Arnold J. Greenspon

Adverse Effect of Ventricular Pacing on Heart Failure and Atrial Fibrillation Among Patients With Normal Baseline QRS Duration in a Clinical Trial of Pacemaker Therapy for Sinus Node Dysfunction

Background Dual‐chamber (DDDR) pacing preserves AV synchrony and may reduce heart failure (HF) and atrial fibrillation (AF) compared with ventricular (VVIR) pacing in sinus node dysfunction (SND). However, DDDR pacing often results in prolonged QRS durations (QRSd) as the result of right ventricular stimulation, and ventricular desynchronization may result. The effect of pacing‐induced ventricular desynchronization in patients with normal baseline QRSd is unknown. Methods and Results Baseline QRSd was obtained from 12‐lead ECGs before pacemaker implantation in MOST, a 2010‐patient, 6‐year, randomized trial of DDDR versus VVIR pacing in SND. Cumulative percent ventricular paced (Cum%VP) was determined from stored pacemaker data. Baseline QRSd <120 ms was observed in 1339 patients (707 DDDR, 632 VVIR). Cum%VP was greater in DDDR versus VVIR (90% versus 58%, P=0.001). Cox models demonstrated that the time‐dependent covariate Cum%VP was a strong predictor of HF hospitalization in DDDR (hazard ratio [HR], 2.99 [95% CI, 1.15 to 7.75] for Cum%VP >40%) and VVIR (HR 2.56 [95% CI, 1.48 to 4.43] for Cum%VP >80%). The risk of AF increased linearly with Cum%VP from 0% to 85% in both groups (DDDR, HR 1.36 [95% CI, 1.09, 1.69]; VVIR, HR 1.21 [95% CI 1.02, 1.43], for each 25% increase in Cum%VP). Model results were unaffected by adjustment for known baseline predictors of HF hospitalization and AF. Conclusions Ventricular desynchronization imposed by ventricular pacing even when AV synchrony is preserved increases the risk of HF hospitalization and AF in SND with normal baseline QRSd. (Circulation. 2003;107:2932‐2937.)

Lead Extraction in the Contemporary Setting: The LExICon Study. An Observational Retrospective Study of Consecutive Laser Lead Extractions

OBJECTIVES This study sought to examine the safety and efficacy of laser-assisted lead extraction and the indications, outcomes, and risk factors in a large series of consecutive patients. BACKGROUND The need for lead extraction has been increasing in direct relationship to the increased numbers of cardiovascular implantable electronic devices. METHODS Consecutive patients undergoing transvenous laser-assisted lead extraction at 13 centers were included. RESULTS Between January 2004 and December 2007, 1,449 consecutive patients underwent laser-assisted lead extraction of 2,405 leads (20 to 270 procedures/site). Median implantation duration was 82.1 months (0.4 to 356.8 months). Leads were completely removed 96.5% of the time, with a 97.7% clinical success rate whereby clinical goals associated with the indication for lead removal were achieved. Failure to achieve clinical success was associated with body mass index <25 kg/m(2) and low extraction volume centers. Procedural failure was higher in leads implanted for >10 years and when performed in low volume centers. Major adverse events in 20 patients were directly related to the procedure (1.4%) including 4 deaths (0.28%). Major adverse effects were associated with patients with a body mass index <25 kg/m(2). Overall all-cause in-hospital mortality was 1.86%; 4.3% when associated with endocarditis, 7.9% when associated with endocarditis and diabetes, and 12.4% when associated with endocarditis and creatinine > or =2.0. Indicators of all-cause in-hospital mortality were pocket infections, device-related endocarditis, diabetes, and creatinine > or =2.0. CONCLUSIONS Lead extraction employing laser sheaths is highly successful with a low procedural complication rate. Total mortality is substantially increased with pocket infections or device-related endocarditis, particularly in the setting of diabetes, renal insufficiency, or body mass index <25 kg/m(2). Centers with smaller case volumes tended to have a lower rate of successful extraction.

16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008.

