Influence of baseline QRS on the left ventricular ejection fraction recovery after frequent premature ventricular complex ablation.

AIMS: Frequent premature ventricular complexes (PVCs) can induce or worsen left ventricular systolic dysfunction. We aimed to investigate the influence of the baseline QRS in the response after PVC ablation in patients with depressed left ventricular ejection fraction (LVEF). METHODS AND RESULTS: Two hundred and fifteen [59 ± 13 years old, 152 (71%) men] consecutive patients with left ventricular (LV) systolic dysfunction and frequent PVCs referred for ablation were included and followed-up for 12 months. Echocardiographic response was defined as an improvement of at least five absolute points in LVEF. Clinical, electrocardiogram, and electrophysiological characteristics were analysed. Mean baseline QRS duration was 110 ms [97-140]. Premature ventricular complex burden significantly decreased after ablation from 23% [16-33] at baseline to 1% [0-8] at 12 months, P < 0.001. Mean PVC burden reduction was 18 [8-30] points. There was a significant improvement of LVEF from 35% [29-40] at baseline to 44% [35-55] at 12 months, P < 0.001. One hundred and thirty (61%) patients were considered as echocardiographic responders. Baseline QRS duration (ms) [odds ratio (OR) 0.98 (0.97-0.99), P = 0.01] was an independent predictor of echocardiographic response. Mean LVEF improvement was 16 [10-21] points when the baseline QRS duration was <90 ms; 12 [4-20] when it was 90-110 ms; 5 [0-15] when it was 110 ± 130 ms; and 0 [0-6] points when it was >130 ms. CONCLUSIONS: In patients with LV systolic dysfunction, intrinsic QRS duration is inversely related to the probability and the degree of echocardiographic response after frequent PVC ablation. Patients with a QRS duration >130 ms at baseline have the poorer response after ablation.

Prediction of premature ventricular complex origin in left vs. right ventricular outflow tract: a novel anatomical imaging approach.

AIMS: Left ventricular (LV) outflow tract ventricular arrhythmias (OTVA) are associated with hypertension (HT), older age, and LV dysfunction, suggesting that LV overload plays a role in the aetiopathogenesis. We hypothesized that anatomical modifications of the LV outflow tract (LVOT) could predict left vs. right OTVA site of origin (SOO). METHODS AND RESULTS: Fifty-six (32 men, 53 ± 18 years old) consecutive patients referred for OTVA ablation were included. Cardiac multidetector computed tomography was performed before ablation and then imported to the CARTO system to aid the mapping and ablation procedure. Anatomical characteristics of the aortic root as well as aortopulmonary valvular planar angulation (APVPA) were analysed. The LV was the OTVA SOO (LVOT-VA) in 32 (57%) patients. These patients were more frequently male (78% vs. 22%, P = 0.001), older (57 ± 18 vs. 47 ± 18 years, P = 0.055), and more likely to have HT (59% vs. 21%, P = 0.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68 ± 5° vs. 55 ± 6°, respectively; P < 0.001). Absolute size of all aortic root diameters was associated with LVOT origin. However, after indexing by body surface area, only sinotubular junction diameter maintained a significant association (P = 0.049). Multivariable analysis showed that APVPA was an independent predictor of LVOT origin. Aortopulmonary valvular planar angulation ≥62° reached 94% sensitivity and 83% specificity (area under the curve 0.95) for predicting LVOT origin. CONCLUSIONS: The measurement of APVPA as a marker of chronic LV overload is useful for the prediction of left vs. right ventricular OTVA origin.

Management of a leadless pacemaker recall via extraction in a patient with a history of multiple previous device implants.

We describe a management strategy of a leadless pacemaker recall (LP) via extraction in a pacemaker-dependent patient with a history of multiple previous device implants. We performed a two-step procedure. First, we implanted a second LP in the right ventricle. Then, 3 days later for concerns about the stability of the newly-implanted device, we retrieved the first LP, 3 years after its original implant. The patient was hemodynamically stable throughout the two procedures and no adverse event occurred in the 3 days of coexistence of the two LPs. Although the limitation of a single case experience, this approach may be taken into consideration when facing similar high-risk cases.

Elucidation of hidden slow conduction by double ventricular extrastimuli: a method for further arrhythmic substrate identification in ventricular tachycardia ablation procedures.

