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PubMed1997

Assessment of viable myocardium and prediction of postoperative improvement in left ventricular function in patients with severe left ventricular dysfunction by quantitative planar stress-redistribution-reinjection 201-T1 imaging.

A noninvasive approach to determine viable but asynergic myocardium will be clinically significant in identifying patients with coronary artery disease and severe left ventricular dysfunction who will benefit most from coronary bypass surgery. Accordingly, 12 patients (mean ejection fraction 0.32 +/- 0.03) underwent quantitative planar stress-redistribution-reinjection thallium scintigraphy and radionuclide ventriculography before and 8 weeks after revascularization for viability and segmental and global left ventricular function assessment, respectively. Reinjection scan showed new fill-in in 63% of segments without redistribution. Postoperative improvement in perfusion and function of asynergic segments were significantly better in viable compared to nonviable segments (P < 0.001, P < 0.01, respectively) with a strong correlation between improvement in 201-T1 uptake and function (P < 0.001). When adequacy of revascularization was considered, the predictive value of a positive preoperative viability test for functional improvement was 83%. Finally, mean ejection fraction and global wall motion score increased significantly after revascularization for the group as a whole (0.32 +/- 0.03 to 0.44 +/- 0.04, P < 0.001 and 24.08 +/- 2.90 to 33.16 +/- 3.32, P < 0.001, respectively). Thus, preoperative quantitative planar stress-redistribution-reinjection thallium imaging detects viable but asynergic segments which improve function postoperatively and may be valuable in selection of patients with severe left ventricular dysfunction for revascularization.

Chi-Square Distribution↗

PubMed1999

Elderly coronary artery bypass graft patients with left ventricular dysfunction are hemodynamically stable after two different doses of rocuronium.

OBJECTIVE: To clarify the detailed hemodynamic responses to bolus administration of 2x 95% effective dose (ED95) and 3x ED95 of rocuronium in elderly patients with left ventricular dysfunction undergoing elective coronary artery bypass grafting (CABG). DESIGN: Prospective, randomized, clinical study. SETTING: University hospital. PARTICIPANTS: Twenty patients aged older than 65 who had coronary artery disease with left ventricular ejection fractions equal to or less than 40%. INTERVENTIONS: Using invasive cardiac monitoring, the detailed hemodynamic profile was obtained before and at 2, 4, 6, 8, and 10 minutes after the injection of rocuronium. MEASUREMENTS AND MAIN RESULTS: Minor changes in all the measured or derived hemodynamic variables within the two groups did not attain statistical significance. Except for a higher baseline and the subsequent mean arterial pressures in one group, there were neither statistically nor clinically significant differences between two different doses of rocuronium in any of the variables at any time. CONCLUSION: The results demonstrate that bolus administration of rocuronium (2x to 3x ED95) in combination with high-dose fentanyl provides sufficient cardiovascular stability among elderly CABG patients with left ventricular dysfunction. The cardiovascular profile of the two different bolus doses was similar. Rocuronium, in both doses, appears to be a suitable agent for muscle relaxation, especially for patients who require a high degree of cardiovascular stability.

Aged↗

PubMed2000

[Tachycardia-induced cardiomyopathy, unusual and reversible cause of left ventricular dysfunction: report of 9 cases].

In this study, 9 cases of tachycardia-induced cardiomyopathy have been reported, with a 7-year follow-up period. The patient population consisted of 5 males and 4 females with a mean age of 41 +/- 18 years (range: 10-70 years). It was difficult to determine the onset of the arrhythmia, due to its frequently asymptomatic course until such time as cardiac insufficiency became apparent (this was the case in 7 patients, while 2 subjects had palpitations). Four cases of AV intranodal reentry tachycardia (3 with an accessory pathway), 2 cases of atrial fibrillation, 1 case of auricular flutter, 1 case of atrial tachycardia and 1 case of ventricular tachycardia were observed. Disappearance of the symptomatology following restoration of sinus rhythm was accompanied by echocardiographically-determined normalization of systolic function on average 5 +/- 4 months post-arrhythmia (range: 1-12 months). Left-ventricular end-diastolic volumes decreased from 60 +/- 5 mm to 51 +/- 4 mm (P < 0.01), and end-systolic volumes from 50 +/- 7 mm to 35 +/- 4 mm (P < 0.001), while the left ventricular shortening fraction increased from 17 +/- 5% to 33 +/- 4% (P < 0.0001). In the differential diagnosis for primary dilated cardiomyopathy, tachycardia-induced cardiomyopathy appears very similar to the former, and only an adequate period of follow-up after the restoration of sinus rhythm can confirm the diagnosis.

