence and size of patient reported hematoma (see Table). Duration of pain was longer after P-IMPLANT. All N-IMPLANT patients indicated to be satisfied with the implant procedure. Three patients were dissatisfied with P-IMPLANT for the following reasons: ongoing pain at implant site; discomfort at implant site; and too numerous people present during the implant procedure. In three N-IMPLANT (2%) the ICM was explanted prematurely. The reasons for explantation were infection (with reimplantation of another ICM), discomfort at implant site and attempt to avoid interferences during magnetic resonance tomography in one patient each. One P-IMPLANT (1%) was explanted prematurely because of ICM malfunction.

Conclusion

Nurse-led implantation of cardiac monitors is effective without compromising patient safety and has excellent patient satisfaction. N-IMPLANT is a suitable model to reduce the workload of physicians.

Comparison of the accuracy of contact force measurement in four commercially available force-sensing ablation catheters

Funding Acknowledgements

Type of funding sources: None.

Background

Contact force-sensing catheters are widely used for ablation of cardiac arrhythmias. They allow precise quantification of catheter-to-tissue contact, which is an important determinant of lesion size and durability. Moreover, contact force information reduces the risk for cardiac perforation and is used for estimation of lesion size. However, the accuracy of contact force sensors across different manufacturers has not been validated independently.

Objective

To compare the accuracy and reproducibility of different force sensing catheters used in cardiac electrophysiology procedures.

Methods

A force measurement setup containing a heated saline water bath and a catheter fixation mechanism was constructed. The setup allows to accurately measure forces applied to a platform with the catheter. We studied four different catheter models, equipped with the following, unique force-measurement technologies (figure 1): 1) multiple-fiber optical sensor; 2) single-fiber optical sensor; 3) inductive sensor; and 4) magnetic field sensors. For each model, we assessed three catheters. Repeated measurements within the force range of 0g to 60g and at electrode-tissue contact angles of 0°, 45°, and 90° were performed and validated against the force measurement unit of our measurement setup.

Results

For each catheter, at least 500 measurements at different contact forces (equally distributed across the measurement range of 0 to 60 grams) were performed. Correlation of measured-force to real-force was ρSpearman=0.99 for MFOS, ρSpearman=0.98 for SFOS, ρSpearman=0.99 for IS, and ρSpearman=0.98 for MFS. MFS and SFOS showed a higher variance for high forces and increased intra-catheter variability compared to MFOS and IS. IS overestimated higher contact force at 0° and 30°. MFS and SFOS underestimated contact force for higher forces at 30° and 45° (figure 2). Within a clinical range of 5g to 40g, the catheters reached the following root-mean-square-error, independent of contact angle: MFOS 0.88g ±0.68g, SFOS 2.15g ±1.74g, IS 0.88g ±0.72g, and MFS 1.13g ±1.01g.

Conclusion

Measured contact by force-sensing catheters correlates well with true exerted electrode-tissue force. Despite an excellent overall correlation, some technologies may be prone to significant errors at higher forces (>10g under-/overestimation of true contact force) with potential clinical consequences related to increased risk of perforation.

Validation of a multipolar pulsed field ablation catheter for endpoint assessment in pulmonary vein isolation procedures

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): FP7/2007-2013, №602299, EU-CERT-ICD

Objective

To validate the performance of a multipolar PFA catheter compared to a standard pentaspline 3D-mapping catheter for endpoint assessment of PVI.

Background

Pulsed field ablation (PFA) for pulmonary vein isolation (PVI) using single-shot devices combines the benefits of high procedural efficacy and safety. A newly available multipolar PFA catheter allows real-time recording of pulmonary vein (PV) signals during PVI.

Methods

Patients undergoing first PVI using PFA with the standard ablation protocol (8 applications per PV) were studied. Entrance- and exit-block (10V/2ms) were assessed using the PFA catheter. Subsequently, a high-density bipolar voltage 3D electro-anatomical map (3D-EAM) was constructed using a standard pentaspline 3D-mapping catheter. Additional PFA applications were delivered only after confirmation of residual PV-connection by 3D-EAM.

