Michael H. Hoskins

Outcome of Subcutaneous Implantable Cardioverter Defibrillator Implantation in Patients with End‐Stage Renal Disease on Dialysis

Although the subcutaneous ICD (S‐ICD®) is an attractive alternative in patients with end‐stage renal disease (ESRD), data on S‐ICD outcomes in dialysis patients are lacking.

Effects of labetalol on hemodynamic parameters and soluble biomarkers of inflammation in acute coronary syndrome in patients with active cocaine use.

Cocaine use is associated with increased cardiovascular mortality and can promote acute coronary syndrome (ACS). Use of β-blockers is controversial in patients who use cocaine, and the safety and efficacy of these medications in ACS in patients actively using cocaine is unknown. We enrolled 90 patients with ACS and positive urine drug screen for cocaine. Patients received standard ACS therapy plus either labetalol (n = 60) or diltiazem (n = 30). Blood pressure and heart rate were measured at baseline and 48 hours. Levels of serum CD40 ligand, interleukin (IL)-6, and choline at baseline and 48 hours were determined. There were no baseline differences in hemodynamics or serum levels of inflammatory markers between the labetalol and diltiazem groups. Both groups experienced a significant and equivalent decrease in BP and HR at 48 hours compared with baseline. At 48 hours of treatment, there were significant decreases of 17% in CD40 ligand (P < .005) and 16% in IL-6 (P < .005) but no change in choline in the diltiazem group. Furthermore, in the labetalol group, there were significant differences of 30% in CD40 ligand (P < .005 time and group comparison), 22% in IL-6 (P < .005 time and group comparison), and 18% in choline (P < .005 time and group comparison). There were no adverse events during hospitalization in any patients who received labetalol. In conclusion, labetalol appears to be safe in cocaine-associated ACS. Furthermore, labetalol provides a beneficial hemodynamic response and, in comparison to diltiazem, potentiates an anti-inflammatory vascular response in this setting.

Combination use of statins and omega-3 fatty acids: an emerging therapy for combined hyperlipidemia

Many patients with coronary heart disease remain at risk for cardiovascular events despite treatment with statins, especially those with combined hyperlipidemia. Since the observation in the 1970s that Greenland Eskimos have reduced cardiovascular mortality despite a high-fat diet, the role of omega-3 fatty acids in human health has generated intense interest. Omega-3 fatty acids have been shown to provide cardiovascular benefits in secondary prevention and have a hypotriglyceridemic effect, as well as other beneficial biological properties. Combination therapy using statins and omega-3 fatty acids has been proposed as a method to improve both low-density lipoprotein cholesterol and triglycerides in patients with combined hyperlipidemia. In addition, combination therapy with omega-3 fatty acids may represent a way to reduce the residual cardiovascular risk seen after statin monotherapy. This review highlights the properties of omega-3 fatty acids and reviews the current evidence for their use alone and in...

Outcomes of Sprint Fidelis and Riata lead extraction: Data from 2 high-volume centers

BACKGROUND The Sprint Fidelis (SF) and the Riata (RT) implantable cardioverter-defibrillator leads have been recalled for premature failure. OBJECTIVE Data on SF and RT extractions are limited; therefore, we performed a pooled analysis to compare the safety and efficacy of lead extraction for the SF and RT lead families. METHODS We retrospectively reviewed consecutive patients undergoing transvenous extraction of SF and RT leads at Emory University and the University of Pittsburgh Medical Center from January 2007 to October 2013. Patients were placed into 2 groups based on the presence of an SF or RT lead. The primary endpoint was a major procedural complication, defined as death, need for urgent cardiac surgery, and hemopericardium or hemothorax that required an intervention. RESULTS A total of 462 patients underwent extraction of recalled leads (SF, n = 360; RT, n = 102). The mean number of leads extracted in the RT group was higher than in the SF group (1.8 ± 0.9 vs 1.3 ± 0.7, P < .001), and there was a longer implantation time in the RT group (5.5 ± 2.5 vs 4.3 ± 2.0 years, P < .001). Complete procedural success was higher in the SF group (99.4% vs 96.1%, P =.024). Clinical success was similar (SF 99.4% vs RT 97.1%, P = .075). There were 6 major procedural complications in the entire cohort (1.3%). The rate of major complications was not different between the SF and RT groups (SF 1.1% vs RT 2.0%, P = .618). Total mortality was 0.65%, with no difference between the groups CONCLUSION Our data from 2 high-volume centers suggest that extraction of SF and RT leads is associated with excellent clinical success and a similar rate of major procedural complications.

