Device-detected atrial sensing amplitudes as a marker of increased risk for new onset and progression of atrial high-rate episodes

BACKGROUND

Atrial high-rate episodes (AHREs) are frequent in patients with cardiac implantable electronic devices. A decrease in device-detected P-wave amplitude may be an indicator of periods of increased risk of AHRE.

OBJECTIVE

The objective of this study was to assess the association between P-wave amplitude and AHRE incidence.

METHODS

Remote monitoring data from 2579 patients with no history of atrial fibrillation (23% pacemakers and 77% implantable cardioverter-defibrillators, of which 40% provided cardiac resynchronization therapy) were used to calculate the mean P-wave amplitude during 1 month after implantation. The association with AHRE incidence according to 4 strata of daily burden duration (≥15 minutes, ≥6 hours, ≥24 hours, ≥7 days) was investigated by adjusting the hazard ratio with the CHA2DS2-VASc score.

RESULTS

The adjusted hazard ratio for 1-mV lower mean P-wave amplitude during the first month increased from 1.10 (95% confidence interval [CI], 1.05-1.15; P < .001) to 1.18 (CI, 1.09-1.28; P < .001) with AHRE duration strata from ≥15 minutes to ≥7 days independent of the CHA2DS2-VASc score. Of 871 patients with AHREs, those with 1-month P-wave amplitude <2.45 mV had an adjusted hazard ratio of 1.51 (CI, 1.19-1.91; P = .001) for progression of AHREs from ≥15 minutes to ≥7 days compared with those with 1-month P-wave amplitude ≥2.45 mV. Device-detected P-wave amplitudes decreased linearly during the 1 year before the first AHRE by 7.3% (CI, 5.1%-9.5%; P < .001 vs patients without AHRE).

CONCLUSION

Device-detected P-wave amplitudes <2.45 mV were associated with an increased risk of AHRE onset and progression to persistent forms of AHRE independent of the patient's risk profile.

Artificial intelligence cloud platform improves arrhythmia detection from insertable cardiac monitors to 25 cardiac rhythm patterns through multi-label classification

BACKGROUND

Electrocardiogram (ECG) is the gold standard for the diagnosis of cardiac arrhythmias and other heart diseases. Insertable cardiac monitors (ICMs) have been developed to continuously monitor cardiac activity over long periods of time and to detect 4 cardiac patterns (atrial tachyarrhythmias, ventricular tachycardia, bradycardia, and pause). However, interpretation of ECG or ICM subcutaneous ECG (sECG) is time-consuming for clinicians. Artificial intelligence (AI) classifies ECG and sECG with high accuracy in short times.

OBJECTIVE

To demonstrate whether an AI algorithm can expand ICM arrhythmia recognition from 4 to many cardiac patterns.

METHODS

We performed an exploratory retrospective study with sECG raw data coming from 20 patients wearing a Confirm Rx™ (Abbott, Sylmar, USA) ICM. The sECG data were recorded in standard conditions and then analyzed by AI (Willem™, IDOVEN, Madrid, Spain) and cardiologists, in parallel.

RESULTS

In nineteen patients, ICMs recorded 2261 sECGs in an average follow-up of 23 months. Within these 2261 sECG episodes, AI identified 7882 events and classified them according to 25 different cardiac rhythm patterns with a pondered global accuracy of 88%. Global positive predictive value, sensitivity, and F1-score were 86.77%, 83.89%, and 85.52% respectively. AI was especially sensitive for bradycardias, pauses, rS complexes, premature atrial contractions, and inverted T waves, reducing the median time spent to classify each sECG compared to cardiologists.

CONCLUSION

AI can process sECG raw data coming from ICMs without previous training, extending the performance of these devices and saving cardiologists' time in reviewing cardiac rhythm patterns detection.

Outcome of the elective or online radiofrequency ablation of typical atrial flutter

BACKGROUND

Radiofrequency ablation of the cavotricuspid isthmus is currently the first-choice treatment of typical atrial flutter and usually it is performed electively. The purpose of this study was to see whether performing on-line ablation has similar clinical results compared to the conventional strategy.

METHODS

Consecutive patients (465) who underwent ablation of the cavotricuspid isthmus for typical atrial flutter (AFL) at our electrophysiology laboratory in the 2008-2017 decade were studied. We evaluated the acute and long-term clinical outcomes of those who were treated electively (337) compared to those who had online ablation (128), that is within 24 hours of presenting to the Department of Cardiology. In patients treated on an emergency basis, a transesophageal echocardiogram was performed to rule atrial thrombi when needed.

RESULTS

No significant intraprocedural difference was observed between the 2 patient groups, with comparable acute electrophysiological success (99% vs. 98%) and serious complications. Even at the subsequent 4-year follow-up, there were no significant differences in the recurrence of typical AFL, onset of atrial fibrillation and other clinical events.

CONCLUSIONS

Online ablation of typical atrial flutter performed at the time of the clinical presentation of the arrhythmia, was shown to be comparable in terms of procedural safety and clinical efficacy in the short and long term compared to an elective ablation strategy.

New insertable cardiac monitors show high diagnostic yield and good safety profile in real-world clinical practice: results from the international prospective observational SMART Registry

AIMS

Insertable cardiac monitors (ICMs) are indicated for long-term monitoring of unexplained syncope or palpitations, and for detection of bradycardia, ventricular tachycardia, and/or atrial fibrillation (AF). The aim of our study was to evaluate the safety and clinical value associated with a new generation ICM (Confirm Rx™, Abbott, Illinois, USA), featuring a new remote monitoring system based on smartphone patient applications.

METHODS AND RESULTS

The SMART Registry is an international prospective observational study. The main endpoints were ICM safety (incidence of serious adverse device and procedure-related events (SADEs) at 1 month), ICM clinical value (incidence of device-detected true arrhythmias and of clinical diagnoses and interventions), and patient-reported experience measurements (PREMs). A total of 1400 subjects were enrolled. ICM indications included syncope (49.1%), AF (18.8%), unexplained palpitations (13.6%), risk of ventricular arrhythmia (6.6%), and cryptogenic stroke (6.0%). Freedom from SADEs at 1 month was 99.4% (95% Confidence Interval: 98.8-99.7%). In the 6-month monitoring period, the ICM detected true cardiac arrhythmias in 45.7% of patients and led to clinical interventions in a relevant proportion of patients; in particular, a pacemaker implant was performed after bradycardia detection in 8.9% of subjects who received an ICM for syncope and oral anticoagulation therapy was indicated after AF detection in 15.7% of subjects with cryptogenic stroke. PREMs showed that 78.2% of subjects were satisfied with the remote monitoring patient app.

CONCLUSION

The evaluated ICM is associated with an excellent safety profile and high diagnostic yield. Patients reported positive experiences associated with the use of their smartphone for the device remote monitoring.

Twenty-year experience of atrial fibrillation ablation: a single-centre cohort study

AIMS

While several studies in the literature have reported results of catheter ablation of AF, few is known regarding outcome for more than 10 years.

