Substrate Mapping for Ventricular Tachycardia Ablation Through High-Density Whole-Chamber Double Extra Stimuli: The S3 Protocol.

BACKGROUND: A partial delineation of targets for ablation of ventricular tachycardia (VT) during a stable rhythm is likely responsible for a suboptimal success rate. The abnormal low-voltage near-field functional components may be hidden within the high-amplitude far-field signal. OBJECTIVES: The aim of this study was to evaluate the benefit and feasibility of functional substrate mapping using a full-ventricle S3 protocol and to assess its colocalization with arrhythmogenic conducting channels (CCs) on late gadolinium enhancement cardiac magnetic resonance. METHODS: An S3 mapping protocol with a drive train of S1 followed by S2 (effective refractory period + 30 ms) and S3 (effective refractory period + 50 ms) from the right ventricular apex was performed in 40 consecutive patients undergoing scar-related VT ablation. Deceleration zones (DZs) and areas of late potentials (LPs) were identified for all maps. A preprocedural noninvasive substrate assessment was done using late gadolinium enhancement cardiac magnetic resonance and postprocessing with automated CC identification. RESULTS: The S3 protocol was completed in 34 of the 40 procedures (85.0%). The S3 protocol enhanced the identification of VT isthmus on the basis of DZ (89% vs 62%; P < 0.01) and LP (93% vs 78%; P = 0.04) assessment. The percentage of CCs unmasked by DZs and LPs using S3 maps was significantly higher than the ones using S2 and S1 maps (78%, 65%, and 48% [P < 0.001] and 88%, 81%, and 68% [P < 0.01], respectively). The functional substrate identified during S3 activation mapping was significantly more extensive than the one identified using S2 and S1, including a greater number of DZs (2.94, 2.47, and 1.82, respectively; P < 0.001) and a wider area of LPs (44.1, 38.2, and 29.4 cm2, respectively; P < 0.001). After VT ablation, 77.9% of patients have been VT free during a median follow-up period of 13.6 months. CONCLUSIONS: The S3 protocol was feasible in 85% of patients, allows a better identification of targets for ablation, and might improve VT ablation results.

Personalized voltage maps guided by cardiac magnetic resonance in the era of high-density mapping.

BACKGROUND: Voltage mapping could identify the conducting channels potentially responsible for ventricular tachycardia (VT). Standard thresholds (0.5-1.5 mV) were established using bipolar catheters. No thresholds have been analyzed with high-density mapping catheters. In addition, channels identified by cardiac magnetic resonance (CMR) has been proven to be related with VT. OBJECTIVE: The purpose of this study was to analyze the diagnostic yield of a personalized voltage map using CMR to guide the adjustment of voltage thresholds. METHODS: All consecutive patients with scar-related VT undergoing ablation after CMR (from October 2018 to December 2020) were included. First, personalized CMR-guided voltage thresholds were defined systematically according to the distribution of the scar and channels. Second, to validate these new thresholds, a comparison with standard thresholds (0.5-1.5 mV) was performed. Tissue characteristics of areas identified as deceleration zones (DZs) were recorded for each pair of thresholds. In addition, the relation of VT circuits with voltage channels was analyzed for both maps. RESULTS: Thirty-two patients were included [mean age 66.6 ± 11.2 years; 25 (78.1%) ischemic cardiomyopathy]. Overall, 52 DZs were observed: 44.2% were identified as border zone tissue with standard cutoffs vs 75.0% using personalized voltage thresholds (P = .003). Of the 31 VT isthmuses detected, only 35.5% correlated with a voltage channel with standard thresholds vs 74.2% using adjusted thresholds (P = .005). Adjusted cutoff bipolar voltages that better matched CMR images were 0.51 ± 0.32 and 1.79 ± 0.71 mV with high interindividual variability (from 0.14-1.68 to 0.7-3.21 mV). CONCLUSION: Personalized voltage CMR-guided personalized voltage maps enable a better identification of the substrate with a higher correlation with both DZs and VT isthmuses than do conventional voltage maps using fixed thresholds.

