Outcomes of leadless pacemaker implantation in patients with mechanical heart valves.

INTRODUCTION: Device infections constitute a major complication of transvenous pacemakers. Mechanical heart valves (MHV) increase the risk of infective endocarditis (IE) and pacemaker infection, requiring lifelong vitamin K-antagonists (VKA), which may affect patient management. Leadless pacemakers (LP) are associated with low infection rates, posing an attractive option in MHV patients requiring permanent pacing. This study describes outcomes following LP implantation in patients with MHV. METHODS: This is a multicenter, observational, retrospective study including consecutive patients implanted with an LP at 5 centers between June 2015 and January 2020. Procedural outcomes, antithrombotic management, complications, performance during follow-up and episodes of bacteremia and IE were compared between patients with and without an MHV (MHV and non-MHV groups). RESULTS: Four hundred fifty-nine patients were included (74 in the MHV group, 16.1%, and 385 in the non-MHV group, 83.9%). Procedural outcomes and acute electrical performance were comparable between groups. Vascular complications and cardiac perforation occurred in 2.7 versus 2.3% (p = 1) and 0% versus 0.8% (p = 1) in the MHV group and non-MHV group. One case of IE occurred in the MHV group and 2 in the non-MHV group. In MHV patients, uninterrupted VKA was used in 83.8%, whereas 16.2% were heparin-bridged. Vascular complication or tamponade occurred in 1 (8.3%) MHV heparin-bridged patient versus 1 (1.6%) MHV uninterrupted VKA patient (p = .3). CONCLUSION: LP implantation outcomes in MHV patients are comparable to the general LP population. Device-related infections are rare following LP implantation, including in patients with MHV. In the MHV group, periprocedural anticoagulation management was not associated with significantly different rates of tamponade or vascular complication.

Impact of routine right parasternal electrocardiographic screening in assessing eligibility for subcutaneous implantable cardioverter-defibrillator.

INTRODUCTION: Between 7% and 15% of patients with an indication for an implantable cardioverter-defibrillator (ICD) are not eligible for implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD) on the basis of the result of the conventional left parasternal electrocardiographic screening (LPES). Our objective was to determine the impact of systematically performing right parasternal electrocardiographic screening (RPES) in addition to conventional LPES, in terms of increasing both the total percentage of potentially eligible patients for S-ICD implantation and the number of suitable vectors per patient. METHODS AND RESULTS: Consecutive patients from the outpatient device clinic who already had an implanted ICD, and no requirement for pacing were enrolled. Conventional left parasternal electrode position and right parasternal electrode positions were used. The automatic screening tool was used to analyze the recordings. Screenings were performed in the supine and standing positions. Overall, 209 patients were included. The mean age was 63.4 ± 13 years, 59.8% had ischemic heart disease, mean QRS duration was 100 ± 31 ms, and 69.9% had a primary prevention ICD indication. Based on conventional isolated LPES, 12.9% of patients were not eligible for S-ICD compared with 11.5% based on RPES alone (P = .664). Considering LPES and RPES together, only 7.2% of patients were not eligible for S-ICD (P < .001). Moreover, the number of patients with more than one suitable vector increased from 66.5% with isolated LPES to 82.3% (23.7% absolute increase [P < .001]). CONCLUSION: Adding an automated RPES to the conventional automated LPES increased patient eligibility for the S-ICD significantly. Moreover, combined screening increased the number of suitable vectors per eligible patient.

Quality of life of patients undergoing conventional vs leadless pacemaker implantation: A multicenter observational study.