METHODS AND RESULTS

The complete population of patients who underwent AF ablation in the years 2002-2021 in the department of cardiology of the hospital of Reggio Emilia has been analysed. The last follow-up was made in the second half of 2022. During this period the technique of ablation remained relatively unchanged as well the physicians performing ablation. Primary endpoint was the recurrence of symptomatic AF, defined as AF that caused symptoms that were defined by the patient as able to alter their quality of life. 669 patients underwent catheter ablation and 618 were followed until 2022. Median age of the patients was 58 ± 9 years and 521 (78%) were male. There were 407 (61%) of patients with paroxysmal AF, 167 (25%) with persistent AF and 95 (14%) with long-lasting AF. A total of 838 procedures were performed, with a mean of 1.25 per patient. 163 (26%) patients had 2 procedures and 6 had 3 ablations. Periprocedural complications occurred in 4.8% of procedures. Follow-up data were available for 618 patients (92.4%). The median follow-up duration was 6.6 years (IQR 3.2-10.8). The estimated recurrence rate of symptomatic AF was 26% at 10 years, 54% at 15 years and 82% at 20 years. The recurrence rate was similar in patients who had performed one procedure and in those who had performed 2 or 3 procedures. Progression to permanent AF occurred in 112 patients (18%). The major events that occurred during the follow-up consisted of total mortality in 4.5%, heart failure in 3.1% and TIA/stroke in 2.4%.

CONCLUSION

Symptomatic AF tends to recur during long-term follow-up despite one or more procedures. Catheter ablation seems able to reduce the rate of symptomatic recurrences and to delay the time of their occurrence. These findings are consistent with the knowledge that an age-dependent progressive structural atriomiopathy is the basis for the development of AF.

Ability to remotely monitor atrial high-rate episodes using a single-chamber implantable cardioverter-defibrillator with a floating atrial sensing dipole

AIMS

To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend remote monitoring (RM) of device-detected atrial high-rate episodes (AHREs) and progression of arrhythmia duration along pre-specified strata (6 min…<1 h, 1 h…<24 h, ≥ 24 h). We used the MATRIX registry data to assess the capability of a single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (DX ICD system) to follow this recommendation in patients with standard indication for single-chamber ICD.

METHODS AND RESULTS

In 1841 DX ICD patients with daily automatic RM transmissions, electrograms of first device-detected AHREs per patient in each duration stratum were adjudicated, and the corresponding positive predictive values (PPVs) for the detections to be true atrial arrhythmia were calculated. Moreover, the incidence and progression of new-onset AF was assessed in 1451 patients with no AF history. A total of 610 AHREs ≥6 min were adjudicated. The PPV was 95.1% (271 of 285) for episodes 6min…<1 h, 99.6% (253/254) for episodes 1 h…<24 h, 100% (71/71) for episodes ≥24 h, or 97.5% for all episodes (595/610). The incidence of new-onset AF was 8.2% (119/1451), and in 31.1% of them (37/119), new-onset AF progressed to a higher duration stratum. Nearly 80% of new-onset AF patients had high CHA2DS2-VASc stroke risk, and 70% were not on anticoagulation therapy. Age was the only significant predictor of new-onset AF.

CONCLUSION

A 99.7% detection accuracy for AHRE ≥1 h in patients with DX ICD systems in combination with daily RM allows a reliable guideline-recommended screening for subclinical AF and monitoring of AF-duration progression.

Implantable cardioverter defibrillator lead performance: A systematic review and individual patient data Meta-analysis

BACKGROUND

Reliable post-approval surveillance of implantable cardioverter-defibrillator (ICD) lead performance remains a challenge. In the past, two ICD leads were recalled due to a high frequency of failures. In this meta-analysis, we sought to provide a combined estimate of failure-free rate for ICD leads by reconstructing individual patient data from published Kaplan-Meier (KM) curves and to investigate whether estimates could be influenced by the characteristics of the study.

METHODS

Observational studies assessing failure-free estimates of transvenous ICD leads with KM method, were identified through a systematic search up to November 2021.

RESULTS

Forty-four studies were eligible that included 41,870 (63.1%) non-recalled leads and 24,493 (36.9%) recalled leads. The 8-year cumulative failure-free rate was 94.1% (CI, 93.6% - 94.6%) for contemporary non-recalled leads and 81.2% (80.3% - 82.0%) for recalled leads (hazard ratio [HR], 3.15 [2.85-3.47], p < 0.001). Failure-free rate was lower in single-center studies in both the non-recalled (HR, 0.28 [0.15-0.51], p < 0.001) and recalled (HR, 0.54 [0.33-0.88], p = 0.014) group compared with multicenter studies. Similarly, estimates were significantly lower in small (i.e. extracted KM curve with <312 leads) versus large studies (HR non-recalled group, 0.54 [CI, 0.33-0.89], p = 0.015; HR recalled group, 0.62 [CI, 0.43-0.89], p = 0.009).

CONCLUSIONS

In this meta-analysis including >66,000 leads, we provide pooled survival curves that may play a role in generating evidence-based standards for assessing clinically acceptable failure rates for ICD leads. Lead performance was underestimated with single-center and small-sized studies; multicenter studies remain the main tool to reliably conduct post-market surveillance of ICD leads.

Five waves of COVID-19 pandemic in Italy: results of a national survey evaluating the impact on activities related to arrhythmias, pacing, and electrophysiology promoted by AIAC (Italian Association of Arrhythmology and Cardiac Pacing)

BACKGROUND

The subsequent waves of the COVID-19 pandemic in Italy had a major impact on cardiac care.

METHODS

A survey to evaluate the dynamic changes in arrhythmia care during the first five waves of COVID-19 in Italy (first: March-May 2020; second: October 2020-January 2021; third: February-May 2021; fourth: June-October 2021; fifth: November 2021-February 2022) was launched.

RESULTS

A total of 127 physicians from arrhythmia centers (34% of Italian centers) took part in the survey. As compared to 2019, a reduction in 40% of elective pacemaker (PM), defibrillators (ICD), and cardiac resynchronization devices (CRT) implantations, with a 70% reduction for ablations, was reported during the first wave, with a progressive and gradual return to pre-pandemic volumes, generally during the third-fourth waves, slower for ablations. For emergency procedures (PM, ICD, CRT, and ablations), recovery from the initial 10% decline occurred in most cases during the second wave, with some variability. However, acute care for atrial fibrillation, electrical cardioversions, and evaluations for syncope showed a prolonged reduction of activity. The number of patients with devices which started remote monitoring increased by 40% during the first wave, but then the adoption of remote monitoring declined.

CONCLUSIONS

The dramatic and profound derangement in arrhythmia management that characterized the first wave of the COVID-19 pandemic was followed by a progressive return to the volume of activities of the pre-pandemic periods, even if with different temporal dynamics and some heterogeneity. Remote monitoring was largely implemented during the first wave, but full implementation is needed.

Reducing the Electrogram Review Burden Imposed by Insertable Cardiac Monitors

BACKGROUND

Insertable cardiac monitors (ICMs) are essential for ambulatory arrhythmia diagnosis. However, definitive diagnoses still require time-consuming, manual adjudication of electrograms (EGMs).

OBJECTIVE

To evaluate the clinical impact of selecting only key EGMs for review.

METHODS

Retrospective analyses of randomly selected Abbott Confirm Rx^TM devices with ≥90 days of remote transmission history was performed, with each EGM adjudicated as true or false positive (TP, FP). For each device, up to 3 "key EGMs" per arrhythmia type per day were prioritized for review based on ventricular rate and episode duration. The reduction in EGMs and TP days (patient-days with at least 1 TP EGM), and any diagnostic delay (from the first TP), were calculated vs. reviewing all EGMs.

RESULTS

In 1,000 ICMs over a median duration of 8.1 months, at least one atrial fibrillation (AF), tachycardia, bradycardia, or pause EGM was transmitted by 424, 343, 190, and 325 devices, respectively, with a total of 95716 EGMs. Approximately 90% of episodes were contributed by 25% of patients. Key EGM selection reduced EGM review burden by 43%, 66%, 77%, and 50% (55% overall), while reducing TP days by 0.8%, 2.1%, 0.2%, and 0.0%, respectively. Despite reviewing fewer EGMs, 99% of devices with a TP EGM were ultimately diagnosed on the same day vs. reviewing all EGMs.

