Biopotential amplifier and signal conditioner. Transducer signal amplifier and conditioner. Cardiovascular blood flowmeter. Extravascular blood flow probe. Adjunctive cardiovascular status indicator. Adjunctive predictive cardiovascular indicator. Adjunctive hemodynamic indicator with decision point. Cardiac monitor (including cardiotachometer and rate alarm). Apex cardiograph (vibrocardiograph). Ballistocardiograph. Echocardiograph. Electrocardiograph. Electrocardiograph software for over-the-counter use. Electrocardiograph lead switching adaptor. Electrocardiograph electrode. Electrocardiograph surface electrode tester. Phonocardiograph. Vectorcardiograph. Medical cathode-ray tube display. Signal isolation system. Line isolation monitor. Portable leakage current alarm. Oscillometer. Oximeter. Ear oximeter. Impedance phlebograph. Impedance plethysmograph. Hydraulic, pneumatic, or photoelectric plethysmographs. Software for optical camera-based measurement of pulse rate, heart rate, breathing rate, and/or respiratory rate. Hardware and software for optical camera-based measurement of pulse rate, heart rate, breathing rate, and/or respiratory rate. Photoplethysmograph analysis software for over-the-counter use. Medical magnetic tape recorder. Paper chart recorder. Apex cardiographic transducer. Extravascular blood pressure transducer. Implantable Intra-aneurysm Pressure Measurement System. Heart sound transducer. Catheter tip pressure transducer. Ultrasonic transducer. Vessel occlusion transducer. Patient transducer and electrode cable (including connector). Radiofrequency physiological signal transmitter and receiver. Telephone electrocardiograph transmitter and receiver.