BACKGROUND: Leadless pacemakers (L-PM) are an emerging effective and safe technology that offer an alternative to conventional pacemakers (C-PM) for right ventricular stimulation. However, there is little information about their potential benefits for quality of life (QoL) in patients with L-PM. We compared QoL between patients with L-PM and C-PM. METHODS: The study population comprised patients undergoing single chamber pacemaker implantation from December 2016 to March 2018. The SF-36 questionnaire was used to evaluate QoL at baseline and at 6 months of followup. We also used a questionnaire consisted of 10 specific questions related to the implant procedure. RESULTS: A total of 106 patients (64 C-PM; 42 L-PM) were included. There were no differences in baseline characteristics between the groups (C-PM vs L-PM), except for age (81.5 vs 77.3 years; P = .012) and diabetes (38% vs 17%; P = .021). Baseline SF-36 scores did not differ between the groups. At 6 months followup, patients in the L-PM group scored significantly higher on physical function (63 vs 42; P < .001), physical role (64 vs 36; P = .004), and mental health (75 vs 65; P = .017), even after adjusting for covariates. Pacemaker-related discomfort and physical restrictions were significantly lower for the L-PM group. CONCLUSION: L-PM is associated with better QoL than C-PM in both physical and mental health. Patients undergoing L-PM implantation reported less procedure-related discomfort, physical restriction, and preoccupation.

Premature ventricular contractions in patients with an implantable cardioverter defibrillator cardiac resynchronization therapy device: Results from the UMBRELLA registry.

BACKGROUND: Premature ventricular contractions (PVC) are known to reduce the percentage of biventricular (BiV) pacing in patients with cardiac resynchronization (CRT), decreasing the clinical response. The aim of this study was to evaluate the prevalence of a high PVC burden, as well as therapeutic action (pharmacotherapy, catheter ablation or device programming), in a large CRT implantable-defibrillator (CRT-D) population. METHODS: Patients with a CRT-D device from the UMBRELLA multicenter prospective remote monitoring registry were included. The PVC count was collected from each remote monitoring transmission. Patients were divided into two high (≥1 transmission ≥200/≥400 PVC/h, respectively) and one low (all transmissions <200 PVC/h) PVC count groups. The PVC burden following a high PVC count transmission was calculated. RESULTS: Of 1268 patients, 135 (11%) and 43 (3.4%) presented high PVC count (≥200/≥400 PVC/h, respectively). The majority of patients in the high PVC groups were not treated (61 [79%] and 32 [74%], respectively. Considering the untreated patients in the high PVC groups, median PVC/h was 199 (interquartile range [IQR]: 196) and 271 (IQR: 330), respectively. The PVC burden (proportion of time with PVC/h ≥ 200/≥400) was 40% (IQR 70) and 29% (IQR 59), respectively. CONCLUSION: A significant proportion of CRT-D patients presented a high PVC count, however, few received treatment. In the untreated patients with a high PVC count, the PVC burden during follow-up varied substantially. Several consecutive recordings of a high PVC count should be warranted before considering therapeutic action such as catheter ablation.

A regular wide QRS complex tachycardia: What is the mechanism?

A 14-year-old girl with a history of recurrent palpitations and documented wide QRS complex tachycardia was referred for electrophysiologic study and catheter ablation.

Diagnosis-to-ablation time in atrial fibrillation: A modifiable factor relevant to clinical outcome.

INTRODUCTION: Recurrences after atrial fibrillation (AF) ablation are still common. Among the reported clinical and imaging predictors of recurrences, diagnosis-to-ablation time (DAT) has been defined as a predictor of ablation outcome in single-center studies. We aimed to validate DAT in a multicenter real-life cohort. METHODS: This was a multicenter study including consecutive patients undergoing first paroxysmal and persistent AF ablation with radiofrequency or cryoballoon catheters during 2013. Cox proportional hazard regression models were performed to identify predictors of recurrence. RESULTS: In total, 309 patients were included across nine centers (71% men, 57 ± 10 years old, 46% with hypertension, and 66% with CHA2 DS2 -VASc ≤ 1). Most patients had paroxysmal AF (67%) and underwent radiofrequency ablation (68%) with a median DAT of 51 (43) months. Patients with DAT ≤ 1 year (16.6%) were less likely to have repeat procedures (4% vs 18%; P = .017). The adjusted proportional hazards Cox model identified hypertension (P = .005), heart failure (P = .011), nonparoxysmal AF (P = .038), DAT > 1 year (P = .007), and LA diameter (P = .026) as independent predictors for AF recurrence. DAT > 1 year was the only modifiable factor independently associated with recurrence (HR 4.2 [95% CI, 1.5-11.9]) CONCLUSION: Diagnosis-to-ablation time is a modifiable factor independently associated with recurrent arrhythmia and repeat ablation after first AF ablation. An early intervention strategy during the first year from AF diagnosis might improve outcomes.

