ORCID Profile
0000-0002-2296-4631
Current Organisation
Inselspital, Universitätsspital Bern
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Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.HRTHM.2016.07.001
Abstract: Long-term outcomes after ventricular tachycardia (VT) ablation are sparsely described. The purpose of this study was to describe long-term prognosis after VT ablation in patients with no structural heart disease (no SHD), ischemic cardiomyopathy (ICM), and nonischemic cardiomyopathy (NICM). Consecutive patients (N = 695: no SHD, 98 ICM, 358 NICM, 239) ablated for sustained VT were followed for a median of 6 years. Acute procedural parameters (complete success [noninducibility of any VT]) and outcomes after multiple procedures were reported. Compared with patients with no SHD or NICM, patients with ICM were the oldest, were more likely to be men, lowest left ventricular ejection fraction, highest drug failures, VT storms, and number of inducible VTs. Complete procedure success was highest in patients with no SHD than in patients with ICM and those with NICM (79%, 56%, 60%, respectively P < .001). At 6 years, ventricular arrhythmia (VA)-free survival was highest in patients with no SHD (77%) than in patients with ICM (54%) and those with NICM (38%) (P < .001), and overall survival was lowest in patients with ICM (48%), followed by patients with NICM (74%) and patients with no SHD (100%) (P < .001). Age, left ventricular ejection fraction, presence of SHD, acute procedural success (noninducibility of any VT), major complications, need for nonradiofrequency ablation modalities, and VA recurrence were independently associated with all-cause mortality. Long-term follow-up after VT ablation shows excellent prognosis in the absence of SHD, highest VA recurrence, and transplantation in patients with NICM and highest mortality in patients with ICM. The extremely low mortality for those without SHD suggests that VT in this population is rarely an initial presentation of a myopathic process.
Publisher: Elsevier BV
Date: 07-2015
Publisher: Oxford University Press (OUP)
Date: 02-04-2015
Abstract: In patients presenting with spontaneous sustained ventricular tachycardia (VT) from the outflow-tract region without overt structural heart disease ablation may target premature ventricular contractions (PVCs) when VT is not inducible. We aimed to determine whether inducibility of VT affects ablation outcome. Data from 54 patients (31 men age, 52 ± 13 years) without overt structural heart disease who underwent catheter ablation for symptomatic sustained VT originating from the right- or left-ventricular outflow region, including the great vessels. A single morphology of sustained VT was inducible in 18 (33%, SM group) patients, and 11 (20%) had multiple VT morphologies (MM group). VT was not inducible in 25 (46%) patients (VTni group). After ablation, VT was inducible in none of the SM group and in two (17%) patients in the MM group. In the VTni group, ablation targeted PVCs and 12 (48%) patients had some remaining PVCs after ablation. During follow-up (21 ± 19 months), VT recurred in 46% of VTni group, 40% of MM inducible group, and 6% of the SM inducible group (P = 0.004). Analysis of PVC morphology in the VTi group further supported the limitations of targeting PVCs in this population. Absence of inducible VT and multiple VT morphologies are not uncommon in patients with documented sustained outflow-tract VT without overt structural heart disease. Inducible VT is associated with better outcomes, suggesting that attempts to induce VT to guide ablation are important in this population.
