Simple Pulse Measure Can Detect AF After Stroke

July 24, 2014

Simple measurement of the peripheral pulse (MPP) at the radial artery is an effective screening tool for diagnosis of atrial fibrillation (AF) in patients who have had a stroke, a new pilot study suggests.

The study, published online in Neurology on July 23, found that health professionals, relatives, and even patients can be trained to distinguish abnormal rhythms just by measuring the pulse.

"With a low rate of false-positive results, MPP offers an easy, ubiquitously available, noninvasive, first-step screening tool to guide ECG [electrocardiography] diagnostics for pAF [paroxysmal AF] after ischemic stroke," the authors, led by Bernd Kallmünzer, MD, Universitätsklinikum Erlangen, Germany, conclude.

They add: "This study provides Class I evidence that MPP by patients or relatives accurately distinguishes AF from normal heart rhythm as compared with continuous ECG."

Larger Trial Now Underway

Dr. Kallmünzer commented to Medscape Medical News that health care professionals, caregivers, and patients can be guided to use pulse measurements as a first step in helping to prevent a second stroke. "This is a feasibility study with a limited number of patients included," he added. "The results are promising but warrant a larger prospective trial, which is already recruiting patients."

In the paper, the authors explain that the diagnosis of AF is of particular clinical relevance because when identified, it can be treated with anticoagulants, which significantly reduce the risk for recurrent stroke and death.

While recent trials have shown impressive rates of AF detection after stroke with prolonged duration of cardiac monitoring, these have involved expensive cardiac monitors, some of which are surgically implanted. "High socioeconomic expense, malcompliance, and the invasiveness of some of these approaches currently limit their use to a minority of affected patients, while the growing number of stroke survivors is lacking access to diagnostic screening tools," Dr. Kallmünzer and colleagues write.

They note that MPP is currently recommended for AF screening in the primary prevention population but has never been applied in the setting of secondary stroke prevention, "probably because several factors including sensomotor and neuropsychological disability of stroke patients were expected to interfere with this simple technique."

For the current study, 256 patients who had sustained a recent acute ischemic stroke and their relatives were instructed on how to detect an abnormal radial pulse.

Three different modalities of pulse measurement were investigated: (1) measurement by a health care professional with positive experience on cardiovascular assessment of patients, (2) measurement by a relative of the patient after successful completion of the tutorial, and (3) self-measurement by the patient after successful completion of the tutorial.

All these were performed as single measurements for at least 30 seconds, with examiners blinded to the current heart rate and rhythm. There was no upper time limit for MPP. Measurements were conducted during the daytime. Patients also underwent simultaneous blinded ECG, and the results of the pulse measurements and ECG observations were compared.

Results showed that 90% of the patients were able to measure their own pulse reliably. Diagnostic sensitivity was highest for pulse measurements when taken by a healthcare professional, followed by relatives.

But even patients managed a diagnostic sensitivity of 54%, and the researchers point out that this was derived from a single measurement and may increase by repeated testing. Specificity was high for pulse measurement by all groups.

Table. Diagnostic Sensitivity and Specificity for Detecting Abnormal Rhythm by Radial Pulse Measurement

Measure Healthcare Professional Relative Stroke Patient
Diagnostic sensitivity (%) 96.5 76.5 54.1
Specificity (%) 94.0 92.9 96.2

 

False-positive results were limited to 6 cases (2.7%), with a positive predictive value of 76.9% and a negative predictive value of 90.0%.

The researchers say their results show that "the majority of stroke patients can be guided to reliable pulse self-measurements with a low rate of false-positive results. In combination with subsequent ECG, it represents an effective, ubiquitously available screening tool."

They add that "[f]or patients who are incompetent or severely disabled, MPP by a nonprofessional relative constitutes an effective alternative."

They note that the new larger prospective trial now underway to examine this concept further is testing 3 pulse measurements per day for 6 months.

The study had no targeted funding. The authors have disclosed no relevant financial relationships.

Neurology. Published online July 23, 2014. Abstract

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