The eradication of ventricular tachycardia (VT) isthmus sites constitutes the minimal procedural endpoint for VT ablation procedures. Contemporary high-resolution computed tomography (CT) imaging, in ...combination with computer-assisted analysis and segmentation of CT data, facilitates targeted elimination of VT isthmi. In this context, inHEART offers digitally rendered three-dimensional (3D) cardiac models which allow preoperative planning for VT ablations in ischemic and non-ischemic cardiomyopathies. To date, almost no data have been collected to compare the outcomes of VT ablations utilizing inHEART with those of traditional ablation approaches.
The presented data are derived from a retrospective analysis of n = 108 patients, with one cohort undergoing VT ablation aided by late-enhancement CT and subsequent analysis and segmentation by inHEART, while the other cohort received ablation through conventional methods like substrate mapping and activation mapping. The ablations were executed utilizing a 3D mapping system (Carto3), with the mapping generated via the CARTO® PENTARAY™ NAV catheter and subsequently merged with the inHEART model, if available.
Results showed more successful outcome of ablations for the inHEART group with lower VT recurrence (27% vs. 42%, p < 0.06). Subsequent analyses revealed that patients with ischemic cardiomyopathies appeared to derive a significant benefit from inHEART-assisted VT ablation procedures, with a higher rate of successful ablation (p = 0.05).
Our findings indicate that inHEART-guided ablation is associated with reduced VT recurrence compared to conventional procedures. This suggests that employing advanced imaging and computational modeling in VT ablation may be valuable for VT recurrences.
Background
High-power short-duration (HPSD) radiofrequency ablation (RFA) is highly efficient and safe while reducing procedure and RF time in pulmonary vein isolation (PVI). The QDot™ catheter is a ...novel contact force ablation catheter that allows automated flow and power adjustments depending on the local tissue temperature to maintain a target temperature during 90 W/4 s lesions. We analysed intraprocedural data and periprocedural safety using the QDot-catheter in patients undergoing PVI for paroxysmal atrial fibrillation (PAF).
Methods
We included
n
= 48 patients undergoing PVI with the QDot-catheter with a temperature-controlled HPSD ablation mode with 90 W/4 s (TC-HPSD). If focal reconnection occurred besides repeat ablation, the ablation mode was changed to 50 W/15 s (QMode).
N
= 23 patients underwent cerebral MRI to detect silent cerebral lesions.
Results
Mean RF time was 8.1 ± 2.8 min, and procedure duration was 84.5 ± 30 min. The overall maximal measured catheter tip temperature was 52.0 °C ± 4.6 °C, mean overall applied current was 871 mA ± 44 mA and overall applied energy was 316 J ± 47 J. The mean local impedance drop was 12.1 ± 2.4 Ohms. During adenosine challenge,
n
= 14 (29%) patients showed dormant conduction. A total of
n
= 24 steam pops were detected in
n
= 18 patients (39.1%), while no pericardial tamponade occurred. No periprocedural thromboembolic complications occurred, while
n
= 4 patients (17.4%) showed silent cerebral lesion.
Conclusions
TC-HPSD ablation with 90 W/4 s using the QDot-catheter led to a reduction of procedure and RF time, while no major complications occurred. Despite optimized temperature control and power adjustment, steam pops occurred in a rather high number of patients, while none of them leads to tamponade or to clinical or neurological deficits.
Electromagnetic interference with implantable cardioverter defibrillators (ICDs) can cause inappropriate shock delivery or temporary inhibition of ICD functions. We present a case of electromagnetic ...interference between a lawn mower and an ICD resulting in an inappropriate discharge of the device due to erroneous detection of ventricular fibrillation.
Abstract
Background
Subcutaneous implantable cardioverter-defibrillators (S-ICD) are an established treatment option for the prevention of sudden cardiac death (SCD). However, data in adults with ...congenital heart disease (ACHD), especially in direct comparison to other patient groups (e.g. cardiomyopathies) are scarce.
Methods
Retrospective single-center study of all patients receiving a S-ICD in the time-period 2012-2020. ACHD patients were compared to non-ACHD patients. Primary outcome was all-cause mortality. Secondary outcome was a combined endpoint of all-cause mortality and appropriate shocks.
Results
Altogether, 79 patients (11 ACHD, 68 non-ACHD patients) with a mean age of 40.6 ± 16.0 years (29.1% female) were included. There was no significant difference for age and sex between both groups. Secondary prevention of SCD was more often the indication for a S-ICD in ACHD (81.8%) than in non-ACHD patients (48.5%; p=0.040). Betablockers were more commonly used in ACHD patients (100% vs. 64.7%; p=0.018). There was no significant difference for other heart failure medications.
