Papers by Andrew Michaels
Clinical Cardiology, 2009
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Journal of Cardiac Failure, 2008
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J Card Fail, 2004
Methods Adult patients referred for cardiac catheterization were enrolled. Patients with atrial a... more Methods Adult patients referred for cardiac catheterization were enrolled. Patients with atrial arrhythmia were excluded. Within a 4-hour period, each subject had left heart catheterization for LVEDP, measurement of serum BNP, and echocardiography for LVEF and E/E'. E/E` ...
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Eurointervention Journal of Europcr in Collaboration With the Working Group on Interventional Cardiology of the European Society of Cardiology, Nov 1, 2007
The role of anticoagulation during percutaneous coronary intervention has been well established. ... more The role of anticoagulation during percutaneous coronary intervention has been well established. However, the role of anticoagulation during diagnostic coronary angiography remains unclear. Prothrombin fragment1+2 (PF1+2) and D-dimer (DD) have been reported to be useful in evaluating thrombotic phenomena. This study was designed to determine whether activation of coagulation occurs during diagnostic coronary angiography as measured by DD and PF1+2. Patients not on anticoagulation (except for aspirin) and with no documented coagulopathy undergoing elective diagnostic coronary angiography were enrolled in this prospective study. Blood samples for DD and PF1+2 were obtained serially after the femoral arterial sheath was placed. Peripheral venous blood was drawn along with an initial arterial blood sample from the sheath; thereafter, arterial blood samples from the sheath were obtained every 10 minutes for a maximum of 60 minutes or until the procedure was completed or when anticoagulation was initiated. A final venous sample was drawn at the end of the procedure. The data were analysed in time interval correlation to the DD and PF1+2 level.Forty-two patients were enrolled in this study, 15 were female (35%). There were 25 (59%) patients with diabetes. The mean fluoroscopic time was 8.8+/-7.81 minutes and the average time for the procedure was 29+/-22.70 minutes. There were 192 blood samples analysed. 67% of patient completed the procedure within 20 minutes and 91% within 30 minutes. Mean venous PF1+2 level was 0.20 nmol/L at baseline and 0.39 nmol/L (p=0.06) at the final interval, while the mean arterial PF1+2 level was significantly elevated. There was an increase of 0.2 nmol/L of arterial PF1+2 every 10 minutes (p<0.001). Mean venous DD at baseline and final levels were 0.41 ug/mL and 0.45 ug/mL respectively (p=0.68). There was a significant change in arterial DD with an increase of 0.02ug/ml every 10 minutes (p=0.023). In diagnostic coronary angiography, there is an early rise in PF1+2 levels in blood drawn through the arterial sheath suggesting that the procedure triggers local activation of coagulation that is not observed systemically. Prophylactic anticoagulation may not be necessary in stable patients without other known risk factors who will be undergoing elective diagnostic coronary angiography for less than 30 minutes. For procedures that are prolonged, or anticipated to be prolonged greater than 30 minutes, it may be advisable to administer anticoagulation to prevent thrombus formation. These findings may not be pertinent to patients with thrombophilia.
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J Electrocardiol, 2008
Using echocardiography as the gold standard to diagnose and classify subtypes of left ventricular... more Using echocardiography as the gold standard to diagnose and classify subtypes of left ventricular hypertrophy (LVH), we compared the diagnostic accuracy of computerized acoustic cardiography, brain natriuretic peptide (BNP), and the Cornell voltage criteria. Three hundred fifty-two patients with suspected heart failure had contemporaneous BNP sampling, 12-lead electrocardiography, computerized acoustic cardiography, and echocardiography. Left ventricular hypertrophy was classified as eccentric vs concentric based on echocardiographic relative wall thickness. Computerized acoustic cardiography was used to measure acoustic and automated electrical parameters. Of all models, BNP combined with either computerized acoustic cardiography (c-statistic, 0.78; 95% confidence interval [CI], 0.74-0.78) or Cornell voltage (c-statistic, 0.76; 95% CI, 0.71-0.81) had the best diagnostic performance for LVH detection. For LVH characterization, the computerized acoustic cardiography model outperformed other models (c-statistic, 0.73; 95% CI, 0.66-0.80). Brain natriuretic peptide combined with either computerized acoustic cardiography or Cornell voltage had the highest diagnostic accuracy for the detection of LVH, compared to Cornell voltage, BNP, or computerized acoustic cardiography alone. Computerized acoustic cardiography outperformed other models for the characterization of LVH subtypes.
