Joseph L. Schuller

Implantable Cardioverter Defibrillator Therapy in Patients with Cardiac Sarcoidosis

ICD Shocks in Cardiac Sarcoidosis. Background: An implantable cardioverter defibrillator (ICD) is indicated for some patients with cardiac sarcoidosis (CS) for prevention of sudden death. However, there are little data regarding the event rates of ICD therapies in these patients. We sought to identify the incidence and characteristics of ICD therapies in this patient population.

Electrocardiographic Characteristics in Patients With Pulmonary Sarcoidosis Indicating Cardiac Involvement

ECG Characteristics of Cardiac Sarcoidosis. Introduction: Sarcoidosis is a multisystem granulomatous disease that can affect the heart. Early identification of cardiac sarcoidosis (CS) is critical because sudden death can be the initial presentation. We sought to evaluate the potential role of the ECG for identification of cardiac involvement in a cohort of patients with biopsy‐proven pulmonary sarcoidosis.

Magnetic Resonance Imaging for Identifying Patients With Cardiac Sarcoidosis and Preserved or Mildly Reduced Left Ventricular Function at Risk of Ventricular Arrhythmias

Background—The purpose of this study was to assess whether delayed enhancement (DE) on MRI is associated with ventricular tachycardia (VT)/ventricular fibrillation or death in patients with cardiac sarcoidosis and left ventricular ejection fraction >35%. Methods and Results—Fifty-one patients with cardiac sarcoidosis and left ventricular ejection fraction >35% underwent DE-MRI. DE was assessed by visual scoring and quantified with the full-width at half-maximum method. The patients were followed for 48.0±20.2 months. Twenty-two of 51 patients (63%) had DE. Forty patients had no prior history of VT (primary prevention cohort). Among those, 3 patients developed VT and 2 patients died. DE was associated with risk of VT/ventricular fibrillation or death (P=0.0032 for any DE and P<0.0001 for right ventricular DE). The positive predictive values of the presence of any DE, multifocal DE, and right ventricular DE for death or VT/ventricular fibrillation at mean follow-up of 48 months were 22%, 48%, and 100%, respectively. Among the 11 patients with a history of VT before the MRI, 10 patients had subsequent VTs, 1 of whom died. Conclusions—RV DE in patients with cardiac sarcoidosis is associated with a risk of adverse events in patients with cardiac sarcoidosis and preserved ejection fraction in the absence of a prior history of VT. Patients with DE and a prior history of VT have a high VT recurrence rate. Patients without DE on MRI have a low risk of VT.

Diagnostic Utility of Signal‐Averaged Electrocardiography for Detection of Cardiac Sarcoidosis

Introduction: Cardiac sarcoidosis (CS) occurs in up to 25% of patients with pulmonary involvement. Early diagnosis is critical because sudden death from ventricular arrhythmias can be the initial presentation. We sought to evaluate the diagnostic utility of signal‐averaged ECG (SAECG) for detection of cardiac involvement of sarcoidosis.

Clinical and biophysical evaluation of variable bipolar configurations during radiofrequency ablation for treatment of ventricular arrhythmias

BACKGROUND Bipolar radiofrequency ablation (bRFA) has been used to create larger ablation lesions and to treat refractory arrhythmias. However, little is known about optimal bRFA settings. OBJECTIVE The purpose of this study was to evaluate various bRFA settings, including active and ground catheter tip orientation and use of variable active and ground catheters during bRFA. METHODS Two ablation catheters, 1 active and 1 ground, were oriented across from each other, with viable bovine myocardium in between. The catheter tips were placed in various combinations perpendicular or parallel to the myocardium. The active catheter was either a 3.5-mm externally irrigated or 8-mm tip, and the ground catheter was either a 4-mm, 3.5-mm irrigated, or 8-mm tip. Retrospective analysis was undertaken for all bRFA performed at University of Colorado. RESULTS The largest and deepest lesions were produced using irrigated active and ground tips, oriented perpendicularly. In 14 cases (10 patients) of bRFA for ventricular tachycardia and premature ventricular complexes, acute success was achieved in 13 of 14 procedures. Long-term success was achieved in 7 of 10 patients, but 3 patients required multiple bRFA ablations. CONCLUSION Active and ground catheter tip orientation and type are important determinants of lesion sizes during bRFA. The largest and deepest lesions, without a higher incidence of steam pops, were achieved using 2 irrigated catheters. As the largest published series to date, bRFA ablation can be performed safely and effectively in humans. Larger studies are necessary to better evaluate bRFA efficacy and safety.

