Obesity and Heart Disease

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Body mass index > 30 kg/m²

• Increased left ventricular mass by imaging in the absence of hypertension or diabetes

• Heart failure and cardiac arrhythmias common

GENERAL CONSIDERATIONS

• Obesity is not only a risk factor for coronary artery disease, but can also cause left ventricular hypertrophy, heart failure, and arrhythmias independent of hypertension

• Fatty infiltration of the conduction system and sleep apnea have been found in obese individuals; both can lead to arrhythmias

• Eccentric left ventricular hypertrophy may be related to increased plasma volume and metabolic demands

• Obesity is also part of the metabolic syndrome, which predisposes to atherosclerosis

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Dyspnea and fatigue are common

• Chest pain and palpitations can occur

PHYSICAL EXAM FINDINGS

• Increased body mass index:

  • – Obese > 30 kg/m²

• Central (truncal or android) obesity (waist circumference > 102 cm men, > 88 cm women) is a risk factor for atherosclerosis

• Lower body (gynecoid) obesity is not a risk factor for coronary artery disease

• Systemic hypertension

• Left ventricular lift or heave

• Signs of heart failure may be present

• S₃ or S₃ may be present

DIFFERENTIAL DIAGNOSIS

• Coronary artery disease

• Dilated cardiomyopathy

• Hypertrophic cardiomyopathy

• Diabetic cardiomyopathy

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Elevated lipids

• Abnormal liver function tests from fatty accumulation

ELECTROCARDIOGRAPHY

• Prolonged QTc

IMAGING STUDIES

• CT and MRI: useful to confirm excess internal fat accumulation

• Echocardiography:

  • – Shows left ventricular hypertrophy, usually eccentric but sometimes concentric

  • – Evidence of systolic or diastolic dysfunction may be present

DIAGNOSTIC PROCEDURES

• Underwater weighing for determination of lean body mass

• Skinfold thickness measures with calipers

• Sleep study to detect sleep apnea

TREATMENT

CARDIOLOGY REFERRAL

• Suspected cardiac disease

• Difficult to control hypertension

HOSPITALIZATION CRITERIA

• Heart failure

• Respiratory failure

• Planned procedure or surgery

MEDICATIONS

• Weight loss through diet, exercise, and approved drugs

• Assessment and treatment of comorbid conditions, such as hyperlipidemia, sleep apnea, and hypertension

• Indicated treatment for heart failure or arrhythmias

SURGERY

• Bariatric surgery in selected cases

MONITORING

• ECG in hospital as appropriate

• Daily weight

DIET AND ACTIVITY

• Diet of 500–1000 kcal/day: 30% total fat, 7% saturated fat

• Aerobic exercise for at least 30 minutes a day

ONGOING MANAGEMENT