Decongestive treatment adjustments in heart failure patients remotely monitored with a multiparametric implantable defibrillators algorithm.

AIMS: HeartLogic algorithm combines data from multiple implantable defibrillators (ICD)-based sensors to predict impending heart failure (HF) decompensation. A treatment protocol to manage algorithm alerts is not yet known, although decongestive treatment adjustments are the most frequent alert-triggered actions reported in clinical practice. We describe the implementation of HeartLogic for remote monitoring of HF patients, and we evaluate the approach to diuretic dosing and timing of the intervention in patients with device alerts. METHODS: The algorithm was activated in 229 ICD patients at eight centers. The median follow-up was 17 months (25th-75th percentile: 11-24). Remote data reviews and patient phone contacts were undertaken at the time of HeartLogic alerts, to assess the patient's status and to prevent HF worsening. We analyzed alert-triggered augmented HF treatments, consisting of isolated increases in diuretics dosage. RESULTS: We reported 242 alerts (0.8 alerts/patient-year) in 123 patients, 137 (56%) alerts triggered clinical actions to treat HF. The HeartLogic index decreased after the 56 actions consisting of diuretics increase. Specifically, alerts resolved more quickly when the increases in dosing of diuretics were early rather than late: 28 days versus 62 days, p < .001. The need of hospitalization for further treatments to resolve the alert condition was associated with higher HeartLogic index values on the day of the diuretics increase (odds ratio: 1.11, 95% CI: 1.02-1.20, p = .013) and with late interventions (odds ratio: 5.11, 95% CI: 1.09-24.48, p = .041). No complications were reported after drug adjustments. CONCLUSIONS: Decongestive treatment adjustments triggered by alerts seem safe and effective. The early use of decongestive treatment and the use of high doses of diuretics seem to be associated with more favorable outcomes.

Long-term outcome of catheter ablation for atrial fibrillation in patients with severe left atrial enlargement and reduced left ventricular ejection fraction.

AIMS: Data regarding the efficacy of catheter ablation in heart failure patients with severely dilated left atrium and reduced left ventricular ejection fraction (LVEF) are scanty. We sought to assess the efficacy of catheter ablation in patients with reduced LVEF and severe left atrial (LA) enlargement, and to compare it to those patients with preserved left ventricular function and equally dilated left atrium. METHODS AND RESULTS: Three patient groups with paroxysmal or persistent atrial fibrillation (AF) undergoing a first pulmonary vein isolation (PVI) were considered: Group 1 included patients with normal or mildly abnormal LA volume (≤41 mL/m2) and normal LVEF; Group 2 included patients with severe LA enlargement (>48 mL/m2) and normal LVEF; and Group 3 included patients with severe LA enlargement and reduced LVEF. Time to event analysis was used to investigate AF recurrences. The study cohort includes 439 patients; Group 3 had a higher prevalence of cardiovascular risk factors. LA enlargement was associated with a two-fold in risk of AF recurrence, on the contrary only a smaller non-significant increase of 30% was shown with the further addition of LVEF reduction. CONCLUSIONS: The long-term outcome of patients with severe LA dilatation and reduced LVEF is comparable to those with severe LA enlargement but preserved LVEF. Long-term efficacy of PVI is certainly affected by the enlargement of the left atrium, but less so by the addition of a reduced LVEF. CA remains the best strategy for rhythm control both in paroxysmal and persistent AF in this subgroup of patients.

Incidence of Ventricular Arrhythmias and 1-Year Predictors of Mortality in Patients Treated With Implantable Cardioverter-Defibrillator Undergoing Generator Replacement.

Background When implantable cardioverter defibrillator (ICD) battery is depleted most patients undergo generator replacement (GR) even in the absence of persistent ICD indication. The aim of this study was to assess the incidence of ventricular arrhythmias and the overall prognosis of patients with and without persistent ICD indication undergoing GR. Predictors of 1-year mortality were also analyzed. Methods and Results Patients with structural heart disease implanted with primary prevention ICD undergoing GR were included. Patients were stratified based on the presence/absence of persistent ICD indication (left ventricular ejection fraction ≤35% at the time of GR and/or history of appropriate ICD therapies during the first generator's life). The study included 371 patients (82% male, 40% with ischemic heart disease). One third of patients (n=121) no longer met ICD indication at the time of GR. During a median follow-up of 34 months after GR patients without persistent ICD indication showed a significantly lower incidence of appropriate ICD shocks (1.9% versus 16.2%, P<0.001) and ICD therapies. 1-year mortality was also significantly lower in patients without persistent ICD indication (1% versus 8.3%, P=0.009). At multivariable analysis permanent atrial fibrillation, chronic advanced renal impairment, age >80, and persistent ICD indication were found to be significant predictors of 1-year mortality. Conclusions Patients without persistent ICD indication at the time of GR show a low incidence of appropriate ICD therapies after GR. Persistent ICD indication, atrial fibrillation, advanced chronic renal disease, and age >80 are significant predictors of 1-year mortality. Our findings enlighten the need of performing a comprehensive clinical reevaluation of ICD patients at the time of GR.

