St. Jude’s ASSERT Study Supports Implantable Device Monitoring To Identify Arrhythmia-Related Stroke Risk

St. Jude Medical has this week announced the publication of results from the ASSERT cohort study in the New England Journal of Medicine (NEJM). The study results, previously presented at an American Heart Association Scientific Sessions meeting, found that pacemaker patients who have no history of atrial tachycardia (AT) or AF, but do have device-detected arrhythmias, are approximately 2.5 times more likely to have a stroke than patients who do not have device-detected arrhythmias.


Atrial fibrillation (AF) is a chaotic, uncontrolled heart rhythm, occuring when the upper chambers of the heart (atria) contract rapidly and irregularly – from 350 to 600 times per minute compared to a normal heart rhythm of 60 to 100 times per minute. AF is known to be a common risk factor for, and cause of, stroke. Because the atria contract so rapidly and irregularly during AF, the heart cannot beat effectively and blood is not pumped completely out of the atria. Blood that pools in the atria may clot and, if the clot moves to an artery in the brain, stroke may occur. Studies show that AF increases the risk of stroke five-fold. The risk for stroke related to AF increases with age, and AF potentially leads to a range of other debilitating symptoms as well.

The study

The ASSERT study, or ASymptomatic AF and Stroke Evaluation in Pacemaker Patients and the AF Reduction Atrial Pacing Trial, was designed to determine whether the detection of arrhythmias using pacemaker-based diagnostics predicts an increased risk of stroke in elderly, hypertensive patients without any history of atrial fibrillation (AF).

The study included 2,580 pacemaker and ICD patients over the age of 65 with hypertension and no history of AF. Subclinical (non-symptomatic) atrial tachyarrhythmias detected by implanted devices occurred in over 10 percent of patients at three months. The risk of systemic embolism (or stroke) associated with non-symptomatic atrial tachyarrhythmias was 13 percent. The diagnostic data and alerts available through St. Jude Medical implantable devices allow physicians and patients to be notified whenever a patient experiences significant atrial arrhythmias (abnormal heartbeats) in the heart’s upper chambers, such as AT or AF.

The trial was sponsored by St. Jude Medical and was conducted by the Population Health Research Institute of McMaster University and Hamilton Health Sciences in Hamilton, Canada.

Clinician comments

Dr. Jeff Healey, principal investigator for the arrhythmias program at the Population Health Research Institute stated; “Approximately 85 percent of atrial arrhythmias documented in the study were picked up only by the pacemaker, proving the device plays a very significant role in identifying patients with a higher risk of stroke. This monitoring technology is a built-in diagnostic tool and a huge value-add to further assist physicians in properly treating their patients.”

Company comments

“The publication of these findings reminds us how important it is to identify patients with an increased risk of stroke. Diagnostic tools and remote monitoring capabilities already found in St. Jude Medical pacemakers and ICDs make it easier for physicians to capture information to manage AT and AF even when the arrhythmias are not accompanied by symptoms,” said Dr. Mark Carlson, chief medical officer and senior vice president of research and clinical affairs for the St. Jude Medical Cardiac Rhythm Management Division. “St. Jude Medical is committed to providing our customers with clinically relevant information that allows them to deliver more timely and effective care to patients around the world.”

Source: St Jude Medical