The aim of this study was to assess adenosine infusion via a cannula in the back of the hand comp... more The aim of this study was to assess adenosine infusion via a cannula in the back of the hand compared with central venous access to achieve peak hyperemia during fractional flow reserve (FFR). Adenosine is often used to induce maximal hyperemia when measuring FFR. The gold standard is continuous infusion via a large central vein; however, the increasing use of the transradial route for angiography makes it desirable to have an alternative route for adenosine. Peripheral venous access is frequently obtained in the hand, but concern exists as to whether adenosine delivery from this site can achieve adequate vasodilation for accurate FFR measurement. Our aim was to address this. Subjects were selected from patients presenting for coronary angiography/intervention who required a pressure-wire study. Subjects received intravenous adenosine infusion sequentially via 2 routes: first, via a 20-gauge hand cannula, and then, after a washout period, via a 5- or 6-French femoral venous sheath. ...
In this work, we propose an automated infarct heterogeneity analysis method for cardiac delayed e... more In this work, we propose an automated infarct heterogeneity analysis method for cardiac delayed enhancement magnetic resonance images (DE-MRI). Advantages of this method include that it eliminates manual contouring of the left ventricle and automatically distinguishes infarct, ...
The majority of patients receiving implantable cardioverter-defibrillator (ICD) implantation unde... more The majority of patients receiving implantable cardioverter-defibrillator (ICD) implantation under current guidelines never develop sustained ventricular arrhythmia; therefore, better markers of risk for sustained ventricular tachycardia and/or ventricular fibrillation are needed. The purpose of this study was to identify cardiac magnetic resonance arrhythmic risk predictors of ischemic cardiomyopathy before ICD implantation. Forty-three subjects (mean age, 64.5 ± 11.9 years) with previous myocardial infarction who were referred for ICD implantation were evaluated by cardiac magnetic resonance imaging (MRI). The MRI protocol included left ventricular functional parameter assessment using steady-state free precession and late gadolinium enhancement MRI using inversion recovery fast gradient echo. Left ventricular functional parameters were measured using cardiac magnetic resonance software. Subjects were followed up for 6-46 months, and the events of appropriate ICD treatments (shocks and antitachycardia pacing) were recorded. Twenty-eight patients experienced 46 spontaneous episodes during a median follow-up duration of 30 months. The total myocardial infarct (MI) size (18.05 ± 11.44 g vs 38.83 ± 19.87 g; P = .0006), MI core (11.63 ± 7.14 g vs 24.12 ± 12.73 g; P = .0002), and infarct gray zone (6.43 ± 4.64 g vs 14.71 ± 7.65 g; P = .0004) were significantly larger in subjects who received appropriate ICD therapy than in those who did not experience an episode of ventricular tachycardia and/or ventricular fibrillation. Multivariate regression analyses for the infarct gray zone and MI core adjusted for New York Heart Association class, diabetes, and etiology (primary or secondary prevention) revealed that the gray zone and MI core were predictors of appropriate ICD therapies (P = .0018 and P = .007, respectively). The extent of MI scar may predict which patients would benefit most from ICD implantation.
To determine the accuracy of multicontrast late enhancement imaging (MCLE) in the assessment of m... more To determine the accuracy of multicontrast late enhancement imaging (MCLE) in the assessment of myocardial viability and wall motion compared to the conventional wall motion and viability cardiac magnetic resonance imaging (MRI) pulse sequences. Forty-one patients with suspected myocardial infarction were studied. Patients underwent assessment of cardiac function with cine steady-state free-precession (SSFP), followed by late gadolinium enhancement (LGE) imaging using inversion recovery gradient echo scanning (IR-GRE) sequence and MCLE. MCLE was compared to cine SSFP in the assessment of wall motion, ejection fraction (EF), left ventricular (LV) mass, LV end-diastolic volume (EDV), and to IR-GRE for measuring infarct size. MCLE, IR-GRE, and SSFP imaging demonstrated excellent agreement in the assessment of EF, LV infarct size, and LV mass (r > 0.95, P < 0.001 for all measures), as well as in the assessment of wall motion (kappa statistic 0.75). MCLE provided coregistered images for the assessment of viability and wall motion without loss of accuracy in the assessment of quantitative cardiac parameters. MCLE provides accurate quantitative cardiac assessment with reduced scan times compared to the conventional sequences and thus may be used as an alternative to conventional cine SSFP and IR-GRE imaging.
