Final answer:
An artificial pacemaker is used to correct an ineffectual cardiac rhythm, providing electrical impulses to the heart muscle and may include a built-in defibrillator.
Step-by-step explanation:
The mechanical device used to correct an ineffectual cardiac rhythm is known as an artificial pacemaker. This medical device transmits electrical impulses to the heart muscle to ensure that the heart continues to contract and pump blood effectively.
Artificial pacemakers can be programmed to provide stimulation either temporarily upon demand or on a continuous basis, depending on the patient's needs. Some advanced models also include built-in defibrillators to address more serious rhythm abnormalities like atrial or ventricular fibrillation.