Catheter Ablation of Ventricular Tachycardia in Ischemic Heart Disease: What Is Known and New Perspectives.

PURPOSE OF THE REVIEW: This review aims to evaluate current evidence regarding ventricular tachycardia ablation in patients with ischemic heart disease and explore novel approaches currently developing to improve procedural and long-term outcomes. RECENT FINDINGS: Recently published trials (PARTITA, PAUSE-SCD, and SURVIVE-VT) have demonstrated the prognostic benefit of prophylactic ventricular tachycardia ablation compared to current clinical practice. Advanced cardiac imaging provides a valuable pre-procedural evaluation of the arrhythmogenic substrate, identifying ablation targets non-invasively. Advanced cardiac mapping techniques allow to better characterize arrhythmogenic substrate during ablation procedure. Emerging technologies like pulsed field ablation and ultra-low temperature cryoablation show promise in ventricular tachycardia ablation. Advancements in mapping techniques, ablation technologies, and pre-procedural cardiac imaging offer promise for improving ventricular tachycardia ablation outcomes in ischemic heart disease.

Non-invasive detection of slow conduction with cardiac magnetic resonance imaging for ventricular tachycardia ablation.

AIMS: Non-invasive myocardial scar characterization with cardiac magnetic resonance (CMR) has been shown to accurately identify conduction channels and can be an important aid for ventricular tachycardia (VT) ablation. A new mapping method based on targeting deceleration zones (DZs) has become one of the most commonly used strategies for VT ablation procedures. The aim of the study was to analyse the capability of CMR to identify DZs and to find predictors of arrhythmogenicity in CMR channels. METHODS AND RESULTS: Forty-four consecutive patients with structural heart disease and VT undergoing ablation after CMR at a single centre (October 2018 to July 2021) were included (mean age, 64.8 ± 11.6 years; 95.5% male; 70.5% with ischaemic heart disease; a mean ejection fraction of 32.3 ± 7.8%). The characteristics of CMR channels were analysed, and correlations with DZs detected during isochronal late activation mapping in both baseline maps and remaps were determined. Overall, 109 automatically detected CMR channels were analysed (2.48 ± 1.15 per patient; length, 57.91 ± 63.07 mm; conducting channel mass, 2.06 ± 2.67 g; protectedness, 21.44 ± 25.39 mm). Overall, 76.1% of CMR channels were associated with a DZ. A univariate analysis showed that channels associated with DZs were longer [67.81 ± 68.45 vs. 26.31 ± 21.25 mm, odds ratio (OR) 1.03, P = 0.010], with a higher border zone (BZ) mass (2.41 ± 2.91 vs. 0.87 ± 0.86 g, OR 2.46, P = 0.011) and greater protectedness (24.97 ± 27.72 vs. 10.19 ± 9.52 mm, OR 1.08, P = 0.021). CONCLUSION: Non-invasive detection of targets for VT ablation is possible with CMR. Deceleration zones found during electroanatomical mapping accurately correlate with CMR channels, especially those with increased length, BZ mass, and protectedness.

Outcomes of transvenous lead extraction in octogenarians using bidirectional rotational mechanical sheaths.

BACKGROUND: Outcomes of transvenous lead extraction (TLE) are well reported in the general population, However, data on safety, efficacy of TLE in octogenarians with a long lead dwell time, using powered extraction tools are limited. The aim of this multicenter study was to evaluate the safety, effectiveness of TLE in octogenarians using the bidirectional rotational mechanical sheaths and mid-term outcome after TLE. METHODS: The study population comprised 83 patients (78.3% male; mean age 85 ± 3 years; [range 80-94 years]) with 181 target leads. All the leads (mean implant duration 112 ± 77 months [range 12-377]) were extracted exclusively using the Evolution RL sheaths (Cook Medical, Bloomington, IN, USA). RESULTS: The main indication for TLE was infection in 84.3% of cases. Complete procedural success rate, clinical success rate, per lead were 93.9% and 98.3%, respectively. Failure of lead extraction was seen in 1.7% of leads. The additional use of a snare was required in 8.4% of patients. Major complications occurred in one patient (1.2%). Thirty-day mortality after TLE was 6%. During a mean time follow-up of 22 ± 21 months, 24 patients (29%) died. No procedure-related mortality occurred. Predictors of mortality included ischemic cardiomyopathy (HR 4.35; 95% CI 1.87-10.13; p = .001), left ventricularejection fraction ≤35% (HR 7.89; 95% CI 3.20-19.48; p < .001), and TLE for systemic infection (HR 4.24; 95% CI 1.69-10.66; p = .002). CONCLUSIONS: At experienced centers bidirectional rotational mechanical sheaths combined with different mechanical tools and femoral approach allowreasonable success and safety in octogenarian with long lead dwell time. Patient's age should not influence the decision to extract or not the leads, although the 30-day and mid-term mortality are significant, especially in the present of specific comorbidities.