CONCLUSIONS

Key EGM selection reduced the EGM review substantially with no delay-to-diagnosis in 99% of patients exhibiting true arrhythmias. Implementing these rules in the Abbott patient care network may accelerate clinical workflow without compromising diagnostic timelines. This article is protected by copyright. All rights reserved.

One-year mortality after implantable defibrillator implantation: do risk stratification models help improving clinical practice?

PURPOSE

The purpose of this study was to assess the available mortality risk stratification models for implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) patients.

METHODS

We conducted a review of mortality risk stratification models and tested their ability to improve prediction of 1-year survival after implant in a database of patients who received a remotely controlled ICD/CRT-D device during routine care and included in the independent Home Monitoring Expert Alliance registry.

RESULTS

We identified ten predicting models published in peer-reviewed journals between 2000 and 2021 (Parkash, PACE, MADIT, aCCI, CHA2DS2-VASc quartiles, CIDS, FADES, Sjoblom, AAACC, and MADIT-ICD non-arrhythmic mortality score) that could be tested in our database as based on common demographic, clinical, echocardiographic, electrocardiographic, and laboratory variables. Our cohort included 1,911 patients with left ventricular dysfunction (median age 71, 18.3% female) from sites not using any risk stratification score for systematic patient screening. Patients received an ICD (53.8%) or CRT-D (46.2%) between 2011 and 2017, after standard physician evaluation. There were 56 deaths within 1-year post-implant, with an all-cause mortality rate of 2.9% (95% confidence interval [CI], 2.3-3.8%). Four predicting models (Parkash, MADIT, AAACC, and MADIT-ICD non-arrhythmic mortality score) were significantly associated with increased risk of 1-year mortality with hazard ratios ranging from 3.75 (CI, 1.31-10.7) to 6.53 (CI 1.52-28.0, p ≤ 0.014 for all four). Positive predictive values of 1-year mortality were below 25% for all models.

CONCLUSION

In our analysis, the models we tested conferred modest incremental predicting power to ordinary screening methods.

AV junction ablation and cardiac resynchronization for patients with permanent atrial fibrillation and narrow QRS: the APAF-CRT mortality trial

AIMS 

In patients with atrial fibrillation (AF) and heart failure (HF), strict and regular rate control with atrioventricular junction ablation and biventricular pacemaker (Ablation + CRT) has been shown to be superior to pharmacological rate control in reducing HF hospitalizations. However, whether it also improves survival is unknown.

METHODS AND RESULTS 

In this international, open-label, blinded outcome trial, we randomly assigned patients with severely symptomatic permanent AF >6 months, narrow QRS (≤110 ms) and at least one HF hospitalization in the previous year to Ablation + CRT or to pharmacological rate control. We hypothesized that Ablation + CRT is superior in reducing the primary endpoint of all-cause mortality. A total of 133 patients were randomized. The mean age was 73 ± 10 years, and 62 (47%) were females. The trial was stopped for efficacy at interim analysis after a median of 29 months of follow-up per patient. The primary endpoint occurred in 7 patients (11%) in the Ablation + CRT arm and in 20 patients (29%) in the Drug arm [hazard ratio (HR) 0.26, 95% confidence interval (CI) 0.10-0.65; P = 0.004]. The estimated death rates at 2 years were 5% and 21%, respectively; at 4 years, 14% and 41%. The benefit of Ablation + CRT of all-cause mortality was similar in patients with ejection fraction (EF) ≤35% and in those with >35%. The secondary endpoint combining all-cause mortality or HF hospitalization was significantly lower in the Ablation + CRT arm [18 (29%) vs. 36 (51%); HR 0.40, 95% CI 0.22-0.73; P = 0.002].

CONCLUSIONS 

Ablation + CRT was superior to pharmacological therapy in reducing mortality in patients with permanent AF and narrow QRS who were hospitalized for HF, irrespective of their baseline EF.

STUDY REGISTRATION

ClinicalTrials.gov Identifier: NCT02137187.

Circadian periodicity affects the type of ventricular arrhythmias and efficacy of implantable defibrillator therapies

INTRODUCTION

Factors influencing malignant arrhythmia onset are not fully understood. We explored the circadian periodicity of ventricular arrhythmias (VAs) in patients with implantable cardioverter and cardiac resynchronization defibrillators (ICD/CRT-D).

METHODS

Time, morphology (monomorphic/polymorphic), and mode of termination (anti-tachycardia pacing [ATP] or shock) of VAs stored in a database of remote monitoring data were adjudicated. Episodes were grouped in six 4-h timeslots from 00:00 to 24:00. Circadian distributions and adjusted marginal odds ratios (ORs), with 95% confidence interval (CI), were analyzed using mixed-effect models and logit generalized estimating equations, respectively, to account for within-subject correlation of multiple episodes.

RESULTS

Among 1303 VA episodes from 446 patients (63% ICD and 37% CRT-D), 120 (9%) self-extinguished, and 842 (65%) were terminated by ATP, 343 (26%) by shock. VAs clustered from 08:00 to 16:00 with 44% of episodes, as compared with 22% from 00:00 to 08:00 (p < .001) and 34% from 16:00 to 24:00 (p = .005). Episodes were more likely to be polymorphic at night with an adjusted marginal OR of 1.66 (CI, 1.15-2.40; p = .007) at 00:00-04:00 versus other timeslots. Episodes were less likely to be terminated by ATP in the 00:00-04:00 (success-to-failure ratio, 0.67; CI, 0.46-0.98; p = .039) and 08:00-12:00 (0.70; CI, 0.51-0.96; p = .02) timeslots, and most likely to be terminated by ATP between 12:00 and 16:00 (success-to-failure ratio 1.42; CI, 1.06-1.91; p = .02).

CONCLUSION

VAs did not distribute uniformly over the 24 h, with a majority of episodes occurring from 08:00 to 16:00. Nocturnal episodes were more likely to be polymorphic. The efficacy of ATP depended on the time of delivery.

Reducing clinical review burden for insertable cardiac monitors

Funding Acknowledgements

Type of funding sources: None.

Background

The insertable cardiac monitor (ICM) is an essential tool for the ambulatory diagnosis of arrhythmias. However, definitive diagnoses still rely on time-consuming, manual adjudication of electrograms (EGMs) transmitted to the patient care network. This EGM review burden may be minimized by automatically selecting a subset of EGMs for fast review without delaying the diagnosis.

Purpose

Develop EGM selection strategies to reduce the EGM review burden without delaying diagnoses.

Methods

A retrospective analysis of 1,000 randomly selected Abbott Confirm Rx devices with 90+ days of remote transmission history was performed, regardless of transmission frequency, and all EGMs were adjudicated as either true or false positive (TP, FP). Up to 3 EGMs per day per arrhythmia type were prioritized for review based on ventricular rate and episode duration, with rules specific to each arrhythmia type: atrial fibrillation (AF), tachycardia, bradycardia, and pause. The resulting reduction in EGM review burden and TP days (patient-days with at least 1 TP EGM), as well as any diagnostic delay from the first transmitted TP, were calculated relative to reviewing all transmitted EGMs.

