The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform

Harold L Dauerman - One of the best experts on this subject based on the ideXlab platform.

Mehdi Rambod - One of the best experts on this subject based on the ideXlab platform.

Richard J. Shemin - One of the best experts on this subject based on the ideXlab platform.

  • Superiority of Retrograde Cardioplegia Coronary Occlusion
    1991
    Co-Authors: Constance K. Haan, Harold L. Lazar, Sheilah Bernard, Richard J. Shemin, John Zallnick, Samuel Rivers
    Abstract:

    Because antegrade cardioplegia may limit the distribution of cardioplegia beyond a Coronary Occlusion, this study was undertaken to determine whether retrograde Coronary sinus cardioplegia provides superior myocardial protection during revascularization of an acute Coronary Occlusion. In 20 adult pigs, the second and third diagonal branches were occluded with a snare for 1?h hours. Animals were then placed on cardiopulmonary bypass and underwent 30 minutes of ischemic arrest with multidose, potassium, crystalloid cardioplegia. In 10 animals, the cardioplegia was given antegrade through the aortic root, whereas in 10 others, it was given retrograde through the Coronary sinus. After the arrest period, the Coronary snares were released and all hearts were reperfused for 3 hours. Postischemic damage in the he presence of Coronary Occlusions can alter the T distribution of antegrade cardioplegia [l]. This can lead to myocardial injury and depressed postoperative left ventricular function. Experimental studies have shown that in the presence of Coronary Occlusions, retrograde cardioplegia results in better myocardial cooling and more complete recovery of function in the area of the myocardium beyond the Occlusions [24]. Nevertheless, recent clinical studies in patients undergoing Coronary artery bypass grafting have shown that retrograde cardioplegia appears to offer no additional myocardial protection as compared with antegrade techniques [5, 61. In these studies, patients had normal ventricular function and stable angina patterns. A more accurate assessment of the potential advantages of retrograde cardioplegia would be in the setting of acute Coronary ischemia such as that which occurs after a failed balloon angioplasty. Attempts to assess the clinical efficacy of a cardioplegia technique after emergent Coronary artery bypass grafting are always difficult because of persistent postoperative wall motion changes, which may be independent of the degree of protection and the relative insensitivity of enzyme levels and scanning techniques. Histochemical staining techniques in the area of risk may be a more sensitive variable to judge the benefits of a cardioplegic

  • Superiority of retrograde cardioplegia after acute Coronary Occlusion.
    The Annals of thoracic surgery, 1991
    Co-Authors: Constance K. Haan, Harold L. Lazar, Samuel Rivers, Sheilah Bernard, John Zallnick, Richard J. Shemin
    Abstract:

    Because antegrade cardioplegia may limit the distribution of cardioplegia beyond a Coronary Occlusion, this study was undertaken to determine whether retrograde Coronary sinus cardioplegia provides superior myocardial protection during revascularization of an acute Coronary Occlusion. In 20 adult pigs, the second and third diagonal branches were occluded with a snare for 1 1/2 hours. Animals were then placed on cardiopulmonary bypass and underwent 30 minutes of ischemic arrest with multidose, potassium, crystalloid cardioplegia. In 10 animals, the cardioplegia was given antegrade through the aortic root, whereas in 10 others, it was given retrograde through the Coronary sinus. After the arrest period, the Coronary snares were released and all hearts were reperfused for 3 hours. Postischemic damage in the myocardium beyond the Occlusions was assessed by wall motion scores using two-dimensional echocardiography (4 = normal to -1 = dyskinesia), the change in myocardial pH from preischemia, and the area of necrosis/area of risk (histochemical staining). Hearts protected with retrograde Coronary sinus cardioplegia had less tissue acidosis (change in pH = 0.08 +/- 0.03 versus 0.41 +/- 0.13; p less than 0.05), higher wall motion scores (2.0 +/- 0.6 versus 1.3 +/- 0.3; not significant), and less myocardial necrosis (43.4% +/- 3.6% versus 73.3% +/- 3.5%; p less than 0.0001). We conclude that retrograde Coronary sinus cardioplegia provides more optimal myocardial protection than is possible with antegrade cardioplegia after revascularization of an acute Coronary Occlusion.

Heikki V. Huikuri - One of the best experts on this subject based on the ideXlab platform.

