Joseph L Schuller

Publications (10)54.23 Total impact

• Article: Endocardial Electrogram Characteristics of Epicardial Ventricular Arrhythmias.

  Wendy S Tzou, Duy T Nguyen, Ryan G Aleong, Paul D Varosy, David F Katz, Russell R Heath, Joseph L Schuller, Christopher M Lowery, Laurent Lewkowiez, William H Sauer
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  ABSTRACT: INTRODUCTION: While most ventricular arrhythmias (VA) can be ablated successfully using an endocardial (endo) approach, epicardial (epi) mapping and ablation is sometimes required. There may be suggestive clues on the surface electrocardiogram; however, identification of an epi origin of VA with certainty remains problematic. METHODS AND RESULTS: All patients referred for ablation of ventricular tachycardia or frequent ventricular ectopy from June 2007 to July 2011 were evaluated. Patients with completed endo and epi electroanatomical activation maps of an epi VA were included (n = 10). Bipolar electrograms (EGMs) in the area of earliest endo activation were analyzed and compared to the area of early epi activation. An EGM component was characterized as far field if it was monophasic and there was inability to capture. We identified 3 characteristics from endo mapping that consistently indicated need for epi ablation: (1) Diffusely early activation (>2 cm(2) region of sites with equally earliest activation within 10 milliseconds). (2) Sequence of a far-field EGM followed by a near-field EGM in the region of earliest endo activation. (3) Inability to capture the far-field component of the earliest EGM (stim-QRS < egm-QRS time) or reproduce morphological features of the VA complex with stimulation at the earliest endo site of activation. CONCLUSIONS: The presence of a diffusely early area of activation and inability to capture a far-field endo EGM indicates that epi ablation may be needed to eliminate a VA.
  Journal of Cardiovascular Electrophysiology 01/2013; · 3.06 Impact Factor
• Article: Use of Stored Implanted Cardiac Defibrillator Electrograms in Catheter Ablation of Ventricular Fibrillation.

  Christopher M Lowery, Wendy S Tzou, Ryan G Aleong, Duy T Nguyen, Paul D Varosy, David F Katz, Russell R Heath, Joseph L Schuller, Laurent Lewkowiez, William H Sauer
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  ABSTRACT: BACKGROUND: Ventricular fibrillation (VF) can be abolished by targeting triggering ventricular ectopy, most often originating in the Purkinje network or right ventricular outflow tract (RVOT). This strategy relies upon the induction of premature ventricular complex (PVC) and/or VF. We sought to evaluate a VF ablation strategy that utilizes analysis of stored implantable cardioverter defibrillator (ICD) electrograms. METHODS: Eleven consecutive patients experiencing frequent VF episodes (≥three episodes in prior month) underwent electrophysiology study and ablation of VF triggers. PVC and VF induction was intentionally avoided or not possible in all of these patients. Pacemapping at likely sites for PVC triggers of VF using an analysis of the morphology and relative timing of the stored far- and near-field ICD electrograms of VF triggers was used to identify potential culprit locations. Radiofrequency energy was applied to these sites for ablation of the identified VF trigger. RESULTS: Areas targeted for ablation included the left posterior fascicle (six), left anterior fascicle (three), RVOT (three) and left ventricular outflow tract (one); two patients had two separate triggers. Ablation was completed successfully without any complications. With a mean follow-up of 288 days (range 45-649), 10 patients are free of VF. CONCLUSION: Ablation of VF triggers can be performed successfully with good short-term outcomes in patients with and without underlying heart disease. Use of stored ICD electrograms with a focus on likely target areas permit ablation without the need for PVC or VF induction. This can be useful when ectopy is not present for mapping and to avoid potentially dangerous initiation of multiple episodes of VF.
  Pacing and Clinical Electrophysiology 10/2012; · 1.35 Impact Factor
• Article: Implantable cardioverter defibrillator therapy in patients with cardiac sarcoidosis.