Aims: Identification of local abnormal electrograms (EGMs) during ventricular tachycardia substrate ablation (VTSA) is challenging when they are hidden within the far-field signal. This study analyses whether the response to a double ventricular extrastimulus during substrate mapping could identify slow conducting areas that are hidden during sinus rhythm. Methods and results: Consecutive patients (n = 37) undergoing VTSA were prospectively included. Bipolar EGMs with >3 deflections and duration <133 ms were considered as potential hidden slow conduction EGMs (HSC-EGM) if located within/surrounding the scar area. Whenever a potential HSC-EGM was identified, a double ventricular extrastimulus was delivered. If the local potential delayed, it was annotated as HSC-EGM. The incidence of HSC-EGM in core, border-zone, and normal-voltage regions was determined. Ablation was delivered at conducting channel entrances and HSC-EGMs. VT inducibility after VTSA obtained was compared with data from a historic control group. 2417 EGMs were analyzed. 575 (23.7%) qualified as potential HSC-EGM, and 198 of them were tagged as HSC-EGMs. Scars in patients with HSC-EGMs (n = 21, 56.7%) were smaller (35.424.7 vs 67.639.1 cm2; P = 0.006) and more heterogeneous (core/scar area ratio 0.250.2 vs 0.450.19; P = 0.02). 28.8% of HSC-EGMs were located in normal-voltage tissue; 81.3% were targeted for ablation. Patients undergoing VTSA incorporating HSC analysis needed less radiofrequency time (17.411 vs 2310.7 minutes; P = 0.016) and had a lower rate of VT inducibility after VTSA than the historic controls (24.3% vs 50%; P = 0.018). Conclusion: Ventricular tachycardia substrate ablation incorporating HSC analysis allowed further arrhythmic substrate identification (especially in normal-voltage areas) and reduced RF time and VT inducibility after VTSA.

Multielectrode vs. point-by-point mapping for ventricular tachycardia substrate ablation: a randomized study.

Aims: Ventricular tachycardia (VT) substrate ablation is based on detailed electroanatomical maps (EAM). This study analyses whether high-density multielectrode mapping (MEM) is superior to conventional point-by-point mapping (PPM) in guiding VT substrate ablation procedures. Methods and results: This was a randomized controlled study (NCT02083016). Twenty consecutive ischemic patients undergoing VT substrate ablation were randomized to either group A [n = 10; substrate mapping performed first by PPM (Navistar) and secondly by MEM (PentaRay) ablation guided by PPM] or group B [n = 10; substrate mapping performed first by MEM and second by PPM ablation guided by MEM]. Ablation was performed according to the scar-dechanneling technique. Late potential (LP) pairs were defined as a Navistar-LP and a PentaRay-LP located within a three-dimensional distance of ≤ 3 mm. Data obtained from EAM, procedure time, radiofrequency time, and post-ablation VT inducibility were compared between groups. Larger bipolar scar areas were obtained with MEM (55.7±31.7 vs. 50.5±26.6 cm2; P = 0.017). Substrate mapping time was similar with MEM (19.7±7.9 minutes) and PPM (25±9.2 minutes); P = 0.222. No differences were observed in the number of LPs identified within the scar by MEM vs. PPM (73±50 vs. 76±52 LPs per patient, respectively; P = 0.965). A total of 1104 LP pairs were analysed. Using PentaRay, far-field/LP ratio was significantly lower (0.58±0.4 vs. 1.64±1.1; P = 0.01) and radiofrequency time was shorter [median (interquartile range) 12 (7-20) vs. 22 (17-33) minutes; P = 0.023]. No differences were observed in VT inducibility after procedure. Conclusion: MEM with PentaRay catheter provided better discrimination of LPs due to a lower sensitivity for far-field signals. Ablation guided by MEM was associated with a shorter radiofrequency time.

Predicting the difficulty of a transvenous lead extraction procedure: Validation of the LED index.

INTRODUCTION: A lead extraction difficulty (LED) score was proposed to predict the difficult transvenous lead extraction (TLE) procedures, defined by means of the fluoroscopy time. The aim of this study was to validate the estimation model based on the LED index above 10 on an independent data set of TLE cases. METHODS: Consecutive patients undergoing TLE between January 2014 and January 2016 were included in this analysis. The fluoroscopy time related to the leads removal was dichotomized as above or below its 90th percentile (PCTL). RESULTS: In total, 446 permanent leads were removed during 233 TLE procedures. Complete procedural success was achieved in 232 (99.1%) patients. The LED index resulted >10 in 83(35.6%) procedures. Among these cases, 20 had fluoroscopy time above the 90th PCTL (23.3 minutes) and were classified as true positive. Over the 150 procedures with LED score <10, 147 were classified as true negative, and only 3 resulted false negative. The sensitivity, the specificity, and the negative predictive value of the LED index in predicting complex cases resulted 86.9 (confidence interval [CI] 66.4-97.2)%, 70.0 (CI 63.3-76.1)%, and 98.0 (CI 94.3-99.6)%, respectively. The multivariate logistic regression analysis confirmed a 12% increased risk of high fluoroscopy for each additional point of the LED score (OR 1.12, CI 1.05-1.21, P = 0.001). CONCLUSION: The validation of the estimation model based on the LED index <10 confirmed its high efficacy in predicting simple TLE procedures.