Adolescent↗

PubMed2002

Recovery kinetics of oxygen uptake after cardiopulmonary exercise test and prognosis in patients with left ventricular dysfunction.

INTRODUCTION: The prognostic value of peak oxygen uptake (peak VO2) in patients with left ventricular systolic dysfunction is currently recognized and accepted. Some studies have shown that other cardiopulmonary exercise test (CPET) parameters have additional value. OBJECTIVES: To evaluate whether our population of patients with left ventricular dysfunction had similar results to those found by other investigators who showed that a slow normalization of oxygen uptake (VO2) during the recovery period of a CPET has prognostic value, and whether the recovery phase parameters have additional prognostic value to peak VO2 in these patients. METHODS: We studied 292 consecutive adult patients (81.5% male; mean age 52.4 +/- 10.6 years) with an ejection fraction below 40% (mean 23.6 +/- 8.8%) given their first symptom-limited CPET between 03/1993 and 08/2000. The etiology was ischemic heart disease in 154, idiopathic cardiomyopathy in 130 and other in 8 patients. NYHA class was I in 7%, II in 50.6% and III in 42.4% of the patients. Two years was defined as the maximum follow-up time; it was 551.5 +/- 242.2 days on average, and 62 events (death or cardiac transplantation) occurred. The following parameters were analyzed: peak VO2 (l/min and ml/kg/min), percent predicted peak VO2 (pred VO2) (l/min and ml/kg/min), VO2 every 15 seconds (sec) of the first 3 minutes of recovery (the difference between peak VO2/kg and VO2/kg every 15 sec in the recovery period (dif VO2), expressed in ml/kg/min, and also the time (sec) to reach 50% of peak VO2 (T1/2). It was considered that a combined end-point was reached if patients died or underwent cardiac transplantation. RESULTS: ROC curves of these parameters showed the following as cut-off values (area under the curve > 0.7) for the occurrence of events: peak VO2 < 60% of pred VO2, dif VO2 at 60 sec (< 3 ml/kg/min), 90 sec (< 5), 120 sec (< 8), 150 sec (< 8.6) and 180 sec (< 10.5) of the recovery and T1/2 > 115 sec. Survival analysis was performed considering pred VO2 < 60%, dif VO2 at 150 sec (the largest area under the curve) and T1/2 > 115 sec. In the survival analysis, when the decrease in VO2 at 150 sec was less than 8.6 ml/kg/min the number of patients with events increased from 9.2% to 43.5% (p < 0.001; log-rank), and when T1/2 was less than 115 sec the number of events increased from 12.3 to 34.2% (p < 0.001; log-rank). When the criteria of T1/2 and dif VO2 at 150 sec were considered together with pred VO2 < 60%, mortality increased from 31 to 54% and from 33 to 51%, respectively (p < 0.001, for both parameters; chi-square). CONCLUSIONS: A slow VO2 kinetics in the recovery period of the CPET by itself identified groups of patients with poor prognosis. The association of these parameters with peak VO2 enhanced the identification of groups at greater risk for events. A global evaluation of the CPET should be performed, considering other parameters besides peak VO2, particularly those related to VO2 kinetics in recovery (T1/2 and dif VO2 at 150 sec) as identified in this study.

Adolescent↗

PubMed2005

CRT-D therapy in patients with left ventricular dysfunction and atrial fibrillation.