During a median follow up of 3.4 years IQR 1.7-5.2, the primary endpoint occurred in 36.4% of ACHD vs. 2.9% of non-ACHD patients (p<0.001). The secondary endpoint occurred also more often in the ACHD patient group compared to non-ACHD patients (54.5% vs. 17.6%, p=0.007). There was a numerically higher number of inappropriate shocks in the ACHD group (27.3% vs. 9.0%), albeit without a statistically significant difference (p=0.078).
Conclusions
In ACHD patients with a S-ICD, mortality as well as a combined endpoint of mortality and appropriate shocks were more common than in non-ACHD patients. The numerically higher number of inappropriate shocks deserves further attention.
Abstract
Aims
To investigate the effectiveness of a combined telemonitoring and telecoaching programme for chronic heart failure patients at high risk for hospitalisation compared to usual care in a ...real life setting. The applied telehealth programme consisted of regular individualised telecoaching sessions as well as daily remote telemonitoring of heart failure signs and symptoms.
Methods
Between January 2018 and September 2020, 6,065 heart failure patients were enrolled in a combined telehealth programme and retrospectively compared to a propensity matched usual care group (n=6,065). All participants were members of a statutory health insurance. Median follow-up was 442 days (IQR 309–681). Endpoints were all cause mortality, number and duration of hospitalisations.
Results
After 1 year the combined telecoaching and telemonitoring programme significantly reduced all-cause mortality probability compared to usual care (11.0 vs. 5.8%, p<0.001). The corresponding number-needed to treat to prevent one death in one year was 19.3. In addition, the number of hospitalisations for heart failure (17.9 vs. 21.8 per 100 patient years, p<0.001) and all cause hospitalisations (129.0 vs. 133.2, p=0.015), as well as their duration (2.0 vs. 2.6 days per year p<0.001, and 12.0 vs. 13.4 days per year p>0.001, respectivel y) were significantly lower in the telehealth group than in the usual care group.
Conclusion
In ambulatory heart failure patients at high risk for hospitalisation, a combined telemonitoring and telecoaching programme led to a reduction of heart failure hospitalisations and all-cause mortality compared to standard care.
Funding Acknowledgement
Type of funding sources: Private company. Main funding source(s): Health Care Systems GmbH (HCSG), Pullach i. Isartal
Background
Remote magnetic navigation systems are used for catheter navigation in cardiac electrophysiological ablation procedures. In this setting, ferromagnetic particles will be moved by changes ...in the magnetic field. It is unknown to what extent cardiac implantable electronic devices (CIED) are affected by the magnetic field when using magnetic navigation, and whether these forces may exceed the limit of 5 N that is set forth by German and European norms for implanted electrodes.
Methods
A total of 121 rhythm devices were examined in a magnetic field of 0.1 T using the NIOBE II
®
Magnetic Navigation System (Stereotaxis, St. Louis, USA). Forces acting on the devices were measured with the force measurement tool Futek LRF 400 (Futek Advanced Sensor Technology Inc., Irvine, CA, USA). A standardized protocol of different movements of the magnetic field including all three dimensions was performed and maximal forces on the CIED were assessed.
Results
Out of 121 devices, 78 different pacemakers (54 different model families from 11 manufacturers) and 43 different cardioverter-defibrillators (26 different model families from 6) were examined. The mean force that could be observed was 0.33 ± 0.13 N for pacemakers (range 0.16–1.12 N) and 1.05 ± 0.11 N for cardioverter-defibrillators (range 0.86–1.38 N) when exposed to the magnetic field.
Conclusion
Exposure of pacemakers or implantable cardioverter-defibrillators to a magnetic field of 0.1 T does not result in a force exceeding the regulatory demanded 5 N that could damage the connected leads.
Abstract
Background
The incidence of complications after implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT-D) implantations is dependent on the number of ...implanted leads. The majority of CRT-D patients have unimpaired sinus node function and do not require atrial pacing. A two-lead CRT-D system with a floating atrial sensing dipole mounted on the right ventricular lead ((CRT-DX) allows dual chamber tachyarrhythmia detection, and atrio-ventricular sequential pacing with a reduced amount of implanted material.
Purpose
This study investigated the clinical efficacy and safety of the CRT-DX system.
Methods
This multicentre, single-arm study observed patients after de novo implantation of a CRT-DX system for 12 months. Patients were eligible for the study when chronotropic competence was proven by heart rates ≥100 bpm during exercise, premature ventricular contractions rate of < 5%/h and absence of atrioventricular block ≥ II. Intraoperatively measured p-wave amplitude of ≥ 1 mV was recommended. The primary safety endpoint was the additional implantation of a right atrial (RA) lead after the initial implantation. As indicators of efficacy, we report the changes in left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) class over the follow-up period.