Prospective evaluation of the multisensor HeartLogic algorithm for heart failure monitoring.

BACKGROUND: The HeartLogic algorithm measures data from multiple implantable cardioverter-defibrillator-based sensors and combines them into a single index. The associated alert has proved to be a sensitive and timely predictor of impending heart failure (HF) decompensation. HYPOTHESIS: We describe a multicenter experience of remote HF management by means of HeartLogic and appraise the value of an alert-based follow-up strategy. METHODS: The alert was activated in 104 patients. All patients were followed up according to a standardized protocol that included remote data reviews and patient phone contacts every month and at the time of alerts. In-office examinations were performed every 6 months or when deemed necessary. RESULTS: During a median follow-up of 13 (10-16) months, the overall number of HF hospitalizations was 16 (rate 0.15 hospitalizations/patient-year) and 100 alerts were reported in 53 patients. Sixty alerts were judged clinically meaningful, and were associated with multiple HF-related conditions. In 48 of the 60 alerts, the clinician was not previously aware of the condition. Of these 48 alerts, 43 triggered clinical actions. The rate of alerts judged nonclinically meaningful was 0.37/patient-year, and the rate of hospitalizations not associated with an alert was 0.05/patient-year. Centers performed remote follow-up assessments of 1113 scheduled monthly transmissions (10.3/patient-year) and 100 alerts (0.93/patient-year). Monthly remote data review allowed to detect 11 (1%) HF events requiring clinical actions (vs 43% actionable alerts, P < .001). CONCLUSIONS: HeartLogic allowed relevant HF-related clinical conditions to be identified remotely and enabled effective clinical actions to be taken; the rates of unexplained alerts and undetected HF events were low. An alert-based management strategy seemed more efficient than a scheduled monthly remote follow-up scheme.

ICD-measured heart sounds and their correlation with echocardiographic indexes of systolic and diastolic function.

BACKGROUND: Novel implantable defibrillators (ICDs) allow first (S1) and third (S3) heart sounds to be measured by means of an embedded accelerometer. ICD-measured S1 and S3 have been shown to significantly correlate with hemodynamic changes in acute animal models. The HeartLogic algorithm (Boston Scientific) measures and combines multiple parameters, including S3 and S1, into a single index to predict impending heart failure decompensation. We evaluated the echocardiographic correlates of ICD-measured S1 and S3 in patients with ICD and cardiac resynchronization therapy ICD. METHODS: The HeartLogic feature was activated in 104 patients. During in-office visits, patients underwent echocardiographic evaluation, and parameters of systolic and diastolic function were correlated with S3 and S1 amplitude measured on the same day as the visit. RESULTS: S3 amplitude inversely correlated with deceleration time of the E-wave (r = -0.32; 95% CI -0.46 - -0.17; P < 0.001), and S1 amplitude significantly correlated with left ventricular ejection fraction (r = 0.17; 95% CI 0.03-0.30; P = 0.021). S3 > 0.9 mG detected a restrictive filling pattern with 85% (95% CI 72%-93%) sensitivity and 82% (95% CI 75%-88%) specificity, while S1 < 1.5 mG detected ejection fraction < 35% with 28% (95% CI 19%-40%) sensitivity and 88% (95% CI 80%-93%) specificity. CONCLUSION: ICD-measured heart sound parameters are significantly correlated with echocardiographic indexes of systolic and diastolic function. This confirms their utility for remote patient monitoring when used as single sensors and their potential relevance when considered in combination with other physiological ICD sensors that evaluate various aspects of heart failure physiology.