  Joseph L Schuller, Matthew Zipse, Thomas Crawford, Frank Bogun, John Beshai, Amit R Patel, Nadera J Sweiss, Duy T Nguyen, Ryan G Aleong, Paul D Varosy, Howard D Weinberger, William H Sauer
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  ABSTRACT: ICD Shocks in Cardiac Sarcoidosis. 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. We performed a cohort study of patients with ICDs at 3 institutions. Cases were those patients with CS and an ICD implanted for primary or secondary prevention of sudden death. Additionally, we included a comparison with historical controls of ICD therapy rates reported in clinical trials evaluating the ICD for primary and secondary prevention of sudden death. Of the 112 CS subjects identified, 36 (32.1%) received appropriate therapies for ventricular tachyarrhythmias (VT) over a mean follow-up period of 29.2 months. VT storm (>3 episodes in 24 hours) occurred in 16 (14.2%) CS subjects. Inappropriate therapies occurred in 13 CS subjects (11.6%). Covariates associated with appropriate ICD therapies included left ventricular ejection fraction (LVEF) <55% (OR 6.52 [95% CI 2.43-17.5]), right ventricular dysfunction (OR 6.73 [95% CI 2.69-16.8]), and symptomatic heart failure (OR 4.33 [95% CI 1.86-10.1]). In our cohort of patients with CS and ICDs, almost one-third receive appropriate therapies. This may be due to a myocardial inflammatory process leading to increased triggered activity and subsequent scarring leading to reentrant tachyarrhythmias. Adjusted predictors of ICD therapies in this population include left or right ventricular dysfunction. (J Cardiovasc Electrophysiol, Vol. 23, pp. 925-929, September 2012).
  Journal of Cardiovascular Electrophysiology 07/2012; 23(9):925-9. · 3.06 Impact Factor
• Article: Utility of cardiac magnetic resonance imaging to differentiate cardiac sarcoidosis from arrhythmogenic right ventricular cardiomyopathy.

  David A Steckman, Preston M Schneider, Joseph L Schuller, Ryan G Aleong, Duy T Nguyen, Gianfranco Sinagra, Giancarlo Vitrella, Francesca Brun, Maria A Cova, Lorenzo Pagnan, Luisa Mestroni, Paul D Varosy, William H Sauer
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  ABSTRACT: Some patients diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) are eventually found to have cardiac sarcoidosis (CS). Accurate differentiation between these 2 conditions has implications for immunosuppressive therapy and familial screening. We sought to determine whether cardiac magnetic resonance imaging (MRI) could be used to identify the characteristic findings to accurately differentiate between CS and ARVC. Consecutive patients with a diagnostic MRI scan indicating CS and/or ARVC constituted the cohort. All patients diagnosed with CS had histologic confirmation of sarcoidosis, and all patients with ARVC met the diagnostic task force criteria. The cardiac MRI data were retrospectively analyzed to identify possible differentiating characteristics. Of the patients, 40 had CS and 21 had ARVC. Those with CS were older and had more left ventricular scar. The presence of mediastinal lymphadenopathy or left ventricular septal involvement was seen exclusively in the patients with CS (p <0.001). A family history of sudden cardiac death was seen only in the ARVC group (p = 0.012). The right ventricular ejection fraction and ventricular volumes were also significantly different between the 2 groups. In conclusion, patients with CS have significantly different cardiac MRI characteristics than patients with ARVC. The cardiac volume, in addition to the degree and location of cardiac involvement, can be used to distinguish between these 2 disease entities. The presence of mediastinal lymphadenopathy and left ventricular septal scar favors a diagnosis of CS and not ARVC. Consideration of CS should be given if these MRI findings are observed during the evaluation for possible ARVC.
  The American journal of cardiology 05/2012; 110(4):575-9. · 3.58 Impact Factor
• Article: The irregular tachycardia that was not atrial fibrillation.

  David F Katz, Paul D Varosy, Duy T Nguyen, Joseph L Schuller, Ryan G Aleong, Russell R Heath, William H Sauer
  Archives of internal medicine 12/2011; 171(22):1985-8. · 11.46 Impact Factor
• Article: Electrocardiographic characteristics in patients with pulmonary sarcoidosis indicating cardiac involvement.

  Joseph L Schuller, Matthew D Olson, Matthew M Zipse, Preston M Schneider, Ryan G Aleong, Howard D Wienberger, Paul D Varosy, William H Sauer
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  ABSTRACT: 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. Our cohort consisted of referred patients with biopsy-proven pulmonary sarcoidosis who demonstrated symptoms consistent with cardiac involvement. The ECG characteristics collected were PR, QRS duration, QT interval, rate, bundle branch block (BBB), fragmented QRS (fQRS). QRS fragmentation was defined as 2 anatomically contiguous leads demonstrating RSR' patterns in the absence of BBB. There were 112 subjects included in the cohort. Of the 52 subjects eventually diagnosed with CS, 39 had an ECG demonstrating fQRS while 21 of the 60 of non-CS patients had fQRS (75% vs 33.9%, P < 0.01). A RBBB or LBBB pattern were both more prevalent in the CS population (RBBB: 23.1% vs 6.7%, P = 0.016; LBBB: 3.8% vs 1.7%, P = 0.6). QRS duration remained significantly associated with CS after exclusion of those with BBB (93.5 +/- 10.6 vs 88 +/- 11 ms; P = 0.04). When fQRS and bundle branch block were combined, 90.4% of CS patient's ECGs contained at least one of the features, compared to 36.7% of noncardiac CS (P < 0.01). The presence of fQRS or BBB pattern in patients with pulmonary sarcoidosis is associated with cardiac involvement and therefore should prompt further evaluation.
  Journal of Cardiovascular Electrophysiology 05/2011; 22(11):1243-8. · 3.06 Impact Factor
• Article: Images in cardiovascular medicine: a mobile tubular mass visualized by transesophageal echocardiography after successful lead extraction.