Results

In 56 patients, 213 PVs were targeted for ablation. Acute PVI was achieved in 100% of PVs: in 199/213 (93%) PVs with the standard ablation protocol alone and in the remaining 14 PVs after additional PFA applications. Accuracy of PV assessment with the PFA catheter after the standard ablation protocol was 91% (194/213 veins). In 5/213 (2.3%) PVs, the PFA catheter incorrectly indicated PV-isolation. In 14/213 (6.6%) the PFA catheter incorrectly indicated residual PV-conduction due to high-output pace-capture. When the output was reduced to 5V/1ms, pace-capture was reduced to 0.9% (2/213).

Conclusion

A novel multipolar PFA catheter allows reliable endpoint assessment for PVI. Due to its design, far-field sensing and high-output pace-capture can occur, which may require adjustment of standard pacing outputs for verification of exit-block.

Incidental arrhythmias during atrial fibrillation screening in a hospital-based patient population

Funding Acknowledgements

Type of funding sources: None.

Introduction

Screening for atrial fibrillation may reveal other, incidental arrhythmias of relevance. We sought to describe such incidental arrhythmias in the prospective STARFIB cohort study, which screened for silent atrial fibrillation in hospitalized patients aged 65-84 years.

Method

Patients included in the STARFIB cohort study had up to three 7-day Holter ECGs, performed in two-month intervals. We analysed all the 7-day Holter ECGs of study participants for the presence of one of the following incidental arrhythmias: 1) sick-sinus-syndrome (SSS), defined as sinus arrest of ≥3 seconds duration; 2) second or higher degree atrioventricular block (AVB); 3) sustained atrial tachycardia of ≥30 seconds duration (AT); and 4) sustained ventricular tachycardia of ≥30 seconds duration (VT).

Results

A total of 2’077 Holter ECGs were performed in 794 patients (mean age 74.7 years; 49% females), resulting in a mean cumulative duration of an analyzable ECG signal of 414±136 hours per patient. We found incidental arrhythmias in 94 patients (11.8%). Among these were SSS in 14 patients (1.8%), AVB in 41 (5.2%), AT in 41 (5.2%), and VT in two (0.3%). The median pause duration in SSS was 4 seconds and SSS resulted in pacemaker implantation in one patient with a pause of 9 seconds duration. The most severe type of AVB found per patient was second degree AVB type Wenkebach in 23 patients (2.9%), second degree AVB type Mobitz or 2:1 AV conduction in 10 patients (1.3%) and complete AVB in 8 (1%; maximum pause 18 seconds). AVB led to pacemaker implantation in 9 patients (1.1%). The median duration and heart rate of AT was 2.2 minutes and 144 bpm, respectively. Initiation of betablocker therapy was recommended in 3 patients (0.4%) due to symptomatic AT. The duration and heart rate of VT was 3 minutes at 216 bpm in one patient and 38 seconds at 150 bpm in another. The former patient with VT experienced syncope and an ICD was implanted, whereas in the latter the betablocker dose was increased. One patient died from a non-cardiac cause during a Holter ECG, which showed progressive bradycardia and finally asystole.

Conclusion

Incidental arrhythmias were frequently discovered during screening for atrial fibrillation and resulted in device therapy in 1.4% of our cohort patients.

Electrophysiological differences of deep sedation with dexmedetomidine versus propofol

Funding Acknowledgements

Type of funding sources: None.

Background

Dexmedetomidine and propofol are commonly used drugs for deep sedation during cardiovascular interventions. Patients undergoing these interventions often have impaired sinus node function or atrioventricular (AV) conduction disease. Anesthetics used for deep sedation may further compromise sinus node function and AV nodal conduction, and thereby interfere with the intervention.

Purpose

To compare the electrophysiological effects of dexmedetomidine and propofol on the function of the sinus node and AV conduction.

Methods

We randomized patients undergoing first atrial fibrilation ablation 1:1 to deep sedation by dexmedetomidine (DEX group) versus propofol (PRO group), according to a standardized protocol. At the end of the ablation procedure with the patients still deeply sedated and hemodynamically stable, we conducted a standard electrophysiological study and assessed sinus node function, properties of AV conduction and atrial refractoriness.

