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5 - Cardiac morphology and ventricular function
- from Section 2 - Pathophysiology
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- By M.A. Alpert, Chairman, Department of Medicine, St. John's Mercy Medical Center, St. Louis, MO, USA; Clinical Professor of Medicine, University of Missouri School of Medicine, Columbia, MO, USA
- Edited by Adrian O. Alvarez
- Edited in association with Jay B. Brodsky, Stanford University School of Medicine, California, Martin A. Alpert, George S. M. Cowan
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- Book:
- Morbid Obesity
- Published online:
- 17 August 2009
- Print publication:
- 04 November 2004, pp 59-68
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- Chapter
- Export citation
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Summary
Introduction
Obesity produces a variety of hemodynamic alterations that affect cardiac morphology and ventricular function. These alterations occur in persons with mild-to-moderate obesity, but are most pronounced in those with morbid obesity. This chapter discusses the hemodynamic changes that occur with mild, moderate and morbid obesity, reviews their impact of cardiac morphology and ventricular function, describes the clinical syndrome of obesity cardiomyopathy and discusses the effects of weight loss on these alterations. These changes in cardiac structure and function may have important implications for anesthesiologists concerning the choice of anesthesia and peri-operative care of the surgical patient.
Classification of obesity
The World Health Organization classifies obesity in terms of body mass index (BMI). The classifications are as follows: lean or normal range (18.5–24.9kg/m2); pre-obese or overweight (25.0–29.9 kg/m2); mild or class I obesity (30.0–34.9 kg/m2); moderate or class II obesity (35.0–39.9 kg/m2); and morbid or class III obesity (≥40.0 kg/m2). Many of the studies cited in this review used this classification system. However, some of the studies used different criteria for obesity and morbid obesity. Obesity was defined by some as ≥20% over ideal body weight or relative weight ≥120%. Morbid obesity was defined by some as ≥twice ideal body weight or relative weight ≥200%.
17 - Electrocardiography
- from Section 6 - Monitoring
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- By M.A. Alpert, Chairman, Department of Medicine, St. John's Mercy Medical Center, St. Louis, MO, USA; Clinical Professor of Medicine, University of Missouri School of Medicine, Columbia, MO, USA
- Edited by Adrian O. Alvarez
- Edited in association with Jay B. Brodsky, Stanford University School of Medicine, California, Martin A. Alpert, George S. M. Cowan
-
- Book:
- Morbid Obesity
- Published online:
- 17 August 2009
- Print publication:
- 04 November 2004, pp 243-254
-
- Chapter
- Export citation
-
Summary
Introduction
There is a worldwide epidemic of obesity in developed nations that involves virtually all ages, races and socio-economic classes. In the US alone nearly one-third of the population is overweight or obese. Consequently, it is logical to assume that a comparable proportion of patients presenting for anesthesia and analgesia will be overweight or obese, and will be subject to the complications of this increasingly common malady. A resting 12-lead electrocardiogram (ECG) is routinely performed on obese patients who present for medical or surgical evaluation. Obesity is associated with a wide variety of ECG abnormalities. Some of these are innocuous. Some may represent alterations in cardiac morphology associated with obesity and/or its co-morbidities. Still others may serve as markers of risk for sudden cardiac death. Many of these alterations are reversible with weight loss. This chapter describes ECG abnormalities associated with obesity. Morbidly obese patients receive special attention because of the large body of information available concerning the ECG in this group. In addition to reviewing alterations in heart rate, axis, waves and intervals, this chapter addresses the issue of arrhythmogenesis by discussing ventricular repolarization, the signal-averaged ECG and heart rate variability. Arrhythmias associated with obesity are also reviewed. Finally, ECG abnormalities and arrhythmias associated with dietary therapy, bariatric surgery and currently available anorexiant drugs are described.