- Email: [email protected]
Effects of acetylcholine concentration on action potential duration restitution of atrial cells—a simulation study
Poster Session 2 / Journal of Electrocardiology 41 (2008) 642–647 with a predilection for women 93.5% (age range, 19-79; n = 143); 91.6% (n = 131) of women and 50% (n = 5) of men were free of cardiac disease based on clinical evaluation, markers of myocardial injury, and echocardiography. Echocardiographic evidence of Left ventricular hypertrophy was evident in 8.4% (age range 40-79, n = 12) of women and 50% (age range, 45-69; n = 5) of men. Left ventricular wall motion abnormalities were found in 8.3% (age range, 40-79; n = 10) of women and in 50% (age range, 45-69; n = 5) of men. Conclusion: Juvenile T-wave pattern persisting into adulthood is more commonly seen in women. Furthermore, it should be considered as a normal variant in women younger than 40 years to avoid misinterpretation. Presenting author: Khalil A. Kaid, MD Newark Beth Israel Medical Center 201 Lyons Ave Newark, NJ 07112, USA 1-973-926-7000; fax 973-741-2384; email [email protected] doi:10.1016/j.jelectrocard.2008.08.028
Diastolic heart sounds as a predictor of acute myocardial ischemia Eunyoung Lee, a Andrew Michaels, b Ronald Selvester, c Barbara Drew, a ( aUniversity of California, San Francisco, CA, USA; bUniversity of Utah, Salt Lake City, UT, USA; cLong Beach Hospital, Long Beach, CA, USA) Background: Although the standard 12-lead electrocardiogram (ECG) is considered the gold standard for the diagnosis of myocardial ischemia that is likely to develop into acute myocardial infarction (MI), nearly half of ECGs in patients presenting to the emergency department with chest pain who subsequently rule in for acute MI with positive serum biomarkers are normal or nonspecific. Aims/methods: To investigate whether diastolic third or fourth heart sounds (S3 or S4) predict acute myocardial ischemia due to coronary occlusion, a prospective comparison study was conducted in a group with ischemia induced by percutaneous coronary intervention (n = 19) and a non-ischemia group (n = 18) with negative angiographic findings for coronary artery disease. Diastolic heart sounds were detected with a novel computerized acoustic cardiography system (Audicor, Inovise Medical Inc, Portland, OR). Results: Of 37 patients, the mean age was 59.4 ± 11.8 years and 51.4% were male. An S4 was more sensitive (73.7%) in predicting ischemia than an S3 (52.6%) or standard ST-T criteria (47.4%). Using logistic regression, both an S3 and S4 were shown to predict ischemia (P b .05), independent of ST-T criteria. The presence of an S3 or S4 with ST-T changes improved the sensitivity to predict ischemia by 31.6%. Conclusion: The use of acoustic cardiography to detect an S3 or S4 may augment the ECG detection of ischemia that is likely to develop into infarction.
645
Presenting author: Eunyoung Lee University of California, San Francisco; Department of Physiological Nursing ECG Monitoring Research Laboratory 2 Koret Way, N631San Francisco, CA 94131, USA 1-415-297-7359; fax 1-520-577-1551; email [email protected] doi:10.1016/j.jelectrocard.2008.08.029
Effects of acetylcholine concentration on action potential duration restitution of atrial cells—a simulation study T. Moukabary, D.E. Haines (Department of Internal Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA) Background: High acetylcholine concentrations ([ACh]) promote propagation of atrial fibrillation (AF). Atrial fibrillation propensity may be a function of restitution properties of atrial myocytes. We sought to define the effects of [ACh] on atrial restitution using a mathematical model. Methods: The human atrial mathematical model by Courtemanche et al was used. [Ach] were varied from 1e-8 up to 0.008 mol/L by steps of 200% to 1000%. After each adjustment, the model was paced by a drive train of 8 beats at an S1S1 interval of 500 milliseconds followed by an S2 stimulus at an S1-S2 interval from 800 to 250 milliseconds. The action potential duration (APD) restitution curve using the diastolic interval between the last S1 and the S2 vs the action potential duration of the beat stimulated by S2, also called S1S2 restitution protocol, was plotted. The maximum slope of the restitution curve was calculated. Slopes more than 1 correlate with AF. Results: Action potential duration progressively shortens with increased [Ach]. At S1S2 of 500 milliseconds, the APD was 