Incidence of appropriate anti-tachycardia therapies after elective generator replacement in patient with heart failure initially implanted with a defibrillator for primary prevention: Results of a meta-analysis.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) is an effective therapy to reduce mortality in heart failure. When the ICD generator approaches the end of life, most of the patients undergo an elective generator replacement (GR) even if they no longer meet implantation criteria. Whether arrhythmic risk should be re-assessed at the time of GR is still an open question. The aim of our study was to assess, via a meta-analysis, the occurrence of appropriate ICD therapies after GR in patients stratified based on the presence/absence of ICD indication at the time of GR. METHODS: Via a systematic literature search for primary prevention studies (January 2000-Sectember 2018), 2976 studies were analyzed. 6 studies were lastly included. Patients were categorized into two groups: "with ICD indication" in case of LVEF≤35% at the time of GR and/or appropriate therapies during the first ICD life; "without ICD indication" in case of a LVEF>35% and no previous ICD therapies. Incidences of appropriate ICD therapies were computed as number of events per 100 person-year. RESULT: We included 478 pts. (65%) with and 255 patients (35%) without persistent ICD indication. The incidence of appropriate therapies was 12.3/100-person-year in patients with vs. 3.4 in patients without persistent ICD indication (2.98 fold higher risk of ICD therapies). CONCLUSION: Patients who no longer meet ICD implantation criteria at the time of GR present a significantly lower risk of appropriate ICD therapies after GR. The results of this study underline the importance of an arrhythmic risk re-stratification at the time of GR.

Preliminary experience with the multisensor HeartLogic algorithm for heart failure monitoring: a retrospective case series report.

AIMS: In the Multisensor Chronic Evaluation in Ambulatory Heart Failure Patients study, a novel algorithm for heart failure (HF) monitoring was implemented. The HeartLogic (Boston Scientific) index combines data from multiple implantable cardioverter defibrillator (ICD)-based sensors and has proved to be a sensitive and timely predictor of impending HF decompensation. The remote monitoring of HF patients by means of HeartLogic has never been described in clinical practice. We report post-implantation data collected from sensors, the combined index, and their association with clinical events during follow-up in a group of patients who received a HeartLogic-enabled device in clinical practice. METHODS AND RESULTS: Patients with ICD and cardiac resynchronization therapy ICD were remotely monitored. In December 2017, the HeartLogic feature was activated on the remote monitoring platform, and multiple ICD-based sensor data collected since device implantation were made available: HeartLogic index, heart rate, heart sounds, thoracic impedance, respiration, and activity. Their association with clinical events was retrospectively analysed. Data from 58 patients were analysed. During a mean follow-up of 5 ± 3 months, the HeartLogic index crossed the threshold value (set by default to 16) 24 times (over 24 person-years, 0.99 alerts/patient-year) in 16 patients. HeartLogic alerts preceded five HF hospitalizations and five unplanned in-office visits for HF. Symptoms or signs of HF were also reported at the time of five scheduled visits. The median early warning time and the time spent in alert were longer in the case of hospitalizations than in the case of minor events of clinical deterioration of HF. HeartLogic contributing sensors detected changes in heart sound amplitude (increased third sound and decreased first sound) in all cases of alerts. Patients with HeartLogic alerts during the observation period had higher New York Heart Association class (P = 0.025) and lower ejection fraction (P = 0.016) at the time of activation. CONCLUSIONS: Our retrospective analysis indicates that the HeartLogic algorithm might be useful to detect gradual worsening of HF and to stratify risk of HF decompensation.

The economic impact of battery longevity in implantable cardioverter-defibrillators for cardiac resynchronization therapy: the hospital and healthcare system perspectives.

AIMS: Patients receiving cardiac resynchronization therapy defibrillators (CRT-Ds) are likely to undergo one or more device replacements, mainly for battery depletion. We assessed the economic impact of battery depletion on the overall cost of CRT-D treatment from the perspectives of the healthcare system and the hospital. We also compared devices of different generations and from different manufacturers in terms of therapy cost. METHODS AND RESULTS: We analysed data on 1792 CRT-Ds implanted in 1399 patients in 9 Italian centres. We calculated the replacement probability and the total therapy cost over 6 years, stratified by device generation and manufacturer. Public tariffs from diagnosis-related groups were used together with device prices and hospitalization costs. Generators were from 3 manufacturers: Boston Scientific (667, 37%), Medtronic (973, 54%), and St Jude Medical (152, 9%). The replacement probability at 6 years was 83 and 68% for earlier- and recent-generation devices, respectively. The need for replacement increased total therapy costs by more than 50% over the initial implantation cost for hospitals and by more than 30% for healthcare system. The improved longevity of recent-generation CRT-Ds reduced the therapy cost by ∼6% in both perspectives. Among recent-generation CRT-Ds, the replacement probability of devices from different manufacturers ranged from 12 to 70%. Consequently, the maximum difference in therapy cost between manufacturers was 40% for hospitals and 19% for the healthcare system. CONCLUSIONS: Differences in CRT-D longevity strongly affect the overall therapy cost. While the use of recent-generation devices has reduced the cost, significant differences exist among currently available systems.

