Implanted pump
Supports blood flow when the heart cannot pump enough.
MASTER’S THESIS · 2024
A lighter, calmer life with a heart pump
A wearable system and controller for people living with a left ventricular assist device — a pump that keeps their heart going 24 hours a day.
01 LVAD IN A NUTSHELL
A pump inside the body. A controller and batteries outside.
In shortLVAD supports the heart continuously, so its external equipment can never simply be taken off.
A left ventricular assist device helps a weakened heart pump blood. A cable passes through the skin and connects the implanted pump to a controller and two batteries worn around the clock.
Driveline
A cable exits through the skin and carries power to the pump.
External kit
A controller and two batteries stay connected day and night.
Inside the bodyLVAD pump
Through the skinDriveline
Always carriedController + 2 batteries
Every day
Check power, alarms and pump readings.
Always ready
Carry a spare controller and spare batteries.
Keep it dry
No water near the controller or driveline.
For years
Many patients live with LVAD for 8–9 years or more.
02 THE PROBLEM
The pump saves lives. The equipment around it was designed for the hospital, not for everyday life.
BASIC KIT2.5 kg
Always on the body
Controller, 2 batteries
Leaving home
+ a spare controller and 2 spare batteries
Travelling
+ chargers and battery clips, dressings, carrying accessories, a shower kit, medicines and prescriptions, medical records, contact cards…
A cable comes out through the skin and connects the implanted pump to an external controller and two batteries. Patients carry them all the time, often for years while waiting for a transplant.
Weight. The basic kit weighs about 2.5 kg, and more when travelling.
Carrying. The standard bag hangs off one shoulder and causes back and neck pain.
Clothing. There is no good place for the kit. People cut holes in clothes or sew their own vests.
Fear. The cable can catch on a door handle. A disconnection can be fatal.
Visibility. Cables and bags make the illness visible to everyone.
HOW PEOPLE COPE TODAY
Shoulder bags, backpacks and cables worn over clothing: hospital equipment carried through ordinary life.
I feel like I look like a bum most of the time.
LVAD patient
My husband carries my backup bag if we’re together. He figures I’m already carrying almost 5 pounds.
LVAD patient
I am afraid to go among people, to be jerked and the driveline will come off.
LVAD patient
My husband wears his batteries on the outside of his clothes so he always gets strange looks. I’m always afraid it will be mistaken for a bomb.
Caregiver
03 RESEARCH
Six methods, including testing the device
In shortThe controller mattered, but batteries, carrying and discretion shaped daily life most.
I combined first-hand experience with patient and clinical evidence. The methods were deliberately different: what people said, what the literature showed and what the equipment did to the body.
LVAD users surveyed in Poland and abroad
rated how the device fits daily life as poor or very poor
asked for lower weight
THE SIX METHODS
SWOT
Carrying solutions already on the marketExisting products improve mobility, but often distribute weight poorly, offer few sizes and feel designed mainly for men.
Surveys
15 LVAD users, aged 20 to 80+People valued battery life and independence, but asked for less weight, fewer cables and a better fit with clothing.
Interviews
Patients, specialists and VAD coordinatorsThe controller was unlikely to shrink soon. Clothing, carrying and battery design offered more realistic leverage.
Scientific sources
Studies and surveys of patients and coordinatorsThe carrying bag was the most criticised element, and many patients already used their own solutions.
Living with the kit
Two weeks wearing a complete HeartMate 3 setCables caught on furniture, the bag competed with everyday luggage and the load caused neck and back pain.
Teardown
Controller and battery taken apart and weighedEach battery weighed more than the controller. Battery technology, not the pump, offered the clearest size and weight gain.
04 FROM RESEARCH TO A DECISION
The direction was chosen, not assumed
In shortKeep medical redundancy, reduce the kit from three main parts to two, and balance the load around the body.
I moved from a broad opportunity map to four battery architectures, then scored the viable options against weighted safety and daily-life criteria.
DESIGN HYPOTHESIS
Better integration with daily life can improve both safety and quality of life. The load has to be lighter, better carried and easier to understand.
