{"id":5889,"date":"2012-07-18T22:26:46","date_gmt":"2012-07-18T22:26:46","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2012\/?p=5889"},"modified":"2012-07-18T22:26:46","modified_gmt":"2012-07-18T22:26:46","slug":"a-wearable-long-term-cardiac-monitor","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2012\/a-wearable-long-term-cardiac-monitor\/","title":{"rendered":"A Wearable, Long-term Cardiac Monitor"},"content":{"rendered":"

With the escalating costs of hospital visits, clinicians are opting to use at-home monitoring devices to diagnose patients.\u00a0 Current ECG Holter monitoring devices typically have 24-48 hour memory and battery capacity [1<\/a>] <\/sup>.\u00a0 With many patients experiencing intermittent heart problems that can occur once every week or month, an event recorder or loop recorder is required [2<\/a>] <\/sup>.\u00a0 However, event recorders can save only up to a few minutes of ECG recordings.\u00a0 This constraint leads to the loss of most of the data, which could be very important in alerting the user to the onset of future episodes.\u00a0 Therefore, we have developed a Holter monitor prototype with the goal of battery and memory capacity of greater than one week.\u00a0 Figure 1 shows a block diagram of the system.<\/p>\n

We based the long-term monitor prototype around a Texas Instruments MSP430 low-power microcontroller that enables high computing power with very low power consumption.\u00a0 The prototype monitor is mounted on standard 3M 2560 Red Dot electrodes. The central board is fabricated on a flexible PCB substrate.\u00a0 Mounting the PCB directly on the electrodes improves the SNR by an estimated 40 dB compared to using wired leads [3<\/a>] <\/sup>.\u00a0 The monitor is \u201cL\u201d-shaped with rounded corners and placed on the patient\u2019s chest (Figure 2).\u00a0 The \u201cL\u201d shape enables several different ECG vectors to be recorded, depending on what the cardiologist wants to observe.\u00a0 The monitor has a micro SD card on board, which is enough to store weeks of ECG data sampled at 250 Hz continuously, without compression.<\/p>\n\n\t\t