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Western Journal of Medicine
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The Journal of invasive cardiology
Intragraft verapamil is effective in treating no-reflow during saphenous vein graft (SVG) percuta... more Intragraft verapamil is effective in treating no-reflow during saphenous vein graft (SVG) percutaneous coronary intervention (PCI). In this study, we assessed the use of intragraft verapamil given pre-PCI to prevent no-reflow. Patients undergoing SVG PCI were randomized to receive intragraft 200 g verapamil or no verapamil immediately prior to PCI. Pre- and post-PCI, vessel flow was assessed using TIMI flow grade and TIMI frame count by blinded angiographic readers. Tissue level perfusion in the graft territory was assessed using the TIMI myocardial perfusion grade (TMPG). CK-MB or troponin I levels were measured 6 12 hours post-PCI. Ten patients were randomized to the verapamil group and 12 were assigned to the placebo group. No-reflow occurred in 33.3% of the placebo group, compared to none of the verapamil patients (p = 0.10). The use of intragraft verapamil prior to SVG PCI increased flow rate in the vessel as assessed by TIMI frame count (53.3 22.4% faster in the verapamil group versus 11.5 38.9% in the placebo group; p = 0.016). There was a trend toward improved myocardial perfusion as assessed by TMPG. There was no difference in the incidence of cardiac biomarker release following PCI. Intragraft administration of verapamil prior to saphenous vein graft PCI reduces no-reflow and is associated with a trend toward improved myocardial perfusion.
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Cardiology research and practice, 2010
We report a case of a 22-year-old female who presented with pericardial effusion and cardiac tamp... more We report a case of a 22-year-old female who presented with pericardial effusion and cardiac tamponade. She was diagnosed with a right atrial mass by computed tomography and was referred to our institution for biopsy of this mass. Transcatheter biopsy was performed with intracardiac echocardiography (ICE) guidance, avoiding the need for transesophageal echocardiography or surgery to obtain the biopsy. ICE for transcatheter biopsy of an intracardiac mass is an attractive modality which provides precise localization of the cardiac structures.
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Current controlled trials in cardiovascular medicine, 2000
Although the TIMI (Thrombolysis In Myocardial Infarction) flow grade classification scheme is wid... more Although the TIMI (Thrombolysis In Myocardial Infarction) flow grade classification scheme is widely used to assess angiographic outcomes, it is limited by poor reproducibility and its categoric nature. The corrected TIMI frame count (CTFC) is a simple, more objective continuous variable index of coronary blood flow that can be broadly and inexpensively applied. This measure of the time for dye to traverse a coronary artery is both accurate (highly correlated with Doppler velocity measurements) and precise (reproducible). The method has been prospectively validated as providing independent risk stratification above and beyond the conventional TIMI flow grades. It has been shown to be a predictor of restenosis, and has been of value in elucidating the underlying pathophysiology of acute myocardial infarction. In view of the above and its ease of use, we anticipate that CTFC will become a widely used method to evaluate coronary blood flow.
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The peri-infarct zone represents the morphologic substrate for reentry ventricular tachycardia af... more The peri-infarct zone represents the morphologic substrate for reentry ventricular tachycardia after myocardial infarction, and its extent is a strong predictor of major cardiac events. Although delayed gadolinium enhancement magnetic resonance imaging (DGE-MRI) was shown to allow for detailed characterization of myocardial infarction by quantifying infarct core zone and peri-infarct zone volume, potentials of DGE-MRI for measuring changes in peri-infarct zone volume are unknown. Therefore, we aimed to assess changes in volume of the peri-infarct zone among patients with ischemic cardiomyopathy treated with chronic vasodilator therapy. Core and peri-infarct zone volumes as assessed with DGE-MRI were measured in 5 patients at baseline and after 6 months treatment with sustained-release dipyridamole. Core zone volume remained stable during follow-up [median (range), 19 mL (9 to 42) vs. 16 mL (11 to 46); P=0.785]. The ratio between the peri-infarct zone and the core zone volume decreased significantly at 6 months compared with baseline [median (range), 0.22 (0.19 to 0.42) vs. 0.18 (0.09 to 0.32); P=0.043], and a trend toward reduction in peri-infarct zone volume was found [median (range), 5 mL (2 to 8) vs. 3 mL (2 to 6); P=0.059]. The peri-infarct zone volume decreased in all but 1 patient over the follow-up. This initial experience suggests that reverse remodeling of the peri-infarct zone with reduction in peri-infarct zone volume may take place in patients with ischemic cardiomyopathy. Quantification of this process may be feasible with DGE-MRI, but further studies are needed to confirm this hypothesis and to further clarify the role of DGE-MRI for the assessment of changes in peri-infarct zone volume in patients with ischemic cardiomyopathy.