Results

In this population and transmission period, at least one AF, tachycardia, bradycardia, and pause EGM was transmitted by 424, 343, 190, and 325 unique devices, respectively, with a total of 35,723, 12,239, 19,752, and 28,002 EGMs, and a total of 6,163, 1,572, 1,438, and 646 TP days. For these patients with ≥1 EGM, the median [IQR] EGM transmission rate was 2.6 [0.7, 11.6], 1.1 [0.4, 4.7], 2.1 [0.6, 10.7], and 3.4 [0.6, 29.9] EGMs/patient/month, respectively. The optimal EGM selection strategy reduced this EGM review burden by 43%, 67%, 76%, and 50%, while only missing 3.4%, 2.2%, 0.3%, and 0.2% of TP days, respectively. Ultimately, 97%, 99%, 99%, and 99% of devices with a TP AF, tachycardia, bradycardia, or pause EGM exhibited no diagnostic delay vs. reviewing all transmitted EGMs.

Conclusion

EGM prioritization rules for selecting up to 3 episodes/day significantly reduced EGM burden across all patients, not just "frequent fliers," with no delay-to-diagnosis in &gt;97% of patients who exhibited a true arrhythmia. Implementing these rules on the patient care network may improve clinical workflow and ICM patient management. Abstract Figure.

Outcome of the elective or online RF ablation of typical atrial flutter

INTRODUCTION

Radiofrequency ablation of the cavotricuspid isthmus is currently the first-choice treatment of typical atrial flutter and usually it is performed electively. The purpose of this study was to see whether performing on-line ablation has similar clinical results compared to the conventional strategy.

METHODS

Consecutive patients (465) who underwent ablation of the cavotricuspid isthmus for typical AFL at our electrophysiology laboratory in the 2008-2017 decade were studied. We evaluated the acute and long-term clinical outcomes of those who were treated electively (337) compared to those who had online ablation (128), that is within 24 hours of presenting to the Cardiology department. In patients treated on an emergency basis, a transoesophageal echocardiogram was performed to rule atrial thrombi when needed.

RESULTS

No significant intraprocedural difference was observed between the 2 patient groups, with comparable acute electrophysiological success (99% vs 98%) and serious complications. Even at the subsequent 4-year follow-up, there were no significant differences in the recurrence of typical AFL, onset of AF and other clinical events.

CONCLUSIONS

Online ablation of typical atrial flutter performed at the time of the clinical presentation of the arrhythmia, was shown to be comparable in terms of procedural safety and clinical efficacy in the short and long term compared to an elective ablation strategy.

853Could baseline electrical parameters be a marker of arrhythmia occurrence and poorer prognosis in implantable cardioverter defibrillator patients?

Funding Acknowledgements

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Background/Introduction: Parameters routinely measured during cardiac devices implantation also depend on bioelectrical properties of the myocardial tissue.

Purpose

To explore the potential association of electrical parameters with clinical outcomes in implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillators (CRT-D) recipients.

Methods

In the framework of the Home Monitoring Expert Alliance, baseline electrical parameters for all implanted leads were compared by occurrence of all-cause mortality, adjudicated ventricular arrhythmia (VA) and atrial high rate episode lasting ≥7 days (7day-AHRE).

Results

In a cohort of 2,976 patients (58.1% ICD) with a median follow-up of 25 months, events rates were 3.1/100 patient-years for all-cause mortality,  18.1/100 patient-years for VA and 8.9/100 patient-years for 7day-AHRE.

At univariate analysis baseline shock impedance was consistently lower in groups with events than in those without, with a 40 Ohm cut-off  better identifying patients at high risk, but at multivariable analysis the adjusted-hazard ratios (HRs) lost statistical significance for any endpoint.

Baseline atrial sensing amplitude during sinus rhythm was lower in patients with 7-day AHRE as compared to those without (2.40 [IQ: 1.62-3.71] Vs 3.50 [IQ: 2.35-4.66] mV, p &lt; 0.01). The adjusted-HR for 7-day AHRE in patients with atrial sensing &gt;1.5 mV versus those with values ≤1.5 mV was 0.44 (95% CI:0.27-0.72), p = 0.001.

Conclusion

Despite in patients with events a lower baseline shock impedance was observed at univariate analysis, the association lost statistical significance at multivariable analysis. Conversely, low sinus rhythm atrial sensing (≤1.5 mV) measured with standard transvenous leads could identify subjects at high risk of long-lasting atrial arrhythmia.

Abstract Figure. AHRE occurrence by atrial sensing

Atrial signal amplitude predicts atrial high-rate episodes in implantable cardioverter defibrillator patients: Insights from a large database of remote monitoring transmissions

BACKGROUND

Parameters measured during implantable cardioverter defibrillator (ICD) implant also depend on bioelectrical properties of the myocardium. We aimed to explore their potential association with clinical outcomes in patients with single/dual-chamber ICD and cardiac resynchronization therapy defibrillator (CRT-D).

METHODS

In the framework of the Home Monitoring Expert Alliance, baseline electrical parameters for all implanted leads were compared by the occurrence of all-cause mortality, adjudicated ventricular arrhythmia (VA), and atrial high-rate episode lasting ≥24 hours (24 h AHRE).

RESULTS

In a cohort of 2976 patients (58.1% ICD) with a median follow-up of 25 months, event rates were 3.1/100 patient-years for all-cause mortality, 18.1/100 patient-years for VA, and 9.3/100 patient-years for 24 h AHRE. At univariate analysis, baseline shock impedance was consistently lower in groups with events than without, with a 40 Ω cutoff that better identified high-risk patients. However, at multivariable analysis, the adjusted-hazard ratios (HRs) lost statistical significance for any endpoint. Baseline atrial sensing amplitude during sinus rhythm was lower in patients with 24 h AHRE than in those without (2.45 [IQR: 1.65-3.85] vs 3.51 [IQR: 2.37-4.67] mV, P < .01). The adjusted HR for 24 h AHRE in patients with atrial sensing >1.5 mV vs those with values ≤1.5 mV was 0.52 (95% CI: 0.33-0.83), P = .006.

CONCLUSIONS

Although lower baseline shock impedance was observed in patients with events, the association lost statistical significance at multivariable analysis. Conversely, low sinus rhythm atrial sensing (≤1.5 mV) measured with standard transvenous leads could identify subjects at high risk of atrial arrhythmia.

P5238Rate, cause and costs of Heart Failure hospitalizations following ICD/CRT-D replacement: preliminary data from an Italian multicenter registry

Background

Heart failure hospitalizations (HFHs) likely represent the main health care expenditure also in implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-D) recipients yet the event rate of HFH and the associated costs after device replacement or upgrade are unknown.

Purpose

To report HFH rates and associated costs within 12 months following ICD/CRT-D device replacement or upgrade procedure from ICD to CRT-D.

Methods

The DEtect long-term COmplications after icD rEplacement (DECODE) was a prospective, single-arm, multicenter cohort study exploring complications in ICD/CRT-D recipients undergoing device replacement or upgrade from ICD to CRT-D. All clinical and survival data of these patients at 12-month follow-up were prospectively analyzed. For each adjudicated HFH, the admission and discharge date were recorded, and ICD-9-CM diagnoses and procedure codes were obtained. The estimated reimbursement for each hospitalization was calculated according to the 2012 Italian national reimbursement rates.