207 milliseconds with [Ach] of 1e-8 mol/L vs 178 milliseconds with [Ach] of 0.0008 mol/L. There was linear relationship between the maximum slope of the APD restitution curve and the [Ach] (0.98 at 1e-8 mol/L vs 5.167 at 0.0008 mol/L, Maximum slope = 5289 ⁎ [Ach] + 0.945). There was also a relationship between the S1S2 yielding the maximum restitution curve slope and the [Ach]. This maximum slope S1S2 interval increased as [Ach] was increased (420 milliseconds at 1e-8 mol/L vs 500 milliseconds at 0.0008 mol/L). Conclusion: Increasing [Ach] increases the maximum restitution curve slopes. This may predispose the atrial myocardium to wave break at high rates and initiation of AF. Presenting author: Talal Moukabary, MD Department of Internal Medicine, William Beaumont Hospital 3601 W. 13 Mile Road Royal Oak, MI 48073, USA 1-248-921-3686; email [email protected] doi:10.1016/j.jelectrocard.2008.08.030
Table. Diastolic heart sounds as predictors of myocardial ischemia (n = 37) Sensitivity (n = 19) Standard 52.6% ST-T criteria (10/19) S3 47.4% (9/19) S4 73.7% (14/19) S3 or S4 84.2% (16/19)
Specificity (n = 18)
Overall Odds ratio P accuracy (95% CI) (n = 37)
100.0% (18/18) 94.4% (17/18) 83.3% (15/18) 77.8% (14/18)
75.7% (28/37) 70.3% (26/37) 78.4% (29/37) 81.1% (30/37)
NAa 15.3 (1.7-139.3) 14.0 (2.8-69.8) 18.7 (3.6-98.2)
b.001b .015c .001c .001c
S3 indicates third heart sound; S4, fourth heart sound; CI, confidence interval. a Odds ratio unavailable because of “zero” case with ST-T criteria in non-ischemia group. b P value of Fisher exact test. c P value of logistic regression.
An intelligent wireless electrocardiographic patch for single-lead electrocardiographic monitoring Venkatarama Subba Rao Nimmala, Jef van de Molengraft, Julien Penders, Bert Gyselinckx, IMEC-NL, High Tech Campus 31, 5656AE Eindhoven, The Netherlands Emerging technologies for body area networks open new opportunities for cardiac monitoring. In a typical setup, a wireless sensor node will monitor heart activity, process the data locally, and transmit it wirelessly to a central node, acting as a gateway to the external world. In this paper, we report an intelligent wireless electrocardiographic (ECG) patch for the continuous monitoring of single-lead ECG. The ECG patch is a hybrid system combining electronic assembly on flexible polyimide substrate and textile integration. This allows achieving flexibility in one dimension—as required for a total fit to body curves, and stretchability in the other direction—as required for optimal, personalized, electrode placement. All the components are embedded in textile and standard ECG electrodes are used for attachment to the body. The total system weighs about 15 g. The wireless
Diastolic heart sounds as a predictor of acute myocardial ischemia Eunyoung Lee, a Andrew Michaels, b Ronald Selvester, c Barbara Drew, a ( aUniversity of California, San Francisco, CA, USA; bUniversity of Utah, Salt Lake City, UT, USA; cLong Beach Hospital, Long Beach, CA, USA) Background: Although the standard 12-lead electrocardiogram (ECG) is considered the gold standard for the diagnosis of myocardial ischemia that is likely to develop into acute myocardial infarction (MI), nearly half of ECGs in patients presenting to the emergency department with chest pain who subsequently rule in for acute MI with positive serum biomarkers are normal or nonspecific. Aims/methods: To investigate whether diastolic third or fourth heart sounds (S3 or S4) predict acute myocardial ischemia due to coronary occlusion, a prospective comparison study was conducted in a group with ischemia induced by percutaneous coronary intervention (n = 19) and a non-ischemia group (n = 18) with negative angiographic findings for coronary artery disease. Diastolic heart sounds were detected with a novel computerized acoustic cardiography system (Audicor, Inovise Medical Inc, Portland, OR). Results: Of 37 patients, the mean age was 59.4 ± 11.8 years and 51.4% were male. An S4 was more sensitive (73.7%) in predicting ischemia than an S3 (52.6%) or standard ST-T criteria (47.4%). Using logistic regression, both an S3 and S4 were shown to predict ischemia (P b .05), independent of ST-T criteria. The presence of an S3 or S4 with ST-T changes improved the sensitivity to predict ischemia by 31.6%. Conclusion: The use of acoustic cardiography to detect an S3 or S4 may augment the ECG detection of ischemia that is likely to develop into infarction.