Publisher: Elsevier BV
Date: 07-2015
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.HRTHM.2015.09.016
Abstract: Arrhythmias in cardiac amyloidosis (CA) result in significant comorbidity and mortality but have not been well characterized. The purpose of this study was to define intracardiac conduction, atrial arrhythmia substrate, and ablation outcomes in a group of advanced CA patients referred for electrophysiologic study. Electrophysiologic study with or without catheter ablation was performed in 18 CA patients. Findings and catheter ablation outcomes were compared to age- and gender-matched non-CA patients undergoing catheter ablation of persistent atrial fibrillation (AF). Supraventricular tachycardias were seen in all 18 CA patients (1 AV nodal reentrant tachycardia, 17 persistent atrial tachycardia [AT]/AF). The HV interval was prolonged (>55 ms) in all CA patients, including 6 with normal QRS duration (≤100 ms). Thirteen supraventricular tachycardia ablations were performed in 11 patients. Of these, 7 underwent left atrial (LA) mapping and ablation for persistent AT/AF. Compared to non-CA age-matched comparator AF patients, CA patients had more extensive areas of low-voltage areas LA (63% ± 22% vs 34% ± 22%, P = .009) and a greater number of inducible ATs (3.3 ± 1.9 ATs vs 0.2 ± 0.4 ATs, P <.001). The recurrence rate for AT/AF 1 year after ablation was greater in CA patients (83% vs 25%), and the hazard ratio for postablation AT/AF recurrence in CA patients was 5.4 (95% confidence interval 1.9-35.5, P = .007). In this group of patients with advanced CA and atrial arrhythmias, there was extensive conduction system disease and LA endocardial voltage abnormality. Catheter ablation persistent AT/AF in advanced CA was associated with a high recurrence rate and appears to have a limited role in control of these arrhythmias.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.JACEP.2015.09.010
Abstract: This study sought to assess loss of pulmonary vein (PV) excitability to pacing relative to the development of entrance block and the anatomic completion of the circumferential radiofrequency ablation (RFA) line. During encircling RFA for PV isolation (PVI), entrance block develops before anatomic completion of encirclement (early) in some patients. We hypothesized that early entrance block may be associated with loss of PV excitability to pacing. In 30 patients undergoing PV isolation (age 61 ± 10 years, 21 men), excitability to pacing was assessed at predefined PV sites when entrance block developed and after completion of the RFA line. Of 60 PV pairs, 37 developed entrance block early, with a gap ≥10 mm in the RFA line. In only 35% of PV pairs in this subgroup, both PV sleeves captured, and all of the capturing PV pairs showed exit block (no conduction from PV to atrium) despite the presence of an excitable gap. In the remaining 23 PV pairs, entrance block did not occur until encircling RFA was anatomically complete. In 83% of these PV pairs, both sleeves captured with exit block (p < 0.001 compared with early block PVs). The majority of PV pairs develops entrance and exit block before complete anatomic encircling by RFA lesions. Early entrance block is frequently associated with loss of PV sleeve excitability, consistent with a spreading wave of injury or edema rather than a permanent conduction barrier. This may help to explain the significant rate of PV conduction recovery associated with the acute endpoints of entrance and exit block.
Publisher: Springer Science and Business Media LLC
Date: 24-04-2019
DOI: 10.1007/S10840-019-00548-5
Abstract: Targets for substrate-based catheter ablation of scar-related ventricular tachycardia (VT) include sites with fractionated and late potentials (LPs). We hypothesized that in patients with cardiac resynchronization therapy (CRT), the pacing mode may influence the timing of abnormal electrograms (EGMs) relative to the surface QRS complex. We assessed bipolar EGM characteristics in left ventricular low bipolar voltage areas (< 1.5 mV) from 10 patients with coronary disease and a CRT device undergoing catheter ablation for VT. EGMs at 81 sites were analyzed during three different pacing modes (biventricular (BiV), right ventricular (RV)-only, and left ventricular (LV)-only) pacing. Stimulus to end of local electrogram duration (Stim-to-eEGM) depended significantly on the stimulation site (BiV, LV, or RV, p = 0.032). Single-chamber pacing unmasked LPs, not present during BiV pacing, in three patients. In another three patients, a concomitant increase in stimulus to end of surface QRS duration caused by single-site pacing compensated for the increase in Stim-to-eEGM duration, thereby prohibiting LP unmasking. The sequence of ventricular activation, as determined by the pacing site in patients with CRT devices, has a major influence on the detection of late potentials during substrate-guided ablation. Further study is warranted to define the optimal approaches, including the rhythm, for substrate mapping, but our findings suggest that BiV pacing may be most likely to obscure detection of late potentials as compared to single-site pacing.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2015
DOI: 10.1161/CIRCEP.115.003202
Abstract: Radiofrequency ablation (RFA) from the epicardial space for ventricular arrhythmias is limited or impossible in some cases. Reasons for epicardial ablation failure and the effect on outcome have not been systematically analyzed. We assessed reasons for epicardial RFA failure relative to the anatomic target area and the type of heart disease and assessed the effect of failed epicardial RFA on outcome after ablation procedures for ventricular arrhythmias in a large single-center cohort. Epicardial access was attempted during 309 ablation procedures in 277 patients and was achieved in 291 procedures (94%). Unlimited ablation in an identified target region could be performed in 181 cases (59%), limited ablation was possible in 22 cases (7%), and epicardial ablation was deemed not feasible in 88 cases (28%). Reasons for failed or limited ablation were unsuccessful epicardial access (6%), failure to identify an epicardial target (15%), proximity to a coronary artery (13%), proximity to the phrenic nerve (6%), and complications ( %). Epicardial RFA was impeded in the majority of cases targeting the left ventricular summit region. Acute complications occurred in 9%. The risk for acute ablation failure was 8.3× higher (4.5–15.0 P .001) after no or limited epicardial RFA compared with unlimited RFA, and patients with unlimited epicardial RFA had better recurrence-free survival rates ( P .001). Epicardial RFA for ventricular arrhythmias is often limited even when pericardial access is successful. Variability of success is dependent on the target area, and the presence of factors limiting ablation is associated with worse outcomes.