Submammary device implantation. Good long-term performance and better patients' satisfaction. A single-center experience.

INTRODUCTION: Device related distress negatively affects the quality of life of cardiac device recipients mostly of women. A submammary approach has been proposed to reduce the physical impact of the implantation. Our aim was to assess the safety of this approach and to evaluate the patients' acceptance of the device. METHODS: We enrolled 42 patients who underwent a submammary device. The primary endpoint was the need for implant revision that was assessed in the study group compared with the overall control group of 72 standard cardiac device recipients (29 females and 43 males)and with the female group (29 females of controls). In the female population (42 women of the submammary group and 29 of controls) patients' acceptance was calculated with the Florida Patient Acceptance Survey (FPAS). RESULTS: The rate of implant revision was similar in the two groups and the revision-free survival was comparable with a median follow-up of about six years (Log rank test p=0.949). Similar results were found when considering only the female population. Patients' acceptance was greater in the submammary group [total FPAS 85 (95%CI 83-86) vs 74.5 (95%CI 70.2-77.3) p<0,001] and a strongly significant superiority of the submammary group was found regarding body image concerns [10 (95%CI 10-10) vs 8 (95%CI 8-8) p<0.001) and device related distress [23 (95%CI 22-23) vs 1 (95%CI 1-1) p<0.001]. CONCLUSIONS: Submammary device implantation is safe and more accepted than standard approach. Our results should encourage cardiologists to suggest this approach to their patients for a better acceptance of the therapy.

Women with nonischemic cardiomyopathy have a favorable prognosis and a better left ventricular remodeling than men after cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) is a well established therapy in heart failure patients who are on optimal medical therapy and have reduced left ventricular ejection fraction (LVEF) and wide QRS complexes. Although women and patients with nonischemic cardiomyopathy are under-represented in CRT trials and registries, there is evidence that these two groups of patients can benefit more from CRT. The aim of our analysis was to investigate the impact of female sex on mortality in a population that included a high percentage of patients (61%) with nonischemic cardiomyopathy. METHODS: We analyzed data on 507 consecutive patients (20% women) who received CRT at two Italian Heart Transplant centers and were followed up for a maximum of 48 months. RESULTS: After multivariate adjustment, women showed a trend toward better survival with regard to all-cause mortality [hazard ratio (HR) 0.32, confidence interval (CI) 0.10-1.04; P = 0.059]. However, this benefit was limited to nonischemic patients with regard to all-cause mortality (HR 0.20, CI 0.05-0.87, P = 0.032) and cardiovascular mortality (HR 0.14, CI 0.02-1.05, P = 0.056). CONCLUSION: Female CRT recipients, at mid-term, have a favorable prognosis than male patients and this benefit appears to be more evident in nonischemic patients. Thus, we strongly believe that the apparent under-utilization of CRT in females is an anomaly that should be corrected.

Longevity of implantable cardioverter-defibrillators for cardiac resynchronization therapy in current clinical practice: an analysis according to influencing factors, device generation, and manufacturer.