OBJECTIVES We analyzed the infection burden associated with the implantation of cardiac implantable electrophysiological devices (CIEDs) in the United States for the years 1993 to 2008. BACKGROUND Recent data suggest that the rate of infection following CIED implantation may be increasing. METHODS The Nationwide Inpatient Sample (NIS) discharge records were queried between 1993 and 2008 using the 9th Revision of the International Classification of Diseases (ICD-9-CM). CIED infection was defined as either: 1) ICD-9 code for device-related infection (996.61) and any CIED procedure or removal code; or 2) CIED procedure code along with systemic infection. Patient health profile was evaluated by coding for renal failure, heart failure, respiratory failure, and diabetes mellitus. The infection burden and patient health profile were calculated for each year, and linear regression was used to test for changes over time. RESULTS During the study period (1993 to 2008), the incidence of CIED infection was 1.61%. The annual rate of infections remained constant until 2004, when a marked increase was observed, which coincided with an increase in the incidence of major comorbidities. This was associated with a marked increase in mortality and in-hospital financial charges. CONCLUSIONS The infection burden associated with CIED implantation is increasing over time and is associated with prolonged hospital stays and high financial costs.

Reperfusion arrhythmia: A marker of restoration of antegrade flow during intracoronary thrombolysis for acute myocardial infarction

We studied the effects of coronary recanalization on arrhythmogenesis in patients undergoing intracoronary thrombolysis during the early hours of myocardial infarction. Catheterization, ventriculography, coronary angiography, and intracoronary streptokinase infusion were performed in 22 patients. Twenty-one of 22 had thrombotic total occlusion of the infarct-related transient thrombolysis with reocclusion by the end of the procedure. In 12 of these 17 patients, restoration of antegrade coronary flow was accompanied by transient arrhythmia. In these 12 patients coronary angiography within seconds of onset of arrhythmia showed vessel patency in a previously totally occluded coronary artery. Two additional patients developed arrhythmias during streptokinase infusion but after reperfusion had already been established. Accelerated idioventricular rhythm was most often noted. Sinus bradycardia and atrioventricular block with hypotension occurred during restoration of flow in arteries supplying the inferoposterior left ventricle. These arrhythmias may be useful noninvasive markers of successful reperfusion during thrombolytic therapy in acute myocardial infarction.

Steady-state serum amiodarone concentrations: relationships with antiarrhythmic efficacy and toxicity.

The relationship of apparent steady-state serum concentrations of amiodarone and its metabolite, desethylamiodarone, to therapeutic and toxic effects was assessed in 127 patients who had treatment-resistant ventricular or supraventricular arrhythmias or were intolerant to other agents. After at least 2 months (mean, 9.8) of treatment with daily maintenance doses of 200 to 600 mg, arrhythmias were effectively suppressed in 78% of patients. Arrhythmias recurred in 47% of patients with serum amiodarone concentrations of less than 1.0 mg/L, whereas only 14% of patients with higher concentrations had recurrences (p less than 0.005). Side effects, most of them mild, occurred in 57%; only 9 patients required discontinuation of drug therapy. The risk of developing adverse reactions was related to serum amiodarone concentrations (p less than 0.0001). Adverse reactions were common in patients with serum values exceeding 2.5 mg/L, although pulmonary complications did occur at lower concentrations. Monitoring serum amiodarone concentrations may differentiate failure of drug therapy from suboptimal dosing and reduce the incidence of concentration-related side effects.

Risk of Major Bleeding with Concomitant Dual Antiplatelet Therapy After Percutaneous Coronary Intervention in Patients Receiving Long-Term Warfarin Therapy

Study Objectives. To characterize the safety of concomitant aspirin, clopidogrel, and warfarin therapy after percutaneous coronary intervention (PCI), and to identify patient characteristics that increase the risk of hemorrhage.

Incidence of unwarranted implantation of permanent cardiac pacemakers in a large medical population.

Because of allegations that the implantation of many permanent cardiac pacemakers has been unjustified, we reviewed the indications for all new pacemakers implanted at 30 hospitals in Philadelphia County between January 1 and June 30, 1983, and paid for by Medicare. Complete chart data were evaluated for 382 implants. We determined whether the indications for implantation were appropriate and adequately documented on the basis of standard clinical practice. Implants were classified as possibly indicated primarily because of inadequate diagnostic evaluation (63 percent) or inadequate documentation of an accepted indication (36 percent). Implants were classified as not indicated primarily because a rhythm abnormality was incorrectly identified as a justifiable indication (84 percent). We found that 168 implants (44 percent) were definitely indicated, 137 (36 percent) possibly indicated, and 77 (20 percent) not indicated. Unwarranted implantation was both prevalent (73 percent of hospitals had an incidence of 10 percent or more) and independent of the type of hospital (university teaching, university-affiliated, and community hospitals). The additional tests most often required to clarify the need for a pacemaker in inadequately evaluated cases included electrophysiologic studies (37 percent) and ambulatory monitoring (31 percent). We conclude that in a large medical population in 1983, the indications for a considerable number of permanent pacemakers were inadequate or incompletely documented.