Publisher: Wiley
Date: 03-11-2017
DOI: 10.1111/JCE.13346
Abstract: Right ventricular (RV)-scar related ventricular tachycardia (VT) is often due to arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) or cardiac sarcoidosis (CS), but some patients whose clinical course has not been described do not fulfill diagnostic criteria for these diseases. We sought to characterize the electrophysiologic substrate and catheter ablation outcomes of such patients, termed RV cardiomyopathy of unknown source (RCUS). Data of 100 consecutive patients who presented with RV cardiomyopathy and/or RV-related VT for ablation were reviewed (51 ARVC/D, 22 CS 27 RCUS). Compared to ARVC/D, RCUS patients were older (P = 0.001), less commonly had RV dilatation (P = 0.001) or dysfunction (P = 0.01) and fragmented QRS, parietal block, and T-wave inversion. Compared to CS, R-CUS patients had less severe LV dysfunction. Extent and distribution of endocardial/epicardial scar and inducible VTs in RCUS patients were comparable with ARVC/D and CS patients. At a median follow-up of 23 months, RCUS patients had more favorable VT-free survival (RCUS 71%, ARVC/D 60%, CS 41%, P = 0.03) and survival free of death or cardiac transplant (RCUS 92%, ARVC/D 92%, CS 62%, P = 0.01). No RCUS patients developed new criteria for ARVC/D or CS in follow-up. Up to one-third of patients with RV scar-related VT are not classifiable as ARVC/D or CS. These patients had a somewhat better prognosis than ARVC/D or sarcoid and did not develop evidence of these diseases during the initial 2 years of follow-up. The extent to which this population comprises mild ARVC/D, CS, or other diseases is not clear.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2015
DOI: 10.1161/CIRCEP.114.002522
Abstract: Ventricular tachycardia (VT) refractory to antiarrhythmic drugs and standard percutaneous catheter ablation techniques portends a poor prognosis. We characterized the reasons for ablation failure and describe alternative interventional procedures in this high-risk group. Sixty-seven patients with VT refractory to 4±2 antiarrhythmic drugs and 2±1 previous endocardial/epicardial catheter ablation attempts underwent transcoronary ethanol ablation, surgical epicardial window (Epi-window), or surgical cryoablation (OR-Cryo age, 62±11 years VT storm in 52%). Failure of endo/epicardial ablation attempts was because of VT of intramural origin (35 patients), nonendocardial origin with prohibitive epicardial access because of pericardial adhesions (16), and anatomic barriers to ablation (8). In 8 patients, VT was of nonendocardial origin with a coexisting condition also requiring cardiac surgery. Transcoronary ethanol ablation alone was attempted in 37 patients, OR-Cryo alone in 21 patients, and a combination of transcoronary ethanol ablation and OR-Cryo (5 patients), or transcoronary ethanol ablation and Epi-window (4 patients), in the remainder. Overall, alternative interventional procedures abolished ≥1 inducible VT and terminated storm in 69% and 74% of patients, respectively, although 25% of patients had at least 1 complication. By 6 months post procedures, there was a significant reduction in defibrillator shocks (from a median of 8 per month to 1 P .001) and antiarrhythmic drug requirement although 55% of patients had at least 1 VT recurrence, and mortality was 17%. A collaborative strategy of alternative interventional procedures offers the possibility of achieving arrhythmia control in high-risk patients with VT that is otherwise uncontrollable with antiarrhythmic drugs and standard percutaneous catheter ablation techniques.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2015
DOI: 10.1161/CIRCEP.114.002714
Abstract: Mapping to identify scar-related ventricular tachycardia re-entry circuits during sinus rhythm focuses on sites with abnormal electrograms or pace-mapping findings of QRS morphology and long stimulus to QRS intervals. We hypothesized that (1) these methods do not necessarily identify the same sites and (2) some electrograms are far-field potentials that can be recognized by pacing. From 12 patients with coronary disease and recurrent ventricular tachycardia undergoing catheter ablation, we retrospectively analyzed electrograms and pacing at 546 separate low bipolar voltage ( .5 mV) sites. Electrograms were characterized as showing evidence of slow conduction if late potentials (56%) or fractionated potentials (76%) were present. Neither was present at (13%) sites. Pacing from the ablation catheter captured 70% of all electrograms. Higher bipolar voltage and fractionation were independent predictors for pace capture. There was a linear correlation between the stimulus to QRS duration during pacing and the lateness of a capturing electrogram ( P .001), but electrogram and pacing markers of slow conduction were discordant at 40% of sites. Sites with far-field potentials, defined as those that remained visible and not captured by pacing stimuli, were identified at 48% of all pacing sites, especially in areas of low bipolar voltage and late potentials. Initial radiofrequency energy application rendered 74% of targeted sites electrically unexcitable. Far-field potentials are common in scar areas. Combining analysis of electrogram characteristics and assessment of pace capture may refine identification of substrate targets for radiofrequency ablation.