  • Diabetes and haemodynamic reactions to acute Coronary Occlusion.
    International journal of cardiology, 2004
    Co-Authors: K.e. Juhani Airaksinen, Minna L. Koivikko, Kari U. O. Tahvanainen, Markku K. Linnaluoto, Matti J Niemelä, Heikki V. Huikuri
    Abstract:

    The risk of early sudden death before hospital admission is higher in diabetic than non-diabetic men with acute myocardial infarction and autonomic nervous activity may modify the clinical outcome of abrupt Coronary Occlusion. Since diabetes mellitus may interfere with autonomic and myocardial function, we decided to study whether diabetes alters autonomic and haemodynamic responses to acute Coronary Occlusion. We analyzed the changes in heart rate, heart rate variability and blood pressure, and the occurrence of ventricular ectopy during a 2-min Coronary Occlusion in 238 non-diabetic and 32 diabetic patients referred for single vessel Coronary angioplasty. The ranges of non-specific responses were determined by analyzing a control group of 19 patients with no ischaemia during a 2-min balloon inflation in a totally occluded Coronary artery. Diabetic patients were more often (p<0.05) female, but there were no significant differences in the occluded vessel or incidence of ST changes or chest pain during Coronary Occlusion between the groups. Incidence of significant heart rate reactions and ventricular arrhythmias was comparable in both groups. Systolic blood pressure decreased (p=0.01) in the diabetic patients during Coronary Occlusion, but did not change significantly in the non-diabetic group. Coronary Occlusion caused more often (34% vs. 14%, p<0.01) a significant decrease in blood pressure in diabetic patients. Logistic regression models developed to analyze the significance of diabetes while controlling for baseline variables and signs of ischaemia identified diabetes to be an independent predictor of hypotensive reactions (odds ratio [OR] 2.9, 95% confidence intervals 1.1-7.8, p<0.05), while female gender and high short-term heart rate variability were other independent predictors of hypotensive reactions. Diabetic patients often develop significant hypotension during the early phase of acute Coronary Occlusion. This abnormality may be related to diabetic cardiomyopathy and impairment of baroreflex-mediated regulation of circulation. Predisposition to hypotension may contribute to the observed differences in the clinical presentation and outcome of acute Coronary events.

  • Diabetes and haemodynamic reactions to acute Coronary Occlusion.
    International Journal of Cardiology, 2003
    Co-Authors: K.e. Juhani Airaksinen, Minna L. Koivikko, Matti Niemelä, Kari U. O. Tahvanainen, Markku K. Linnaluoto, Heikki V. Huikuri
    Abstract:

    Abstract Background: The risk of early sudden death before hospital admission is higher in diabetic than non-diabetic men with acute myocardial infarction and autonomic nervous activity may modify the clinical outcome of abrupt Coronary Occlusion. Since diabetes mellitus may interfere with autonomic and myocardial function, we decided to study whether diabetes alters autonomic and haemodynamic responses to acute Coronary Occlusion. Methods: We analyzed the changes in heart rate, heart rate variability and blood pressure, and the occurrence of ventricular ectopy during a 2-min Coronary Occlusion in 238 non-diabetic and 32 diabetic patients referred for single vessel Coronary angioplasty. The ranges of non-specific responses were determined by analyzing a control group of 19 patients with no ischaemia during a 2-min balloon inflation in a totally occluded Coronary artery. Results: Diabetic patients were more often ( p p =0.01) in the diabetic patients during Coronary Occlusion, but did not change significantly in the non-diabetic group. Coronary Occlusion caused more often (34% vs. 14%, p . Logistic regression models developed to analyze the significance of diabetes while controlling for baseline variables and signs of ischaemia identified diabetes to be an independent predictor of hypotensive reactions (odds ratio [OR] 2.9, 95% confidence intervals 1.1–7.8, p Conclusions: Diabetic patients often develop significant hypotension during the early phase of acute Coronary Occlusion. This abnormality may be related to diabetic cardiomyopathy and impairment of baroreflex-mediated regulation of circulation. Predisposition to hypotension may contribute to the observed differences in the clinical presentation and outcome of acute Coronary events.

  • Arterial baroreflex impairment in patients during acute Coronary Occlusion.
    Journal of the American College of Cardiology, 1998
    Co-Authors: K.e. Juhani Airaksinen, Matti Niemelä, Kari U. O. Tahvanainen, Dwain L. Eckberg, Antti Ylitalo, Heikki V. Huikuri
    Abstract:

    AbstractObjectives. We tested whether acute Coronary Occlusion interferes with arterial baroreceptor control of heart rate in humans.Background. Subnormal baroreflex sensitivity (BRS) is an importa...