Intermuscular two-incision technique for implantation of the subcutaneous implantable cardioverter defibrillator: a 3-year follow-up.

PURPOSE: The aim of the present study was to evaluate the outcome of patients underwent subcutaneous implantable cardioverter defibrillator (S-ICD) implantation with the intermuscular (IM) two-incision technique during 3-year follow-up. METHODS: the study population consisted of 105 consecutive patients (79 male; median 50 [13-77] years) underwent S-ICD implantation with the IM two-incision technique. The composite primary end point of the study consisted of device-related complications and inappropriate shocks (IAS). Secondary end points included the individual components of the primary end point, death from any cause, appropriate therapy, major adverse cardiac events, hospitalization for heart failure, and heart transplantation. RESULTS: According to the PRAETORIAN score, the risk of conversion failure was classified as low in 99 patients (94.3%), intermediate in 6 (5.7%).Ventricular fibrillation was successfully converted at ≤65 J in 97.4% of patients. During a median follow-up of 39 (16-53) months, 10 patients (9.5%) experienced device-related complications, and 9 (8.5%) patients reported IAS. Lead-associated complications were the most common (5 patients, 4.7%), including 2 cases of lead failure (1.9%). Pocket complications were reported in 2 patients (1.9%). Extra-cardiac oversensing (3.8%) represented the leading cause of IAS. No T-wave oversensing episodes were recorded. Twelve patients (11.4%) experienced appropriate shocks. Eight patients (7.6%) died during follow-up. IAS or device-related complications did not impact on mortality. CONCLUSIONS: The overall device-related complications and IAS rates over 3 years of follow-up were 9.5% and 8.5%, respectively. According to our findings, the IM two-incision technique allows for optimal positioning of the device achieving a low PRAETORIAN score with a high conversion rate. IM two-incision technique allows low incidence of pocket complications, shifting the type of complications towards lead-related complications, which represent the most common complications. The IM two-incision technique would not seem to impact the occurrence of IAS. Management of complications are safe without impact on the outcome.

Subcutaneous implantable cardioverter defibrillator after transvenous lead extraction: safety, efficacy and outcome.

BACKGROUND: Subcutaneous implantable cardioverter defibrillator (S-ICD) is a suitable alternative for transvenous ICD (TV-ICD) patients who have undergone transvenous lead extraction (TLE). Limited data are available on the outcome of S-ICD patients implanted after TLE. We assessed the safety, efficacy, and outcome of S-ICD implantation after TLE of TV-ICD. METHODS: The study population consisted of 36 consecutive patients with a median age of 52 (44-66) years who underwent S-ICD implantation after TLE of TV-ICD. RESULTS: Indications for TLE were infection (63.9%) and lead malfunction (36.1%). During a median follow-up of 31 months, 3 patients (8.3%) experienced appropriate therapy and 7 patients (19.4%) experienced complications including inappropriate therapy (n = 4; 11.1%), isolated pocket erosion (n = 2; 5.5%), and ineffective therapy (n = 1; 2.8%). No lead/hardware dysfunction was reported. Premature device explantation occurred in 4 patients (11%). Eight patients (22.2%) died during follow-up, six of them (75%) because of refractory heart failure (HF). There were no S-ICD-related deaths. Predictors of mortality included NYHA class ≥ 2 (HR 5.05; 95% CI 1.00-26.38; p = 0.04), hypertension (HR 22.72; 95% CI 1.05-26.31; p = 0.02), diabetes (HR 10.64; 95% CI 2.05-55.60; p = 0.001) and ischemic heart disease (HR 5.92; 95% CI 1.17-30.30; p = 0.01). CONCLUSION: Our study provides evidences on the use of S-ICD as an alternative after TV-ICD explantation for both infection and lead failure. Mortality of S-ICD patients who underwent TV-ICD explantation does not appear to be correlated with the presence of a prior infection, S-ICD therapy (appropriate or inappropriate), or S-ICD complications but rather to worsening of HF or other comorbidities.

