Carlos Cigarroa - Academia.edu (original) (raw)

Uploads

Papers by Carlos Cigarroa

Research paper thumbnail of Identifying likely candidates for coronary revascularization with dobutamine echocardiography

Research paper thumbnail of Time course of improvement in left ventricular function, mass and geometry in patients with congestive heart failure treated with beta-adrenergic blockade

Journal of the American College of Cardiology, 1995

Objectives. We examined the time course of ventricular functional improvement in patients with di... more Objectives. We examined the time course of ventricular functional improvement in patients with dilated cardiomyopathy who received beta-blockade and the long-term effects of beta-blockade on ventricular mass and geometry in these patients. Background. Previous studies have shown that beta-adrenergic blocking agents when administered long term improve ventricular function in patients with heart failure. However, the time course of improvement in ventricnlar function and the long-term effects of beta-blockade on ventricular mass and geometry are not known. Methods. Twen~-six men with dilated cardiomyopathy underwent serial echocardiography on days 0 and 1 and months 1 and 3 of either metoprolol (n = 16) or standard therapy (n = 10). At 3 months all patients on standard therapy were crossed over to metoprolol, and late echocardiograms were obtained after 18-+ 5 (mean _+ SD) months of metoprolol therapy. All echocardiograms were read in blinded manner. Results. Patients treated with metoprolol had an initial decline (day 1 vs. day 0) in ventricular function (increase in end-systolic volume and decrease in ejection fraction). Ventricular function improved between months 1 and 3 (p = 0.013, metoprolol vs. standard therapy). Left ventricular mass regressed at 18 months (333-+ 85 to 275-+ 53 g, p = 0.011) but not at 3 months. Left ventricular shape became less spherical and assumed a more normal elliptical shape by 18 months (major/minor axis ratio 1.5-+ 0.2 to 1.7-+ 0.2, p = 0.0001). Conclusions. Patients with heart failure treated with metoprolol do not demonstrate an improvement in systolic performance until after 1 month of therapy and may have a mild reduction in function initially. Long-term therapy with metoprolol results in a reversal of maladaptive remodeling with reduction in left ventricular volumes, regression of left ventricular mass and improved ventricular geometry by 18 months.

Research paper thumbnail of Quantitative Assessment of Simulated Regurgitant Flow Using Direct Digital Acquisition of Doppler Color Flow Images

Echocardiography, 1997

Analysis of jet momentum and proximal isovelocity surface area (PISA) have been shown to be accur... more Analysis of jet momentum and proximal isovelocity surface area (PISA) have been shown to be accurate in quantitating regurgitant flow for axisymmetric free jets. However, eccentric jets directed against chamber walls are often encountered in clinical practice and could confound the assessment of regurgitant flow. Thus, we used direct digital color flow mapping to calculate flow by the momentum method and PISA in a flow model. Steady flow jets were driven through a 2-mm round orifice at flow rates of 3, 6, 9, 12, 15, and 20 mLIsec. Jets were directed centrally and against the lateral wall of a 150 m L chamber. The raw data from a 3.2512.5 MHz transducer Ningmed CFM 750) was digitally transferred to a Macintosh IIci computer for analysis of the velocities comprising the jets. By linear regression, PISA was accurate in assessing flow for both free jets and wall jets (r" = 0.98) with regression lines approximating unity. The momentum method was highly accurate for free jets (r" = 0.98) but systematically underestimated flow for wall jets (r" = 0.70, y = 0. 2 1~ + 0.88). Thus, analysis of simulated regurgitant flow using digital display of velocities encoded in the color flow jet is accurate for free jets by both the PISA and momentum techniques. I n wall jets, the momentum technique underestimates flow because the requirement for jet axisymmetry is not met.

Research paper thumbnail of Exaggerated pressor response to treadmill exercise in chronic cocaine abusers with left ventricular hypertrophy

Circulation, 1992

BACKGROUND Chronic cocaine abuse has been associated with a high prevalence of left ventricular h... more BACKGROUND Chronic cocaine abuse has been associated with a high prevalence of left ventricular hypertrophy (LVH) in normotensive individuals at rest. This study was conducted to determine whether chronic cocaine abusers with LVH would manifest an exaggerated pressor response to treadmill exercise. METHODS AND RESULTS Forty-nine normotensive chronic cocaine abusers underwent Bruce protocol treadmill exercise testing until they attained 85% maximum predicted heart rate. A peak exercise systolic blood pressure greater than or equal to 210 mm Hg was defined as abnormal. In addition, they underwent two-dimensional echocardiography and had left ventricular mass determined by the area-length method. LVH was defined as left ventricular mass greater than or equal to 105 g/m2 and a posterior wall thickness greater than or equal to 1.2 cm. Age- and race-matched control subjects also underwent echocardiography and exercise testing. Group differences in peak exercise blood pressure in cocaine a...