Results

Between 2013 and 2015, 983 patients (mean age = 71 years, mean LVEF = 35%, NYHA class I/II = 75.6%) were enrolled: 900 (91.6%) patients underwent device replacement (446 ICD/454 CRT-D) and 83 (8.4%) upgrade from ICD to CRT-D. After 12 months, 66 (6.7%) patients died, 40 (60.6%) for cardiovascular reasons. Fifty-five (5.6%) patients experienced at least 1 HFH. Overall, 91 HFH (9.6% event rate 95% CI, 7.7–11.7) occurred. Among the variables tested at univariate analysis, only LVEF ≤35%, AF history and renal disease were confirmed as HFH predictors at multivariate analysis. HFH rate was significantly higher following upgrade procedures and occurrence of HFH was associated with an eleven-fold increased mortality risk (95% CI: 5.9 to 20.5; p<0.0001). The cumulative cost associated with HFHs incurred over the 12 months follow-up was 515305 €. The mean cost per HFH was 5662±9497 € [ranging from 3144 € to 64479 €] while the mean cost per patient with events was 9369±12687 €.

Conclusion

Underlying cardiac disease and renal failure are the main drivers of HFH and mortality, and of higher healthcare expenditures in ICD/CRT-D recipients following device replacement or upgrade. Accurate clinical assessment is needed to support the decision-maker at the time of ICD replacement to take an appropriate clinical and economic sustainable decision.

Acknowledgement/Funding

None

Are Atrial High-Rate Episodes Associated With Increased Risk of Ventricular Arrhythmias and Mortality?

OBJECTIVES

This study evaluated the temporal association between atrial high-rate episodes (AHREs) and sustained ventricular arrhythmias (VAs) in a remotely monitored cohort with implantable cardioverter-defibrillators (ICD) with and/or without cardiac resynchronization therapy with a defibrillator (CRT-D).

BACKGROUND

Clinical relevance of AHREs in terms of VA rate and survival has not been outlined yet.

METHODS

This study analyzed data of patients with ICDs and CRT-Ds from the nationwide Home Monitoring Expert Alliance network. The cohort included 2,435 patients with a median follow-up of 25 months (interquartile range: 13 to 42 months) and age 70 years (range 61 to 77 years); 19.7% were women, 51.4% had coronary artery disease, and 45.2% had a CRT-D. There were 3,410 appropriate VA episodes; 498 (14.6%) were preceded by AHREs within 48 h; in 85.5% of this group, AHREs were still ongoing at episode onset.

RESULTS

In a longitudinal analysis, the odds ratios (ORs) of experiencing any VA in a 30-day interval with AHREs versus intervals without AHREs were 2.35 (95% confidence interval [CI]: 1.86 to 2.97; p < 0.001) for ventricular tachycardia (VT), 3.06 (95% CI: 2.35 to 3.99; p < 0.001) for fast VT, 1.84 (95% CI: 1.36 to 2.48; p < 0.001) for self-extinguishing ventricular fibrillation (VF), and 2.31 (95% CI: 1.17 to 4.57; p = 0.01) for VF. ORs decreased with increasing AHRE burden. Patients with AHREs 48 h before VAs were more likely to experience VA recurrences (adjusted hazard ratio [HR]: 1.78; 95% CI: 1.41 to 2.24; p < 0.001) and had higher overall mortality (HR: 2.67; 95% CI: 1.68 to 4.23; p < 0.001).

CONCLUSIONS

AHREs were not uncommon 48 h before VAs, which tended to be distributed around intervals with AHREs. Temporal connection between AHREs and VAs was a marker of increased risk of VA recurrence and a poorer prognosis.

Real-life outcome of implantable cardioverter-defibrillator and cardiac resynchronization defibrillator replacement/upgrade in a contemporary population: observations from the multicentre DECODE registry

Aims

The benefit of prolonged implantable cardioverter-defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) therapy following device replacement is hindered by clinical and procedure-related adverse events (AEs). Adverse events rate is highest in more complex devices and at upgrades, as per the REPLACE registry experience, but is changing owing to the improvement in device technology and medical care. We aimed at understanding the extent and type of AEs in a contemporary Italian population.

Methods and results

Detect long-term complications after ICD replacement (DECODE) was a prospective, single-arm, multicentre cohort study aimed at estimating medium- to long-term AEs in a large population of patients undergoing ICD/cardiac resynchronization defibrillator replacement/upgrade from 2013 to 2015. We prospectively analysed all clinical and device-related AEs at 12-month follow-up (FU) of 983 consecutive patients (median age 71 years, 76% male, 55% ischaemic, 47% CRT-D) followed for 353 ± 49 days. Seven percent of the patients died (60.6% for cardiovascular reasons), whereas 104 AEs occurred; 43 (4.4%) patients needed at least one surgical action to treat the AE. Adverse events rates were 3.3/100 years lead-related, 3.4/100 years bleedings, and 1.6/100 years infective. The primary endpoint was predicted by hospitalization in the month prior to the procedure [hazard ratio (HR) = 2.23, 1.16–4.29; 0.0169] and by upgrade (HR = 1.75, 1.02–2.99, 0.0441). One hundred and twelve (11.4%) patients met the combined endpoint of death from any cause, cardiac implantable electronic device (CIED)-related infection, and surgical action/hospitalization required to treat the AE. Hospitalization within 30 days prior to the procedure (HR = 2.07, 1.13–3.81; 0.0199), anticoagulation (HR = 1.97, 1.26–3.07; 0.003), and ischaemic cardiomyopathy (HR = 1.67, 95% confidence interval 1.06–2.63; P = 0.0276) were associated with the combined endpoint during FU.

Conclusions

Adverse events following CIED replacement/upgrade are lower than previously reported, possibly owing to improved patients care. Hospitalization in the month prior to the procedure, upgrade, and clinical profile (anticoagulation, ischaemic cardiomyopathy) hint to increased risk, suggesting an individualized planning of the procedure to minimize overall AEs.

Clinical trial registration

URL: http://clinicaltrials.gov/ Identifier: NCT02076789.

Long-term outcomes after prophylactic ICD and CRT-D implantation in nonischemic patients: Analysis from a nationwide database of daily remote-monitoring transmissions

INTRODUCTION

Clinical trials did not provide conclusive evidence concerning the benefit of prophylactic implantable cardioverter-defibrillators (ICDs) in patients with severe nonischemic cardiomyopathy (NICM). We aimed to compare incidence of appropriate sustained ventricular arrhythmia (SVA) and device therapy in ischemic cardiomyopathy (ICM) vs NICM ICD and/or cardiac resynchronization therapy (CRT-D) patients.

METHODS AND RESULTS

We analyzed remote-monitoring data from devices of the Home Monitoring Expert Alliance network. SVA recordings were adjudicated by three independent electrophysiologists. Our cohort included 1,946 patients who received either an ICD (55%) or a CRT-D (45%) for primary prevention of sudden cardiac death. Median (interquartile range) age was 70 (62-77) years, 81% were male, and 52% were in the ICM group. Patients were remotely monitored for a maximum follow-up of 5 years. The 5-year product-limit estimate of SVA incidence in patients with an ICD was 47.3% (95% confidence interval [CI], 41.0%-53.9%) in the ICM group and 44.7% (36.9%-53.3%) in the NICM group. In patients with a CRT-D, SVA incidence was 45.7% (37.3%-55.0%) in ICM patients and 49.2% (40.4%-58.7%) in NICM patients. The adjusted hazard ratio for SVA in the ICM vs NICM group was 0.96 (95% CI: 0.70-1.30, P = .77) in ICD patients and 0.85 (95% CI: 0.61-1.18, P = .34) in CRT-D patients. SVAs triggered appropriate device therapies with similar incidence in all groups.

CONCLUSION

In a large cohort of remotely monitored ICD and CRT-D recipients, SVA incidence did not significantly differ in ICM and NICM patients.

