Biomedical subjects

Shaun Cho

Publications and source records attributed to Shaun Cho.

3 recordsLinked to original sources

PubMed2003

Prevalence and prognostic value of exercise-induced ventricular arrhythmias.

OBJECTIVE: The purpose of this study was to determine the prevalence and prognostic significance of exercise-induced ventricular arrhythmias (EIVAs) in patients referred for exercise testing, considering the arrhythmic substrate and exercise-induced ischemia. BACKGROUND: EIVAs are frequently observed during exercise testing, but their prognostic significance is uncertain. The design of this study was a retrospective analysis of prospectively collected data, and it took place in 2 university-affiliated Veterans Affairs Medical Centers. Patients comprised 6213 consecutive males referred for exercise tests. We measured clinical exercise test responses and all-cause mortality after a mean follow-up of 6 +/- 4 years. EIVAs were defined as frequent premature ventricular contractions (PVCs) constituting >10% of all ventricular depolarizations during any 30 second electrocardiogram recording, or a run of > or =3 consecutive PVCs during exercise or recovery. RESULTS: A total of 1256 patients (20%) died during follow-up. EIVAs occurred in 503 patients (8%); the prevalence of EIVAs increased in older patients and in those with cardiopulmonary disease, resting PVCs, and ischemia during exercise. EIVAs were associated with mortality irrespective of the presence of cardiopulmonary disease or exercise-induced ischemia. In those without cardiopulmonary disease, mortality differed more so later in follow up than earlier. In those without resting PVCs, EIVAs were also predictive of mortality, but in those with resting PVCs, poorer prognosis was not worsened by the presence of EIVAs. CONCLUSIONS: Exercise induced ischemia does not affect the prognostic value of EIVAs, whereas the arrhythmic substrate does. EIVAs and resting PVCs are both independent predictors of mortality after consideration of other clinical and exercise-test variables. These findings are of limited clinical significance because of the modest change in risk and the lack of any established intervention. However, they explain some of the previous controversy and highlight the need to consider resting PVCs and follow-up duration in assessing the clinical implications of EIVAs.

Electrocardiography↗

PubMed2002

Peripheral edema.

Peripheral edema often poses a dilemma for the clinician because it is a nonspecific finding common to a host of diseases ranging from the benign to the potentially life threatening. A rational and systematic approach to the patient with edema allows for prompt and cost-effective diagnosis and treatment. This article reviews the pathophysiologic basis of edema formation as a foundation for understanding the mechanisms of edema formation in specific disease states, as well as the implications for treatment. Specific etiologies are reviewed to compare the diseases that manifest this common physical sign. Finally, we review the clinical approach to diagnosis and treatment strategies.

Cardiomyopathy, Restrictive↗

PubMedDate not supplied

Prognostic value of exercise tests in male veterans with chronic coronary artery disease.

PURPOSE: The authors evaluate the prognostic value of treadmill testing in a large consecutive series of patients with chronic coronary artery disease. Exercise testing is widely performed, but analyses of the prognostic value of test results have largely concentrated on patients referred for the diagnosis of coronary artery disease, patients after an acute coronary event or procedure, or patients with congestive heart failure. METHODS: All patients referred for evaluation at two university-affiliated Veterans Affairs Medical Centers who underwent exercise treadmill tests for clinical indications between 1987 and 2000 were determined to be dead or alive using the Social Security Death Index after a mean 5.8-year follow-up. Patients without established heart disease and those with congestive heart failure were excluded, leaving the target population of those with a history myocardial infarction or coronary intervention. Clinical and exercise test variables were collected prospectively according to standard definitions; testing and data management were performed in a standardized fashion using a computer-assisted protocol. All-cause mortality was used as the endpoint for follow-up. Standard survival analysis was performed including Kaplan Meier curves and the Cox Hazard Model. RESULTS: Of the 1,473 patients with coronary artery disease who had exercise testing, 273 (19%) patients had a revascularization procedure (Revascularization group); 813 (55%) had a history of myocardial infarction, diagnostic Q waves (MI group), or both; and 387 (26%) had a history of myocardial infarction or Q wave and revascularization (Combined group). Mean age of the patients was 61.8 +/- 9 years. A total of 401 deaths occurred during a mean follow-up of 5.8 years with an annual mortality rate of 4.5%. Only two variables, age and maximal exercise capacity, were independently and statistically associated with time to death in all three groups and were the strongest predictors of all cause mortality. CONCLUSION: A simple score based on METs, age, and history of myocardial infarction or diagnostic Q waves can stratify prognosis in patients with chronic coronary artery disease. The score enabled the identification of a group at low risk (32% of the cohort) with an annual mortality rate of 2%, a group at intermediate risk (42% of the cohort) with an annual mortality rate of about 4%, and a group at high risk (26% of the cohort) with an average annual mortality rate of approximately 7%.

Age Factors↗