US6045513A - Implantable Medical Device For Tracking Patient Functional Status - Google Patents

This invention relates to the field of implantable medical devices for enabling enhanced medical monitoring of patients, most particularly for use with exercise sensing, and has utility to the sector of monitoring patients typically and particularly these with situations reminiscent of Cardiac Heart Failure (CHF). A rise in the ability to carry out activities of every day living (ADL) is an indicator of enhancing health and functional status, whereas a decrease in the flexibility to carry out each day activities may be an important indicator of worsening well being. Activities of daily dwelling are submaximal actions performed throughout day by day life. Examples are going to work, cleansing the home, vacuuming the home, cooking and cleaning, working in the garden, short stroll to grocery shops, cleansing the automobile, and gradual paced night walks. Impairment of useful status may be seen in adjustments in the ability to carry out exercises and ADL. This can be affected by many physiological elements comparable to progressive decompensation within the setting of left ventricular cardiac (LV) dysfunction, beta blocker remedy, symptomatic arrhythmias, and depression.



These changes could happen over a long time frame and may be too delicate to be discerned by patients. Patients with cardiac illness resulting in slight limitation of physical activity. They're comfy at rest. Patients with cardiac illness leading to inability to carry on any physical exercise without discomfort. Symptoms of heart failure or of the anginal syndrome could also be present even at rest. For instance, if a patient complains vaguely of fatigue and shortness of breath and is not ready to describe the limitations to his/her daily activities, a pattern of activities might assist the clinician. If the exercise data might show a considerable decrease in patient actions, then the clinician might take the next step such as the analysis of cardiac profile, pulmonary dysfunction, or iTagPro features present drug therapy. Alternatively, if the long term trend of exercise on this affected person is persistently common, (i.e., no lower in affected person activity), the clinician might take different steps to know the distinction between affected person symptoms and system indicated exercise information.



Clinicians can also encounter conditions when patients are reluctant to discuss their signs. In conditions comparable to these, a development of exercise knowledge could help the clinician to question the affected person or the patient's spouse and enable the patient to return forward with their signs. Heart Failure is a syndrome characterized by the coexistence of left ventricular dysfunction (low EF), arrhythmias, ItagPro pulmonary and peripheral congestion, and signs of fatigue and shortness breath. A majority of ICD patients have low EF ( ⁇ 40%) and decreased purposeful capability (NYHA Class II, III and IV), and are prone to growing coronary heart failure. Clinical heart failure is a progressive disease; therefore early identification and well timed therapy might stop hospitalizations, cut back the price of care and enhance patient lives. Further, the lack to perform exercise and actions develop over a protracted period of time and iTagPro features hence may be difficult to discern and quantify. An objective measure of long run developments of affected person exercise could also be useful in early identification of symptoms of heart failure and within the development of coronary heart failure.



A gradual lower in patient actions over the last 8 months might lead the clinician to suspect the event of coronary heart failure. This will lead the clinician to take the next step in differential diagnosis. Further, there's usually a 30-60 day time period immediately after initiation of drug therapy throughout which the affected person is probably not very energetic. Most patients acclimate to the therapy after this interval, but some do not. By having an objective measurement of affected person actions, the titration and adjustment to beta blockers and other medicine might be enhanced. Arrhythmias may cause symptoms such as palpitations, fatigue, or presyncope. Some patients may spend a big period of time in arrhythmias resembling atrial fibrillation and should not be capable of perform every day actions. Such issues could be coordinated with measurements of activity for increased diagnostic value. Medtronic brand implantable medical devices with piezoelectric crystal or accelerometer based activity sensors have the flexibility to transform a raw activity sign into the 2 second activity counts.