Hybrid Minimally Invasive Approach for Transvenous Lead Extraction: A Feasible Technique in High-Risk Patients.

INTRODUCTION: Despite the overall safety, transvenous lead extraction (TLE) remains a challenging procedure with inherent risks, where surgery can still be required in elective cases. In this study, we report our experience with a minimally invasive "hybrid" approach, defined as a procedure performed by an electrophysiologist with the support of a cardiac surgeon in the same operative session. METHODS AND RESULTS: We reported 12 cases of planned hybrid lead extraction; minithoracotomy and thoracoscopy were performed on 10 (83%) and 2 (17%) patients, respectively. A total of 25 leads out of 27 (median lead age 19 years) were successfully extracted with laser, mechanical or combined transvenous sheath. In 3 patients, the direct monitoring of vascular and myocardial integrity allowed for prompt treatment of potential vascular injury during the lead extraction maneuvers. Mean in-hospital stay was 4 ± 2 days. There were no major intraoperative complications and no deaths occurred after 30 days' follow-up. CONCLUSION: The hybrid approach, with minithoracotomy or thoracoscopy, is feasible and it might increase the safety in the most challenging TLE procedures: the minimally invasive surgical intervention allows for continuous monitoring of the critical cardiac structures and prompt treatment of potential complications.

The effects of gender on electrical therapies for the heart: procedural considerations, results and complications: A report from the XII Congress of the Italian Association on Arrhythmology and Cardiostimulation (AIAC).

Use of cardiac implantable devices and catheter ablation is steadily increasing in Western countries following the positive results of clinical trials. Despite the advances in scientific knowledge, tools development, and techniques improvement we still have some grey area in the field of electrical therapies for the heart. In particular, several reports highlighted differences both in medical behaviour and procedural outcomes between female and male candidates. Women are referred later for catheter ablation of supraventricular arrhythmias, especially atrial fibrillation, leading to suboptimal results. On the opposite females present greater response to cardiac resynchronization, while the benefit of implantable defibrillator in primary prevention seems to be less pronounced. Differences on aetiology, clinical profile, and development of myocardial scarring are the more plausible causes. This review will discuss all these aspects together with gender-related differences in terms of acute/late complications. We will also provide useful hints on plausible mechanisms and practical procedural aspects.

The novel active fixation coronary sinus lead: efficacy and safety of transvenous extraction procedure.

AIMS: Benefits of cardiac resynchronization therapy (CRT) are well known for heart failure; however, some patients might experience complications related to the coronary sinus (CS) lead (high pacing threshold, phrenic nerve stimulation, and dislodgment) with unfavourable impact on quality of life, costs, and management. Lead stability is one of the most common unmet needs for CRT procedures. METHODS AND RESULTS: Recently, new model Medtronic 20066 Attain Stability(®) (Maastricht, The Netherlands) active fixation LV lead has been released, to overcome this issue. The lead has a small side helix of 0.20 mm (0.008 in.) that allows for secure placement of the lead within the vein at the desired location. We report our first experience with the extraction of this novel active fixation left ventricular lead. CONCLUSION: In our case, to our knowledge the first reported in humans, the extraction of this new model of active fixation lead was proved to be a safe and effective procedure at 8 months after implantation. Indeed, under angiographic and fluoroscopic check, there was no documented dissection or damage to the CS during and after removal of the lead. The rotation manoeuvre was effective when combined with moderate traction of the lead itself.

Acute electrocardiographic differences between Takotsubo cardiomyopathy and anterior ST elevation myocardial infarction.