Results

Of 160 patients (65±11 years old; 32% female) included into the study, 80 patients were randomized to the DEX and PRO group each. Procedure duration (128±59 minutes) and sedation depth, as assessed by the "Modified Observer’s Assessment of Alertness/Sedation" score (median 3; interquartile range 2, 3), was not different among groups. DEX group patients received a mean of 231±111 mcg of dexmedetomidine and PRO group patients a mean of 657±356 mg of propofol. The table shows the results of the electrophysiological study. DEX group patients had lower sinus rate and longer unadjusted sinus node recovery time (SNRT) at pacing cycle lengths of 600, 500 and 400 ms. However, both corrected (SNRT-RR) and normalized (SNRT/RR) SNRT did not differ among groups. Compared to PRO group patients, AV nodal conduction was slower in DEX group patients as evidenced by longer PR and AH intervals, and a higher Wenckebach cycle length and AV node effective refractory period (ERP) was observed. Conduction properties in the His-Purkinje system were not different among groups, as QRS width and HV interval were similar. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients (21%) during the electrophysiological study, without differences among groups.

Conclusions

Sinus rate and AV conduction are slower during deep sedation with dexmedetomidine compared to propofol. These differences in electrophysiological effects need to be taken into account when using these anesthetics during cardiovascular interventions.

Patient characteristics, predictors and outcome of pacemaker patients upgraded to an implantable cardioverter defibrillator

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pacemaker (PM) patients may require a later upgrade to an implantable cardioverter-defibrillator (ICD). Limited data exists on this patient population. We sought to characterize this population, to assess predictors for ICD upgrade, and to report the outcome.

Methods

From our prospective PM and ICD implantation registry, all patients who underwent PM and/or ICD implantations at our center were analyzed. Patient characteristics and outcome of PM patients with subsequent ICD upgrade were compared to age- and sex-matched patients with de novo ICD implantation, and to PM patients without later upgrade.

Results

Of 1’301 ICD implantations, 60 (5%) were upgrades from PMs. Median time from PM implantation to ICD upgrade was 2.6 years (IQR 1.3-5.4) Of 2’195 PM patients, 28 patients underwent subsequent ICD upgrade, corresponding to an estimated annual incidence of an ICD upgrade of at least 0.33%. Lower LVEF (p=0.05) and male sex (p=0.038) were independent predictors for ICD upgrade. Transplant- and LVAD-free survival was worse both for upgraded ICD patients compared to matched patients with de novo ICD implantation (p=0.05; Figure, panel A), as well as for PM patients with later upgrade compared to matched PM patients not requiring an upgrade (p=0.036; Figure, panel B).

Conclusions

One of twenty ICD implantations are upgrades of patients with a PM. At least one of 30 PM patients will require an ICD upgrade in the following 10 years. Predictors for ICD upgrade are male sex and lower LVEF at PM implantation. Upgraded patients have worse outcome.

Diagnostic reliability of AV synchrony self-diagnostics in leadless VDD pacemakers

Funding Acknowledgements

Type of funding sources: None.

Introduction

Leadless pacemakers (PMs) capable of atrio-ventricular (AV) synchronous pacing have been introduced recently. These devices provide mechanical atrial sensing by detection of the atrial contraction via an accelerometer. Atrial tracking may be disturbed by external influences such as body motions and higher heart rates in real life. To track the amount of AV synchronous pacing, the device statistic classifies all sensed and paced QRS complexes according to presumed AV synchrony. The reliability of this self-diagnostics to estimate the true degree of AV synchrony, however, is insufficiently studied.

Purpose

To investigate the informative value of the device statistics offered by leadless VDD PMs regarding true AV snychrony.

Methods

We prospectively included all patients who received a leadless VDD PM between 07/2020 and 05/2021 at our center in this observational study. During the regular outpatient follow-ups, device interrogation was performed, which included evaluation of the PM statistics. True AV synchrony (defined as a QRS complex preceded by a p-wave within 300ms) was analyzed repeatedly during follow-up using Holter ECGs.