The number of patients with atrial fibrillation and congestive heart failure has steadily increased in the United States. The presence of atrial fibrillation increases morbidity and mortality for patients with left ventricular dysfunction. The emergence of cardiac resynchronization therapy to improve symptoms and survival from congestive heart failure may provide benefits for those with atrial fibrillation; we review the pathophysiology of atrial fibrillation in the presence of left ventricular dysfunction and the promise of cardiac resynchronization therapy to improve symptoms for the for these patients.

Atrial Fibrillation↗

PubMed2003

[Left ventricular dysfunction in Churg-Strauss syndrome].

Churg-Strauss syndrome is a rare disorder characterized by hypereosinophilia and a systemic vasculitis occurring inpatients with asthma and allergic rhinitis. Vasculitis commonly affects the lungs, the heart, the skin, and the peripheral nervous system. Cardiac involvement is characterized by acute and constrictive pericarditis, myocarditis and endocarditis, as well as ischemic cardiomyopathy. Endomyocardial fibrosis similar to Loeffler's syndrome has been rarely described. In the presented case, a 43 year old man with a history of allergy and asthma suffered from increasing dyspnea, fever, pulmonary infiltates and cardiomyopathy. Laboratory studies were notable for marked hypereosinophilia. In a bronchoscopic lavage and transbronchial biopsy eosinophilic infiltrates accompanied by vasculitis were found, Churg-Strauss syndrome was diagnosed. Echocardiogram showed endomyocardial deposits in the apex of the right ventricle, right ventricular function was normal particular in the basal segments. The left ventricle was slightly enlarged and left ventricular function was impaired. The diastolic mitral in-flow showed a restrictive pattern. Additionally, a pericardial effusion was observed without signs of tamponade. The patient received corticosteroids, cyclophosphamide and cardiomyopathy-specific therapy and showed a marked improvement after 4 months.

Adult↗

PubMed2003

Decreasing significance of left ventricular dysfunction and reoperative surgery in predicting coronary artery bypass grafting-associated mortality: a twelve-year study.

OBJECTIVES: Patients undergoing coronary artery bypass grafting are older and have greater comorbidity than those operated on previously. We evaluated the changes in the predictors of in-hospital mortality among patients undergoing coronary artery bypass grafting during the last 12 years. METHODS: Data on demographic characteristics, preoperative risk factors, operative variables, and hospital outcomes were collected prospectively for all patients undergoing isolated coronary artery bypass grafting at a single institution from January 1, 1990, to December 31, 2001. To examine the effect of time on patient risk profiles and outcomes, we divided patients into three groups according to year of operation (1990-1993 n = 5171, 1994-1997 n = 5977, 1998-2001 n = 6893). RESULTS: In-hospital mortality declined from 2.4% (1990-1993) to 1.2% (1998-2001, P <.0001). Left ventricular dysfunction, increasing age, female gender, hypertension, diabetes, cardiogenic shock, congestive heart failure, peripheral vascular disease, reoperative coronary artery bypass grafting, left main disease, and urgent surgery independently predicted in-hospital mortality in the entire cohort of 18,041 patients. Severe left ventricular dysfunction was the most significant predictor of in-hospital mortality in the 12-year cohort, but it had a declining influence with time (1990-1993 odds ratio 7.1, 1994-1997 odds ratio 5.1, 1998-2001 not statistically significant) because of improving outcomes. Reoperative coronary artery bypass grafting similarly decreased in significance as a predictor of mortality. Emergency coronary artery bypass grafting was performed less frequently in recent years, but the requirement for emergency surgery carried an increasing odds ratio for mortality. CONCLUSIONS: Despite increasing patient age and comorbidity, improvements in perioperative management have reduced the significance of severe left ventricular dysfunction and reoperative coronary artery bypass grafting but not emergency surgery as predictors of in-hospital mortality.

Age Factors↗

PubMed1994

Usefulness of indium-111 antimyosin scintigraphy in confirming myocardial injury in patients with anthracycline-associated left ventricular dysfunction.

