ABSTRACT: The aim of this study was to investigate whether bipolar pacemaker current lead can activate blood platelets. The null hypothesis was that 1 minute of electrical stimulation of platelets would not influence their subsequent reactivity to adenosine diphosphate (ADP).
Both platelets and muscle cells contain actin and myosin filaments, and both cells are activated following calcium influx. Muscle cells open their calcium channels and contract when exposed to an electric current. Current through a bipolar pacemaker lead will expose a small volume of blood, including platelets, to the depolarizing current. Platelet activation may ensue, resulting in aggregation, release reaction, and contraction. In contrast, a unipolar pacemaker system will not depolarize blood, but transmit current directly into the myocardium, and the current afterward passes through other tissues before returning to the pacemaker can.
Platelet-rich plasma was prepared from two healthy subjects. Platelet reactivity to the agonist ADP was tested in paired samples in an aggregometer in a case/control setup.
Eighteen of 46 tested pairs of platelet-rich plasma showed increased reactivity in the paced sample; 26 were unchanged while two showed decreased reactivity in the paced sample. Using a two-sided sign test, the null hypothesis was rejected (P = 0.0004).
The study demonstrates increased reactivity to ADP in platelets exposed in vitro to stimulation by pacemaker current. The clinical relevance of these findings remains to be investigated.
Pacing and Clinical Electrophysiology 06/2009; 32(5):627-31. · 1.35 Impact Factor
Clinical Chemistry 12/2008; 54(11):1924-5. · 7.91 Impact Factor
ABSTRACT: In order to enable clinicians to refer the right persons suspected of familial hypercholesterolemia (FH) for mutation screening, a retrospective study was conducted in a Danish FH cohort.
The study comprised 643 probands and 395 relatives, of which 421 individuals had a pathogenic mutation, and 211 had cardiovascular disease (CVD). Logistic regression, Cox regression, and receiver operating characteristics (ROC) curves were used to find optimal predictive variables for mutation status and evaluate risk factors for CVD.
Age alone had significant predictive power in both genders. ROC curves and area under the curve plots found no parameters capable of predicting mutation status. The only significant risk factor for CVD in both genders was mutation carrier status.
No parameters could decipher mutation status a priori. All individuals fulfilling the FH criteria should therefore be referred in order to facilitate family tracing and genetic counseling.
Clinical Biochemistry 01/2008; 40(18):1347-52. · 2.08 Impact Factor
ABSTRACT: Hemolysis affects many biochemical analyses, and when pronounced the result is replaced by an autoreply pointing out the hemolysis present. However, for proper treatment it is crucial to know whether hemolysis is due to sampling (in vitro) or is taking place in the patient (in vivo). At present, no consensus exists on how to help clinicians differentiate between the two. Clinical surveillance is still necessary, and a future challenge will be improving the dialogue between clinicians and clinical biochemists. This article reviews the benefits of doing so and suggests procedures to help differentiate.
Ugeskrift for laeger 09/2006; 168(33):2653-5.