Results
Overall, 110 patients were implanted with the complete CRT-DX system. Mean age of study participants was 62 ± 12 years and 77 (70%) were male. The underlying heart disease was non-ischemic in 66 (60%) patients and 103 (93%) had a left bundle branch block. NYHA class was II in 60 (54.5%) and III in 50 (45.5%) patients. ICD placement was performed in 13 (11.8%) patients for the secondary prevention of sudden cardiac death. A total of 104 patients completed the follow-up, 2 patients died, 1 had the system explanted for infection, 2 withdrew consent and 1 was lost to follow-up. The primary endpoint of RA lead implantation was met in 2 (1.8%) participants (Figure 1). One patient required atrial pacing and one patient, who had shown a p-wave amplitude < 1 mV at implantation, lost atrial sensing. The mean RA sensing amplitude remained stable during follow-up (4.6 ± 1.8 mV, 4.9 ± 1.8 mV and 4.6 ± 1.8 mV at 1, 6 and 12 months, respectively; Figure 2). The LVEF improved by 14.7% ± 11.0%, from 26.3% ± 6.9% to 40.8% ± 10.7% (p < 0.00001). Changes in NYHA class were available in 87 patients with 35 (40.2%) improved by one class and 13 (14.9 %) by two classes. Thirty-four (39.1%) had no change and 5 (5.7%) worsened by one class (global p < 0.00001).
Conclusion
The two-lead CRT-DX system showed a low requirement of subsequent RA lead implantations (1.8%) and stable RA sensing amplitudes. Our results suggest a CRT response similar to that of conventional three-lead CRT-D systems. CRT-DX systems appear to be a feasible alternative for patients with chronotropic competence.Kaplan-Meier curve for primary endpointDaily mean RA sensing amplitude
Abstract
Background
Left ventricular lead (LVL) implantation can be challenging in Cardiac Resynchronization Therapy (CRT). Therefore, contrast is commonly used to visualize the coronary venous ...system. However, contrast use is correlated with substantial risks such as contrast-induced nephropathy and anaphylactic reaction. Case studies suggest feasibility of LVL implantation without coronary sinus (CS) venography.
Purpose
We aimed to compare the procedure characteristics, outcome, and safety of contrast-free and contrast-aided LVL implantation.
Methods
346 LVL implantations performed between 2017 and 2019 were analyzed. 167 were contrast free (No-Contrast Group: NCG), and 179 were contrast-aided (Contrast Group: CG). The intervention duration, fluoroscopy duration, and radiation dose were evaluated. The primary outcome was procedural success. The secondary outcomes were LVL position, LVL threshold value, QRS duration and LVEF. Operative complications and lead revisions were surrogates for the intervention’s safety.
Results
The LVL implantation success rate varied from 62.9% in the NCG to 96.6% in the CG (Figure 1). Contrast-free interventions were associated with shorter procedure and fluoroscopy durations, and smaller radiation doses (100.8±41.0 vs 131.1±50.0min (p<0.01), 15.7±11.2 vs 26.0±17.5min (p<0.01) and 475.3±422.7 vs 897.3±779.1Gy.cm2 (p<0.01) respectively). The intraoperative LVL threshold values were equivalent (0.96±0.65 in the NCG vs 1.05±0.65V in the CG, TOST-p<0.01), and contrast use did not significantly influence the follow-up LVL threshold, QRS shortening and LVEF increase (1.11±0.55 vs 1.22±0.93V (p=0.62), -10.5±28.3 vs -13.2±26.3ms (p=0.16) and 2.3±8% vs 4.1±8.4% (p=0.40)). More intraoperative complications (CS dissection, perforation, mechanically-induced arrhythmia and other respiratory or circulatory problems) were observed during the contrast-aided procedures (9.5% in the CG versus 1.9% in the NCG, p=0.04). However, the postoperative complication rates (ICU admission, pericardial effusion, pneumothorax, infection and LVL revision) did not differ (9.5% in the NCG, 12.8% in the CG, p=0.55). In contrast-free LVL implantation failure cases, intraoperatively crossing over from the NCG to CG did not result in longer procedures or different intraprocedural complication rates (131.8±46.8 vs 131.1±50.0min in the CG (p=0.9) and 6.5% vs 9.5%, (p=0.6)).
Conclusion
Contrast-free LVL implantation was associated with shorter intervention and fluoroscopy durations and less radiation. Less intraoperative complications were observed without contrast, and the postoperative complication rate was similar to contrast-aided procedures. This technique was successful in almost 2/3 of the cases. In case of failure and crossover to contrast, the initial contrast free attempt did not result in more adverse events than in fully contrast-aided procedures. It is therefore reasonable to consider an initial contrast-free approach for CRT implantation.Compared groups
Abstract
Funding Acknowledgements
Type of funding sources: Private company. Main funding source(s): Pfizer Global Medical Grant
Background
Amyloid transthyretin cardiomyopathy (ATTR-CM) is a ...progressive infiltrative cardiomyopathy caused by extracellular deposition of amyloid fibrils. The disease is characterized by congestive heart failure, conduction abnormalities and arrhythmias. Due to the limited overall prognosis, ICDs were rarely indicated in ATTR-CM. However, with the development of new targeted therapies, the role of ICD therapy for ATTR-CM should be reevaluated. Hence, there is an urgent and unmet need to identify patients at high risk for ventricular tachycardias who might possibly benefit from ICD therapy.