AIMS: Device replacement at the time of battery depletion of implantable cardioverter-defibrillators (ICDs) may carry a considerable risk of complications and engenders costs for healthcare systems. Therefore, ICD device longevity is extremely important both from a clinical and economic standpoint. Cardiac resynchronization therapy defibrillators (CRT-D) battery longevity is shorter than ICDs. We determined the rate of replacements for battery depletion and we identified possible determinants of early depletion in a series of patients who had undergone implantation of CRT-D devices. METHODS AND RESULTS: We retrieved data on 1726 consecutive CRT-D systems implanted from January 2008 to March 2010 in nine centres. Five years after a successful CRT-D implantation procedure, 46% of devices were replaced due to battery depletion. The time to device replacement for battery depletion differed considerably among currently available CRT-D systems from different manufacturers, with rates of batteries still in service at 5 years ranging from 52 to 88% (log-rank test, P < 0.001). Left ventricular lead output and unipolar pacing configuration were independent determinants of early depletion [hazard ratio (HR): 1.96; 95% 95% confidence interval (CI): 1.57-2.46; P < 0.001 and HR: 1.58, 95% CI: 1.25-2.01; P < 0.001, respectively]. The implantation of a recent-generation device (HR: 0.57; 95% CI: 0.45-0.72; P < 0.001), the battery chemistry and the CRT-D manufacturer (HR: 0.64; 95% CI: 0.47-0.89; P = 0.008) were additional factors associated with replacement for battery depletion. CONCLUSION: The device longevity at 5 years was 54%. High left ventricular lead output and unipolar pacing configuration were associated with early battery depletion, while recent-generation CRT-Ds displayed better longevity. Significant differences emerged among currently available CRT-D systems from different manufacturers.

Anatomical mapping for atrial fibrillation ablation: a head-to-head comparison of ultrasound-assisted reconstruction versus fast anatomical mapping.

BACKGROUND: Accuracy in left atrial (LA) anatomical reconstruction is crucial to the safe and effective performance of catheter ablation of atrial fibrillation (AF). The aim of this study was to evaluate the accuracy of LA reconstruction performed with intracardiac echocardiography (ICE) as compared to fast anatomical mapping (FAM) both integrated in the CARTO mapping system (Biosense Webster, Diamond Bar, CA, USA). METHODS: A multislice computed tomography (MSCT) was preacquired from 29 patients with AF who underwent catheter ablation and 3D-LA geometry was reconstructed using both ICE and FAM separately. The accuracy of the LA anatomical definition was evaluated by comparing LA volumes, LA and pulmonary vein (PV) diameters obtained using ICE and FAM versus MSCT (gold standard). RESULTS: Anterior-posterior and superior-inferior LA diameters were shorter in ICE versus MSCT (32 ± 10 vs 46 ± 9 mm and 48 ± 7 vs 53 ± 7 mm, P < 0.01) but similar in FAM versus MSCT (45 ± 9 vs 46 ± 9 mm and 52 ± 10 vs 53 ± 7 mm). Latero-septal LA diameter was similar in ICE versus MSCT (63 ± 11 vs 63 ± 9 mm) but larger in FAM versus MSCT (69 ± 9 vs 63 ± 9 mm, P < 0.001). LA volume was lower in ICE versus MSCT (73 ± 30 mL vs 116 ± 45 mL, P < 0.0001) and slightly larger in FAM versus MSCT (132 ± 45 vs 116 ± 45 mL, P = 0.06). PV diameters were similar in FAM versus MSCT but significantly underestimated with ICE. CONCLUSIONS: Overall accuracy in the LA and PV anatomical reconstruction was found to be superior with FAM compared to ICE-guided approach. ICE resulted in a significant underestimate of both LA and PV dimensions, while FAM slightly overestimated LA geometry.

Positive trend in survival to hospital discharge after out-of-hospital cardiac arrest: a quantitative review of the literature.

BACKGROUND: Seven editions of cardiopulmonary resuscitation (CPR) and emergency cardiovascular care guidelines have been published with many changes, in particular, about CPR. OBJECTIVES: The aim of our study was to evaluate the temporal trend of survival to hospital discharge after out-of-hospital cardiac arrest (OHCA) as a possible effect of guidelines changes. METHODS: We searched PubMed for observational studies on 'survival to hospital discharge after OHCA'. Survival to discharge was the primary outcome; prehospital return of spontaneous circulation and survival to hospital admission were our secondary endpoints. All data were analyzed according to the year of inclusion: group 1 before 2000; group 2 between 2000 and 2005; and group 3 after 2005. Mortality rates were compared between groups by means of a group frequency-weighted log-linear model. RESULTS: We considered 38 of 201 studies for a total of 156 301 patients. Survival to hospital discharge rate was 5.0% [95% confidence interval (CI) 4.9-5.2) in group 1; 6.1% (95% CI 5.9-6.4) in group 2; and 9.1% (95% CI 8.9-9.4) in group 3 (P < 0.001). A statistically significant decrease in risk of mortality in group 2 vs. group 1 (risk ratio 0.988, 95% CI 0. 985-0.0.992, P < 0.001) and in group 3 vs. group 2 (risk ratio 0.967, 95% CI 0.964-0.971, P < 0.001) was observed. Similar trends were observed for return of spontaneous circulation and survival to hospital admission. CONCLUSION: Survival to hospital discharge after OHCA has significantly improved. Many aspects may influence survival, but surely, the reduction of time and an early and good quality CPR have positively influenced the outcome.

