APPENDIX A: OVERVIEW OF THE MEDTRONIC 5388 DUAL CHAMBER PACEMAKER

A schematic of the Medtronic 5388 is shown below (Figure A1); a few selected dials and buttons will be explained within this appendix. The Medtronic manual should be used for a comprehensive review of the device; the manual was used to construct this brief review in the event that the Medtronic manual would be unavailable in the deployed setting.

Figure A1. Schematic of the Medtronic 5388

POWER ON/OFF: The ON button is marked in green (number 11, Figure A1) and the OFF button is number 12 above. Press the ON key once. The upper screen lights up and the pacers initiates a self-test. Once a successful self-test is completed the following occurs: A sufficiently charged battery will allow the device to begin sensing and pacing in both the atrium and ventricle at the following nominal parameter values. Press the “OFF” button twice within 5 seconds. After the first press, a message appears in the lower screen telling the user to press OFF a second time to turn the device off.

Table A1. The power up values for the 5388 dual Medtronic pacemaker

EMERGENCY/ASYNCHRONOUS BUTTON: Press this key (number 13, Fig A1) once to select high-output, dual- chamber asynchronous (DOO) pacing at any time, whether the device is off or locked. Use caution to avoid accidentally activating the Emergency key. This button should be used if electromagnetic interference causes over sensing inhibiting the pacemaker from firing causing hemodynamic instability. The device will pace at the following values:

Table A2. Emergency Values

Adjusting the rate, A output, and V output in emergency mode: These parameters can be adjusted using the three upper dials (numbers 4, 5, and 6) on the right side of device marked in yellow in Figure A1; these dials will be detailed below. To return the device to demand or synchronous pacing:

- Press the ON key once if the asynchronous pacing message is displayed in the lower screen.
- Press the ON key twice if the asynchronous pacing message is not displayed in the lower screen. The first press of the ON key causes the asynchronous message to appear.
- The number 14 in Figure A1 identifies the lower screen.

The device will begin synchronous pacing with the following values:

Table A3. Current Settings

ADJUSTING RATE, A OUTPUT, AND V OUTPUT: the parameter settings are displayed numerically and graphically. The dials for adjustment are the numbers 4, 5, and 6 respectively (marked in yellow, Figure A1). The line next to each dial shows the range available for each parameter. The liner graph appears above the corresponding numerical value.

Rate dial (number 4 in Figure A1): The optimal RATE setting once the device turns on is 80 BPM. The pacing rate ranges from 30 to 200 beats per minute (BPM). Turning the RATE knob clockwise increases the rate, and counter-clockwise decreases the rate.

A (Atrial) OUTPUT dial (number 5 in Figure A1: The atrial output ranges from 0.1 to 20 mA. Turn the dial clockwise to increase A OUTPUT. Turn the dial counterclockwise to decrease or turn A OUTPUT OFF. When A OUTPUT is set to OFF, both the atrial output and the atrial sensitivity are turned off (i.e., there is no atrial pacing or sensing).

V (Ventricle) OUTPUT dial (number 6 in Figure A1): The ventricular output ranges from 0.1 to 25 mA. Turn the dial clockwise to increase V OUTPUT. Turn the dial counterclockwise to decrease or turn V OUTPUT to OFF. When V OUTPUT is set to OFF, both the ventricular output and the ventricular sensitivity are turned off (i.e. there is no ventricular pacing or sensing).

PACE LEDs

- Two green LEDs at the top of the device, marked PACE, number 1 in Figure A1, indicate delivery of a pacing pulse but do not necessarily indicate the pacing pulse has initiated cardiac stimulation.
- The green LED next to the A flashes each time the device delivers a pacing pulse on the atrial channel.
- The green LED next to the V flashes each time the device delivers a pacing pulse on the ventricular channel.
- The blue LEDs next to both flash when the device senses a native impulse and thus inhibits a pacing pulse in synchronous mode.

Adjusting Atrial and Ventricular Sensitivities

- The lower screen (number 14, Figure a1) allows adjustment of the atrial and ventricle sensitivities.
- Depressing the Menu button (number 9, Figure A1) and then using the Select button (number 8, Figure A1) to choose Menu 1 allows access to change the sensing values for the atrium and ventricle.
  - Atrial sensitivity (A SENSITIVITY),
  - Ventricular sensitivity (V SENSITIVITY),
  - A-V Interval (A-V INTERVAL),
  - and Atrial tracking option (A TRACKING).
- Unless manually adjusted, the atrial sensitivity (A SENSITIVITY) is set to the nominal value of 0.5 mV.
- When selected, the A SENSITIVITY may be adjusted between 0.4 and 10 mV by turning the Menu Parameter dial.
- Unless manually adjusted, ventricular sensitivity (V SENSITIVITY) is set to the nominal value of 2.0 mV.
- When selected, the sensitivity may be adjusted between 0.8 and 20 mV by turning the Menu Parameter dial.