We hypothesized that multicontrast late-enhancement (MCLE) MRI would improve the identification o... more We hypothesized that multicontrast late-enhancement (MCLE) MRI would improve the identification of papillary muscle involvement (PM-MI) in patients with myocardial infarction (MI), compared with conventional late gadolinium enhancement (LGE) MRI using the inversion recovery fast gradient echo (IR-FGRE) technique. Cardiac LGE-MRI studies using both MCLE and IR-FGRE pulse sequences were performed on a 1.5 Tesla (T) MRI system in 23 patients following MI. In all patients, PM-MI was confirmed by the diagnostic criteria as outlined below: (a) the increased signal intensity of PM was the same or similar to that of adjacent hyper-enhanced left ventricular (LV) infarct segments; and (b) the hyper-enhanced PM region was limited to the PM area defined by precontrast cine images of steady-state free precession (SSFP). Visual contrast score was rated according to the differentiation between LV blood pool and hyper-enhanced infarct myocardium. Quantitative contrast-noise ratios (CNR) of infarct relative to blood pool and viable myocardium were also measured on MCLE and IR-FGRE images. Of these 23 patients, 13 studies demonstrated primarily involvement of the territories of the right coronary (RCA, 8 patients) and/or left circumflex (LCX, 5 patients) arteries and 10 involved the territories of left anterior descending artery (LAD) with some LCX involvement. Although both IR-FGRE and MCLE determined the presence and extent of LV MI, better visual contrast scores were achieved in MCLE (2.9 ± 0.3) compared with IR-FGRE (1.6 ± 0.8, P < 0.001). The CNRs of infarct relative to LV blood pool showed a significant statistical difference (n = 23, P < 0.00001) between MCLE (16.2 ± 7.2) and IR-FGRE images (4.8 ± 4.1), which is consistent with the result of visual contrast scores between infarct and LV blood pool. The CNRs of infarct versus viable myocardium did not demonstrate a significant statistical difference (n = 23, P = 0.61) between MCLE (14.4 ± 7.0) and IR-FGRE images (13.6 ± 6.1). MCLE clearly demonstrated PM-MI in all cases (100%, 23/23) while only 39% (9/23) could be visualized on the corresponding IR-FGRE images. In conclusion, MCLE imaging provides better contrast between blood pool and infarct myocardium, thus improving the determination of PM-MI.
American Journal of Respiratory and Critical Care Medicine, Jul 1, 2005
Phosphodiesterase type 5 (PDE5) inhibition has been proposed for the treatment for pulmonary arte... more Phosphodiesterase type 5 (PDE5) inhibition has been proposed for the treatment for pulmonary arterial hypertension (PAH). This study compared adding sildenafil, a PDE5 inhibitor, to conventional treatment with the current practice of adding bosentan, an endothelin receptor antagonist. Twenty-six patients with PAH, idiopathic or associated with connective tissue disease, World Health Organization (WHO) functional class III, were randomized in a double-blind fashion to receive sildenafil (50 mg twice daily for 4 weeks, then 50 mg three times daily) or bosentan (62.5 mg twice daily for 4 weeks, then 125 mg twice daily) over 16 weeks. Changes in right ventricular (RV) mass (using cardiovascular magnetic resonance), 6-minute walk distance, cardiac function, brain natriuretic peptide, and Borg dyspnea index. When analyzed by intention to treat, there were no significant differences between the two treatment groups. One patient on sildenafil died suddenly. Patients on sildenafil who completed the protocol showed significant changes from baseline, namely, reductions in RV mass (-8.8 g; 95% confidence interval [CI], -2, -16; n = 13, p = 0.015) and plasma brain natriuretic peptide levels (-19.4 fmol x ml(-1); 95% CI, -5, -34; p = 0.014) and improvements in 6-minute walk distance (114 m; 95% CI, 67, 160; p = 0.0002), cardiac index (0.3 L x min(-1) x m(-2); 95% CI, 0.1, 0.4; p = 0.008), and systolic left ventricular eccentricity index (-0.2; 95% CI, -0.02, -0.37; p = 0.031). Bosentan improved 6-minute walk distance (59 m; 95% CI, 29, 89; n = 12, p = 0.001) and cardiac index (0.3; 95% CI, 0.1, 0.4; p = 0.008). Sildenafil added to conventional treatment reduces RV mass and improves cardiac function and exercise capacity in patients with PAH, WHO functional class III. Safety monitoring is important until more experience is obtained.