Results

We analysed 34 Holter ECGs from 20 outpatients (816 hours of ECG in total). Patients had a median age of 80 years (interquartile range 76-86 years), 55% were females. For Holter ECG sequences that showed high degree or complete AV-Block (>80% ventricular pacing), the percentage of paced beats that were presumed to be AV synchronous by the device statistic (ratio "AM-VP"/total VP) correlated well with AV synchrony as assessed using Holter-ECGs (Kendall’s τ=0.312, p<0.001). AV synchrony in the Holter ECG was different in patients with <66.6% presumed AV synchrony than in patients with >66.6% presumed AV synchrony (p<0.001, figure). For Holter ECG sequences with mostly preserved intrinsic AV conduction (<20% ventricular pacing), the ratio "AM-VP"/total VP was not predictive for true AV synchrony (Kendall’s τ=0.07, p=n.s.). In this situation, however, "VS only" (Kendall’s τ=0.110, p=0.005) correlated with true AV synchrony (due to AV conduction mode switch) and "VP only" showed an inverse correlation with AV synchrony (Kendall’s τ=-0.215, p<0.001).

Conclusion

Leadless PMs provide device statistics that show a correlation with true AV synchrony. The clinical setting as well as the device programming (e.g. AV conduction mode switch) significantly influence the predictive value of the different parameters of the device’s statistics.

Durability of CLOSE-guided pulmonary vein isolation in persistent atrial fibrillation - First results from a prospective remapping study

Funding Acknowledgements

Type of funding sources: None.

Background

The CLOSE protocol for pulmonary vein isolation (CLOSE-PVI) combines ablation index and inter-lesion distance (≤6 mm) targets. CLOSE-PVI has been shown to result in high clinical success rates. Data on durability of PVI after CLOSE-PVI mainly derive from repeat procedures in paroxysmal atrial fibrillation (AF) patients with recurrent AF.

Purpose

We sought to assess the incidence of pulmonary vein (PV) reconnections during a staged redo procedure performed independently of AF recurrence 6 months after CLOSE-PVI in patients with persistent AF.

Methods

In this prospective, single-center study, patients with symptomatic persistent AF (EHRA score >1) undergoing AF ablation were included. Close-PVI was performed during the index procedure. A blanking period of 3 months was applied. Seven-day Holter ECGs were performed at 3 and 6 months post ablation. All patients underwent a staged redo procedure including high-density voltage mapping of the left atrium at 6 months after the index procedure.

Results

Overall, 20 patients were included (median age: 68 years [IQR 63-71]; 20% women; median duration of persistent AF: 8 months [IQR 5-15]; median LAVI 45 ml/m2 [IQR 43-53]). All PVs were successfully isolated with CLOSE-PVI during the index procedure. Four patients (20%) had AF recurrence. The redo procedure was performed after a median of 6.1 months (IQR 5.6-7.3). Of 80 PVs, 71 (89%) were still isolated. No patient had a common ostium. Reconnections were observed in 3 left superior (15%), in one left inferior (5%), in one right superior (5%) and in 4 right inferior (20%) PVs. Fourteen patients (74%) had completely isolated PVs. Two of four patients with AF recurrence (50%) and 12 of 16 patients without AF recurrence (75%) had completely isolated PVs (p=0.33).

Conclusions

CLOSE-PVI achieves durable PVI after 6 months in the majority of patients with persistent AF. In half of persistent AF patients with recurrence after CLOSE-PVI, all PVs are still isolated. These patients may need adjunctive ablation.

Impact of clinical risk factor profile vs. atrial fibrillation phenotype on outcome after pulmonary vein isolation

Aims

Catheter ablation for atrial fibrillation (AF) is increasingly performed. Both clinical risk factors as well as the AF phenotype have been shown to influence ablation outcomes. The inter-relationship of the two however is incompletely understood.