Research paper thumbnail of Dobutamine stress echocardiography identifies hibernating myocardium and predicts recovery of left ventricular function after coronary revascularization

Circulation, 1993

BACKGROUND The identification of hibernating myocardium is important in selecting patients who wi... more BACKGROUND The identification of hibernating myocardium is important in selecting patients who will benefit from coronary revascularization. This study was performed to determine whether dobutamine stress echocardiography (DSE) could identify hibernating myocardium and predict improvement in regional systolic wall thickening after revascularization. METHODS AND RESULTS DSE was performed in 49 consecutive patients with multivessel coronary disease and depressed left ventricular function. Contractile reverse during DSE was defined by the presence of two criteria: (1) improved systolic wall thickening in at least two adjacent abnormal segments and (2) > or = 20% improvement in regional wall thickening score. Postoperative echocardiograms were evaluated for improved regional wall thickening in 25 patients at least 4 weeks after successful coronary revascularization. All studies were read in blinded fashion. Contractile reserve during DSE was present in 24 (49%) of 49 patients. The pr...

Research paper thumbnail of Relation of thrombus in the left atrial appendage by transesophageal echocardiography to clinical risk factors for thrombus formation

The American Journal of Cardiology, 1994

Research paper thumbnail of Racial differences in the prevalence of left ventricular hypertrophy among chronic cocaine abusers

The American Journal of Cardiology, 1995

There are racial differences in the prevalence and pattern of left ventricular (LV) hypertrophy i... more There are racial differences in the prevalence and pattern of left ventricular (LV) hypertrophy in hypertension. This study was performed to determine whether racial differences also exist in LV hypertrophy among chronic cocaine users. We studied 112 chronic cocaine abusers < 45 years old in whom normal blood pressures (< or = 140/90 mm Hg) were recorded 3 times daily for 3 weeks. LV wall thickness and mass were measured echocardiographically. Technically adequate studies were obtained in 79 blacks and 33 whites. Self-reported cocaine use was higher in whites than in blacks (688 +/- 516 vs 431 +/- 468 $/week, p = 0.03). There were no group differences in terms of duration of cocaine use, age, height, weight, blood pressure, LV dimensions, or left atrial size. However, posterior wall thickness (1.13 +/- 0.17 vs 1.03 +/- 0.14 cm, p = 0.0035) and LV mass index (113 +/- 25 vs 94 +/- 19 g/m2, p = 0.0001) were significantly greater in blacks. LV hypertrophy, defined as an M-mode LV mass index > or = 134 g/m2, was present in 24 blacks (30%) and 2 whites (6%) (p = 0.011). When defined as a posterior wall thickness > or = 1.2 cm and a 2-dimensional echocardiographic LV mass index > or = 105 g/m2, LV hypertrophy was present in 37 of 79 blacks (47%) and in 6 of 33 whites (18%) (p = 0.0086). Cocaine-related LV hypertrophy is more prevalent in black men than in white men.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Dobutamine echocardiography in predicting improvement in global left ventricular systolic function after coronary bypass or angioplasty in patients with healed myocardial infarcts

The American Journal of Cardiology, 1995

The aim of this study was to determine whether low-dose dobutamine echocardiography (DE) could pr... more The aim of this study was to determine whether low-dose dobutamine echocardiography (DE) could predict quantitative improvement in global left ventricular (LV) systolic function after coronary revascularization. Low-dose DE was performed in 71 consecutive patients with coronary artery disease and LV dysfunction. Successful coronary bypass surgery or angioplasty was performed in 44 patients, 37 of whom had a resting echocardiogram 1 to 3 months afterward. Group A consisted of 20 patients with contractile reserve during DE, and group B consisted of 17 patients without contractile reserve. As expected, regional wall motion score index (mean +/- SD) improved in group A (1.62 +/- 0.39 to 1.38 +/- 0.31, p < 0.01) but not group B (1.56 +/- 0.42 to 1.57 +/- 0.41, p = NS). In addition, LV ejection fraction (LVEF) improved after bypass surgery or angioplasty in group A (38 +/- 5% to 42 +/- 5%, p < 0.01), but not in group B (38 +/- 7% to 39 +/- 8%, p = NS). In group A, a significant linear correlation was observed between the number of segments with contractile reserve and the improvement in LVEF (r = 0.91, p < 0.0001). A good correlation also existed between the improvement in regional wall motion score index during dobutamine infusion and the improvement in LVEF after bypass surgery or angioplasty (r = 0.90, p < 0.0001). In conclusion, low-dose DE can be used to predict quantitative improvement in global LV systolic function after coronary bypass or angioplasty.

