Theory of Operations:

The Model 2A generates cardiac stimulation pulses which are administered to the patient's heart via the TAPSCOPE 550, an 18 Fr esophageal stethoscope with bipolar pacing electrodes. All circuitry is contained on a single printed circuit board mounted behind the front control panel. When the power switch is toggled to ON, DC power from 2 D-cell batteries is applied to a power regulation circuitry, a DC-DC converter, and a rectangular pulse forming circuit with a constant current output stage whose amplitude can be varied over a broad range of load impedances. Hospital Biomedical Engineers requiring a complete Model 2A Service Manual (including circuitry schematics and parts list) should contact CardioCommand Customer Service at 1-800-231-6370.

Device Specifications:

Electrical

RATE: Continuously variable, 50-200 BPM
AMPLITUDE: Continuously variable, 5.5-40 mA rectangular waveform
DURATION: Constant at 10 msecs/pulse
Accuracy: Stimulus parameters within ± 10 % of full scale
On/Off: Toggle switch
Impedance: Constant current over loads up to 2k ohms at 20 mA
Defibrillation: Protected up to 400 Joules

Physical

Size: 2.92" (7.4 cm) high x 4.73" (12) deep x 6.70" (17) wide
Weight: 0.7 lbs (.32 kg) without batteries
Material: Impact-resistant ABS plastic enclosure

Power Supply

Battery type: 1.4 V Alkaline D-cell (2). The unit should operate normally for 70 hours with fully charged batteries at specified operating conditions.
Continued operation on low-batteries may result in erratic output.
Warning: Use of batteries other than those recommended by manufacturer may result in the Model 2A not operating within specifications.

Cable

10 foot cable assembly provides connection between TAPSCOPE esophageal cardiac pacing/recording catheter and Model 2A TAPSYSTEM stimulator.

Indicator Lights

• A yellow LED illuminates to indicate low battery.
• A green LED indicator flashes with each stimulus pulse delivered only
  when an appropriate load impedance is connected to the stimulator.

Model 550 TAPSCOPE:

18 French esophageal stethoscope with MA100 Series Thermistor and bipolar electrodes for connection to Model 2A Stimulator (cardiac pacing) or to EC-View Adaptor (ECG recording). Esophageal catheter has markings indicating Depth of Insertion of electrodes from the lips (cm).

Each single-use, disposable TAPSCOPE is individually pouched. 25 units are shipped per carton.

EC-View ECG Adaptor:

When the TAPSCOPE is not used for pacing, the bipolar electrodes can be used for monitoring of the esophageal ECG using the EC-View Adaptor. Two snap contacts allow attachment of standard ECG leads for connection with ECG monitors or other recording devices. Adaptors are individually pouched and shipped as single units.

2A Pole Mount:

Metal frame for attaching Model 2A TAPSYSTEM to hospital pole.