BACKGROUND: In patients with cardiac dysfunction due to anthracycline-induced myocyte damage, continuation of anthracyclines carries a high risk, and modification of chemotherapy is thus indicated. The condition, however, must be distinguished from other causes of cardiac dysfunction, e.g., the transient negative inotropic effect which may accompany and follow the intravenous administration of anthracyclines. In the present study the efficacy of 111In-antimyosin in confirming myocyte injury and its potential applicability in differentiating causes of cardiac dysfunction during anthracycline therapy are evaluated. PATIENTS AND METHODS: Twenty-seven patients with asymptomatic left ventricle ejection fraction (LVEF) decrease (median LVEF 47%, range 38%-50%) during chemotherapy with anthracyclines (dose range 100-700 mg/m2 doxorubicin or equivalent) were subsequently studied with 111In-antimyosin cardiac scintigraphy. The degree of myocardial uptake, an indicator of heart muscle cell injury, evaluated both visually and quantitatively by means of heart-to-lung ratios (HLR) obtained from 48-hour planar images, was analyzed in relation to the further clinical and LVEF course. The results were also compared with 111In-antimyosin data from 5 patients who had normal LVEF during chemotherapy and 5 patients who had received no anthracyclines. The distribution pattern of myocardial uptake was assessed by means of single photon emission computed tomography (SPECT). RESULTS: a) Fourteen patients presented with persistent LVEF decrease (median LVEF 42.5%, range 32%-47%) after discontinuation of anthracycline therapy. In 11 of these patients intense and diffuse, as shown by SPECT, cardiac uptake of 111In-antimyosin (HLR 1.87-2.45) was observed. In two patients with intense antimyosin cardiac uptake, spurious HLR values (1.23-1.55) were found which were caused by unexpected lung uptake and focal heart uptake, respectively. All patients with intense cardiac 111In-antimyosin uptake showed persistently decreased LVEF on follow-up (4-26 weeks) and 4 of them subsequently developed congestive heart failure. In another patient with no intense uptake (HLR 1.15) and persistent decrease in LVEF, metastatic cardiac involvement was found. b) In 13 patients with improvement or normalisation of the LVEF (median LVEF 53%, range 51%-63%), generally less intense or slight cardiac uptake (HLR range: 1.20-1.88) was seen; the HLR in these patients, who continued chemotherapy without complications, was consistently lower (p < 0.01) than in patients with persistently decreased LVEF, and comparable to values of patients who had normal LVEF. CONCLUSIONS: 111In-antimyosin scintigraphy can be useful to differentiate cardiac dysfunction caused by severe myocardial injury from temporary decreases in LVEF, without severe concomitant myocyte damage, which may occur during anthracycline therapy. Intense myocardial uptake of 111In-antimyosin can be used as an important confirmatory criterium for the clinical decision to discontinue anthracycline therapy.

Adult↗

PubMed1988

Left ventricular dysfunction in excess of the size of infarction: a possible management strategy.

In this report we describe two patients whose left ventricular dysfunction was far in excess of infarct size as evidenced by ECG changes and the magnitude of creatine kinase release. Both patients demonstrated redistribution in myocardial beds remote from the infarct zone on delayed rest thallium 201 images and both had multivessel disease evident on coronary angiography. Both patients experienced relief of symptoms and improvement in regional and global left ventricular function after revascularization surgery. The possible mechanisms of left ventricular dysfunction in myocardial beds remote from the zone of infarction are discussed.

Adult↗

PubMed2002

Assessment by radionuclide ventriculography of postischemic regional left ventricular dysfunction in patients with healed myocardial infarction or angina pectoris.

Postischemic left ventricular (LV) dysfunction has been observed in experimental animal models after brief, complete coronary artery occlusion followed by reperfusion, but less relevant information is available for humans. The incidence and duration of postischemic LV dysfunction was examined by exercise radionuclide ventriculography in 50 patients with coronary artery disease. Cardiac imaging was performed at rest and was repeated during exercise and then immediately after and 5, 10, and 20 minutes after exercise. LV regional wall motion abnormalities were noted in 50 segments during exercise; they persisted in 30 of 50 segments after exercise, and remained apparent for 20 minutes in 11 segments. In contrast, in 33 segments, wall motion abnormalities were noted only after exercise and continued for 20 minutes in 13 of 33 segments. Exercise-related wall motion abnormalities were observed in 63 segments (76%) after exercise, and in 24 of 63 segments abnormalities continued for 20 minutes after exercise, although parameters of LV hemodynamic functions approached normal values after exercise. The mechanism of postexercise dysfunction is considered to involve acute myocardial stunning after a brief episode of myocardial ischemia, whereas regional wall motion abnormalities observed only after exercise seem to be related to increased levels of catecholamines or sympathetic overdrive, which mask less significant myocardial ischemia during exercise.