Seasonal trend of ventricular arrhythmias in a nationwide remote monitoring database of implantable defibrillators and cardiac resynchronization devices

BACKGROUND

The occurrence of sustained ventricular arrhythmias (SVA) may be influenced by environmental factors. We aimed to investigate annual periodic trends of SVA from the intracardiac electrograms (IEGMs) stored in the implantable defibrillators (ICDs) or cardiac resynchronization therapy (CRT-D) recipients.

METHODS

Data from the Home Monitoring Expert Alliance project, a pooled repository of remote monitoring transmissions were analyzed. All IEGMs stored were independently adjudicated by three cardiac electrophysiologists. Periodicity of SVA was evaluated with Generalized Estimating Equations (GEE) models, including periodic terms depending on months in a year.

RESULTS

A total of 2936 ICD/CRT-D patients (median age 70 years, 79.6% male) were followed for a median period of 25[13-44] months. Most prevalent structural heart diseases were ischemic (50.8%) and idiopathic dilated (30.6%) cardiomyopathies. Overall, 942 (32.1%) patients experienced a total of 4824 SVA. At GEE analysis, we found a significant periodic component (p = 0.048) when considering both shocked and non-shocked episodes. SVA less frequently occurred in Junes and Julies (3.7 × 1000 patient-month). No evidence of significant periodicity was collected in the subgroup of ischemic patients.

CONCLUSIONS

In this RM-based cohort of ICD/CRT-T patients, we observed an annual periodicity of SVA occurrence, with a lower incidence in summer months.

Impact of pacemaker longevity on expected device replacement rates: Results from computer simulations based on a multicenter registry (ESSENTIAL)

BACKGROUND

The rate of device replacement in pacemaker recipients has not been investigated in detail.

HYPOTHESIS

Current pacemakers with automatic management of atrial and ventricular pacing output provide sufficient longevity to minimize replacement rate.

METHODS

We considered a cohort of 542 pacemaker patients (age 78 ± 9 years, 60% male, 71% de-novo implants) and combined 1-month projected device longevity with survival data and late complication rate in a 3-state Markov model tested in several Monte Carlo computer simulations. Predetermined subgroups were: age < or ≥ 70; gender; primary indication to cardiac pacing.

RESULTS

At the 1-month follow-up the reported projected device longevity was 153 ± 45 months. With these values the proportion of patients expected to undergo a device replacement due to battery depletion was higher in patients aged <70 (49.9%, range 32.1%-61.9%) than in age ≥70 (24.5%, range 19.9%-28.8%); in women (39.9%, range 30.8%-48.1%) than in men (32.0%, range 24.7%-37.5%); in sinus node dysfunction (41.5%, range 30.2%-53.0%) than in atrio-ventricular block (33.5%, range 27.1-38.8%) or atrial fibrillation with bradycardia (27.9%, range 18.5%-37.0%). The expected replacement rate was inversely related to the assumed device longevity and depended on age class: a 50% increase in battery longevity implied a 5% reduction of replacement rates in patients aged ≥80.

CONCLUSIONS

With current device technology 1/4 of pacemaker recipients aged ≥70 are expected to receive a second device in their life. Replacement rate depends on age, gender, and primary indication owing to differences in patients' survival expectancy. Additional improvements in device service time may modestly impact expected replacement rates especially in patients ≥80 years.

Does the CHA2DS2-VASc score reliably predict atrial arrhythmias? Analysis of a nationwide database of remote monitoring data transmitted daily from cardiac implantable electronic devices

BACKGROUND

CHA₂DS₂-VASc is a validated score for predicting stroke in patients with atrial fibrillation (AF).

OBJECTIVE

The purpose of this study was to assess whether the CHA₂DS₂-VASc score can predict new-onset AF in a cohort of patients with a cardiac implantable electronic device (CIED) followed with remote monitoring.

METHODS

Using the database of the Home Monitoring Expert Alliance project, we selected 2410 patients with no documented AF who had received a CIED with diagnostics on atrial high rate episodes (AHREs). The primary endpoint was time to first day with cumulative AHRE burden ≥15 minutes, 5 hours, 24 hours, and ≥7 consecutive days.

RESULTS

During a median duration of 24.1(11.5-42.9) months, the incidence of AHRE increased with increasing CHA₂DS₂-VASc. At 6 years, occurrence of ≥15-minute AHRE was 80.2% (CHA₂DS₂-VASc ≤1) vs 93.7% (CHA₂DS₂-VASc ≥5), whereas ≥5-hour AHRE incidence was 68.4% (CHA₂DS₂-VASc ≤1) vs 92.5% (CHA₂DS₂-VASc ≥5). Occurrence of ≥24-hour and ≥7-day AHREs also increased with increasing CHA₂DS₂-VASc: 9.1% and 3.9% (CHA₂DS₂-VASc ≤1) vs 40.4% and 28.7% (CHA₂DS₂-VASc ≥5), respectively. Adjusted hazard ratio for unitary CHA₂DS₂-VASc increase ranged from 1.09 (confidence interval 1.04-1.14; P <.001) with AHRE burden ≥15 minutes to 1.26 (confidence interval 1.11-1.42; P <.001) with AHRE burden ≥7 days. At receiver operating curve analysis, CHA₂DS₂-VASc ≥2 was estimated to predict persistent forms of AHREs with 95.8% sensitivity but 11.7% specificity at 3 years. CHA₂DS₂-VASc ≥5 had 77.0% specificity but 34.6% sensitivity.

CONCLUSION

In a CIED population with no previous diagnosis of clinical AF, AHRE incidence increased with increasing CHA₂DS₂-VASc score. The association was stronger with longer AHREs, but the accuracy of CHA₂DS₂-VASc as AHRE predictor was moderate.

Implantation of single lead cardioverter defibrillator with floating atrial sensing dipole in a pregnant patient without using fluoroscopy

In this case report, we look into the implant procedure of a single-lead ICD with floating atrial sensing dipole in a pregnant woman, without using fluoroscopy. This system benefits the proper positioning of the lead. This is possible thanks to the simultaneous display of both the atrial and ventricular dipoles on the electro-anatomical mapping system. This technique may be taken into consideration for the few rare cases where fluoroscopy is absolutely contraindicated.

Long-Term Results After Single and Multiple Procedures of Ablation of Ventricular Tachycardia

INTRODUCTION

The aim of this study was to assess long-term results after single and multiple procedures of catheter ablation of ventricular tachycardia (VT). While it is generally accepted that multiple procedures are sometimes necessary in order to achieve long-term clinical success, the literature on this issue displays wide variability.

METHODS

We assessed the outcome of 160 consecutive patients who underwent 214 ablation procedures in the period 2008 to May 2015: 93 had overt structural heart disease (SHD) (previous myocardial infarction in 74 cases) and 67 had no SHD.

RESULTS

After the first procedure, the 1-year actuarial recurrence rates were 25% in patients with SHD and 5% in those without. However, recurrences increased progressively after the first year, reaching 46% and 35%, respectively, at 5 years. Overall, VT recurred in 35/93 (38%) patients with SHD and 22/67 (33%) patients without. Redo (1 to 4) procedures were performed in 28 (20%) patients with SHD and 18 (27%) patients without. After the last procedure, the 1-year actuarial recurrence rates were 5% in patients with SHD and 7% in those without, and the corresponding rates at 5 years were 23% and 7%. During follow-up, 21 patients died (all in the SHD group): no death was related to VT recurrence.

CONCLUSIONS

During long-term follow-up, VT frequently recurs after the first procedure, both in patients with SHD and in those without; multiple procedures are needed in order to increase the success rate.