New-Onset Exertional Dyspnea in a Young Patient With Previous Blunt Chest Trauma.

CASE PRESENTATION: A 16-year-old male patient was admitted to our Cardiology Department for new-onset exertional dyspnea (NYHA functional class II-III). He had no family history of cardiovascular diseases, no cardiovascular risk factors, and an unremarkable medical history, except for a blunt chest trauma after a motorbike accident 2 years earlier.

The valuable interaction among cardiac surgeon and electrophysiologist for transvenous rotational mechanical lead extraction.

BACKGROUND: Recent studies have shown that Evolution RL bidirectional rotational mechanical sheath (Cook Medical, USA) is an effective and safe technique for transvenous lead extraction (TLE). We reported our experience with the bidirectional rotational mechanical tools using a multidisciplinary approach highlighting the value of a joint cardiac surgeon and electrophysiologist collaboration. METHODS: The study population comprised 84 patients (77% male; mean age 65 ± 18 years) undergoing TLE. After a multidisciplinary evaluation, a combined procedure was considered. RESULTS: The main indication for TLE was infection in 54 cases (64%). Overall, 152 leads were extracted with a mean implant duration of 94 ± 63 months (range 12-421). Complete procedural success rate, clinical success rate, and lead removal with clinical success rate were 91.6% (77/84), 97.6% (82/84), and 98.6% (150/152), respectively. Eighteen combined procedures were performed in 12 patients (14%), such as "hybrid approach" (n = 2) or TLE concomitant to: 1) transcatheter aspiration procedure for large vegetation (n = 8); 2) left ventricular assistance device implantation as bridge to cardiac transplantation (n = 1); 3) permanent pacing with epicardial leads (n = 6); 4) tricuspid valve replacement (n = 1). One major complication (1.2%) and 11 (13%) minor complications were encountered. No injury to the superior vena cava occurred and no procedure-related deaths were reported. During a mean time follow-up of 21 ± 18 months, 17 patients (20%) died. They were more often diabetics (p = .02), and they underwent TLE more often for infection (p = .004). CONCLUSIONS: Our results support the finding that excellent outcomes can be achieved in performing TLE of chronically implanted leads by using the Evolution RL bidirectional rotational mechanical sheath and a multidisciplinary team approach involving both electrophysiologist and cardiac surgeon as first line operators.

Extraction of a very old His bundle pacing lead: A safe and effective procedure?

Permanent His bundle pacing (HBP) has rapidly been adapted into clinical practice in recent years as a physiologic pacing. The 3830 (Medtronic Inc, MN, USA) pacing lead commonly used for HBP is lumenless, and there are limited reports available on extraction of this lead. No data exists on transvenous lead extraction (TLE) of very old HBP lead. Concerns remain about injury to the conduction system during extraction and the lack of lumen for placing a locking stylet for TLE when powered sheaths are required. We reported a unique case of TLE of very old HBP lead (14 years and 3 months) and other two leads, such as passive atrial and passive right ventricular apex backup.

Successful jugular implantable defibrillator lead extraction with bidirectional rotational mechanical sheath.

Bidirectional rotational mechanical sheath is an effective and safe technique for transvenous lead extraction of chronically implanted leads. However, data about powered mechanical sheath through jugular vein are lacking. Our report demonstrated that bidirectional rotational mechanical sheath represents an effective and safe approach for removal of chronically implanted jugular leads.