Methods
Between 2020 and 2022, 120 patients were diagnosed with ATTR-CM in a tertiary referral center. Of those, 63 were prospectively evaluated for the presence of ventricular arrhythmias using 24 hours Holter-ECG. Ventricular arrhythmias were further characterized as sustained (sVT) and non-sustained ventricular tachycardias (nsVT).
Results
In our cohort of unselected ATTR-CMP patients the prevalence of ventricular tachycardias was high with 47.6 % (n= 30/63). Of those, the majority were non-sustained VTs (84%) and the minority sustained VT (16%). Patients with ventricular tachycardias showed significantly more severe left ventricular (LV) hypertrophy, reduced LV ejection fraction (LV-EF) and larger left atrial volumes as well as a trend towards smaller LV cavities (table 1). Interestingly, no significant differences in prevalence of coronary artery disease or cardiac markers such as NTproBNP and troponin were seen between patients with and without ventricular tachycardias (table 1).
Furthermore, we evaluated the multivariable predictive performance for discriminating between patients with and without ventricular tachycardias using two backward variable selection procedures (model 1 p-value based and model 2 Akaike information criterion (AIC) based). In the first model, LVEF (OR = 0.865 0.776;0.963, p=0.008), LVEED (0.837 0.708;0.991, p=0.039), and LV mass indexed by BSA (1.0281.003;1.055, p=0.031) remained independent predictors of occurrence of ventricular arrhythmias, while in the second model sodium concentration (1.287 0.929;1.783, p=0.129) and betablocker medication (5.078, 0.819;31.477, p=0.081) also were retained. Comparing the area under the Receiver Operating-Characteristic (AUROC) we observed no significant difference between both models (AUROC: 0.846 0.711;0.937 vs. 0.870 0.737;0.951, p=0.57, figure 1).
Conclusion
The prevalence of ventricular tachycardia in ATTR-CM is high. Patients with ventricular tachycardia show advanced stage of left ventricular disease, with LVEDD, LV-EF and LV mass indexed by BSA being predictors of ventricular tachycardias in two multivariable predictive models. Further studies validating the predictive value of those variables are needed, including the assessment of nsVT and sVT in predicting sudden cardiac death, possibly allowing the use as a risk score for ventricular arrhythmias.
Figure 1
Table 1
Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Radiofrequency current remains one of the most important techniques for catheter ablation. Creating durable lesions is key ...for sufficient and safe procedures. Several possibilities were tested for estimating the progress of lesion formation. For instance, force-time-integral, ablation index and lesion size index are used to assess quality of RF-application and, therefore, lesion size and durability. Nevertheless, recovered conduction after acute conduction block remains an issue in RF-ablation. The aim of this study was to evaluate local impedance (LI) changes as real time surrogate for lesion formation.
Methods
RF-lesions were created using an ex vivo porcine cardiac model and a force and local impedance sensing catheter. The experimental setup consisted of a saline-filled container, a dispersive electrode, a heated thermostat and a circulation pump to imitate in vivo conditions. Global impedance was kept at 120 Ohm as well as the temperature at 37°C. RF-lesions were created using identic values of RF duration and contact force. RF power (20W, 30W, 40W, 50W) and level of electrode-tissue-coupling were also systematically varied between minor and full coupling. In minor ETC-level, only the distal end of the catheter is in contact with the tissue. In full ETC-level, the whole catheter tip is in contact with the tissue.
All parameters (power, temperature, global and local impedance, contact force, ETC, lesion size) were measured constantly during application of RF-current, enabling real-time correlation of RF parameters and lesion size. In case of an audible steam pop, RF application was stopped.
Results
Including a total of 8654 measurements into the analysis, maximum diameter and depth were 9.51 ± 1.91 mm and 7.29 ± 2.50 mm in average. Local impedance correlated well with lesion depth (r= 0,78, p<0,001), as well as lesion diameter (r=0,652, p<0,001, Figure 1).
After significant declines of LI at the beginning of RF-application, it slowly approximates a minimum. Lesion size on the other hand, rises exponentially in first seconds and gets closer to a maximum after more than 25 seconds. This relationship is illustrated in Figure 2. With decreasing lesion growth at the end of RF-application, LI changes decrease to low level (Figure 3).
Conclusion
Lesion formation in RF-ablation is not linear during application of RF current. Local impedance changes seem to be a suitable real-time surrogate for assessing changes in lesion size during ablation.
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