  • Gender Difference in Autonomic and Hemodynamic Reactions to Abrupt Coronary Occlusion
    Journal of the American College of Cardiology, 1998
    Co-Authors: K.e. Juhani Airaksinen, Kari U. O. Tahvanainen, Markku K. Linnaluoto, Markku J. Ikäheimo, Heikki V. Huikuri
    Abstract:

    Abstract Objectives. We sought to determine whether there are gender-related differences in autonomic and hemodynamic responses to abrupt Coronary Occlusion. Background. The risk of sudden death before hospital admission is higher in men with an acute myocardial infarction. The reasons for this gender-related difference are not well understood. Cardiovascular autonomic regulation modifies the outcome of acute Coronary events, and there are gender differences in the autonomic regulation of heart rate (HR) in normal physiologic circumstances. Methods. We analyzed the changes in HR, HR variability and blood pressure and the occurrence of ventricular ectopic beats during a 2-min Coronary Occlusion in 140 men and 65 women referred for single-vessel Coronary angioplasty. The ranges of nonspecific responses were determined by analyzing a control group of 19 patients with no ischemia during a 2-min balloon inflation in a totally occluded Coronary artery. Results. Women more often had ST segment changes (p Conclusions. Vagal activation is more common in women than in men during abrupt Coronary Occlusion and may have beneficial antiarrhythmic effects, modifying the outcome of acute Coronary events.

José A. Barrabés - One of the best experts on this subject based on the ideXlab platform.

  • Distension of the Ischemic Region Predicts Increased Ventricular Fibrillation Inducibility Following Coronary Occlusion in Swine
    Revista espanola de cardiologia (English ed.), 2012
    Co-Authors: José A. Barrabés, Jaume Figueras, Jaume Candell-riera, Luis Agulló, Javier Inserte, David Garcia-dorado
    Abstract:

    Abstract Introduction and objectives Distension of the ischemic region has been related to an increased incidence of spontaneous ventricular arrhythmias following Coronary Occlusion. This study analyzed whether regional ischemic distension predicts increased ventricular fibrillation inducibility after Coronary Occlusion in swine. Methods In 18 anesthetized, open-chest pigs, the left anterior descending Coronary artery was ligated for 60 min. Myocardial segment length in the ischemic region was monitored by means of ultrasonic crystals. Programmed stimulation was applied at baseline and then continuously between 10 and 60 min after Coronary Occlusion. Results Coronary Occlusion induced a rapid increase in end-diastolic length in the ischemic region, which reached 109.4% (0.9%) of baseline values 10 min after Occlusion ( P r =0.67; P =.002) with the number of induced ventricular fibrillation episodes and inversely ( r =–0.55; P =.018) with the number of extrastimuli needed for ventricular fibrillation induction. Conclusions Regional ischemic expansion predicts increased ventricular fibrillation inducibility following Coronary Occlusion. These results highlight the potential influence of mechanical factors, acting not only on the triggers but also on the substrate, in the genesis of malignant ventricular arrhythmias during acute ischemia.

  • Ventricular fibrillation during acute Coronary Occlusion is related to the dilation of the ischemic region.
    Basic research in cardiology, 2002
    Co-Authors: José A. Barrabés, Luis Agulló, David Garcia-dorado, Ferran Padilla, Lourdes Trobo, Julio Carballo, Jordi Soler-soler
    Abstract:

    Myocardial stretch induces several electrophysiological changes and arrhythmias, but little is known on its possible role in triggering ventricular fibrillation (VF) during acute Coronary Occlusion. In thiopental-anesthetized, open-chest pigs submitted to a 40-min ligation of the left anterior descending Coronary artery, the association between the early increase in end-diastolic length (measured by means of ultrasonic crystals) in the ischemic region and subsequent VF was analyzed. Animals received no treatment (n = 35) or intravenous nitroglycerin (2.5 μg/kg/min for 20 min, starting 10 min after Coronary Occlusion, n = 8) or Gd3+ (80 μM/kg for 35 min, starting 5 min before Occlusion, n = 15). Twenty-four animals (41 %) had VF, 16 to 39 min after Coronary Occlusion. The magnitude of ischemic dilation and the incidence of VF were similar among groups. End-diastolic length in the ischemic region 15 min after Coronary Occlusion was 115.7 ± 1.2 % of baseline in animals with VF and 111.4 ± 0.9 % in those without (P = 0.007), and was the strongest predictor of this arrhythmia (P = 0.003) after adjusting for treatment and other possible confounding variables. Thus, the dilation of the ischemic region is closely and independently associated with VF following Coronary Occlusion. Although the interventions tested in the present study failed to protect against this arrhythmia, the results strongly suggest an influence of ischemic dilation on VF.