Research paper thumbnail of Identifying likely candidates for coronary revascularization with dobutamine echocardiography

Research paper thumbnail of Time course of improvement in left ventricular function, mass and geometry in patients with congestive heart failure treated with beta-adrenergic blockade

Journal of the American College of Cardiology, 1995

Objectives. We examined the time course of ventricular functional improvement in patients with di... more Objectives. We examined the time course of ventricular functional improvement in patients with dilated cardiomyopathy who received beta-blockade and the long-term effects of beta-blockade on ventricular mass and geometry in these patients. Background. Previous studies have shown that beta-adrenergic blocking agents when administered long term improve ventricular function in patients with heart failure. However, the time course of improvement in ventricnlar function and the long-term effects of beta-blockade on ventricular mass and geometry are not known. Methods. Twen~-six men with dilated cardiomyopathy underwent serial echocardiography on days 0 and 1 and months 1 and 3 of either metoprolol (n = 16) or standard therapy (n = 10). At 3 months all patients on standard therapy were crossed over to metoprolol, and late echocardiograms were obtained after 18-+ 5 (mean _+ SD) months of metoprolol therapy. All echocardiograms were read in blinded manner. Results. Patients treated with metoprolol had an initial decline (day 1 vs. day 0) in ventricular function (increase in end-systolic volume and decrease in ejection fraction). Ventricular function improved between months 1 and 3 (p = 0.013, metoprolol vs. standard therapy). Left ventricular mass regressed at 18 months (333-+ 85 to 275-+ 53 g, p = 0.011) but not at 3 months. Left ventricular shape became less spherical and assumed a more normal elliptical shape by 18 months (major/minor axis ratio 1.5-+ 0.2 to 1.7-+ 0.2, p = 0.0001). Conclusions. Patients with heart failure treated with metoprolol do not demonstrate an improvement in systolic performance until after 1 month of therapy and may have a mild reduction in function initially. Long-term therapy with metoprolol results in a reversal of maladaptive remodeling with reduction in left ventricular volumes, regression of left ventricular mass and improved ventricular geometry by 18 months.

Research paper thumbnail of Quantitative Assessment of Simulated Regurgitant Flow Using Direct Digital Acquisition of Doppler Color Flow Images

Echocardiography, 1997

Analysis of jet momentum and proximal isovelocity surface area (PISA) have been shown to be accur... more Analysis of jet momentum and proximal isovelocity surface area (PISA) have been shown to be accurate in quantitating regurgitant flow for axisymmetric free jets. However, eccentric jets directed against chamber walls are often encountered in clinical practice and could confound the assessment of regurgitant flow. Thus, we used direct digital color flow mapping to calculate flow by the momentum method and PISA in a flow model. Steady flow jets were driven through a 2-mm round orifice at flow rates of 3, 6, 9, 12, 15, and 20 mLIsec. Jets were directed centrally and against the lateral wall of a 150 m L chamber. The raw data from a 3.2512.5 MHz transducer Ningmed CFM 750) was digitally transferred to a Macintosh IIci computer for analysis of the velocities comprising the jets. By linear regression, PISA was accurate in assessing flow for both free jets and wall jets (r" = 0.98) with regression lines approximating unity. The momentum method was highly accurate for free jets (r" = 0.98) but systematically underestimated flow for wall jets (r" = 0.70, y = 0. 2 1~ + 0.88). Thus, analysis of simulated regurgitant flow using digital display of velocities encoded in the color flow jet is accurate for free jets by both the PISA and momentum techniques. I n wall jets, the momentum technique underestimates flow because the requirement for jet axisymmetry is not met.

Research paper thumbnail of Exaggerated pressor response to treadmill exercise in chronic cocaine abusers with left ventricular hypertrophy

Circulation, 1992

BACKGROUND Chronic cocaine abuse has been associated with a high prevalence of left ventricular h... more BACKGROUND Chronic cocaine abuse has been associated with a high prevalence of left ventricular hypertrophy (LVH) in normotensive individuals at rest. This study was conducted to determine whether chronic cocaine abusers with LVH would manifest an exaggerated pressor response to treadmill exercise. METHODS AND RESULTS Forty-nine normotensive chronic cocaine abusers underwent Bruce protocol treadmill exercise testing until they attained 85% maximum predicted heart rate. A peak exercise systolic blood pressure greater than or equal to 210 mm Hg was defined as abnormal. In addition, they underwent two-dimensional echocardiography and had left ventricular mass determined by the area-length method. LVH was defined as left ventricular mass greater than or equal to 105 g/m2 and a posterior wall thickness greater than or equal to 1.2 cm. Age- and race-matched control subjects also underwent echocardiography and exercise testing. Group differences in peak exercise blood pressure in cocaine a...