A scoring algorithm for the accurate differential diagnosis of regular wide QRS complex tachycardia.

BACKGROUND: The differential diagnosis of regular wide QRS complex tachycardia (RWQRST) remains the subject of numerous publications, all of which aim at diagnosis during the acute phase. Although an accurate diagnosis is necessary to make long-term decisions, it often leads to invasive testing. METHODS: Criteria with high positive predictive values (PPVs) for diagnosis can be obtained by analyzing the electrocardiogram (ECG) data during RWQRST and comparing them with these data at baseline. By assigning points to these criteria, a scoring algorithm to accurately diagnose numerous patients can be obtained. A total of 352 consecutive patients with RWQRST were included. Two electrophysiologists blind to patient condition analyzed the 16 criteria considered as having high PPVs. RESULTS: A total of 149 (42.3%) cases were supraventricular tachycardia (SVT), and 203 (57.7%) cases were ventricular tachycardia (VT). A higher percentage of patients with VT had structural heart disease (86.7% vs 16.1%). Seven of the 16 criteria analyzed had PPVs > 95%, and each criterion was assigned a score. A final score of -1 was indicative of SVT (PPV 98%); a score of 1 was indicative of VT (PPV 98%); and a score of ≥2 was indicative of VT (PPV 100%). A score of ≠0 was obtained for 51.7% of all cases of tachycardia, making it possible to reach a highly accurate diagnosis in approximately half of all cases. No cases of VT scored -1, and no cases of SVT scored ≥2. CONCLUSIONS: The current scoring system stands out for its high PPV (98%) and specificity (98%), enabling an accurate diagnosis for more than half of the patients.

Estimation of the effects of multipoint pacing on battery longevity in routine clinical practice.

Aims: Multipoint pacing (MPP) permits simultaneous multisite pacing of the left ventricle (LV); initial studies suggest haemodynamic and clinical benefits over conventional (single LV site) cardiac resynchronization therapy (CRT). The aim of this study was to estimate the impact of MPP activation on battery longevity in routine clinical practice. Methods and results: Patient (n = 46) and device data were collected from two centres at least 3 months after MPP-CRT device implantation. Multipoint pacing programming was based on the maximal possible anatomical LV1/LV2 separation according to three predefined LV pacing capture threshold (PCT) cut-offs (≤1.5 V; ≤4.0 V; and ≤6.5 V). Estimated battery longevity was calculated using the programmed lower rate limit, lead impedances, outputs, and pacing percentages. Relative to the longevity for conventional CRT using the lowest PCT (8.9 ± 1.2 years), MPP activation significantly shortened battery longevity for all three PCT cut-offs (≤1.5 V, -5.6%; ≤4.0 V, -16.9%; ≤6.5 V, -21.3%; P's <0.001). When compared with conventional CRT based on longest right ventricle-LV delay (8.3 ± 1.3 years), battery longevity was significantly shortened for the MPP ≤ 4.0 V and ≤6.5 V cut-offs (-10.8 and -15.7%, respectively; P's <0.001). Maximal LV1/LV2 spacing was possible in 23.9% (≤1.5 V), 56.5% (≤4.0 V), and 69.6% (≤6.5 V) of patients. Conclusion: Multipoint pacing activation significantly reduces battery longevity compared with that for conventional CRT configuration. When reasonable MPP LV vector PCTs (≤4.0 V) are achieved, the decrease in battery longevity is relatively small which may prompt the clinician to activate MPP.

Delta of the local ventriculo-atrial intervals at the septal location to differentiate tachycardia using septal accessory pathways from atypical atrioventricular nodal re-entry.