645
Presenting author: Eunyoung Lee University of California, San Francisco; Department of Physiological Nursing ECG Monitoring Research Laboratory 2 Koret Way, N631San Francisco, CA 94131, USA 1-415-297-7359; fax 1-520-577-1551; email [email protected] doi:10.1016/j.jelectrocard.2008.08.029
Effects of acetylcholine concentration on action potential duration restitution of atrial cells—a simulation study T. Moukabary, D.E. Haines (Department of Internal Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA) Background: High acetylcholine concentrations ([ACh]) promote propagation of atrial fibrillation (AF). Atrial fibrillation propensity may be a function of restitution properties of atrial myocytes. We sought to define the effects of [ACh] on atrial restitution using a mathematical model. Methods: The human atrial mathematical model by Courtemanche et al was used. [Ach] were varied from 1e-8 up to 0.008 mol/L by steps of 200% to 1000%. After each adjustment, the model was paced by a drive train of 8 beats at an S1S1 interval of 500 milliseconds followed by an S2 stimulus at an S1-S2 interval from 800 to 250 milliseconds. The action potential duration (APD) restitution curve using the diastolic interval between the last S1 and the S2 vs the action potential duration of the beat stimulated by S2, also called S1S2 restitution protocol, was plotted. The maximum slope of the restitution curve was calculated. Slopes more than 1 correlate with AF. Results: Action potential duration progressively shortens with increased [Ach]. At S1S2 of 500 milliseconds, the APD was 207 milliseconds with [Ach] of 1e-8 mol/L vs 178 milliseconds with [Ach] of 0.0008 mol/L. There was linear relationship between the maximum slope of the APD restitution curve and the [Ach] (0.98 at 1e-8 mol/L vs 5.167 at 0.0008 mol/L, Maximum slope = 5289 ⁎ [Ach] + 0.945). There was also a relationship between the S1S2 yielding the maximum restitution curve slope and the [Ach]. This maximum slope S1S2 interval increased as [Ach] was increased (420 milliseconds at 1e-8 mol/L vs 500 milliseconds at 0.0008 mol/L). Conclusion: Increasing [Ach] increases the maximum restitution curve slopes. This may predispose the atrial myocardium to wave break at high rates and initiation of AF. Presenting author: Talal Moukabary, MD Department of Internal Medicine, William Beaumont Hospital 3601 W. 13 Mile Road Royal Oak, MI 48073, USA 1-248-921-3686; email [email protected] doi:10.1016/j.jelectrocard.2008.08.030
Table. Diastolic heart sounds as predictors of myocardial ischemia (n = 37) Sensitivity (n = 19) Standard 52.6% ST-T criteria (10/19) S3 47.4% (9/19) S4 73.7% (14/19) S3 or S4 84.2% (16/19)
Specificity (n = 18)
Overall Odds ratio P accuracy (95% CI) (n = 37)
100.0% (18/18) 94.4% (17/18) 83.3% (15/18) 77.8% (14/18)
75.7% (28/37) 70.3% (26/37) 78.4% (29/37) 81.1% (30/37)
NAa 15.3 (1.7-139.3) 14.0 (2.8-69.8) 18.7 (3.6-98.2)
b.001b .015c .001c .001c
S3 indicates third heart sound; S4, fourth heart sound; CI, confidence interval. a Odds ratio unavailable because of “zero” case with ST-T criteria in non-ischemia group. b P value of Fisher exact test. c P value of logistic regression.
An intelligent wireless electrocardiographic patch for single-lead electrocardiographic monitoring Venkatarama Subba Rao Nimmala, Jef van de Molengraft, Julien Penders, Bert Gyselinckx, IMEC-NL, High Tech Campus 31, 5656AE Eindhoven, The Netherlands Emerging technologies for body area networks open new opportunities for cardiac monitoring. In a typical setup, a wireless sensor node will monitor heart activity, process the data locally, and transmit it wirelessly to a central node, acting as a gateway to the external world. In this paper, we report an intelligent wireless electrocardiographic (ECG) patch for the continuous monitoring of single-lead ECG. The ECG patch is a hybrid system combining electronic assembly on flexible polyimide substrate and textile integration. This allows achieving flexibility in one dimension—as required for a total fit to body curves, and stretchability in the other direction—as required for optimal, personalized, electrode placement. All the components are embedded in textile and standard ECG electrodes are used for attachment to the body. The total system weighs about 15 g. The wireless