Methods

In a retrospective analysis of a prospective registry of patients undergoing a first pulmonary vein isolation, the association of 8 predefined clinical risk factors (age >70 years, female gender, hypertension, BMI >30 kg/m2, coronary artery disease, heart failure, chronic kidney disease (CKD; eGFR<60ml/min/1.73m2) and diabetes mellitus) and the AF phenotype (paroxysmal vs. persistent AF) were assessed as well as their impact on AF recurrence during follow-up.

Results

Overall, 715 patients were enrolled (median age 63 years, 27% females, 69% paroxysmal AF). The prevalence of obesity, hypertension, heart failure and CKD was significantly higher in persistent AF, while female gender was more prevalent in paroxysmal AF. After 2 years of follow-up, overall freedom from recurrence was 46%, and was higher in paroxysmal AF compared to persistent AF (54.1% vs. 29.1%, p<0.001). Of the clinical risk factors, obesity (p=0.02), CKD (p=0.01) and heart failure (p=0.01) were significantly associated with lower arrhythmia-free survival, and there was a trend for hypertension and coronary artery disease (both p<0.2). A risk score composed of those 5 factors was associated with recurrences in patients with paroxysmal AF (p=0.04, Figure 1), but not in those with persistent AF (p=0.85, Figure 2).

Conclusion

Clinical risk factors predict outcome after pulmonary vein isolation in patients with paroxysmal, but not persistent AF. This is likely due to a strong association of those risk factors with the occurrence of persistent AF.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

P311Hypertrophic cardiomyopathy and other forms of left ventricular hypertrophy. The P wave can make the difference

Background

Structural disarray of hypertrophied myocytes and interstitial fibrosis characterize hypertrophic cardiomyopathy (HCM). These morphological changes also affect atrial myocytes and, together with hemodynamic alterations because of HCM, may lead to atrial cardiomyopathy. 

Purpose

To investigate the incremental value of P-wave parameters to differentiate left ventricular hypertrophy (LVH) because of HCM from LVH in hypertensive heart disease (HHD) and athletes heart. 

Methods

In a prospective study, we compared electrocardiographic (including signal-averaged ECG of the P wave) and echocardiographic data of patients with HCM, HHD and athletes heart. We developed a predictive model with a simple scoring system to identify HCM.

Results

We compared data of 27 patients with HCM (70% males, 49.8 ± 14.5 years), 324 patients with HHD (52% males, 74.8 ± 5.5 years), and 215 subjects with athletes heart (72% males, 42.3 ± 7.5). The table shows the significant differences among the 3 groups. We included the following parameters into a predictive score to differentiate HCM from other forms of LVH: QRS width (>88ms = 1 point), P-wave integral (>688µVs = 1 point) and septum thickness (>12mm = 2 points). A score >2 (Youden index 0.626) correctly classified HCM in 81% of the cases with a sensitivity and specificity of 82% an 81%, respectively. 

Conclusion Differentiation of HCM from other forms of LVH is improved by including atrial parameters. A simple scoring system including septum thickness, QRS width and P wave integral allowed identification of patients with HCM with a sensitivity and specificity of >80%. This score needs to be validated prospectively.

Table 1 HCM HHD Athletes P-value HCM vs HHD* HCM vs Athletes* 95%-CI P-value 95%-CI P-value P-wave duration [ms] 152.7 ± 25.8 143.9 ± 16.5 133.5 ± 14.2 <0.001 -16.9 -24.6 to -9.1 <0.001 -16.3 -22.7 to -9.9 <0.001 P-wave integral [µVs] 850.4 ± 272.4 672.0 ± 235.4 773.1 ± 260.1 <0.001 -198.6 -320.8 to -76.3 0.002 -68.2 -169.7 to 33.2 0.187 QRS [ms] 110.3 ± 27.3 96.9 ± 20.3 95.1 ± 9.8 <0.001 -16.4 -24.7 to -8.1 <0.001 -13.8 -20.8 to -6.9 <0.001 QTc [ms] 447.9 ± 27.2 438.6 ± 24.5 414.0 ± 22.9 <0.001 -21.1 -32.7 to -9.5 <0.001 -30.8 -40.5 to -21.2 <0.001 LVMMI [g/m2] 153.6 ± 55.5 133.5 ± 30.3 98.6 ± 19.7 <0.001 -15.3 -29.7 to -0.9 0.038 -56.1 -67.7 to -44.6 <0.001 IVS [ms] 16.8 ± 4.2 11.8 ± 2.2 10.3 ± 1.5 <0.001 -5.2 -6.3 to -4.1 <0.001 -6.4 -7.3 to -5.6 <0.001 LAVI [ml/m2] 43.2 ± 13.9 30.5 ± 9.7 30.8 ± 9.5 <0.001 -14.6 -20.0 to -9.3 <0.001 -12.2 -16.6 to -7.9 <0.001 The table shows the study result after univariate and multivariate (*; adjusting for age and sex) analysis.

