Aims: As arrhythmias in the long QT syndrome(LQTS) are triggered by heart rate deceleration or acceleration, we speculated that the sudden bradycardia and subsequent tachycardia that follow adenosine injection would u...Aims: As arrhythmias in the long QT syndrome(LQTS) are triggered by heart rate deceleration or acceleration, we speculated that the sudden bradycardia and subsequent tachycardia that follow adenosine injection would unravel QT changes of diagnostic value in patients with LQTS. Methods and results: Patients(18 LQTS and 20 controls) received intravenous adenosine during sinus rhythm. Adenosine was injected at incremental doses until atrioventricular block or sinus pauses lasting 3 s occurred. The QT duration and morphology were studied at baseline and at the time of maximal bradycardia and subsequent tachycardia. Despite simitar degree of adenosine- induced bradycardia(longest R- R 1.7± 0.7 vs. 2.2± 1.3 s for LQTS and controls, P=NS), the QT interval of LQT patients increased by 15.8± 13.1% , whereas the QT of controls increased by only 1.5± 6.7% (P< 0.001). Similarly, despite similar reflex tachycardia(shortest R- R 0.58± 0.07 vs. 0.55± 0.07s for LQT patients and controls, P=NS), LQTS patients developed greater QT prolongation(QTc=569± 53 vs. 458± 58 ms for LQT patients and controls, P< 0.001). The best discriminator was the QTc during maximal bradycardia. Notched T- waves were observed in 72% of LQT patients but in only 5% of controls during adenosine- induced bradycardia(P< 0.001). Conclusion: By provoking transient bradycardia followed by sinus tachycardia, this adenosine challenge test triggers QT changes that appear to be useful in distinguishing patients with LQTS from healthy controls.展开更多
Background: We have introduced a concept of using the erythrocyte as a sensor for the detection of enhanced inflammation- sensitive protein concentrations. We presently evaluated the capability of this new biomarker t...Background: We have introduced a concept of using the erythrocyte as a sensor for the detection of enhanced inflammation- sensitive protein concentrations. We presently evaluated the capability of this new biomarker to detect the presence of inflammation in individuals with a history of a vascular disease as opposed to individuals with atherothrombotic risk factors but no clinically evident vascular disease. Methods: The degree of erythrocyte adhesiveness/aggregation was determined in the peripheral venous blood by using a simple blood test. Blood was drawn into a syringe containing sodium citrate and trickled onto a slide at an angle of 30° . The slides were than scanned by a blinded technician by using an image analyzer to determine the area that is covered by the erythrocytes. Results: One hundred fifty- six subjects(61 women and 95 men) of 2586(1238 women and 1348 men) met the criteria of a definite vascular disease(history of stroke, myocardial infarction, coronary artery bypass grafting, or peripheral vascular disease). The degree of erythrocyte aggregation was significantly(P=.008) higher in men, but not in women, with vascular disease as opposed to these without a vascular disease. The results of receiver operating characteristic curve analysis confirmed the diagnostic superiority of the erythrocyte aggregation biomarker over other commonly used markers of the acute phase in men. Similar results were obtained by using discriminant analysis. Finally, a significant correlation was found between the degree of erythrocyte aggregation and other markers of the acute phase suggesting its relevance for the detection and quantitation of low- grade inflammation in individuals with atherothrombosis. Conclusion: Erythrocyte adhesiveness/aggregation may be a useful biomarker to detect internal inflammation in individuals with atherothrombosis.展开更多
文摘Aims: As arrhythmias in the long QT syndrome(LQTS) are triggered by heart rate deceleration or acceleration, we speculated that the sudden bradycardia and subsequent tachycardia that follow adenosine injection would unravel QT changes of diagnostic value in patients with LQTS. Methods and results: Patients(18 LQTS and 20 controls) received intravenous adenosine during sinus rhythm. Adenosine was injected at incremental doses until atrioventricular block or sinus pauses lasting 3 s occurred. The QT duration and morphology were studied at baseline and at the time of maximal bradycardia and subsequent tachycardia. Despite simitar degree of adenosine- induced bradycardia(longest R- R 1.7± 0.7 vs. 2.2± 1.3 s for LQTS and controls, P=NS), the QT interval of LQT patients increased by 15.8± 13.1% , whereas the QT of controls increased by only 1.5± 6.7% (P< 0.001). Similarly, despite similar reflex tachycardia(shortest R- R 0.58± 0.07 vs. 0.55± 0.07s for LQT patients and controls, P=NS), LQTS patients developed greater QT prolongation(QTc=569± 53 vs. 458± 58 ms for LQT patients and controls, P< 0.001). The best discriminator was the QTc during maximal bradycardia. Notched T- waves were observed in 72% of LQT patients but in only 5% of controls during adenosine- induced bradycardia(P< 0.001). Conclusion: By provoking transient bradycardia followed by sinus tachycardia, this adenosine challenge test triggers QT changes that appear to be useful in distinguishing patients with LQTS from healthy controls.
文摘Background: We have introduced a concept of using the erythrocyte as a sensor for the detection of enhanced inflammation- sensitive protein concentrations. We presently evaluated the capability of this new biomarker to detect the presence of inflammation in individuals with a history of a vascular disease as opposed to individuals with atherothrombotic risk factors but no clinically evident vascular disease. Methods: The degree of erythrocyte adhesiveness/aggregation was determined in the peripheral venous blood by using a simple blood test. Blood was drawn into a syringe containing sodium citrate and trickled onto a slide at an angle of 30° . The slides were than scanned by a blinded technician by using an image analyzer to determine the area that is covered by the erythrocytes. Results: One hundred fifty- six subjects(61 women and 95 men) of 2586(1238 women and 1348 men) met the criteria of a definite vascular disease(history of stroke, myocardial infarction, coronary artery bypass grafting, or peripheral vascular disease). The degree of erythrocyte aggregation was significantly(P=.008) higher in men, but not in women, with vascular disease as opposed to these without a vascular disease. The results of receiver operating characteristic curve analysis confirmed the diagnostic superiority of the erythrocyte aggregation biomarker over other commonly used markers of the acute phase in men. Similar results were obtained by using discriminant analysis. Finally, a significant correlation was found between the degree of erythrocyte aggregation and other markers of the acute phase suggesting its relevance for the detection and quantitation of low- grade inflammation in individuals with atherothrombosis. Conclusion: Erythrocyte adhesiveness/aggregation may be a useful biomarker to detect internal inflammation in individuals with atherothrombosis.
