What indicates improved contractility in the heart?

Improved contractility in the heart is indicated by the inotropic effect. The inotropic effect refers to changes in the strength or force of the heart's contractions. When inotropic agents are introduced—such as positive inotropes like dopamine or digoxin—they enhance the contractile performance of the myocardial muscle. This leads to a more effective pumping action, thereby improving cardiac output and overall efficiency of the heart.

In contrast, the chronotropic effect pertains to changes in heart rate, while the dromotropic effect pertains to the conduction velocity through the heart's conduction system. P wave activity refers to atrial depolarization and is associated with the electrical activity in the heart but does not directly indicate contractility. Therefore, the inotropic effect is the clear indicator of improved contractility, highlighting its crucial role in cardiac function.