The aim of this study was to assess adenosine infusion via a cannula in the back of the hand comp... more The aim of this study was to assess adenosine infusion via a cannula in the back of the hand compared with central venous access to achieve peak hyperemia during fractional flow reserve (FFR). Adenosine is often used to induce maximal hyperemia when measuring FFR. The gold standard is continuous infusion via a large central vein; however, the increasing use of the transradial route for angiography makes it desirable to have an alternative route for adenosine. Peripheral venous access is frequently obtained in the hand, but concern exists as to whether adenosine delivery from this site can achieve adequate vasodilation for accurate FFR measurement. Our aim was to address this. Subjects were selected from patients presenting for coronary angiography/intervention who required a pressure-wire study. Subjects received intravenous adenosine infusion sequentially via 2 routes: first, via a 20-gauge hand cannula, and then, after a washout period, via a 5- or 6-French femoral venous sheath. ...
In this work, we propose an automated infarct heterogeneity analysis method for cardiac delayed e... more In this work, we propose an automated infarct heterogeneity analysis method for cardiac delayed enhancement magnetic resonance images (DE-MRI). Advantages of this method include that it eliminates manual contouring of the left ventricle and automatically distinguishes infarct, ...
The majority of patients receiving implantable cardioverter-defibrillator (ICD) implantation unde... more The majority of patients receiving implantable cardioverter-defibrillator (ICD) implantation under current guidelines never develop sustained ventricular arrhythmia; therefore, better markers of risk for sustained ventricular tachycardia and/or ventricular fibrillation are needed. The purpose of this study was to identify cardiac magnetic resonance arrhythmic risk predictors of ischemic cardiomyopathy before ICD implantation. Forty-three subjects (mean age, 64.5 ± 11.9 years) with previous myocardial infarction who were referred for ICD implantation were evaluated by cardiac magnetic resonance imaging (MRI). The MRI protocol included left ventricular functional parameter assessment using steady-state free precession and late gadolinium enhancement MRI using inversion recovery fast gradient echo. Left ventricular functional parameters were measured using cardiac magnetic resonance software. Subjects were followed up for 6-46 months, and the events of appropriate ICD treatments (shocks and antitachycardia pacing) were recorded. Twenty-eight patients experienced 46 spontaneous episodes during a median follow-up duration of 30 months. The total myocardial infarct (MI) size (18.05 ± 11.44 g vs 38.83 ± 19.87 g; P = .0006), MI core (11.63 ± 7.14 g vs 24.12 ± 12.73 g; P = .0002), and infarct gray zone (6.43 ± 4.64 g vs 14.71 ± 7.65 g; P = .0004) were significantly larger in subjects who received appropriate ICD therapy than in those who did not experience an episode of ventricular tachycardia and/or ventricular fibrillation. Multivariate regression analyses for the infarct gray zone and MI core adjusted for New York Heart Association class, diabetes, and etiology (primary or secondary prevention) revealed that the gray zone and MI core were predictors of appropriate ICD therapies (P = .0018 and P = .007, respectively). The extent of MI scar may predict which patients would benefit most from ICD implantation.
To determine the accuracy of multicontrast late enhancement imaging (MCLE) in the assessment of m... more To determine the accuracy of multicontrast late enhancement imaging (MCLE) in the assessment of myocardial viability and wall motion compared to the conventional wall motion and viability cardiac magnetic resonance imaging (MRI) pulse sequences. Forty-one patients with suspected myocardial infarction were studied. Patients underwent assessment of cardiac function with cine steady-state free-precession (SSFP), followed by late gadolinium enhancement (LGE) imaging using inversion recovery gradient echo scanning (IR-GRE) sequence and MCLE. MCLE was compared to cine SSFP in the assessment of wall motion, ejection fraction (EF), left ventricular (LV) mass, LV end-diastolic volume (EDV), and to IR-GRE for measuring infarct size. MCLE, IR-GRE, and SSFP imaging demonstrated excellent agreement in the assessment of EF, LV infarct size, and LV mass (r > 0.95, P < 0.001 for all measures), as well as in the assessment of wall motion (kappa statistic 0.75). MCLE provided coregistered images for the assessment of viability and wall motion without loss of accuracy in the assessment of quantitative cardiac parameters. MCLE provides accurate quantitative cardiac assessment with reduced scan times compared to the conventional sequences and thus may be used as an alternative to conventional cine SSFP and IR-GRE imaging.