Adult↗

PubMed1995

Costs and effects of enalapril therapy in patients with symptomatic heart failure: an economic analysis of the Studies of Left Ventricular Dysfunction (SOLVD) Treatment Trial.

The clinical results of the Studies of Left Ventricular Dysfunction (SOLVD) Treatment Trial have been published previously, but no evaluation of cost-effectiveness based on the primary data has been reported. The authors used a decision analytic model based on primary data from SOLVD to estimate years of survival (overall, by New York Heart Association Class, and quality-adjusted) and to estimate costs of nonfatal hospitalizations, ambulatory care, therapy with enalapril, and deaths. Clinical and resource utilization data were derived from participants in SOLVD, and cost data were derived from the United States. Therapy with enalapril during the approximate 48-month follow-up period in SOLVD resulted in a gain of 0.16 year of life and savings of dollars 718. During the patient's lifetime, a survival benefit of 0.40 year, a cost per year of life saved of dollars 80, and a cost per quality-adjusted life year of dollars 115 with the use of enalapril were projected. The results indicated a net savings and gain in life expectancy during the SOLVD treatment trial. The lifetime projection suggests that therapy with angiotensin-converting enzyme inhibitors, such as enalapril, is extremely attractive when compared with many commonly used interventions in patients with cardiovascular disease or heart failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2000

Left ventricular dysfunction predicted by early troponin I release after high-dose chemotherapy.

OBJECTIVES: We investigated the role of cardiac troponin I (cTnI) in patients with aggressive malignancies treated with high-dose chemotherapy (HDC). BACKGROUND: High dose chemotherapy is potentially limited by cardiac toxicity. Considering the fact that cardiac dysfunction may become clinically evident weeks or months after HDC, the availability of an early marker of myocardial injury, able to predict late ventricular impairment, is a current need. METHODS: We measured, in 204 patients (45+/-10 years) affected by cancer resistant to conventional treatment, the cTnI plasma concentration after every single cycle of HDC. According to the cTnI value (< or = or >0.4 ng/ml), patients were divided into a troponin positive (cTnI+, n = 65) and a troponin negative (cTnI-, n = 139) group. All patients underwent echocardiographic examination during the following seven months. RESULTS: In the cTnI- group, left ventricular ejection fraction (LVEF) progressively decreased after HDC, reaching a maximal reduction after three months; however, myocardial depression was transient and no longer detectable at later follow-up. By contrast, in the cTnI+ group LVEF reduction was more marked and still evident at the end of the follow-up. In cTnI+ patients, a close relationship between the short-term cTnI increment and the greatest LVEF reduction was found (r = -0.87, p<0.0001). CONCLUSIONS: The elevation of cTnI in patients undergoing HDC for aggressive malignancies accurately predicts the development of future LVEF depression. In this setting, cTnI can be considered a sensitive and reliable marker of acute minor myocardial damage with relevant clinical and prognostic implications.

Adult↗

PubMedDate not supplied

Comparison of technetium 99m-tetrofosmin and thallium-201 single photon emission computed tomographic imaging for the assessment of viable myocardium in patients with left ventricular dysfunction.