Research paper thumbnail of Dobutamine stress echocardiography identifies hibernating myocardium and predicts recovery of left ventricular function after coronary revascularization

Circulation, 1993

BACKGROUND The identification of hibernating myocardium is important in selecting patients who wi... more BACKGROUND The identification of hibernating myocardium is important in selecting patients who will benefit from coronary revascularization. This study was performed to determine whether dobutamine stress echocardiography (DSE) could identify hibernating myocardium and predict improvement in regional systolic wall thickening after revascularization. METHODS AND RESULTS DSE was performed in 49 consecutive patients with multivessel coronary disease and depressed left ventricular function. Contractile reverse during DSE was defined by the presence of two criteria: (1) improved systolic wall thickening in at least two adjacent abnormal segments and (2) > or = 20% improvement in regional wall thickening score. Postoperative echocardiograms were evaluated for improved regional wall thickening in 25 patients at least 4 weeks after successful coronary revascularization. All studies were read in blinded fashion. Contractile reserve during DSE was present in 24 (49%) of 49 patients. The pr...

Research paper thumbnail of Relation of thrombus in the left atrial appendage by transesophageal echocardiography to clinical risk factors for thrombus formation

The American Journal of Cardiology, 1994

Research paper thumbnail of Racial differences in the prevalence of left ventricular hypertrophy among chronic cocaine abusers

The American Journal of Cardiology, 1995

There are racial differences in the prevalence and pattern of left ventricular (LV) hypertrophy i... more There are racial differences in the prevalence and pattern of left ventricular (LV) hypertrophy in hypertension. This study was performed to determine whether racial differences also exist in LV hypertrophy among chronic cocaine users. We studied 112 chronic cocaine abusers < 45 years old in whom normal blood pressures (< or = 140/90 mm Hg) were recorded 3 times daily for 3 weeks. LV wall thickness and mass were measured echocardiographically. Technically adequate studies were obtained in 79 blacks and 33 whites. Self-reported cocaine use was higher in whites than in blacks (688 +/- 516 vs 431 +/- 468 $/week, p = 0.03). There were no group differences in terms of duration of cocaine use, age, height, weight, blood pressure, LV dimensions, or left atrial size. However, posterior wall thickness (1.13 +/- 0.17 vs 1.03 +/- 0.14 cm, p = 0.0035) and LV mass index (113 +/- 25 vs 94 +/- 19 g/m2, p = 0.0001) were significantly greater in blacks. LV hypertrophy, defined as an M-mode LV mass index > or = 134 g/m2, was present in 24 blacks (30%) and 2 whites (6%) (p = 0.011). When defined as a posterior wall thickness > or = 1.2 cm and a 2-dimensional echocardiographic LV mass index > or = 105 g/m2, LV hypertrophy was present in 37 of 79 blacks (47%) and in 6 of 33 whites (18%) (p = 0.0086). Cocaine-related LV hypertrophy is more prevalent in black men than in white men.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Dobutamine echocardiography in predicting improvement in global left ventricular systolic function after coronary bypass or angioplasty in patients with healed myocardial infarcts

The American Journal of Cardiology, 1995

The aim of this study was to determine whether low-dose dobutamine echocardiography (DE) could pr... more The aim of this study was to determine whether low-dose dobutamine echocardiography (DE) could predict quantitative improvement in global left ventricular (LV) systolic function after coronary revascularization. Low-dose DE was performed in 71 consecutive patients with coronary artery disease and LV dysfunction. Successful coronary bypass surgery or angioplasty was performed in 44 patients, 37 of whom had a resting echocardiogram 1 to 3 months afterward. Group A consisted of 20 patients with contractile reserve during DE, and group B consisted of 17 patients without contractile reserve. As expected, regional wall motion score index (mean +/- SD) improved in group A (1.62 +/- 0.39 to 1.38 +/- 0.31, p < 0.01) but not group B (1.56 +/- 0.42 to 1.57 +/- 0.41, p = NS). In addition, LV ejection fraction (LVEF) improved after bypass surgery or angioplasty in group A (38 +/- 5% to 42 +/- 5%, p < 0.01), but not in group B (38 +/- 7% to 39 +/- 8%, p = NS). In group A, a significant linear correlation was observed between the number of segments with contractile reserve and the improvement in LVEF (r = 0.91, p < 0.0001). A good correlation also existed between the improvement in regional wall motion score index during dobutamine infusion and the improvement in LVEF after bypass surgery or angioplasty (r = 0.90, p < 0.0001). In conclusion, low-dose DE can be used to predict quantitative improvement in global LV systolic function after coronary bypass or angioplasty.