BACKGROUND: The aim of this study was to compare ECG findings between anterior ST elevation myocardial infarction (STEMI) and Takotsubo cardiomyopathy (TC) in a similar sample of postmenopausal women. METHODS: Between 2008 and 2011, 27 patients with TC were retrospectively enrolled and matched with 27 STEMI patients with the same age and sex taken from the prospective database of our laboratory. RESULTS: The absence of abnormal Q waves, the ST depression in aVR and the lack of ST elevation in V1 were significantly associated with TC (respectively: 52% vs 18%, p=0.01; 47% vs 11%, p=0.01; 80% vs 41%, p=0.01). The combination of these ECG findings identified TC with a specificity of 95% and a positive predictive value of 85.7%. CONCLUSIONS: The ECG on admission may be useful to distinguish TC from anterior STEMI. The combination of three ECG findings identifies patients with TC with high specificity and positive predictive value.

Dynamic changes of repolarization abnormalities in takotsubo cardiomyopathy.

OBJECTIVE: This study analyses dynamicchangesin dispersion of ventricularrepolarization over the time course of takotsubo cardiomyopathy (TC), and their relationships with clinical features and life-threatening arrhythmias. METHODS AND RESULTS: All consecutive patients admitted to our division between January 2008 and December 2011 with a diagnosis of TC were analysed. Patients with prior myocardial infarction, symptoms-onset-to-admission time greater than 12 hours, an implanted pacemaker, or under treatment with drugs affecting QTinterval, were excluded. Standard 12-lead ECG recordings during the acute, subacute and chronic phases were collected for each patient. Twenty-four patients (23 women, 63 +/- 14 years) were includedin our analysis. Only one patient experienced ventricular arrhythmias (4.2%). Significant increases were observed in QT and QTc intervals (from 420 ?423 to 505 +/- 66 ms, P < 0.00001, and from 479 +/- 33 to 551 +/- 51 ms, P < 0.00001, respectively), QTdispersion (from 59 +/- 18 to 100 +/- 44 ms, P=0.0006), Tpeak-to-Tend (from 82 +/- 20 to 123 +/- 39 ms, P=0.00006) and Tpeak-to-Tend/QT (from 0.20 +/- 0.33 to 0.26 +/- 0.57, P=0.0003) during the subacute phase. All these parameters returned to baseline values in the chronic phase and did not show any significant differences between the acute and chronic phases. CONCLUSIONS: A marked increase in QTc, QT dispersion, Tpeak-to-Tend and Tpeak-to-Tend/QT was observed during the subacute phase; this increase was transient and reverted in allpatients before hospital discharge. Ofnote, these findings were not associated with an increased risk of life-threatening arrhythmias.

Early atrial fibrillation detection is associated with higher arrhythmic burden in patients with loop recorder after an embolic stroke of undetermined source.

Background: After an embolic stroke of undetermined source (ESUS), long-term monitoring is recommended to start an anticoagulation therapy in patients with documented atrial fibrillation (AF). Literature is sparse about the AF burden following an ESUS, although this might have significant implications in terms of clinical management and therapeutic strategy. Our primary aim was to evaluate a possible association between early detection of AF (within 90 days from the ILR implantation) and higher AF burden. Methods: This is a retrospective single-center study of 129 consecutive patients who received implantable loop recorders (ILRs) after an ESUS for detection of subclinical AF and their AF burden. Results: Mean age was 70.3 ± 10.4 years old (males: 51.9%). Atrial fibrillation was found in 40.3% of patients. Patients with AF were older, presented a higher CHAD2S2-Vasc Score and greater left atrial volume compared with patients without AF. The median AF burden was 1.2%; 59% of patients had the first AF episode within 90 days from the ILR implant while 41% experienced the first episode later than 90 days. The AF burden was significantly higher in the former group. Of note, the univariate analysis showed that only early AF detection was significantly associated with AF burden >1% (OR 20.0; 95% CI 1.68-238.6, p = 0.01). Conclusions: The early AF detection was found to be significantly associated with a higher burden of AF.

Video-Assisted Thoracoscopic Monitoring of Laser Lead Extraction by Femoral Route.

A 72-year-old man with a dual-chamber implantable defibrillator was referred to our center for transvenous lead extraction because of pocket infection and presence of an abandoned lead. We decided to proceed with a video-assisted thoracoscopic approach because of patient history and documented complete occlusion of the right subclavian vein. During the use of excimer laser for persistent adhesions, the ventricular lead broke down at the level of cavoatrial junction. To successfully remove the remaining portion of lead, we decided to use the excimer laser by femoral route. A final angiography through the laser sheath showed the integrity of the myocardial wall. We report a case of laser-assisted transvenous lead extraction unconventionally performed by the femoral route. A preventive minimally invasive cardiac surgery was implemented to provide more safety in this high-risk procedure. This technique may avoid the need of a full sternotomy in case of major bleeding complications.