We hypothesized that multicontrast late-enhancement (MCLE) MRI would improve the identification o... more We hypothesized that multicontrast late-enhancement (MCLE) MRI would improve the identification of papillary muscle involvement (PM-MI) in patients with myocardial infarction (MI), compared with conventional late gadolinium enhancement (LGE) MRI using the inversion recovery fast gradient echo (IR-FGRE) technique. Cardiac LGE-MRI studies using both MCLE and IR-FGRE pulse sequences were performed on a 1.5 Tesla (T) MRI system in 23 patients following MI. In all patients, PM-MI was confirmed by the diagnostic criteria as outlined below: (a) the increased signal intensity of PM was the same or similar to that of adjacent hyper-enhanced left ventricular (LV) infarct segments; and (b) the hyper-enhanced PM region was limited to the PM area defined by precontrast cine images of steady-state free precession (SSFP). Visual contrast score was rated according to the differentiation between LV blood pool and hyper-enhanced infarct myocardium. Quantitative contrast-noise ratios (CNR) of infarct relative to blood pool and viable myocardium were also measured on MCLE and IR-FGRE images. Of these 23 patients, 13 studies demonstrated primarily involvement of the territories of the right coronary (RCA, 8 patients) and/or left circumflex (LCX, 5 patients) arteries and 10 involved the territories of left anterior descending artery (LAD) with some LCX involvement. Although both IR-FGRE and MCLE determined the presence and extent of LV MI, better visual contrast scores were achieved in MCLE (2.9 ± 0.3) compared with IR-FGRE (1.6 ± 0.8, P < 0.001). The CNRs of infarct relative to LV blood pool showed a significant statistical difference (n = 23, P < 0.00001) between MCLE (16.2 ± 7.2) and IR-FGRE images (4.8 ± 4.1), which is consistent with the result of visual contrast scores between infarct and LV blood pool. The CNRs of infarct versus viable myocardium did not demonstrate a significant statistical difference (n = 23, P = 0.61) between MCLE (14.4 ± 7.0) and IR-FGRE images (13.6 ± 6.1). MCLE clearly demonstrated PM-MI in all cases (100%, 23/23) while only 39% (9/23) could be visualized on the corresponding IR-FGRE images. In conclusion, MCLE imaging provides better contrast between blood pool and infarct myocardium, thus improving the determination of PM-MI.
American Journal of Respiratory and Critical Care Medicine, Jul 1, 2005
Phosphodiesterase type 5 (PDE5) inhibition has been proposed for the treatment for pulmonary arte... more Phosphodiesterase type 5 (PDE5) inhibition has been proposed for the treatment for pulmonary arterial hypertension (PAH). This study compared adding sildenafil, a PDE5 inhibitor, to conventional treatment with the current practice of adding bosentan, an endothelin receptor antagonist. Twenty-six patients with PAH, idiopathic or associated with connective tissue disease, World Health Organization (WHO) functional class III, were randomized in a double-blind fashion to receive sildenafil (50 mg twice daily for 4 weeks, then 50 mg three times daily) or bosentan (62.5 mg twice daily for 4 weeks, then 125 mg twice daily) over 16 weeks. Changes in right ventricular (RV) mass (using cardiovascular magnetic resonance), 6-minute walk distance, cardiac function, brain natriuretic peptide, and Borg dyspnea index. When analyzed by intention to treat, there were no significant differences between the two treatment groups. One patient on sildenafil died suddenly. Patients on sildenafil who completed the protocol showed significant changes from baseline, namely, reductions in RV mass (-8.8 g; 95% confidence interval [CI], -2, -16; n = 13, p = 0.015) and plasma brain natriuretic peptide levels (-19.4 fmol x ml(-1); 95% CI, -5, -34; p = 0.014) and improvements in 6-minute walk distance (114 m; 95% CI, 67, 160; p = 0.0002), cardiac index (0.3 L x min(-1) x m(-2); 95% CI, 0.1, 0.4; p = 0.008), and systolic left ventricular eccentricity index (-0.2; 95% CI, -0.02, -0.37; p = 0.031). Bosentan improved 6-minute walk distance (59 m; 95% CI, 29, 89; n = 12, p = 0.001) and cardiac index (0.3; 95% CI, 0.1, 0.4; p = 0.008). Sildenafil added to conventional treatment reduces RV mass and improves cardiac function and exercise capacity in patients with PAH, WHO functional class III. Safety monitoring is important until more experience is obtained.
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