Tissue Doppler-Derived Left Ventricular Systolic Velocity Is Associated with Lethal Arrhythmias in Cardiac Device Recipients Irrespective of Left Ventricular Ejection Fraction.

BACKGROUND: Life-threatening arrhythmias (LTAs) can trigger sudden cardiac death or provoke implantable cardioverter-defibrillator (ICD) discharges that escalate morbidity and mortality. Longitudinal myofibrils predominate in the subendocardium, which is uniquely sensitive to arrhythmogenic triggers. In this study, we test the hypothesis that mitral annular systolic velocity (S'), a simple routinely obtained tissue Doppler index of LV long-axis systolic function, might predict lethal arrhythmias irrespective of left ventricular ejection fraction (LVEF). METHODS: This is a retrospective analysis of data from 302 patients (mean age, 68 years; LVEF, 32%; 77% male; 52% ischemic; 35% primary prevention; and 53% cardiac resynchronization therapy defibrillator [CRT-D]) who were followed up (median, 15 months) at two centers after receipt of an ICD or CRT-D for diverse indications. S', averaged from tissue Doppler-derived medial and lateral mitral annular velocities, was correlated with the primary outcome of time to sustained ventricular tachycardia (VT) or fibrillation (VF) needing device therapy. RESULTS: The median S' was 5.1 (interquartile range, 4.0-6.2) cm/sec and lower in CRT-D than ICD subjects (4.5 [3.8-5.6] cm/sec vs 5.5 [4.8-6.8] cm/sec, P < .001). Fifty-six (19%) subjects had LTA. Each 1 cm/sec higher S' correlated to a 30% decreased risk of LTA (hazard ratio = 0.70; 95% CI, 0.57-0.87; P = .001) independently of age, sex, ß-blocker use, center, ICD use, and LVEF. Adding S' to the baseline Cox model improved net reclassification (P = .02). An S' > 5.6 cm/sec was the best cutoff and linked to a 58% lower LTA risk than an S' ≤ 5.6 cm/sec (95% CI, 0.23-0.85; P = .02). CONCLUSIONS: A higher S' is associated with a reduced probability of LTA in cardiac device recipients irrespective of LVEF and may have the potential to be used clinically to titrate medical, device, and ablative therapies to mitigate future arrhythmic risk.

The impact of the presence of left atrial low voltage areas on outcomes from pulmonary vein isolation.

BACKGROUND: AF ablation (AFA) with pulmonary vein isolation (PVI) is highly successful for paroxysmal atrial fibrillation (PAF). However, success rates for persistent AF (PsAF) are significantly lower. In this study we evaluate the impact of left atrial (LA) low voltage areas (LVA) on response to AFA. METHODS: Consecutive patients undergoing first-time radiofrequency AFA were included (n = 160, 53% PAF). PVI was performed followed by LA voltage mapping during sinus rhythm. Patients were categorized as having LVA based on the presence of LVA (0.2-0.5 mV) in the LA assessed visually by the operator intra-procedurally. Further adjunctive LA ablation was performed at the operators' discretion. The end-point was recurrence of any sustained atrial arrhythmia (atrial fibrillation/tachycardia/flutter) during 12 months follow-up. RESULTS: All patients had PVI and 23 (14%) had adjunctive LA ablation. LVA were found in 49 (31%) patients and were an independent predictor of arrhythmia recurrence. Patients with LVA compared to those without had significantly lower 12-month arrhythmia-free survival in both PAF (38% vs 76%; P = 0.002) and PsAF (27% vs 61%; P = 0.015). PsAF patients without LVA (93% had PVI alone) had similar arrhythmia-free survival to patients with PAF (61% vs 67%, respectively; P = 0.42). Recurrence in patients with LVA compared to those without was more likely to be an organized atrial arrhythmia rather than AF (16/30 recurrences vs 2/26, P < 0.001). CONCLUSIONS: The presence of LVA predicts AFA success as well as the type of arrhythmia recurrence. The absence of LVA identifies PsAF patients that respond well to a PVI-based ablation strategy.

The impact of catheter ablation for atrial fibrillation in heart failure.