Tumor necrosis factor-α predicts response to cardiac resynchronization therapy in patients with chronic heart failure.

BACKGROUND: Pro-inflammatory cytokines contribute to the pathophysiology of heart failure (HF) and are up-regulated in affected patients. We investigated whether pro-inflammatory cytokines might predict the response to cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 were assessed in 91 patients before CRT. Response to CRT was defined as a decrease ≥15% in left ventricular end-systolic volume (LVESV) at 6 months. Baseline TNF-α did correlate with LVESV reduction (P=0.001) after CRT. The subject group was divided according to tertiles of TNF-α. From the lower to the upper tertile LVESV (-31±28%, -17±17%, -9±22%) and LV end-diastolic volume (-23±25%, -14±16%, -4±18%) were progressively less reduced after CRT (P<0.001). The proportion of responders to CRT was 70%, 42% and 33%, according to the lower, intermediate and upper tertile of TNF-α distribution (P=0.01). Serious cardiac events (cardiac death, HF hospitalization or urgent heart transplantation) occurred in 63% of patients in the upper tertile vs. 32% and 17% in the intermediate and lower tertiles, respectively, during a median follow-up of 47 months (P<0.001). CONCLUSIONS: Circulating TNF-α predicts the degree of LV reverse remodeling after CRT and may contribute to the early identification of those patients at higher risk of events after device implantation.

A comprehensive electrocardiographic, molecular, and echocardiographic study of Brugada syndrome: validation of the 2013 diagnostic criteria.

BACKGROUND: The debate on the diagnostic value of high intercostal spaces (ICSs) and of the number of diagnostic leads in Brugada syndrome (BrS) has been settled by a recent expert consensus statement. OBJECTIVE: To test the validity, and the underlying anatomy, of the new electrocardiographic (ECG) diagnostic criteria using echocardiographic, molecular, and clinical evidence in 1 clinical study population with BrS. METHODS: We analyzed 114 patients with BrS and with a spontaneous or drug-induced type 1 ECG pattern recorded in 1 or more right precordial leads in fourth, third, and second ICSs. The right ventricular outflow tract (RVOT) was localized by using echocardiography. All probands were screened on the SCN5A gene. RESULTS: The percentage of mutation carriers (MCs) and the event rate were similar regardless of the diagnostic ICS (fourth vs high ICSs: MCs 23% vs 19%; event rate 22% vs 28%) and the number of diagnostic leads (1 vs ≥2: MCs 20% vs 22%; event rate 22% vs 27%). The concordance between RVOT anatomical location and the diagnostic ICSs was 86%. The percentage of the diagnostic ECG pattern recorded was significantly increased by the exploration of the ICSs showing RVOT by echocardiography (echocardiography-guided approach vs conventional approach 100% vs 43%; P < .001). CONCLUSION: The high ICSs are not inferior to the standard fourth ICS for the ECG diagnosis of BrS, and the interindividual variability depends on the anatomical location of the RVOT as assessed by using echocardiography. This approach significantly increases diagnostic sensitivity without decreasing specificity and fully supports the recently published new diagnostic criteria.

Failure of implantable cardioverter-defibrillator leads: a matter of lead size?