  Russell R Heath, Joseph L Schuller, William H Sauer, Paul D Varosy, Duy T Nguyen, Ryan G Aleong
  Circulation 05/2011; 123(19):e590-1. · 14.74 Impact Factor
• Article: Life-threatening ST-segment elevation without coronary artery disease.

  Russell R Heath, Paul D Varosy, David F Katz, Joseph L Schuller, Ryan G Aleong, William H Sauer, Duy T Nguyen
  Archives of internal medicine 05/2011; 171(9):801, 802-3. · 11.46 Impact Factor
• Article: Diagnostic utility of signal-averaged electrocardiography for detection of cardiac sarcoidosis.

  Joseph L Schuller, Christopher M Lowery, Matthew Zipse, Ryan G Aleong, Paul D Varosy, Howard D Weinberger, William H Sauer
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  ABSTRACT: 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. Subjects with biopsy proven sarcoidosis and symptoms suggestive of possible cardiac involvement were included in the cohort. Standard criteria for SAECG were used. Subjects were considered to have CS if they met criteria established by the Japanese Ministry of Health and Welfare modified to include cardiac MRI. Of the 88 patients in the cohort 27 had evidence of CS independent of the SAECG results. The SAECG was abnormal in 14 of these 27 patients and 11 of the 61 of the subjects without cardiac involvement (P < 0.01). The sensitivity of SAECG detection of CS was 52% with a specificity of 82%. For the entire cohort, SAECG had a positive predictive value (PPV) of 0.56 and a negative predictive value (NPV) of 0.79. Within a subgroup of 67 patients with an unfiltered QRS duration of <100 ms, the specificity for diagnosing cardiac sarcoidosis improves to 100% with a reduced sensitivity of 36.8. Of the SAECG parameters, LAS40 was significantly associated with the diagnosis of cardiac sarcoidosis for the entire cohort (P < 0.01) and among the subgroup of patients with an unfiltered QRS duration of <100 ms (P < 0.01). SAECG is a useful screening tool in the evaluation of sarcoidosis for detection of cardiac involvement.
  Annals of Noninvasive Electrocardiology 01/2011; 16(1):70-6. · 1.10 Impact Factor
• Article: Utility of postoperative testing of implantable cardioverter-defibrillators.

  William H Sauer, Christopher M Lowery, Royce L Bargas, Joseph L Schuller, Christoper S Stees, Ryan G Aleong, Paul D Varosy
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  ABSTRACT: Implantable cardioverter-defibrillators (ICDs) can provide life-saving therapies for ventricular arrhythmias. Arrhythmia induction and defibrillation threshold testing is often performed at implantation and postoperatively during long-term follow-up to ensure proper device function. We sought to evaluate the prevalence and predictors of occult device malfunction at follow-up defibrillation testing in asymptomatic individuals. A cohort of 853 patients underwent 1,578 defibrillation tests during the 13-year study period. Defibrillation efficacy was evaluated primarily by the two-shock (2S) method, with an adequate safety margin ≥ 10 joules (J) less than the maximum energy delivered by the ICD. A total of 38 testing failures requiring intervention were discovered during testing (2.4% of all tests). There were 11 ICD system failures resulting in failure to defibrillate, six with underdetection of ventricular fibrillation, and 21 clinically significant increases in defibrillation threshold. There was a higher incidence of failure in older ICD systems (1996-2002) compared to newer ICD systems (2003-2009), reaching statistical significance (3.6% vs 1.0%; P < 0.01). There were 178 subjects (20.8%) with a >20-J safety margin on previous testing, detected R waves >7.0 mV, and all system components implanted after 2003 at the time of testing who did not have any testing failures (0% vs 5.6%; P < 0.01). Postoperative defibrillation testing identifies a small number of ICD malfunctions in asymptomatic individuals. ICD testing failure is seen more frequently in older systems and in those with borderline results from prior interrogation or testing. These findings suggest that serial postoperative defibrillation testing is not indicated in asymptomatic patients without suspicion for specific problems.
  Pacing and Clinical Electrophysiology 10/2010; 34(2):186-92. · 1.35 Impact Factor