BACKGROUND: Tetrofosmin is a new technetium 99m-labeled myocardial perfusion agent that has demonstrated favorable imaging characteristics in recent clinical trials. However, it is not certain whether 99mTc-tetrofosmin compared with thallium 201 would underestimate myocardial viability in regions with left ventricular dysfunction. METHODS: To this end 15 patients (mean age 52+/-7 years) with coronary artery disease and left ventricular dysfunction (ejection fraction 35%+/-8%) documented on angiography underwent both quantitative rest-redistribution 201Tl and rest 99mTc-tetrofosmin single photon emission computed tomography imaging. RESULTS; Of 240 total segments on rest-redistribution 201Tl protocol 139 (58%) segments had irreversible 201Tl defects. Of these segments 79 (57%) had only mild to moderate reduction of 201Tl uptake (51% to 85% of normal uptake), whereas the remaining 60 (43%) had severely reduced tracer uptake (< or = 50% of normal uptake). On 99mTc-tetrofosmin protocol 180 (75%) segments had abnormal 99mTc-tetrofosmin uptake; of these segments 120 (67%) had mild to moderate reduction of 99mTc-tetrofosmin uptake, whereas 60 (33%) had severely reduced activity. Among hypokinetic regions concordance between 201Tl and 99mTc-tetrofosmin regarding myocardial viability with a cutoff point of 50% of peak activity was obtained in 28 (90%) of 31 segments (K' = 0.80), leaving only 3 of 31 regions discordant (p = NS). Similarly, among akinetic or dyskinetic regions concordance between the two tracers regarding myocardial viability was achieved in 54 (93%) regions (K' = 0.75), leaving only 4 of the 58 regions discordant (p = NS). CONCLUSIONS: These data show that when the severity of uptake was considered within abnormal segments, a similar amount of 201Tl viable regions were observed by 99mTc-tetrofosmin. Thus these two agents may provide comparable information about myocardial viability when quantitative analysis of defect severity is performed.

Adult↗

PubMed2003

Determinants of exercise-induced changes in mitral regurgitation in patients with coronary artery disease and left ventricular dysfunction.

OBJECTIVES: We sought to examine the determinants of exercise-induced changes in ischemic mitral regurgitation (MR) in patients with left ventricular (LV) dysfunction. BACKGROUND: In the post-myocardial infarction (MI) phase, ischemic MR contributes to worsening of symptoms and of LV dysfunction. METHODS: In this study, 70 patients in the chronic, post-MI phase, with LV ejection fraction <45% and at least mild MR, underwent semi-supine exercise Doppler echocardiography. The effective regurgitant orifice (ERO) of MR was quantified at rest and during exercise. Exercise-induced changes in ERO were compared with changes in mitral deformation and in local and global LV remodeling. RESULTS: The wide range of exercise-induced ERO changes that were observed was unrelated to the degree of MR at rest (r = 0.20). Effective regurgitant orifice changes correlated best with changes in mitral deformation (i.e., differences in systolic mitral tenting area, systolic annular area, and coaptation height) (p < 0.0001). Posterior displacement of the papillary muscles was associated with larger changes in the ERO in both infarct groups. In patients with inferior MI, a decrease in the ERO was related to improvement in wall motion (r = 0.68). The independent predictors of ERO changes during exercise were changes in systolic annular area for all infarct categories, in tenting area and wall motion score in the global population and those with inferior infarction, and in apical displacement of mitral leaflets for patients with anterior MI. CONCLUSIONS: The degree of MR at rest is unrelated to exercise-induced changes in EROs, which are related to those in local LV remodeling and in mitral deformation but not those in global LV function.

Echocardiography, Doppler↗

PubMed1994

Coronary artery by-pass without cardiopulmonary by-pass for patients with severe left ventricular dysfunction.