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles

Background—Remote heating of metal located near a radiofrequency ablation source has been previously demonstrated. Therefore, ablation of cardiac tissue treated with metallic nanoparticles may improve local radiofrequency heating and lead to larger ablation lesions. We sought to evaluate the effect of magnetic nanoparticles on tissue sensitivity to radiofrequency energy. Methods and Results—Ablation was performed using an ablation catheter positioned with 10 g of force over prepared ex vivo specimens. Tissue temperatures were measured and lesion volumes were acquired. An in vivo porcine thigh model was used to study systemically delivered magnetically guided iron oxide (FeO) nanoparticles during radiofrequency application. Magnetic resonance imaging and histological staining of ablated tissue were subsequently performed as a part of ablation lesion analysis. Ablation of ex vivo myocardial tissue treated with metallic nanoparticles resulted in significantly larger lesions with greater impedance changes and evidence of increased thermal conductivity within the tissue. Magnet-guided localization of FeO nanoparticles within porcine thigh preps was demonstrated by magnetic resonance imaging and iron staining. Irrigated ablation in the regions with greater FeO, after FeO infusion and magnetic guidance, created larger lesions without a greater incidence of steam pops. Conclusions—Metal nanoparticle infiltration resulted in significantly larger ablation lesions with altered electric and thermal conductivity. In vivo magnetic guidance of FeO nanoparticles allowed for facilitated radiofrequency ablation without direct infiltration into the targeted tissue. Further research is needed to assess the clinical applicability of this ablation strategy using metallic nanoparticles for the treatment of cardiac arrhythmias.

Synthetic opioids and arrhythmia risk: a new paradigm?

The most commonly prescribed class of medications in the United States for chronic severe pain is opioid analgesics. Due to their low cost and widespread availability, the synthetic opioids are popular choices among clinicians and patients. However, there is an increasingly recognized risk of QT prolongation with several drugs in this class, and recently propoxyphene (Darvon) was withdrawn from the market by the Food and Drug Administration (FDA) due to, in part, the risk of QT prolongation and ventricular arrhythmias 1 Updated Epidemiological Review of Propoxyphene Safety. [FDA Alert]. Rockville, MD: U.S. Food and Drug Administration; 2010. Available from: http://www.fda.gov/downloads/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/UCM234383.pdf on 5 May 2012.

Use of half-normal saline irrigant with cooled radiofrequency ablation within the great cardiac vein to ablate premature ventricular contractions arising from the left ventricular summit

A 62‐year‐old man was referred to our institution for high‐density, symptomatic premature ventricular contractions (PVCs) with resultant decrease in left ventricular (LV) function having failed prior ablation attempts. Successful, durable ablation of the patients mid‐myocardial PVC arising from the LV summit region was achieved through the proximal great cardiac vein with ablation depth augmented by use of half‐normal saline irrigant. Though standard ablation of ventricular arrhythmias using normal saline irrigation from the coronary venous system has been well‐reported, this may be of limited value in addressing mid‐myocardial sites of origin. This novel case describes the safe use of cooled radiofrequency ablation with use of half‐normal saline irrigant from the distal coronary sinus as an option to address complex sites of PVC origin such as the LV summit.

Repeat ablation of refractory ventricular arrhythmias in patients with nonischemic cardiomyopathy: Impact of midmyocardial substrate and role of adjunctive ablation techniques

Multiple ablations are often necessary to manage ventricular arrhythmias (VAs) in nonischemic cardiomyopathy (NICM) patients. We assessed characteristics and outcomes and role of adjunctive, nonstandard ablation in repeat VA ablation (RAbl) in NICM.

Impact of Alcohol Consumption on Atrial Fibrillation Outcomes Following Pulmonary Vein Isolation

Background Moderate to heavy alcohol use has been shown to be associated with increased atrial fibrillation (AF) incidence. However, the relationship between alcohol use and AF recurrence after pulmonary vein isolation (PVI) is not well known. Objective We sought to study the impact of different alcohol consumption levels on outcomes after AF ablation. Methods A retrospective analysis was performed of 226 consecutive patients undergoing first time PVI for AF. Clinical data were collected including alcohol intake classified into 3 groups: none-rare (< 1 drink/ week), moderate (1-7 drinks/ week), and heavy (> 7 drinks/ week). Patients were followed for recurrences within the first 3 months (blanking period; early recurrence) and after 3 months up to 1 year (late recurrence) after the ablation. Results Paroxysmal and persistent AF had early recurrence rates of 29.1% and 32.2%, and late recurrence rates of 30.2% and 44.1%, respectively. The none-rare alcohol group had a higher frequency of diabetes mellitus (p=0.007). Neither moderate or heavy alcohol consumption, in reference to the none-rare group, was significantly predictive of early or late AF recurrence on adjusted multivariate logistic regression analysis (p>0.05). Conclusion Despite known associations between alcohol and incidence of AF, alcohol consumption is not associated with early or late AF recurrence after PVI in this cohort.