Generator replacement is associated with an increased rate of ICD lead alerts

BACKGROUND Lead malfunction is an important cause of morbidity and mortality in patients with an implantable cardioverter-defibrillator (ICD). We have shown that the failure of recalled high-voltage leads significantly increases after ICD generator replacement. However, generator replacement has not been recognized as a predictor of lead failure in general. OBJECTIVE The purpose of this study is to assess the effect of ICD generator exchange on the rate of ICD lead alerts. METHODS A time-dependent Cox proportional hazards model was used to analyze a database of remotely monitored ICDs. The model assessed the impact of generator exchange on the rate of lead alerts after ICD generator replacement. RESULTS The analysis included 60,219 patients followed for 37 ± 19 months. The 5-year lead survival was 99.3% (95% confidence interval 99.2%-99.4%). Of 60,219 patients, 7458 patients (12.9%) underwent ICD generator exchange without lead replacement. After generator replacement, the rate of lead alerts was more than 5-fold higher than in controls with leads of the same age without generator replacement (hazard ratio 5.19; 95% confidence interval 3.45-7.84). A large number of lead alerted within 3 months of generator replacement. Lead alerts were more common in patients with single- vs dual-chamber ICDs and in younger patients. Sex was not associated with lead alerts. CONCLUSION Routine generator replacement is associated with a 5-fold higher risk of lead alert compared to age-matched leads without generator replacement. This suggests the need for intense surveillance after generator replacement and the development of techniques to minimize the risk of lead damage during generator replacement.

Clinical Performance of Magnetic Resonance Imaging Conditional and Nonconditional Cardiac Implantable Electronic Devices: CLINICAL OUTCOMES: MRI AND CIED

This study compared risks associated with magnetic resonance imaging (MRI) in patients with non‐MRI conditional and MRI conditional pacing and defibrillator systems with particular attention to clinically actionable outcomes.

Electrogram Characteristics of Ablated and Non-Ablated Myocardium in Humans: A Comparison of Miniaturized Embedded Electrodes and Conventional Ablation Electrodes

Intracardiac electrogram voltage remains an important metric for radiofrequency lesion application. Embedded micro‐electrodes within ablation catheters are now approved for use in humans.

Intermediate-term mortality and incidence of ICD therapy in octogenarians after cardiac resynchronization therapy

Background Clinical outcomes of cardiac resynchronization therapy (CRT) in patients over the age of 80 have not been well described. Methods We retrospectively identified 96 consecutive patients ≥ 80 years old who underwent an initial implant or an upgrade to CRT, with or without defibrillator (CRT-D vs. CRT-P), at our institution between January 2003 and July 2008. The control cohort consisted of 177 randomly selected patients < 80 years old undergoing CRT implant during the same time period. The primary efficacy endpoint was all-cause mortality at 36 months, assessed by Kaplan-Meier time to first event curves. Results In the octogenarian cohort, mean age at CRT implant was 83.1 ± 2.9 years vs. 60.1 ± 8.8 years among controls (P < 0.001). Across both groups, 70% were male, mean left ventricular ejection fraction (LVEF) was 24.8% ± 14.1% and QRS duration was 154 ± 24.8 ms, without significant differences between groups. Octogenarians were more likely to have ischemic cardiomyopathy (74% vs. 37%, P < 0.001) and more likely to undergo upgrade to CRT instead of an initial implant (42% vs. 19%, P < 0.001). The rate of appropriate defibrillator shocks was lower among octogenarians (14% vs. 27%, P = 0.02) whereas the rate of inappropriate shocks was similar (3% vs. 6%, P = 0.55). At 36 months, there was no significant difference in the rate of all-cause mortality between octogenarians (11%) and controls (8%, P = 0.381). Conclusion Appropriately selected octogenarians who are candidates for CRT have similar intermediate-term mortality compared to younger patients receiving CRT.