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EuroIntervention, 2007
The role of anticoagulation during percutaneous coronary intervention has been well established. ... more The role of anticoagulation during percutaneous coronary intervention has been well established. However, the role of anticoagulation during diagnostic coronary angiography remains unclear. Prothrombin fragment1+2 (PF1+2) and D-dimer (DD) have been reported to be useful in evaluating thrombotic phenomena. This study was designed to determine whether activation of coagulation occurs during diagnostic coronary angiography as measured by DD and PF1+2. Patients not on anticoagulation (except for aspirin) and with no documented coagulopathy undergoing elective diagnostic coronary angiography were enrolled in this prospective study. Blood samples for DD and PF1+2 were obtained serially after the femoral arterial sheath was placed. Peripheral venous blood was drawn along with an initial arterial blood sample from the sheath; thereafter, arterial blood samples from the sheath were obtained every 10 minutes for a maximum of 60 minutes or until the procedure was completed or when anticoagulation was initiated. A final venous sample was drawn at the end of the procedure. The data were analysed in time interval correlation to the DD and PF1+2 level.Forty-two patients were enrolled in this study, 15 were female (35%). There were 25 (59%) patients with diabetes. The mean fluoroscopic time was 8.8+/-7.81 minutes and the average time for the procedure was 29+/-22.70 minutes. There were 192 blood samples analysed. 67% of patient completed the procedure within 20 minutes and 91% within 30 minutes. Mean venous PF1+2 level was 0.20 nmol/L at baseline and 0.39 nmol/L (p=0.06) at the final interval, while the mean arterial PF1+2 level was significantly elevated. There was an increase of 0.2 nmol/L of arterial PF1+2 every 10 minutes (p<0.001). Mean venous DD at baseline and final levels were 0.41 ug/mL and 0.45 ug/mL respectively (p=0.68). There was a significant change in arterial DD with an increase of 0.02ug/ml every 10 minutes (p=0.023). In diagnostic coronary angiography, there is an early rise in PF1+2 levels in blood drawn through the arterial sheath suggesting that the procedure triggers local activation of coagulation that is not observed systemically. Prophylactic anticoagulation may not be necessary in stable patients without other known risk factors who will be undergoing elective diagnostic coronary angiography for less than 30 minutes. For procedures that are prolonged, or anticipated to be prolonged greater than 30 minutes, it may be advisable to administer anticoagulation to prevent thrombus formation. These findings may not be pertinent to patients with thrombophilia.
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Resuscitation, 2008
This is the second case report in literature that describes the simultaneous acoustic cardiograph... more This is the second case report in literature that describes the simultaneous acoustic cardiographic, electrocardiographic, and invasive hemodynamic events that occurred before, during and after ventricular fibrillation that was successfully cardioverted to sinus rhythm. The absence of heart sounds, which are linked to the lack of effective myocardial contractility, correlated well with invasive hemodynamic data, indicating the lack of perfusion during ventricular fibrillation. These observations, coupled with the challenges of pulse detection as a sign of adequate perfusion during resuscitation suggest that acoustic cardiography may be a potentially effective supplemental diagnostic tool during the resuscitation of malignant arrhythmias.
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New England Journal of Medicine, 1997
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Mayo Clinic Proceedings, 2005
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Journal of the American Society of Echocardiography, 2008
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Journal of the American College of Cardiology, 2004
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Journal of the American College of Cardiology, 2003
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Journal of Medical Engineering & Technology, 2011
Rheumatic mitral stenosis severity has been assessed by the systolic time interval between the QR... more Rheumatic mitral stenosis severity has been assessed by the systolic time interval between the QRS onset and the first heart sound (QS1) by phonocardiography. We hypothesized that non-invasive computerized acoustic cardiography could evaluate mitral stenosis severity compared with echocardiography and invasive haemodynamics in patients undergoing percutaneous transvenous mitral commissurotomy (PTMC). 27 patients underwent computerized acoustic cardiography, echocardiography, and invasive haemodynamic measurements prior to and after PTMC. The mean age was 31 ± 10 years, and 21 (78%) were female. By echocardiography, mitral valve area increased from 0.82 ± 0.14 to 1.50 ± 0.24 cm(2) (p < 0.0001). The QS1 interval decreased from 101.7 ± 12.9 to 93.2 ± 9.2 ms (p < 0.0001). The change in the QS1 interval correlated with the change in mitral valve area by echocardiography (p = 0.037), right ventricular systolic pressure (p < 0.0001), and the invasive mitral valve gradient (p = 0.076). Acoustic cardiography may be used as an adjunctive non-invasive diagnostic tool to assess mitral stenosis severity.
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Papers by Andrew Michaels