Abstract Figure 1

P1492Comparison of the long-term performance of the quadripolar IS-4 and the bipolar IS-1 left ventricular lead for cardiac resynchronization therapy

BACKGROUND

The implantation of left ventricular (LV) leads for cardiac resynchronization therapy (CRT) and the management of lead-related complications can be challenging. The introduction of the quadripolar IS-4 LV lead may have facilitated the implantation procedure and may have reduced lead-related complications. Data of long-term follow-up (FU) comparing the IS-4 lead with the IS-1 LV lead are rare and conflicting.

PURPOSE

Comparison of lead-related complications and all-cause mortality between CRT patients who received an IS-4 or an IS-1 LV lead in the long-term FU.

METHODS

Adults with an indication for a CRT-Defibrillator or CRT-Pacemaker, a successful endovascular IS-4 or IS-1 LV lead implantation, and a minimal FU of three years were included in this retrospective study. The combined primary endpoint was freedom from lead-related complications defined as (i) occurrence of persisting high pacing threshold (>2.75V/0.4ms), (ii) unresolved phrenic nerve stimulation, (iii) LV lead dislodgement/disruption, (iv) the necessity of re-interventions affecting the LV lead, and (v) LV lead deactivation/explantation. Secondary endpoints were all singular complications and all-cause mortality.

RESULTS

Eligible for the study were 133 patients (IS-4 n = 66; IS-1 n = 67) with a mean FU of 4.03 ± 1.93 years. Baseline characteristics of both patient groups did not differ significantly. Freedom from lead-related complications was higher in patients with an IS-4 lead as compared to an IS-1 lead (Figure 1; 87.9% vs. 65.7%; p = 0.002). The secondary outcomes showed a higher rate of LV lead dislodgement/disruption (4.5% vs. 17.9%; p = 0.015) in the IS-1 patient group and more patients suffered from unresolved phrenic nerve stimulation with an IS-1 lead (3.0% vs. 13.4%; p = 0.029). LV lead deactivation/explantation during FU and LV lead-related re-interventions were fewer in case of an IS-4 lead (4.5% vs 22.4%; p = 0.003; 6.1% vs. 17.9%; p = 0.036, respectively). The rate of persisting high pacing thresholds and all-cause mortality did not differ (4.5% vs. 9.0%; p = 0.492; 22.7% vs 25.4%; p = 0.721, respectively).

CONCLUSION

The quadripolar IS-4 LV lead showed in this retrospective study a better long-term performance than the bipolar IS-1 lead.

Abstract Figure 1

P2855Unexpectedly high rate of lead failure of the Microport (formerly Sorin/Livanova) Beflex and Vega pacemaker electrodes: A single centre experience

Introduction

Pacing leads remain the weak link of current pacemaker systems. Various differences in design and material exist among companies. Lead performance is mainly assessed via post-marketing studies of the manufacturing companies. Reliable independent reports are rare. We aimed to study the early and long-term performance of the Microport (formerly Sorin/Livanova) Beflex and Vega leads at our centre, for which a lead survival >99% at 3 years has been reported by the company.

