Final answer:
In infective endocarditis, a patient may develop atrioventricular (AV) block, which is an interruption in the normal conduction pathways of the heart. AV block can be classified into degrees, with third-degree block showing no correlation between atrial and ventricular activity. This can be observed on an electrocardiogram (ECG).
Step-by-step explanation:
Atrioventricular (AV) block refers to an interruption in the normal conduction pathway between the atria and ventricles of the heart. In infective endocarditis, which is an infection of the heart valves, a patient may develop AV block. AV blocks can be classified into degrees - first-degree, second-degree, and third-degree blocks. In a third-degree or complete block, there is no correlation between atrial activity (the P wave) and ventricular activity (the QRS complex). This can be observed on an electrocardiogram (ECG) as a lack of relationship between the P waves and QRS complexes.