**6. Diagnosis of coronary artery disease (CAD) in obesity**

CAD has been associated with higher measures of central adiposity, including WC and WHR inclusive those with normal weight and BMI. The degree and duration of obesity expressed as excess BMI years and WC years are stronger predictors of CAD [21].

Many changes can occur in the patients with CAD. There are noninvasive and invasive modalities to assess CAD in patients with obesity. These will be described below.

#### **6.1 Noninvasive CAD assessment**

#### *6.1.1 Electrocadiography*

Obesity has the potential to affect the ECG in several ways: displacing the heart by elevating the diaphragm in the supine position, increasing the cardiac workload, and increasing the distance between the heart and the recording electrodes.

Several electrocardiographic changes are associated with obesity (**Table 1**).

More frequent ST-segment depression is seen in patients with overweight and CAD, and insulin concentration may be related to the development of the ST-segment depression over time [21].


#### **Table 1.**

*Electrocardiographic changes in importance order.*

### *6.1.2 Treadmill stress test*

Many patients with obesity fail to achieve 80–85% of the age-predicted heart rate needed for diagnostically valid results.

Chronotropic competence can be reduced in obesity, with a prior study showing that peak heart rate, heart rate recovery, and chronotropic index are lower in patients with obesity, regardless of fitness level [45].

### *6.1.3 Stress ecocardiography*

Stress echocardiography is highly feasible in most cases for patients with obesity through either physiological stress (treadmill exercise) or pharmacological stress (dobutamine).

However, stress echocardiography is highly operator-dependent and can be limited in the presence of poor acoustic windows related to pulmonary disease, breast size, obesity, and respiratory motion. Contrast study in obesity patients is suggested because the sensitivity is better than without contrast. Contrasted images improved sensitivity and specificity (82% vs 70% and 78% vs. 67%, respectively) [46].