Method

In this single centre, retrospective study we analysed the performance of all right ventricular Microport pacemaker leads implanted at our centre between January 2014 and January 2018. Only first pacemaker implants were considered. Lead failure was defined as any lead issue requiring reintervention during follow-up (dislocation, perforation, electrical abnormalities such as lead noise or excessively high thresholds).

Results

A total of 271 Microport right ventricular pacing leads were implanted (233 Beflex and 38 Vega leads). Mean patient age was 76±13.1 years (66% men). Dual chamber pacemakers were implanted in 162 patients (60%) and single chamber in 109 (40%). Mean threshold at implant was 0.6V/0.5ms (range 0.3–1.2V), mean R wave 13.2 mV (range 1.5–30mV) and mean impedance 816 Ohm (range 469–1639 Ohm). Patients without available follow-up information were excluded (N=18, 6.6%). The remaining 253 patients (93.4%) were analysed. Median follow-up was 1.26 years, IQR [25%=0.91 and 75%=2.24]. We observed a total of 25 lead failures (10%). Lead dislocation occurred in 2 cases (0.8%), lead perforation in 5 cases (2%), electrical abnormalities in 6 cases (2.4%) and excessively high threshold in 12 cases (4.8%; mean voltage 4V, range 2–7.5V; mean pulse width 0.75ms, range 0.35–1ms). Yearly incidence of lead failure per 100 leads was 6.1% (95%-CI [4.09–8.98] with a failure rate of 12.74% at 3 year in Kaplan-Meier analysis (Figure).

Figure 1

Conclusion

We found an unexpectedly high rate of lead failure of the Microport Beflex and Vega pacing leads at our centre. The two main reasons for premature lead failure were excessively high thresholds as well as electrical abnormalities during follow-up. Comparison of lead performance with other centres and against other leads are needed to further assess the magnitude of the problem.

[Catheter ablation for atrial fibrillation: clinically established or still an experimental method]

Interventional treatment for atrial fibrillation has been introduced as a therapeutic option since the pulmonary veins (PV) have been discovered as the dominant sources of paroxysmal atrial fibrillation (PAF). Elimination of PV conduction is the initial goal during catheter ablation in this setting. The success rate after the initial procedure varies between 60 and 85 %, with more than 80 % after subsequent interventions. Supported by the current guidelines, interventional treatment of AF is indicated in case of symptomatic arrhythmias refractory to antiarrhythmic treatment. The introduction of the combined, stepwise approach has been another important breakthrough with regard to the treatment of chronic persistent atrial fibrillation (CAF). This strategy includes the combination of all conventional ablation strategies (PV isolation, ablation of complex fractionated atrial electrograms, linear ablation) with the goal of AF termination. The first procedure for CAF treatment is quite frequently also only the first step towards stable sinus rhythm with a favourable outcome after AF termination (> 80 % sinus rhythm). In more than half of the patients predominantly other atrial arrhythmias than AF have to be targeted in a second procedure. This approach is currently under clinical investigation and so far not "clinically established" due to the fact that it is a quite time consuming and challenging procedure even in experienced centres. Future studies may help to identify predictors for procedure failure (e.g. LA size, AF duration, atrial cycle length, spectral analysis) in order to improve patient selection. Additionally, it has to be underscored, that in paroxysmal atrial fibrillation the relatively high recurrence rate after the first procedure still is the subject of further investigations. This aspect might be improved by the introduction of novel strategies (i.e. testing of concealed PV conduction after ablation with adenosine) or new technologies (i.e. robotic navigation) for PAF ablation.

[Surface ECG presentation and intracardiac electrogram characteristics of uncommon supraventricular tachycardia entities]

The vast majority of patients with supraventricular tachycardias present with specific 12-lead surface ECG characteristics allowing the diagnosis of the underlying mechanisms prior to the invasive electrophysiological study. However, an accurate diagnosis remains challenging in a subset of patients, even when using well-established stimulation maneuvers and sophisticated conventional mapping methods. Thus, the aim of the present manuscript is to describe some cases with uncommon entities of supraventricular tachycardias where the combined interpretation of 12-lead ECG presentation and invasive electrophysiological characteristics revealed the correct diagnoses.