Digital Signal Processing Chip Implementation for Detection and Analysis of Intracardiac Electrograms

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72573/1/j.1540-8159.1994.tb02456.x.pd

Paroxysmal Bundle Branch Block of Supraventricular Origin: A Possible Source of Misdiagnosis in Detecting Ventricular Tachycardia Using Time Domain Analyses of Intraventricular Electrograms

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72385/1/j.1540-8159.1990.tb02060.x.pd

Effect of Propranolol on Ventricular Rate During Atrial Fibrillation in the Wolff-Parkinson-White Syndrome

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74695/1/j.1540-8159.1987.tb04511.x.pd

The role of [beta]-blockade therapy for ventricular tachycardia induced with isoproterenol: A prospective analysis

Isoproterenol is sometimes required for ventricular tachycardia (VT) induction. However, the role of [beta]-blockade for treatment of such VT has not been critically assessed. The use of [beta]-blockade was evaluated prospectively in 14 consecutive patients who required isoproterenol 2.4 +/- 1.3 (+/-S. D.) [mu]g/min to induce sustained monomorphic VT (>30 seconds, or requiring termination due to hemodynamic collapse) after a negative baseline study. The VT mechanisms were enhanced automaticity (group A, six patients), triggered automaticity (group B, three patients), and reentry (group C, five patients). Groups A and B had serial intravenous electropharmacologic tests with propranolol alone (0.2 mg/kg), verapamil alone (0.15 mg/kg), and propranolol plus verapamil, and group C had serial tests with propranolol alone, procainamide or quinidine (class la drug) alone, and propranolol plus a class la drug until VT could no longer be induced. All six patients in group A responded to propranolol alone. In group B, one patient responded to verapamil alone, and two patients responded to propranolol plus verapamil. In group C, three patients responded to propranolol alone, one patient responded to a class la drug alone, and one patient responded to propranolol plus a class la drug. During a follow-up of 7 to 37 (17.9 +/- 10.7) (+/-S. D.) months, VT has not recurred in any patient. Three patients treated initially with propranolol alone have required substitution of amiodarone due to refractory congestive heart failure. In patients requiring isoproterenol for VT induction, [beta]-blockade alone appears to be effective in preventing reinduction of VT caused by enhanced automaticity. A heterogeneous response occurs when the VT mechanisms are triggered automaticity or reentry.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28950/1/0000787.pd

Identification of ventricular tachycardia using morphologic analysis of the intraventricular electrogram

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27624/1/0000668.pd

A new computer diagnostic system for ventricular and supraventricular arrhythmias

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27625/1/0000669.pd

Automated interpretation of cardiac arrhythmias : Design and evaluation of a computerized model

Historically, the development of computerized models that utilize the deductive methods used by clinicians for the interpretation of cardiac arrhythmias have been limited by the absence of a consistently reliable means of detecting atrial activation. In this study, a theoretical model was developed with a hierarchical organization of problem-solving strategies utilizing automated analysis of atrial activation from a commercially available esophageal pill electrode and ventricular activation from a simultaneously recorded surface electrocardiographic lead. The theoretical model was then tested in 21 patients with 1 or more or 28 distinct supraventricular and ventricular arrhythmias. Of the 641 individual cardiac cycles analyzed, 636 (99.2%) were correctly identified. The accuracy of a contextual, that is, more comprehensive, interpretation of consecutive cardiac cycles was 638/641 (99.5%). The following cardiac arrhythmias were identified: sinus rhythm, sinus bradycardia, atrial premature depolarizations, atrial flutter, and supraventricular tachycardias with normal and aberrant ventricular conduction, first-degree and second-degree heart block; junctional escape, junctional rhythm, idioventricular rhythm, ventricular premature depolarization, and ventricular tachycardia with and without retrograde activation; atrial bigeminy, atrial trigeminy, atrial couplets, ventricular bigeminy, ventricular trigeminy, and ventricular couplets. This study represents the first computerized model ever developed to incorporate the morphology and timing of atrial activation with the morphology and timing of ventricular activation for arrhythmia diagnosis. Such modeling appears to be capable of achieving accurate interpretation of spontaneous, complex clinical cardiac arrhythmias and atrioventricular relationships.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31035/1/0000712.pd

An Analysis of Post-Pacing R-R Intervals During Atrial Fibrillation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74691/1/j.1540-8159.1986.tb04496.x.pd

Autonomic regulation therapy to enhance myocardial function in heart failure patients: the ANTHEM-HFpEF study.

BackgroundApproximately half of the patients presenting with new-onset heart failure (HF) have HF with preserved left ventricular ejection fraction (HFpEF) and HF with mid-range left ventricular ejection fraction (HFmrEF). These patients have neurohormonal activation like that of HF with reduced ejection fraction; however, beta-blockers and angiotensin-converting enzyme inhibitors have not been shown to improve their outcomes, and current treatment for these patients is symptom based and empiric. Sympathoinhibition using parasympathetic stimulation has been shown to improve central and peripheral aspects of the cardiac nervous system, reflex control, induce myocyte cardioprotection, and can lead to regression of left ventricular hypertrophy. Beneficial effects of autonomic regulation therapy (ART) using vagus nerve stimulation (VNS) have also been observed in several animal models of HFpEF, suggesting a potential role for ART in patients with this disease.MethodsThe Autonomic Neural Regulation Therapy to Enhance Myocardial Function in Patients with Heart Failure and Preserved Ejection Fraction (ANTHEM-HFpEF) study is designed to evaluate the feasibility, tolerability, and safety of ART using right cervical VNS in patients with chronic, stable HFpEF and HFmrEF. Patients with symptomatic HF and HFpEF or HFmrEF fulfilling the enrolment criteria will receive chronic ART with a subcutaneous VNS system attached to the right cervical vagus nerve. Safety parameters will be continuously monitored, and cardiac function and HF symptoms will be assessed every 3 months during a post-titration follow-up period of at least 12 months.ConclusionsThe ANTHEM-HFpEF study is likely to provide valuable information intended to expand our understanding of the potential role of ART in patients with chronic symptomatic HFpEF and HFmrEF

Ventricular Tachycardia Detection Using Bipolar Electrogram Analysis is Site Specific

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75656/1/j.1540-8159.1992.tb03039.x.pd