Provocation of ventricular tachycardia after consumption of alcohol

CARDIAC conduction abnormalities and dysrhythmias often occur in the presence of cardiomyopathy and a history of excessive alcohol consumption. Using the repetitive ventricular response, we provoke...

Efficacy and safety of implantable cardiac defibrillators for treatment of ventricular arrhythmias in patients with cardiac sarcoidosis

AIMS Implantable cardiac defibrillator (ICD) implantation is a class IIA recommendation for patients with cardiac sarcoidosis (CS). However, little is known about the efficacy and safety of ICDs in this population. The goal of this multicentre retrospective data review was to evaluate the efficacy and safety of ICDs in patients with CS. METHODS AND RESULTS Electrophysiologists at academic medical centres were asked to identify consecutive patients with CS and an ICD. Clinical information, ICD therapy history, and device complications were collected for each patient. Data were collected on 235 patients from 13 institutions, 64.7% male with mean age 55.6 ± 11.1. Over a mean follow-up of 4.2 ± 4.0 years, 85 of 234 (36.2%) patients received an appropriate ICD therapy (shocks and/or anti-tachycardia pacing) and 67 of 226 (29.7%) received an appropriate shock. Fifty-seven of 235 patients (24.3%) received a total of 222 inappropriate shocks. Forty-six adverse events occurred in 41 of 235 patients (17.4%). Patients who received appropriate ICD therapies were more likely to be male (73.8 vs. 59.6%, P = 0.0330), have a history of syncope (40.5 vs. 22.5%, P = 0.0044), lower left ventricular ejection fraction (38.1 ± 15.2 vs. 48.8 ± 14.7%, P ≤ 0.0001), ventricular pacing on baseline electrocardiogram (16.1 vs. 2.1%, P = 0.0002), and a secondary prevention indication (60.7 vs. 24.5%, P < 0.0001) compared with those who did not receive appropriate ICD therapies. CONCLUSION Patients with CS and ICDs are at high risk for ventricular arrhythmias. This population also has high rates of inappropriate shocks and device complications.

Timing of the most recent device procedure influences the clinical outcome of lead-associated endocarditis results of the MEDIC (Multicenter Electrophysiologic Device Infection Cohort).

OBJECTIVES The purpose of this study was to determine whether the timing of the most recent cardiac implantable electronic device (CIED) procedure, either a permanent pacemaker or implantable cardioverter-defibrillator, influences the clinical presentation and outcome of lead-associated endocarditis (LAE). BACKGROUND The CIED infection rate has increased at a time of increased device use. LAE is associated with significant morbidity and mortality. METHODS The clinical presentation and course of LAE were evaluated by the MEDIC (Multicenter Electrophysiologic Device Cohort) registry, an international registry enrolling patients with CIED infection. Consecutive LAE patients enrolled in the Multicenter Electrophysiologic Device Cohort registry between January 2009 and May 2011 were analyzed. The clinical features and outcomes of 2 groups were compared based on the time from the most recent CIED procedure (early, <6 months; late, >6 months). RESULTS The Multicenter Electrophysiologic Device Cohort registry entered 145 patients with LAE (early = 43, late = 102). Early LAE patients presented with signs and symptoms of local pocket infection, whereas a remote source of bacteremia was present in 38% of patients with late LAE but only 8% of early LAE (p < 0.01). Staphylococcal species were the most frequent pathogens in both early and late LAE. Treatment consisted of removal of all hardware and intravenous administration of antibiotics. In-hospital mortality was low (early = 7%, late = 6%). CONCLUSIONS The clinical presentation of LAE is influenced by the time from the most recent CIED procedure. Although clinical manifestations of pocket infection are present in the majority of patients with early LAE, late LAE should be considered in any CIED patient who presents with fever, bloodstream infection, or signs of sepsis, even if the device pocket appears uninfected. Prompt recognition and management may improve outcomes.