Incidence and Time Course for Developing Heart Failure With High-Burden Right Ventricular Pacing

Background— Although right ventricular pacing can contribute to cardiomyopathy, the impact of complete atrioventricular block (cAVB) on heart failure (HF) development in pacemaker patients has not been well characterized. We evaluated the incidence and time course for developing HF after pacemaker implantation for cAVB. Methods and Results— A MarketScan database identified patients undergoing dual-chamber pacemaker implantation from 2008 to 2014. Patients with cAVB were identified by an atrioventricular node ablation or diagnosis of third-degree AVB. Patients with ≥1 year of continuous MarketScan enrollment before and after implant and without a previous diagnosis of HF were dichotomized into those with cAVB and without AVB. The primary end point was new HF assessed over acute (0–6 months) and chronic (6 months to 4 years) phases post–pacemaker implantation. The cohort included 6994 cAVB patients and 14 208 patients without AVB, followed for 2.35 years (interquartile range, 1.62–3.39 years). After adjustment for baseline covariates, patients with cAVB experienced an increased risk of new-onset HF in the acute phase (hazard ratio, 1.62; 95% confidence interval, 1.48–1.79; P<0.001). Although the risk of HF remained elevated among those with cAVB in the chronic phase, the effect was attenuated (hazard ratio, 1.16; 95% confidence interval, 1.08–1.25; P<0.001). After pacemaker implantation, younger patients (⩽55 years of age) and those with an antecedent history of atrial fibrillation experienced the highest risk of HF associated with cAVB. Conclusions— Patients with a diagnosis of cAVB, and thus presumed to have a higher burden of right ventricular pacing, experienced an increased risk of new-onset HF after pacemaker implantation compared with those without AVB. Better tools are needed to identify patients at high risk of developing HF in the setting of right ventricular pacing and to determine whether these patients benefit from upfront biventricular pacing.

Time Course of Subsequent Shocks After Initial Implantable Cardioverter-Defibrillator Discharge and Implications for Driving Restrictions

IMPORTANCE Although guidelines recommend driving restrictions for 3 to 6 months after appropriate implantable cardioverter-defibrillator (ICD) shocks, contemporary data to support these recommendations are lacking. OBJECTIVE To define the time course of subsequent shocks after an initial ICD discharge. DESIGN, SETTING, AND PARTICIPANTS Retrospective analysis of a nationwide cohort of 14 230 ICD recipients enrolled in a remote monitoring program. Participants underwent ICD implantation from October 1, 2008, to December 31, 2013, and experienced at least 1 shock. The risk of driving after an ICD shock was estimated using the risk for harm (RH) formula, and an annual RH of less than 5 events per 100 000 ICD recipients was deemed safe. The likelihood of loss of consciousness associated with an ICD shock was estimated using a cautious value of 32% and an estimate of 14% based on contemporary data. Data were extracted and analyzed from December 17, 2014, to October 31, 2015. MAIN OUTCOMES AND MEASURES Time course of subsequent shocks after an initial ICD discharge. RESULTS Of 73 503 ICD recipients who underwent remote monitoring, 14 230 (19.4%) experienced at least 1 ICD shock and were included in this analysis (10 870 men [76.4%]; 3360 women [23.6%]; median age at device implantation, 68 years; interquartile range [IQR], 60-76 years). The cumulative incidence of receiving a second shock was 14.5% (IQR, 13.9%-15.1%) at 1 month and 28.7% (IQR, 27.9%-29.5%) at 6 months. The time from implantation to initial shock had an inverse association with the likelihood of receiving a second shock (lowest quartile of time at 6 months, 31.6% [95% CI, 30.2%-33.2]; highest quartile of time at 6 months, 25.3% [95% CI, 23.8%-26.9%]). The number of ICD therapy zones was also significantly associated with the incidence of a second shock (1 therapy zone, 20.8% [95% CI, 19.4%-22.3%] at 3 months to 51.5% [95% CI, 48.5%-53.7%] at 3 years; 3 therapy zones, 26.9% [95% CI, 24.8%-29.0%] at 3 months to 57.3% [95% CI, 54.1%-60.5%] at 3 years). When a likelihood of loss of consciousness of 32% associated with an ICD shock was used, the RH while driving fell below the accepted threshold at 4 to 6 months after an initial shock. However, when a contemporary estimate for loss of consciousness associated with an ICD shock of 14% was used, the RH fell below the threshold at 1 month after an initial shock. CONCLUSIONS AND RELEVANCE In this large cohort of ICD recipients, the incidence of a second shock after an initial ICD discharge was lower than previously reported and depended on several programmed ICD variables. These data, with future research to derive contemporary estimates of the likelihood of fatality resulting from an ICD shock while driving, should support the development of evidence-based guidelines for driving restrictions in ICD recipients.