Left Ventricular Reverse Remodeling Elicited by a Quadripolar Lead: Results from the Multicenter Per4mer Study

BACKGROUND

To understand the impact of a quadripolar left ventricular (LV) lead on reverse remodeling and phrenic nerve stimulation (PNS) in congestive heart failure patients treated by cardiac resynchronization therapy at 8-month follow-up (FU).

METHODS

One hundred and fifty-eight patients received an LV Medtronic Performa lead (Medtronic Inc., Minneapolis, MN, USA) and were reevaluated at FU by echocardiography and measurement of electrical parameters.

RESULTS

A targeted LV lead placement was achieved in 140 (89%) patients. Super responders and responders were 76 (50%) and 26 (18%), respectively, at FU; seven (4%) died and 13 (8%) were hospitalized for any cause. Nonischemic etiology was the only independent predictor of reverse remodeling. The configurations available only with the Performa leads reduced PNS occurrence at 8 V@0.4 ms from 43 (27%) to 14 (9%) of patients at implantation, and from 44 (28%) to 19 (12%) at last FU, compared to configurations available with bipolar leads. Patients with detectable PNS had >10/16 pacing configurations with a PNS safety margin >2 V both at implantation and at FU. During FU 16 (10%) patients had an adverse event possibly related to the lead or to modification of the underlying heart disease but 99% of these events were fixed by reprogramming of the pacing vector.

CONCLUSIONS

Performa Lead enables an increased capability to achieve a targeted lead positioning in the broad clinical scenario of large- and small-volume implanting centers, with a relevant impact on the occurrence of reverse remodeling compared to literature data. The enhanced management of PNS resulted in a dislodgement rate of only 1%.

Atrial sensor, remote monitoring and new anticoagulant drugs: Identification and treatment of a patient with unknown and asymptomatic atrial flutter

This case report describes how new tools and technologies can drive a different approach in the management of arrhythmic patients. An unknown and asymptomatic atrial flutter was detected by the atrial sensor mounted in a single lead implantable cardioverter defibrillator. Moreover daily remote monitoring of the device allowed early notification and prompt clinical reaction. Anticoagulant therapy onset, radiofrequency ablation and the following anticoagulant therapy removal were driven by the device data transmissions.

Assessment of a standardized algorithm for cardiac pacing in older patients affected by severe unpredictable reflex syncopes

AIMS

Opinions differ regarding the effectiveness of cardiac pacing in patients affected by reflex syncope. We assessed a standardized guideline-based algorithm in different forms of reflex syncope.

METHODS AND RESULTS

In this prospective, multi-centre, observational study, patients aged >40 years, affected by severe unpredictable recurrent reflex syncopes, underwent carotid sinus massage (CSM), followed by tilt testing (TT) if CSM was negative, followed by implantation of an implantable loop recorder (ILR) if TT was negative. Those who had an asystolic response to one of these tests received a dual-chamber pacemaker.

POPULATION

253 patients, mean age 70 ± 12 years, median 4 (3-6) syncopes, 89% without or with short prodromes. Of these patients, 120 (47%) received a pacemaker and 106 were followed up for a mean of 13 ± 7 months: syncope recurred in 10 (9%). The recurrence rate was similar in 61 CSM+ (11%), 30 TT+ (7%), and 15 ILR+ (7%) patients. The actuarial total syncope recurrence rate was 9% (95% confidence interval (CI), 6-12) at 1 year and 15% (95% CI, 10-20) at 2 years and was significantly lower than that observed in the group of 124 patients with non-diagnostic tests who had received an ILR: i.e. 22% (95% CI, 18-26) at 1 year and 37% (95% CI, 30-43) at 2 years (P = 0.004).

CONCLUSION

About half of older patients with severe recurrent syncopes without prodromes have an asystolic reflex for which cardiac pacing goes along with a low recurrence rate. The study supports the clinical utility of the algorithm for the selection of candidates to cardiac pacing in everyday clinical practice.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique identifier: NCT01509534.

E/A ratio before cardiac resynchronization therapy predicts left ventricle reverse remodeling

AIM

Clinical experience shows that about 2 out of 3 patients with indication to resynchronization therapy (CRT) may have improvements in NYHA class, echocardiographic parameters and survival. However, specific clinical or technical parameters that identify responder patients have not yet been found. Aim of the present study was to assess the efficacy of CRT and to estimate the predictive value of specific echocardiographic parameters.

METHODS

All patients who underwent CRT from January 2004 till June 2009, at our Institution, were clinically examined and evaluated by echo and ECG before implant. Between January and February 2010, among a population of 55 patients (41 M, 14F, mean age 66.3±5.9), 42 patients (33 M) were considered in the final multiparametric analysis. Of the 13 excluded patients, 6 died, 2 underwent cardiac transplantation and 5 were lost to follow-up. Basal characteristics of the study population were: ischemic etiology in 15 out of 42 patients, back-up defibrillation in 39 patients. The mean follow-up period was 26.2±13.0 months. Patients had been classified as CRT responders if they showed an inverse left ventricle (LV) remodeling, defined as a 10% reduction of end-diastolic diameter (LVEDD) compared to the basal measure.

RESULTS

Echo parameters significantly improved after CRT: LVEDD was significantly (P<0.05) reduced (basal vs. CRT: 76±7 mm vs. 64±10 mm, P=0.00004); basal ejection fraction (EF) was 21±5% vs. 37±14% after CRT (P=0.00001); mitral regurgitation (MR) (grading from 1 to 4) was 2.8±0.6 vs. 2.3±0.9 (P=0.00998); QRS duration was 157±25 ms vs. 135±23 ms (P=0.00036), and NYHA class 2.6±0.5 vs. 2.1±0.4, P=0.00006). Only a positive trend of the E/A ratio was observed (P=0.088). Among 42 patients, 24 (57%) had an inverse LV remodeling and were defined as CRT responders. By comparing responder with no-responder patients, the basal values of echo parameters like EF, LVEDD, MR, QRS, NYHA class were similar in the two groups; while E/A was statistically different between the two groups (P=0.02), being less severe in responder patients.

CONCLUSION

Our experience confirms that about 2 out of 3 patients are responder to CRT and their clinical improvements remain stable in a long term follow-up. Patients with a less severe E/A ratio are more likely to improve their clinical condition as shown by the reverse remodeling measured through the LVEDD.

Ablation of typical atrial flutter: a prospective study of cooled-tip versus 8-mm-tip catheters

AIM

Both ablation catheters with irrigated system and 8mm tip-catheters have shown to be more effective for typical atrial flutter radiofrequency (RF) ablation when compared to conventional 4 mm tip catheter. The purpose of this prospective study was to compare the efficiency of radiofrequency catheter ablation (RFA) of the cavotricuspid isthmus using a new type of open irrigation-tip catheter versus 8 mm tip-catheters to eliminate atrial flutter (AFL).

METHODS

Sixty consecutive patients, matched for age, presence of cardiopathy, atrial dimensions and comorbidity, underwent RF ablation of cavotricuspid isthmus (CTI) for the treatment of typical atrial flutter, using an open irrigated tip catheter - Surround Flow™ - (N.=30) or an 8-mm-tip catheter (N.=30). The RF pulses were applied point-by-point for 30 seconds, with power limited at 35 w for the irrigated catheter and by temperature control (60/70 w) for the 8-mm catheter.

RESULTS

The CTI block was successfully performed in 100% of cases. There was no significant difference with regard to ablation parameters, such as total time of RF ablation (608±324 vs. 556±244 s, P=0.79), number of RF applications (12±8 vs. 10±5, P=0.56), total procedure duration (86.4±23.6 vs. 78.1±22.5 min, P=0.58) and time of fluoroscopy (12±6 vs. 14±6 min, P=0.25) and periprocedural complications (1 groin hematoma in the 8 mm group). During follow-up of 11.6 months on average, one patient in the 8 mm group had recurrence of typical atrial flutter.