Image-based criteria to identify the presence of epicardial arrhythmogenic substrate in patients with transmural myocardial infarction.

BACKGROUND: Patients with transmural myocardial infarction (MI) who undergo endocardial-only substrate ablation are at increased risk for ventricular tachycardia recurrence. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) can be used to assess infarct transmurality (IT). However, the degree of IT associated with an epicardial arrhythmogenic substrate (AS) has not been determined. OBJECTIVE: The purpose of this study was to determine the degree of IT observed by LGE-CMR and multidetector computed tomography (MDCT) that predicts the presence of epicardial AS. METHODS: The study included 38 post-MI patients. Ten patients with a subendocardial infarction underwent endocardial-only mapping, and 28 with a classic transmural MI (C-TMI), defined as hyperenhancement ≥75% of myocardial wall thickness (WT), underwent endo-epicardial mapping. LGE-CMR/MDCT data were registered to high-density endocardial or epicardial maps to be analyzed for the presence of AS. RESULTS: Of the 28 post-MI patients with C-TMI, 18 had epicardial AS (64%) and 10 (36%) did not. An epicardial scar area ≥14 cm2 on LGE-CMR identified patients with epicardial AS (sensitivity 1, specificity 1). Mean WT in the epicardial scar area in these patients was lower than in patients without epicardial AS (3.14 ± 1.16 mm vs 5.54 ± 1.78 mm; P = .008). A mean WT cutoff value ≤3.59 mm identified patients with epicardial AS (sensitivity 0.91, specificity 0.93). CONCLUSION: An epicardial scar area ≥14 cm2 on LGE-CMR and mean CT-WT ≤3.59 mm predict epicardial AS in post-MI patients.

Efficacy of second-generation cryoballoon ablation in paroxysmal and persistent atrial fibrillation patients.

AIMS: In this study, we aimed to compare the efficacy of single pulmonary vein isolation with the second-generation cryoballoon (CB-Adv) and predictors of atrial fibrillation recurrences in patients with paroxysmal (PAF) and persistent atrial fibrillation (PersAF). METHODS: Consecutive PAF and PersAF patients undergoing CB-Adv for the first time were enrolled. Patients were followed with in-clinic visits including Holter ECG. Atrial arrhythmic episodes symptomatic or documented lasting more than 30 s were considered as recurrences. RESULTS: A total of 96 consecutive patients [77 men (80%), mean age 57.4 ±â€Š9.9 years] were included in this analysis. About 56 (58%) patients had PAF and 40 had (42%) PersAF. The mean procedural and fluoroscopy times were 116 ±â€Š24 and 33 ±â€Š12 min, respectively. Procedure-related complications occurred in four (4.2%) patients.At the 12-month follow-up, after a 3-month blanking period, freedom from recurrences was achieved in 59% [confidence interval (CI): 49-69%] of patients, 62% (CI: 48-75%) in PAF, and 54% (CI: 38-71%) in PersAF group. The difference was not statistically significant at the Kaplan-Meier survival analysis (P = 0.242). Cardioversion to restore sinus rhythm was less frequently needed in PAF group [5% (CI: 1-15%) vs. 25% (CI: 13-41%), P < 0.001]. Redo procedure was performed in 7% (CI: 3-15%) of patients. In the Cox regression analysis, early atrial-tachyarrhythmia recurrence was the only independent predictor of 1-year recurrence (hazard ratio 2.11, CI: 1.06-4.20, P = 0.03). CONCLUSION: The success rate at 12 months after a single CB-Adv procedure was 62% in patients with PAF and 54% in study participants with PersAF. Early atrial-tachyarrhythmia recurrence appeared to be the only independent predictor of late atrial fibrillation recurrence.

Thoracoscopic Implantation of an Array Electrode in the Pericardium Transverse Sinus to Reduce Defibrillation Threshold.

Among the implantable cardioverter defibrillator recipients, there is still a subgroup of patients in whom the defibrillation threshold is too high and the maximal shock output of the implantable cardioverter defibrillator can fail to terminate a ventricular arrhythmia. We report a new thoracoscopic minimally invasive approach to place a standard array electrode in the transverse pericardial sinus of a patient implanted with a cardiac resynchronization and defibrillation therapy device with persistent high defibrillation threshold. This approach was developed to achieve very low shock impedance with a consequent increase in the current flow and reduction of defibrillation threshold.

