Biomedical subjects

John Windle

Publications and source records attributed to John Windle.

5 recordsLinked to original sources

PubMed2005

Association of myocardial ischemia with mortality and implantable cardioverter-defibrillator therapy in patients with coronary artery disease at risk of arrhythmic death.

OBJECTIVES: We sought to assess the relation between myocardial ischemia during stress echocardiography and major events in patients with implantable cardioverter-defibrillator (ICD). BACKGROUND: The association of myocardial ischemia with subsequent ICD therapy and mortality is unknown. METHODS: We studied 90 patients (age 65 +/- 13 years, 27 women) with history of coronary heart disease who received ICD for primary (53 patients) or secondary (37 patients) prevention of sudden cardiac death. Sixty-five (72%) patients had a previous coronary artery bypass surgery. Patients underwent exercise treadmill or dobutamine stress echocardiography. Ischemia was defined as new or worsening wall motion abnormalities. End points were death and appropriate ICD therapy. RESULTS: Mean ejection fraction was 34 +/- 12%. During a mean follow-up of 2.8 +/- 1.5 years, 5 patients died and 19 patients had ICD therapy. Ischemia was detected in 20 of 24 patients with subsequent events and in 24 of 66 patients without (83% vs. 36%, p < 0.001). Events occurred in 17 of the 32 patients (53%) with both ischemia and inducible ventricular tachycardia (VT) on electrophysiologic (EP) studies. None of the 16 patients without ischemia or inducible VT on EP studies had events. In a Cox multivariate analysis model, independent predictors of events were a history of spontaneous sustained VT (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.3 to 3.8), inducible VT on EP studies (HR 1.7, 95% CI 1.2 to 4.5), and ischemia (HR 2.1, 95% CI 1.2 to 3.5). CONCLUSIONS: Ischemia during stress echocardiography is an independent predictor of death and ICD therapy in patients with coronary heart disease at high risk of arrhythmic death. Patients without inducible ischemia or VT on a previous EP study have a very low risk of events. A combination of ischemia and a positive EP study is associated with a very high risk of events.

Aged↗

PubMed2005

Incidence of cardiac arrhythmias with therapeutic versus diagnostic ultrasound and intravenous microbubbles.

OBJECTIVE: The purpose of this study was to determine the type of arrhythmias induced with therapeutic versus diagnostic transthoracic low-frequency ultrasound (TLFUS) transducers in the presence of intravenous microbubbles. METHODS: Intravenous perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles were infused or given as a bolus injection while TLFUS was applied in the standard parasternal and apical views with either a 1-MHz therapeutic ultrasound transducer or high-mechanical-index diagnostic ultrasound (1.7 MHz). RESULTS: Significantly more ectopy was produced by the therapeutic transducer, especially at higher-intensity settings in the continuous wave mode after bolus injections of PESDA (P < .001 compared with lower intensities and lower continuous infusion rates). Six patients (15%) had either clinical supraventricular tachycardia or nonsustained ventricular tachycardia after intravenous PESDA with therapeutic TLFUS. In comparison, diagnostic high-mechanical-index ultrasound produced only isolated ventricular ectopy and no sustained ventricular arrhythmias. CONCLUSIONS: Intravenously injected microbubbles and low-frequency therapeutic transducers operating at longer duty cycles and wide beam widths have the capability of eliciting clinically important arrhythmias in patients at high risk for such events.

Adult↗

PubMed2003

Safety and feasibility of dobutamine stress echocardiography in patients with implantable cardioverter defibrillators.

Coronary artery disease is the underlying etiology of left ventricular dysfunction and arrhythmias in most patients who receive implantable cardioverter defibrillators (ICDs). The aim of this study was to assess the safety and feasibility of dobutamine stress echocardiography (DSE) in patients with an ICD. DSE (dobutamine up to 50 microg/kg/min, atropine up to 2 mg) was performed in 87 patients with an ICD and known or suspected coronary artery disease. The ICD was inactivated before the stress test and reactivated after the study; no serious complications occurred. DSE is a safe and feasible method for evaluating myocardial ischemia in patients with an ICD.

Aged↗

PubMed2003

Web-based physician order entry: an open source solution with broad physician involvement.

Computerized physician order entry (CPOE) is a disruptive technology but holds great promise for reducing medical errors, improving workflow and in the long run, producing cost-savings. However, many studies have reported significant physician resistance to implementing CPOE. In this manuscript we present a two-prong strategy for quick implementation of CPOE: 1) a web-based deployment tool using an open source, secure environment that allows rapid development and deployment of content, and 2) the development of a large set of disease specific order sets and knowledge bases based on established vocabulary standards such as LOINC and SNOMED CT by teams of multidisciplinary content experts at the departmental level. The order sets can be viewed, edited and signed through a standard browser interface. This paper presents the conceptual framework and implementation requirements for such an endeavor.

Attitude of Health Personnel↗

PubMed2003

Rapid deployment of physician order entry using web-based, disease-specific order sets.

Computerized physician order entry (POE) is a disruptive technology that holds great promise to reduce medical errors and improve workflow. However, Studies have reported significant physician resistance. This presentation will describe a two-pronged strategy to build broad support for POE: To build a secure, open source, browser-based platform to support POE and create a large number of disease-specific order-sets for immediate use. This presentation will demonstrate the conceptual framework and implementation requirements for such an endeavor.

Attitude of Health Personnel↗