What tool is commonly used for ECG lead placement?

The standard tool for ECG lead placement is a 12-lead ECG machine. This device is specifically designed to record the electrical activity of the heart from multiple angles, which is crucial for diagnosing various cardiac conditions. The 12-lead ECG machine provides a comprehensive view of the heart's electrical activity by using multiple electrodes placed on the patient's chest, limbs, and sometimes the back. Each lead offers unique information about different parts of the heart, making it essential for accurate assessment and diagnosis.

Other tools mentioned, such as an ultrasound device, a stethoscope, or a blood pressure monitor, do not serve the purpose of recording electrical activity from the heart. An ultrasound device is used for imaging, a stethoscope is for auscultation, and a blood pressure monitor measures blood pressure levels, none of which are intended for ECG lead placement or the assessment of electrical heart activity.