Ranolazine therapy in drug-refractory ventricular arrhythmias.

AIMS: Ranolazine is an antiischemic and antianginal agent, but experimental and preclinical data provided evidence of additional antiarrhythmic properties. The aim of this study was to evaluate the safety and efficacy of ranolazine in reducing episodes of ventricular arrhythmias in patients with recurrent antiarrhythmic drug-refractory ventricular arrhythmias or with chronic angina. METHODS: Seventeen implantable cardioverter defibrillator (ICD) recipients, who had experienced a worsening of their ventricular arrhythmia burden, and 12 ICD recipients with angina were enrolled. Patients were followed up for 6 months after the addition of ranolazine (postranolazine). Data were compared with before its administration (preranolazine). RESULTS: In the Arrhythmias group, a significant reduction was found in the median number of ventricular tachycardia episodes per patient (4 vs. 0, P = 0.01), and in ICD interventions in terms of both antitachycardia pacing (2 vs. 0, P = 0.04) and shock delivery (2 vs. 0, P = 0.02) after the addition of ranolazine. Moreover, fewer patients experienced episodes of nonsustained ventricular tachycardia (71 vs. 41%, P = 0.04), ventricular tachycardia (76 vs. 24%, P = 0.01), ICD antitachycardia pacing (47 vs. 18%, P = 0.02), and ICD shocks (47 vs. 6%, P = 0.03). In the Angina group, none of the patients developed major ventricular arrhythmias while on ranolazine treatment. No adverse effects were observed. CONCLUSION: In this small study, ranolazine proved to be effective, well tolerated, and safe in reducing ventricular arrhythmia episodes and ICD interventions in patients with recurrent antiarrhythmic drug-refractory events. In addition, none of the patients with chronic angina developed major ventricular arrhythmias.

Unexpected challenging case of coronary sinus lead extraction.

An 84-year-old woman implanted with cardiac resynchronization therapy defibrillator underwent transvenous lead extraction 4 mo after the implant due to pocket infection. Atrial and right ventricular leads were easily extracted, while the attempt to remove the coronary sinus (CS) lead was unsuccessful. A few weeks later a new extraction procedure was performed in our center. A stepwise approach was used. Firstly, manual traction was unsuccessfully attempted, even with proper-sized locking stylet. Secondly, mechanical dilatation was used with a single inner sheath placed close to the CS ostium. Finally, a modified sub-selector sheath was successfully advanced over the electrode until it was free of the binding tissue. The post-extraction lead examination showed an unexpected fibrosis around the tip. No complications occurred during the postoperative course. Fibrous adhesions could be found in CS leads recently implanted requiring non-standard techniques for its transvenous extraction.

Clinical recognition of pure premature ventricular complex-induced cardiomyopathy at presentation.

BACKGROUND: Frequent premature ventricular complexes (PVCs) can induce or worsen left ventricular (LV) systolic dysfunction. OBJECTIVE: The purpose of this study was to identify the clinical pattern of patients having a "pure PVC-induced" cardiomyopathy at presentation. METHODS: This prospective multicenter study included 155 consecutive patients (age 55 ± 12 years, 96 men [62%], 23% ±12% mean PVC burden) with LV dysfunction and frequent PVCs submitted for ablation and followed up for at least 12 months. Patients with a previously diagnosed structural heart disease (50 [32%]) and those without complete PVC abolition during follow-up who did not normalize LV ejection fraction (LVEF) (24 [15%]) were excluded from the analysis. RESULTS: Of the remaining 81 patients, 41 (51%) had a successful sustained ablation, did not have normalized LVEF, and were classified as having PVC-worsened nonischemic cardiomyopathy, and 40 (49%) who had normalized LVEF were considered as having pure PVC-induced cardiomyopathy. The latter group had higher baseline PVC burden (27% ± 12% vs 12% ± 8%; P <.001), smaller LV end-diastolic diameter (58 ± 5 mm vs 60 ± 6 mm; P = .05), and shorter intrinsic QRS (105 ± 12 vs 129 ± 24 ms; P <.001). Any of the following baseline characteristics accurately identified patients who will not normalize LVEF after PVC ablation (85% sensitivity, 98% specificity): intrinsic QRS >130 ms, baseline PVC burden <17%, and LV end-diastolic diameter >63 mm. CONCLUSION: Almost half of patients with frequent PVCs and low LVEF of unknown origin normalize LVEF after sustained PVC abolition, and these patients can be identified before ablation.