CONCLUSION

Efficacy and safety of CTI ablation was comparable between both techniques (open irrigated catheter and 8mm tip catheter). The ablation parameters were comparable and homogeneous between the two groups.

Implantable cardioverter defibrillator system with floating atrial sensing dipole: a single-center experience

BACKGROUND

The concept of a single-lead dual-chamber implantable cardioverter defibrillator (ICD) with floating sensing atrial dipole has been proven safe and functional. We report a single-center experience with this ICD system; the major focus of the work is on the recorded atrial activation and its stability on a medium term follow-up.

METHODS

Thirteen patients received a DX ICD (BIOTRONIK SE & Co, Berlin, Germany) with the Linox Smart S DX(ProMRI) ICD lead; the implantation data were reported. Daily P- and R-wave sensing amplitude was collected and followed up during 200 days; their coefficient of variance (CV) was calculated. In addition, all the atrial and ventricular high-rate episodes were analyzed.

RESULTS

The total x-ray exposure time was 3.9 ± 1.8 minutes. The overall mean sensing was 4.2 ± 1.9 mV for P wave and 12.9 ± 4.5 mV for R wave. The CV was significantly higher for the P-wave amplitude than for the R-wave one (0.25 ± 0.11 vs 0.08 ± 0.06; P < 0.001). A total of 27 high ventricular rate episodes were recorded and correctly discriminated by the device. Fifty-six high atrial rate episodes were recorded, 49 were true arrhythmic events.

CONCLUSIONS

The single-lead ICD system with floating atrial dipole provides reliable atrial sensing amplitude over time. The physician, without the implantation of an additional lead, has the atrial information that may be used for the discrimination of supraventricular tachyarrhythmia/ventricular tachycardia, for the early detection of atrial fibrillation episodes and for the evaluation of changes in the patient's heart status.

Radiofrequency catheter ablation of atrioventricular nodal re-entry tachycardia: selective approach to the slow pathway via the cephalic veins

Inferior venous access to the right heart is not possible in some patients due to vena caval obstruction. Here we describe a case of a patient with atrioventricular nodal re-entry tachycardia where radiofrequency ablation from the inferior vena cava was impossible because of the presence of important stenosis of the distal part of the vein. Catheter ablation of the slow pathway could be performed successfully using a superior approach via the cephalic veins.

Characterization of myocardial hypertrophy in prehypertensive spontaneously hypertensive rats: interaction between adrenergic and nitrosative pathways

OBJECTIVE AND METHODS

Left ventricular hypertrophy in human and experimental hypertension is not always associated with pressure overload but seems to precede an increase in blood pressure. In this study, performed in male 5-week-old prehypertensive spontaneously hypertensive rats (SHR; n = 65) and age-matched Wistar-Kyoto rats (n = 56), the relationship between myocardial structure and activation of the adrenergic and nitric oxide systems was evaluated.

RESULTS

Body weight, blood pressure and heart rate were similar in both groups. A higher left ventricle/body weight ratio was found in SHR, as a result of greater mononuclear (+47%) and binuclear (+43%) myocyte volumes, without changes in interstitial collagen. Both adrenergic and nitric oxide pathways were activated in SHR, as expressed by higher myocardial norepinephrine content, tyrosine hydroxylase activity, myocardial nitric oxide synthase 3 expression and protein nitration, indicating greater peroxynitrite (ONOO) generation from nitric oxide and superoxide. No difference was measured in nitric oxide synthase 1 expression, whereas nitric oxide synthase 2 was undetectable. A positive correlation between myocardial tyrosine hydroxylase activity and protein nitration was observed in SHR (r = 0.328; P < 0.01). Early treatment with a superoxide dismutase mimetic, 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl, from the third to the fifth week of age, reduced ONOO generation, protein nitration and sympathetic activation in SHR without changes in myocardial structure.

CONCLUSION

In prehypertensive SHR, left ventricular hypertrophy is associated with adrenergic and nitrosative imbalance. Early superoxide dismutase mimetic treatment in SHR effectively reduces higher myocardial ONOO generation, sympathetic activation, and heart rate without affecting the development of myocardial hypertrophy.

Standardized-care pathway vs. usual management of syncope patients presenting as emergencies at general hospitals

AIMS

The study hypothesis was that a decision-making approach improves diagnostic yield and reduces resource consumption for patients with syncope who present as emergencies at general hospitals.

METHODS AND RESULTS

This was a prospective, controlled, multi-centre study. Patients referred from 5 November to 7 December 2001 were managed according to usual practice, whereas those referred from 4 October to 5 November 2004 were managed according to a standardized-care pathway in strict adherence to the recommendations of the guidelines of the European Society of Cardiology. In order to maximize its application, a decision-making guideline-based software was used and trained core medical personnel were designated-both locally in each hospital and centrally-to verify adherence to the diagnostic pathway and give advice on its correct application. The 'usual-care' group comprised 929 patients and the 'standardized-care' group 745 patients. The baseline characteristics of the two study populations were similar. At the end of the evaluation, the standardized-care group was seen to have a lower hospitalization rate (39 vs. 47%, P=0.001), shorter in-hospital stay (7.2+/-5.7 vs. 8.1+/-5.9 days, P=0.04), and fewer tests performed per patient (median 2.6 vs. 3.4, P=0.001) than the usual-care group. More standardized-care patients had a diagnosis of neurally mediated (65 vs. 46%, P=0.001) and orthostatic syncope (10 vs. 6%, P=0.002), whereas fewer had a diagnosis of pseudo-syncope (6 vs. 13%, P=0.001) or unexplained syncope (5 vs. 20%, P=0.001). The mean cost per patient and the mean cost per diagnosis were 19 and 29% lower in the standardized-care group (P=0.001).

CONCLUSION

A standardized-care pathway significantly improved diagnostic yield and reduced hospital admissions, resource consumption, and overall costs.

[Comparative study of results of catheter ablation in ventricular tachycardia of different etiologies]

BACKGROUND

The aim of this study was to assess long-term results and adverse events in patients with ventricular tachycardia from different etiologies.

METHODS

The recurrence rate of tachycardia, consequent further therapies (other catheter ablation procedures, drug therapy and implantable defibrillator) and clinical events have been assessed in 60 consecutive patients undergoing ventricular tachycardia catheter ablation between January 2000 and December 2004.

RESULTS

During a median follow-up of 20 months (interquartile range 13-36 months), tachycardia recurred in 27 patients (45%) after a median of 3 months (interquartile range 1-12 months). A second procedure was performed in 11 patients; it was successful in 8 patients. Four patients underwent pharmacological therapy which was successful in all cases. Overall, after ablation (> or =1 procedures) and pharmacological therapy, tachycardia was cured in 75% of cases. All the 20 patients without structural heart disease were cured with ablation vs. 62% of patients with heart disease (p = 0.001). Patients with dilated cardiomyopathy reported worst results (33% success, p = 0.03). Recurrences were predicted by acute failure of procedure (p = 0.05), presence of heart disease (p = 0.006) and history of atrial arrhythmias (p = 0.02). On a multivariate analysis, only structural heart disease continued to be an independent predictor of ventricular tachycardia recurrence.

CONCLUSIONS

Catheter ablation of ventricular tachycardia has a high percentage of recurrences in patients with heart disease, whereas is curative in subjects without structural heart disease.