Another popular article from an active research group that delve into medical devices security is ''Reliability and security of implantable and wearable medical devices" from the Implantable Bio-medical Microsystems book chapter. It can be observed that Implantable devices is where most of the research is in as the word suggests it is intrusive and hence much more of a threat than non-intrusive medical devices.
The highlights of this reading is as follows:

• Reliability and security issues are realized at the network level through the composition of unreliable and unsecured individual nodes. Security to be an issue only at the network level when combined unlike wearables that require every node to be secure.
• Reliability is the key issue and factors like power system, processor, memory, software, radio communication,humans, hardware etc can be responsible for issues.
• Mechanism to assure the same include - fail-safe, trusted platform modules and malware detection units based on various physical characteristics. 

Privacy is another important aspect that goes hand in hand with security especially in the age of mobile health or mHealth. Privacy is one concern that provides the meaningful use in Electronic Health Records. An introduction to privacy requirements and aspects of mHealth are discussed in the survey paper ''Privacy in Mobile Technology for Personal Healthcare" which is worth a read. 

One thing we will observe in medical device security is that all issues are a double-edged sword!!