Atrial fibrillation (AF) commonly co-exists with systolic heart failure (SHF) and its presence is associated with a worse prognosis. Despite this, a rhythm control approach using antiarrhythmic drugs (AADs) to reduce AF burden has demonstrated no prognostic benefit. Catheter ablation (AFA) is more effective than AADs at reducing AF burden. We performed a meta-analysis to evaluate the impact of AFA on outcomes in SHF. Electronic databases were systematically searched. We included only randomized controlled trials that examined the impact of AFA on clinical outcomes in patients with SHF (LVEF <50%). We included studies with any ablation strategy that incorporated pulmonary vein isolation and any control group. Seven studies (n = 858) were included with a mean follow-up of 6-38 months. In comparison to controls, AFA was associated with significant reductions in all-cause mortality (relative risk [RR] 0.52, P = 0.0009) and unplanned or heart failure hospitalization (RR 0.58, P < 0.00001). Compared to controls, AFA was also associated with significant improvements in LVEF (mean difference 6.30%, P < 0.00001), Minnesota Living with Heart Failure Questionnaire score (mean difference 9.58, P = 0.0003), 6-minute walk distance (mean difference 31.78 m, P = 0.003) and VO 2 max (mean difference 3.17, P = 0.003). However, major procedure-related complications occurred in 2.4%-15% of ablation patients. In patients with AF and SHF, catheter ablation has significant benefits. Further work is needed to establish the role of ablation in the routine treatment of SHF patients with AF.

Day-case device implantation-A prospective single-center experience including patient satisfaction data.

PURPOSE: Many centers perform day-case cardiac rhythm management (CRM) device implantation. However, there is a paucity of prospective data concerning this approach. We performed a prospective single-center study of day-case device implantation, including data on patient satisfaction. METHODS: All patients scheduled for a new elective device were considered for a day-case procedure. Exclusion criteria were living alone or without a suitable carer, advancing age/frailty, a metallic valve, and persistent complete heart block. Following discharge, patients were reviewed in device clinic at 6 weeks with an anonymized questionnaire. RESULTS: During the study period (May 2014-August 2016), 797 new CRM devices were implanted. Of these, 232 were elective and included in the analysis; 101 were planned to be day-case and 131 scheduled for overnight stay. Of the 101 day-case patients, 52 had a pacemaker, 28 an implantable cardioverter defibrillator (ICD), 16 a cardiac resynchronization therapy pacemaker/defibrillator, and five a subcutaneous-ICD. Complications were similar in the day-case (n  =  12, 12%) and overnight stay (n  =  15, 11%) groups (P  =  0.92). In the day-case group, 93 (92%) patients went home the same day. An estimated 111 overnight bed days were saved, translating to a cost saving of £61,912 (euro 70,767, $79,211). Note that 99% (n  =  100) of patients returned the questionnaire. Patient satisfaction was universally high. The majority (n  =  98, 98%) felt ready to go home on discharge; only a minority (n  =  5, 5%) would have preferred an overnight stay. CONCLUSIONS: A significant proportion of elective new CRM device implants can be performed as day-case procedures. With appropriate selection patient acceptability of same-day discharge is high.

Outcomes with single-coil versus dual-coil implantable cardioverter defibrillators: a meta-analysis.

Aims: Dual-coil implantable cardioverter defibrillator (ICD) leads have traditionally been used over single-coil leads due to concerns regarding high defibrillation thresholds (DFT) and consequent poor shock efficacy. However, accumulating evidence suggests that this position may be unfounded and that dual-coil leads may also be associated with higher complication rates during lead extraction. This meta-analysis collates data comparing dual- and single-coil ICD leads. Methods and results: Electronic databases were systematically searched for randomized controlled trials (RCT) and non-randomized studies comparing single-coil and dual-coil leads. The mean differences in DFT and summary estimates of the odds-ratio (OR) for first-shock efficacy and the hazard-ratio (HR) for all-cause mortality were calculated using random effects models. Eighteen studies including a total of 138,124 patients were identified. Dual-coil leads were associated with a lower DFT compared to single coil leads (mean difference -0.83J; 95% confidence interval [CI] -1.39--0.27; P = 0.004). There was no difference in the first-shock success rate with dual-coil compared to single-coil leads (OR 0.74; 95%CI 0.45-1.21; P=0.22). There was a significantly lower risk of all-cause mortality associated with single-coil leads (HR 0.91; 95%CI 0.86-0.95; P < 0.0001). Conclusion: This meta-analysis suggests that single-coil leads have a marginally higher DFT but that this may be clinically insignificant as there appears to be no difference in first-shock efficacy when compared to dual-coil leads. The mortality benefit with single-coil leads most likely represents patient selection bias. Given the increased risk and complexity of extracting dual-coil leads, centres should strongly consider single-coil ICD leads as the lead of choice for routine new left-sided ICD implants.

