Final answer:
sEMG cannot capture the effectiveness of the heart's pumping; for that, an echocardiogram or nuclear medicine imaging is required.
Step-by-step explanation:
sEMG, or surface electromyography, can be used to capture various physiological events, but it has limitations in what it can reliably detect. sEMG cannot capture the effectiveness of the heart's pumping, as this requires additional tests, such as an echocardiogram or nuclear medicine imaging. While sEMG or ECG can detect electrical activity, certain conditions such as pulseless electrical activity may show on an ECG although there is no corresponding pumping action. Other techniques, like MEG, use sensors such as the SQUID for measuring very small magnetic fields related to brain activity, providing insights into conditions such as Alzheimer's disease and epilepsy, but do not assess the heart's effectiveness.