1 · THREE POSSIBLE DIRECTIONS
Route 1CHOSEN
Adapt to today
- What
- Clothing and accessories for different activities
- Key values
- Comfort, fit, activity, modularity
Route 2NOT PURSUED
Optimise what exists
- What
- A better version of today’s external kit
- Key values
- Efficiency, ergonomics, safety
Route 3CHOSEN
A new solution
- What
- A device based on technology becoming feasible
- Key values
- Integration, miniaturisation, smart management
2 · FOUR BATTERY SCENARIOS
Scenario 01
Today
Controller + 2 external batteries
- Benefit
- Safe and proven
- Trade-off
- Heavy; three main parts
Scenario 02
Smaller batteries
Controller + 2 smaller external batteries
- Benefit
- Lighter and more comfortable
- Trade-off
- Still three parts to carry
Scenario 03CHOSEN
Built-in + one spare
Controller with a built-in battery + 1 external battery
- Benefit
- Lighter, balanced and redundant
- Trade-off
- Requires a redesigned controller
Scenario 04
Modular batteries
Controller + configurable battery modules
- Benefit
- Flexible and personal
- Trade-off
- More connections that can fail
3 · WEIGHTED DECISION MATRIX
| Criterion | Scenario 2Smaller batteries | Scenario 3Built-in + one spare | Scenario 4Modular batteries |
|---|---|---|---|
| Safetyweight ×5 |  3/3 |  2/3 |  1/3 |
| Reliabilityweight ×5 | 3/3 |  3/3 |  2/3 |
| Weightweight ×4 | 1/3 | 2/3 | 3/3 |
| Mobilityweight ×4 | 2/3 | 3/3 | 3/3 |
| Number of partsweight ×3 | 1/3 | 3/3 | 2/3 |
| Technical feasibilityweight ×2 | 3/3 | 3/3 | 2/3 |
| Weighted total | 512nd | 60Recommended | 493rd |
Each scenario scores 1–3. The score is multiplied by the criterion weight; safety and reliability carry the highest weight because failure can be life-threatening.
THE DECISION
A controller with a built-in battery, plus one slide-on spare.
Two power sources preserve the redundancy a life-supporting device needs. Integrating one battery reduces the main parts from three to two and distributes weight more evenly.
05 PHYSICAL PROTOTYPING
Dozens of models, fittings and knitted samples
In shortThe controller, battery and wearable system developed together because every change affected grip, weight and access.
The process moved between the hand and the body. Open the section to see the controller, placement and knitwear tracks.
Open the physical processThree tracks · ten documented process materials
main parts to carry and connect
less battery volume for the same energy
battery size chosen after body tests
01
Controller
From sketches to foam blocks and 3D prints held by people of different ages.
02
Battery placement
Foam batteries at the hips, waist and back; belt and vest mock-ups worn under clothes.
03
Knitwear
Seamless 3D knit with breathable zones against the skin and stronger zones carrying the load.
06 INTERFACE
From five button presses to certainty at a glance
In shortShow all essential readings together, keep time left visible and turn every alarm into a clear next step.
Patients must check the device, but they do not want to keep looking at it. I began by auditing the HeartMate 3 controller, then connected each research insight to a design decision.
One value per press
1× pressSpeed
2× pressFlow
3× pressPI
4× pressPower
5× pressBackup
- Up to five presses to see all readings.
- Battery level shown mainly as LED bars.
- No plain-language next step.
My controller
B1 99% B2 99%20 h 40 min
Speed RPM5500
Flow LPM3.2
Power W5.2
Pulsatility PI5.1
— All four readings on one screen, at a glance — 0 extra presses.
— Each battery in % plus the time left in hours and minutes.
— Alarms in plain words, always with the next step.
presses needed today
left when the current icon turns red
minimum text after readability tests
controller, phone and watch
3 · FROM INSIGHT TO DECISION
01
Constant checking of the battery causes stress, fear and worry.