Identifying patients with less potential to benefit from implantable cardioverter-defibrillator therapy: comparison of the performance of four risk scoring systems.

PURPOSE: Patients at high non-sudden cardiac death risk may gain no significant benefit from implantable cardioverter-defibrillator (ICD) therapy. A number of approaches have been proposed to identify these patients, including single clinical markers and more complex scoring systems. The aims of this study were to use the proposed scoring systems to (1) establish how many current ICD recipients may be too high risk to derive significant benefit from ICD therapy and (2) evaluate how well the scoring systems predict short-term mortality in an unselected ICD cohort. METHODS: We performed a single-centre retrospective observational study of all new ICD implants over 5 years (2009-2013). We used four published scoring systems (Bilchick, Goldenberg, Kramer and Parkash) and serum urea to identify new ICD recipients whose short-term predicted mortality risk was high. We evaluated how well the scoring systems predicted death. RESULTS: Over 5 years, there were 406 new implants (79% male, mean age 70 (60-76), 58% primary prevention). During a follow-up of 936 ± 560 days, 96 patients died. Using the scoring systems, the proportion of ICD recipients predicted to be at high short-term mortality risk were 5.9% (Bilchick), 34.7% (Goldenberg), 7.4% (Kramer), 21.4% (Parkash) and 25% (urea, cut-off of >9.28 mM). All four risk scores predicted mortality (P < 0.0001); however, none outperformed urea for the prediction of 1- or 3-year mortality. CONCLUSIONS: Using published scoring systems, a significant proportion of current ICD recipients are at high short-term mortality risk. Although all four scoring systems predicted mortality during follow-up, none significantly outperformed serum urea.

Impact of the introduction of a standardised ICD programming protocol: real-world data from a single centre.

PURPOSE: Randomised trials have shown that empiric ICD programming, using long detection times and high detection zones, reduces device therapy in ICD recipients. However, there is less data on its effectiveness in a "real-world" setting, especially secondary prevention patients. Our aim was to evaluate the introduction of a standardised programming protocol in a real-world setting of unselected ICD recipients. METHODS: We analysed 270 consecutive ICD recipients implanted in a single centre-135 implanted prior to protocol implementation (physician-led group) and 135 after (standardised group). The protocol included long arrhythmia detection times (30/40 or equivalent) and high rate detection zones (primary prevention lower treatment zone 200 bpm). Programming in the physician-led group was at the discretion of the implanter. The primary endpoint was time-to-any therapy (ATP or shocks). Secondary endpoints were time-to-inappropriate therapy and time-to-appropriate therapy. The safety endpoints were syncopal episodes, hospital admissions and death. RESULTS: At 12 months follow-up, 47 patients had received any ICD therapy (physician-led group, n = 31 vs. standardised group, n = 16). There was a 47 % risk reduction in any device therapy (p = 0.04) and an 86 % risk reduction in inappropriate therapy (p = 0.009) in the standardised compared to the physician-led group. There was a non-significant 30 % risk reduction in appropriate therapy (p = 0.32). Results were consistent across primary and secondary prevention patients. There were no significant differences in the rates of syncope, hospitalisation, and death. CONCLUSIONS: In unselected patients in a real-world setting, introduction of a standardised programming protocol, using long detection times and high detection zones, significantly reduces the burden of ICD therapy without an increase in adverse outcomes.