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.HRTHM.2015.02.016
Abstract: Ventricular arrhythmias (VAs) from the left ventricular outflow tract (LVOT) region can be inaccessible for ablation because of epicardial fat or overlying coronary arteries. We describe surgical cryoablation of this type of VA. From March 2009 to 2014, 190 consecutive patients with VAs originating from the LVOT underwent ablation at our institution. Four patients (2%) underwent surgical cryoablation for highly symptomatic VAs after failing catheter ablation. In all patients, endocardial or percutaneous epicardial mapping was consistent with origin in the LVOT. In 2 patients, the points of earliest activation during VAs were marked with a bipolar pacing lead in the overlying cardiac vein for guidance during surgery. Surgical cryoablation was successful in 3 of the 4 patients. The fourth patient subsequently had successful endocardial catheter ablation. During a mean follow-up of 22 ± 16 months (range 4-42 months), all patients showed abolition of or marked reduction in symptomatic VA. However, 1 patient subsequently required percutaneous intervention to the left anterior descending coronary artery another developed progressive left ventricular systolic dysfunction caused by nonischemic cardiomyopathy and a third patient underwent permanent pacemaker implantation because of complete atrioventricular block after concomitant aortic valve replacement. Surgical cryoablation is an option for highly symptomatic drug-resistant VAs emanating from the LVOT region. Despite extensive preoperative mapping, the procedure is not effective for all patients, and coronary injury is a risk.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2015
DOI: 10.1161/CIRCEP.115.002818
Abstract: Arrhythmia origin in close proximity to the phrenic nerve (PN) can hinder successful catheter ablation. We describe our approach with epicardial PN displacement in such instances. PN displacement via percutaneous pericardial access was attempted in 13 patients (age 49±16 years, 9 females) with either atrial tachycardia (6 patients) or atrial fibrillation triggered from a superior vena cava focus (1 patient) adjacent to the right PN or epicardial ventricular tachycardia origin adjacent to the left PN (6 patients). An epicardially placed steerable sheath/4 mm-catheter combination (5 patients) or a vascular or an esophageal balloon (8 patients) was ultimately successful. Balloon placement was often difficult requiring manipulation via a steerable sheath. In 2 ventricular tachycardia cases, absence of PN capture was achieved only once the balloon was directly over the ablation catheter. In 3 atrial tachycardia patients, PN displacement was not possible with a balloon however, a steerable sheath/catheter combination was ultimately successful. PN displacement allowed acute abolishment of all targeted arrhythmias. No PN injury occurred acutely or in follow up. Two patients developed acute complications (pleuro-pericardial fistula 1 and pericardial bleeding 1). Survival free of target arrhythmia was achieved in all atrial tachycardia patients however, a nontargeted ventricular tachycardia recurred in 1 patient at a median of 13 months’ follow up. Arrhythmias originating in close proximity to the PN can be targeted successfully with PN displacement with an epicardially placed steerable sheath/catheter combination, or balloon, but this strategy can be difficult to implement. Better tools for phrenic nerve protection are desirable.
No related grants have been discovered for Samuel Baldinger.