Hélio Penna Guimarães

The Guardian: an implantable system for chronic ambulatory monitoring of acute myocardial infarction

The AngelMed Guardian is an implantable medical device that records cardiac data and detects ischemic events using a standard pacemaker intracardiac lead positioned in the right ventricular apex. The Guardian has been implanted in 55 people in the United States and Brazil and is currently undergoing a Food and Drug Administration phase 2 pivotal trial in the United States. The Guardian detects acute ischemic events by analyzing ST-segment shifts. The ST-segment shifts are calculated as the difference between the ST deviation of a current 10-second electrogram window and a baseline ST deviation value. If the ST-segment shift is greater than a heart rate-dependent programmable threshold, then the device generates an emergency alert signal. Results thus far have demonstrated that (i) the intracardiac electrogram is relatively noise-free and (ii) the ST-shift technique used by the Guardian is effective for detecting acute ischemic events.

Disseminated Intravascular Coagulation in Cardiac Surgery

Disseminated intravascular coagulation (DIC) is a complex thrombohemorrhagic disease, secondary to an underlying clinical disease,1 producing both thrombosis and hemorrhage. It is initiated by a number of defined disorders and consists of the following components2: exposure of blood to procoagulants; formation of fibrin in the circulation; fibrinolysis; depletion of clotting factors; and end-organ damage. Systemic activation of coagulation in its most extreme form is known as DIC,3 which occurs in approximately 1% of hospital admissions.4