Systematic review
The time left is always at the top of the screen, and a light strip shows the status from a distance — green when all is well, red for an alarm.
02
People want to check discreetly — in a seminar, a café, at the cinema.
Patient quotes
The screen is mirrored on the phone and the watch; less critical alarms can be a vibration only.
03
A phone can run out of battery.
Analysis
The screen stays on the controller as the independent source of truth. It is larger than before; the app only adds to it.
04
Alarms are rare, and stressful when they come.
Interviews, audit
One main button wakes the screen and confirms alarms — the one the hand already knows. A low-battery alarm cannot be dismissed until the battery is replaced.
05
A message without an action leaves people guessing.
Audit
Three alarm levels, each with its own colour, sound and a plain message with the next step: “20 minutes left. Please replace battery B1.”
06
Users aged 30 to 70 held the models with one hand, often in daylight.
User tests
Convex buttons of at least 12 mm, all on one side, so the device works upright or sideways; 18 px text.
07
People fear the cable will be pulled out, or the battery attached wrongly.
Systematic review, interviews
The battery slides onto a rail and can go on only one way; a lock turns green when it is secure.
See interface testingModels, printed screens and daylight readability tests
07 THE SOLUTION
A controller that answers before you ask
In shortTwo parts instead of three, one screen with everything that matters, and the same information on the phone and wrist.
Status light
Green means the system is working; red signals an alarm, visible without taking the controller out.
One main button
Wakes the screen and confirms alarms — one familiar action under stress.
Everything on one screen
Both batteries, time left and four pump readings stay visible together.
Slide-on battery
It fits only one way and the lock turns green when secure.
Soft, rounded form
Designed for either hand, upright or sideways, with controls on one edge.
ONE SYSTEM, THREE SCREENS
The same answer, at the right level of attention
In shortThe controller is always complete. Phone and watch make routine checks more discreet.
99%B199%B2♥
20 h 40 min left
Speed RPM5500
Flow LPM3.2
Power W5.2
Pulsatility PI5.1
Controller
Independent source of truth: every reading, every alarm and the main action.
99%B199%B2♥
20 h 40 min left
Speed RPM5500
Flow LPM3.2
Power W5.2
Pulsatility PI5.1
Phone
A discreet check without taking the controller out.
99%B199%B2♥
20 h 40 min left
Speed RPM5500
Flow LPM3.2
Power W5.2
Pulsatility PI5.1
Watch
A glance at the wrist; lower-priority alarms can use vibration.
05 ALARMS
Three priorities. Every message says what to do next.
In shortUrgency changes the colour, sound and dismissal rule — not the clarity of the instruction.
A critical alarm takes over the screen and cannot be dismissed until the problem is solved. Lower priorities ask for attention without creating the same stress.
High priority
Direct threat: low battery or pump failure.
20 MINUTESOF POWER LEFTREPLACE BATTERY B1
- Reaction
- Only when solved
Medium priority
Needs attention soon: loose cable or changed readings.
CHECK CABLEWHITE CABLE IS LOOSERECONNECT THE CABLE
- Reaction
- After confirming
Low priority
A reminder, such as charging the backup battery.
REMINDERBACKUP BATTERYCHARGE IT TONIGHT
- Reaction
- When convenient
06 PHYSICAL INTERACTION
No wrong way to connect the battery
In shortThree steps provide visible and tactile feedback before the patient trusts the connection.
In tests, sliding the battery onto a rail was the easiest connection to understand.
1
Slide it on
The rail accepts the battery in only one direction.
2
Lock it
The control turns green when the connection is secure.
3
See the status
The light strip confirms normal operation at a glance.
08 OUTCOME
A concept shaped by patients, clinicians and dozens of models
In shortThe final system reduces physical complexity and makes essential information easier to check, understand and act on.
main parts to carry and connect
less battery volume for the same energy
one consistent interface at different attention levels
WHAT I LEARNED
In medical design, the hardest problems are often around the device rather than inside it: in clothing, habits, social situations and the small moments when a person needs certainty.