BACKGROUND: Small-diameter implantable cardioverter-defibrillator (ICD) Sprint Fidelis and Riata leads have been recalled owing to an increased risk of lead failure, thus arousing the suspicion that lead size might be a critical issue. OBJECTIVE: To compare the incidence of failure of small-diameter (≤8 F) and standard-diameter (>8 F) ICD leads implanted in a single center. METHODS: From January 2003 to December 2010, 190 Sprint Fidelis, 182 Riata/Riata ST, 99 Optim (Riata Optim/Durata), and 419 standard-diameter leads were implanted in our center. RESULTS: During a median follow-up of 33 months, the overall failure rate was 6.3%. Follow-up duration was similar for Sprint Fidelis, Riata, and standard-diameter leads but shorter for the Optim group. The failure rate was significantly higher in Sprint Fidelis leads than in both standard-diameter (4.8%/year vs 0.8%/year; P<.001) and Riata/Riata ST (4.8%/year vs 2.6%/year; P = .03) leads. The incidence of lead failure in Riata/Riata ST leads proved significantly higher than in standard-diameter leads (2.6%/year vs 0.8%/year; P = .001). No cases of lead failure were recorded in the Optim group. On multivariable analyses, small-diameter (hazard ratio [HR] 5.03, 2.53-10.01, P<.001), Sprint Fidelis (HR 6.3, 3.1-13.3, P<.001), or Riata/Riata ST (HR 4.5, 1.9-10.5, P = .001) leads and age<60 years (HR 2.3, 1.3-4.3, P = .005) were found to independently increase the risk of lead failure. CONCLUSIONS: Compared with standard-diameter leads, both Sprint Fidelis and Riata/Riata ST small-diameter ICD leads are at an increased risk of failure, although the incidence of events is significantly lower in the Riata than in the Sprint Fidelis group.

Vagal reflexes following an exercise stress test: a simple clinical tool for gene-specific risk stratification in the long QT syndrome.

OBJECTIVES: The study assessed whether heart rate (HR) reduction following an exercise stress test (ExStrT), an easily quantifiable marker of vagal reflexes, might identify high- and low-risk long QT syndrome (LQTS) type 1 (LQT1) patients. BACKGROUND: Identification of LQTS patients more likely to be symptomatic remains elusive. We have previously shown that depressed baroreflex sensitivity, an established marker of reduced vagal reflexes, predicts low probability of symptoms among LQT1. METHODS: We studied 169 LQTS genotype-positive patients < 50 years of age who performed an ExStrT with the same protocol, on and off ß-blockers including 47 South African LQT1 patients all harboring the KCNQ1-A341V mutation and 122 Italian LQTS patients with impaired (I(Ks)-, 66 LQT1) or normal (I(Ks)+, 50 LQT2 and 6 LQT3) I(Ks) current. RESULTS: Despite similar maximal HR and workload, by the first minute after cessation of exercise the symptomatic patients in both I(Ks)- groups had a greater HR reduction compared with the asymptomatic (19 ± 7 beats/min vs. 13 ± 5 beats/min and 27 ± 10 beats/min vs. 20 ± 8 beats/min, both p = 0.009). By contrast, there was no difference between the I(Ks)+ symptomatic and asymptomatic patients (23 ± 9 beats/min vs. 26 ± 9 beats/min, p = 0.47). LQT1 patients in the upper tertile for HR reduction had a higher risk of being symptomatic (odds ratio: 3.28, 95% confidence interval: 1.3 to 8.3, p = 0.012). CONCLUSIONS: HR reduction following exercise identifies LQT1 patients at high or low arrhythmic risk, independently of ß-blocker therapy, and contributes to risk stratification. Intense exercise training, which potentiates vagal reflexes, should probably be avoided by LQT1 patients.

Pharmacological therapy following catheter ablation of atrial fibrillation.

Catheter ablation has been proven to be an effective treatment for patients with drug-resistant atrial fibrillation. Nevertheless its efficacy is limited to 60-80% of patients in different studies. Whether the use of pharmacological therapy after catheter ablation of atrial fibrillation might increase the procedural success rate is still a matter of debate. There is general agreement that antiarrhythmic drugs (AADs) are useful in the management of arrhythmias occurring in the very early period after catheter ablation (blanking period). On the contrary, limited data are available on the efficacy of AADs over a longer period. Some patients remain free of arrhythmia recurrences by the use of AADs that were ineffective before catheter ablation: whether this latter situation is to be considered a partial success of catheter ablation or a treatment failure, thus demanding a redo procedure, is still an open question. Some studies have also investigated the role of non-AADs [angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, statins and corticosteroids] in preventing atrial fibrillation recurrences after catheter ablation, reporting conflicting results. Whereas there is a general consensus on the use of anticoagulation therapy in the first phase after catheter ablation, no definite data are available on the proper long-term management of anticoagulation therapy after catheter ablation. This review focuses on the still open issue of what is the optimal pharmacological treatment of patients after catheter ablation of atrial fibrillation.