Aims: Tachycardia mediated by septal accessory pathways (AP) and atypical atrioventricular nodal re-entry (AVNRT) require careful electrophysiologic evaluation for differential diagnosis. We aim to describe the differential behaviour of local ventriculo-atrial (VA) intervals which predicts the tachycardia mechanism. Methods and results: The local VA intervals at the para-Hisian septum were measured under three different situations: (i) tachycardia; (ii) sustained entrainment from the right ventricular apex (RVA); and (iii) continuous pacing from the RVA during sinus rhythm. Differences were computed as follows: Δ-VAentr = VA during entrainment - VA during tachycardia; and Δ-VApac = VA while pacing during sinus rhythm - VA during tachycardia. In contrast to AVNRT, we hypothesized that an invariable retrograde conduction through the septal AP will keep the result of the subtractions close to 0 ms in cases of ortodromic atrioventricular re-entrant tachycardia (AVRT). We analysed 55 atypical AVNRT (45% posterior type) and 82 AVRT (10 anteroseptal, 18 para-Hisian, 12 mid-septal, and 42 posteroseptal). Δ-VAentr was longer for AVNRT (98.5 ± 40.3 ms) compared with septal AP (-5.7 ± 19.3 ms; P < 0.001). A value of 50 ms showed 98.7% sensitivity and 92% specificity (AUC 0.99; 95% CI 0.98-1). According to physiological criteria, a negative Δ-VAentr remains unobserved in the case of AVNRT (positive predictive value 100% for septal AP). Δ-VApac was also longer for AVNRT (66.5 ± 14.6 ms) compared with septal AP (-9.7 ± 3.3 ms; P < 0.001). A value of 50 ms showed 100% sensitivity and 74% specificity (AUC 0.86; 95% CI 0.76-0.93). Conclusions: Delta of the local VA intervals enables distinction between atypical AVNRT and AVRT mediated by septal AP.

Paradoxical preexcitation during cryoablation of a concealed parahisian accessory pathway.

A 16-year-old male presented with an orthodromic atrioventricular reentrant tachycardia over a concealed parahisian accessory pathway (AP). Cryoablation of the AP resulted in transient manifestation of a fully preexcited sinus rhythm of parahisian AP morphology. Potential causes for the paradoxical preexcitation include inadvertent atrioventricular nodal block, sourse-sink mismatch, as well as the activation of a dormant AP capable of anterograde conduction.

Number of Beats in the Transition Zone With Fixed SA Interval during Right Ventricular Overdrive Pacing Determines Accessory Pathway Location in Orthodromic Reentrant Tachycardia.

BACKGROUND: Ventricular overdrive pacing (VOP) produces reset during the transition zone (TZ) of QRS fusion in orthodromic reentrant tachycardia (ORT) and after the TZ in atrioventricular nodal reentrant tachycardia (AVNRT), and this represents a simple diagnostic maneuver to differentiate the two tachycardia mechanisms. OBJECTIVE: The purpose of this study was to determine whether the number of beats with reset in the TZ predicts accessory pathway (AP) location in ORT. METHODS: We retrospectively reviewed 57 patients with ORT (21 left-sided AP, 20 septal AP, and 16 right-sided AP) and 20 patients with AVNRT (19 typical AVNRT and one atypical AVNRT) who underwent VOP from the right ventricular apex. We analyzed the number of beats with reset during or after the TZ, demonstrated by fixed ventricular stimulus-atrial (SA) interval during VOP. RESULTS: The overall mean tachycardia cycle length [CL] minus VOP CL was 22.6 ± 7.5 ms with no statistical difference between the groups (P = 0.480). The mean number of beats in the TZ with fixed SA interval was 2.5 ± 1.4 for the whole ORT group, 1.1 ± 0.4 for left-sided AP (range 1-2), 2.8  ±  0.9 for septal AP (range 1-5), and 4.0 ± 0.9 for right-sided AP (range 3-6) (P < 0.001). Using a cutoff >2 beats distinguished right- versus left-sided AP in all cases. CONCLUSION: Assessing the number of beats in the TZ with fixed SA interval during VOP helps to determine AP location in ORT and adds valuable information to an established simple diagnostic pacing maneuver, especially when a two-catheter simplified approach is employed.