OBJECTIVES: To evaluate results of coronary artery bypass grafting (CABG) without cardiopulmonary by-pass (CPB) for patients with severe left ventricular dysfunction. MATERIALS AND METHODS: Fifty-three patients with severe LV dysfunction (EF < 35%) underwent CABG without cardiopulmonary by-pass (CPB) between December 1991 and December 1993. They comprise 22% of 242 patients operated on without CPB by one of the authors (RM) in this period. There were 45 (85%) males and eight (15%) females. Twelve (23%) patients were over 70 years. Nine (17%) were re-do CABG. Ten (19%) were referred for operation within the first 24 hours of evolving MI, and 13 (25%) up to two weeks after acute MI. Nine (17%) had preoperative EF < 20%, and six patients (11%) were in cardiogenic shock. Mean number of grafts/pt was 1.8 and IMA was used in 41 (77%). Only 14 patients (26%) received a graft to a circumflex marginal artery. Ischemic time was 8 +/- 4 min/graft (mean +/- SD) when anastomosed to the LAD or RCA, and 14 +/- 7 min/graft when anastomosed to a marginal branch. RESULTS: One patient (1.9%) died perioperatively, and two (3.7%) suffered a non-fatal MI. At two-year follow-up there were three late deaths, one of them from cancer. Three patients had return of angina, two of them were reoperated upon. CONCLUSIONS: These results suggest that CABG without CPB may be advantageous for patients with severe LV dysfunction.

Adult↗

PubMed1999

Cardiomyocytes from hearts with left ventricular dysfunction after ischemia-reperfusion do not manifest contractile abnormalities.

OBJECTIVES: This study evaluated contractile function in cardiomyocytes isolated from hearts with global left ventricular dysfunction following ischemia-reperfusion. BACKGROUND: Ischemia followed by reperfusion is associated with transient contractile dysfunction, termed "stunning." It is not clear whether this phenomenon is primarily due to intrinsic cardiomyocyte contractile dysfunction. METHODS: Global contractile dysfunction was induced in isolated perfused rat hearts (n = 8) using a model of transient global ischemia (20 min) followed by reperfusion (20 min). Hearts perfused uninterrupted for 40 min were used as controls (n = 8). Cardiomyocytes were isolated using enzymatic digestion and were studied under varying degrees of inotropy (using increasing extracellular calcium [Ca2+]o) and loading conditions (varying extracellular perfusate viscosity). Mechanical function was studied with video edge detection and intracellular calcium ([Ca2+]i) kinetics using fura-2 AM. RESULTS: Global ischemia-reperfusion increased left ventricle (LV) end diastolic pressure (450% vs. 33%, p < 0.01) and reduced LV developed pressure (9% vs. 33%, p < 0.01), LV positive (3% vs. 26%, p < 0.01) and negative (5% vs. 33%, p < 0.01) dP/dt. However, cells isolated from these hearts did not manifest contractile dysfunction. In fact, cell shortening (p < 0.0001) and peak rate of cell shortening (p < 0.05) and increase in [Ca2+]i with each contraction (p < 0.024) were higher in these cells during stimulation with [Ca2+]o of 1 to 10 mmol/liter. The EC50 values for calcium dose response and the slope of the relation between change in [Ca2+]i and change in cell length were no different between the groups. Cell loading (with increasing superfusate viscosity from 1 cp to 300 cp) also did not reveal any abnormalities in cells from the hearts subjected to ischemia-reperfusion. CONCLUSIONS: Cardiomyocytes isolated from hearts with ischemia-reperfusion-induced LV dysfunction or "stunning" have normal contractile function and normal [Ca2+]i transients, when studied both in the unloaded and loaded state. Our data suggest that nonmyocyte factors such as abnormalities in extracellular matrix or abnormal myocyte-interstitial tissue coupling may be important for the genesis of cardiac contractile failure in the stunned heart.

Animals↗

PubMed1981

Complex ventricular arrhythmias after myocardial infarction during convalescence and follow-up: a harbinger of multi-vessel coronary disease, left ventricular dysfunction and sudden death.

Sixty-one medically treated patients had coronary and left ventricular angiography and 24-hour electrocardiographic monitoring 10-24 days after myocardial infarction, and then had serial 24-hour electrocardiographic monitoring during the 13 +/- 11 months after myocardial infarction. Complex ventricular arrhythmias (2 or more sequential ventricular premature depolarizations (VPDs), multiform VPDs, bigeminy) during follow-up were associated with a high mortality rate and occurred most commonly in the setting of three-vessel coronary disease, proximal left anterior descending coronary disease and low left ventricular ejection fraction. By contrast, patients without complex VPDs in either the late hospital or posthospital phase of myocardial infarction had no mortality during the year following myocardial infarction; furthermore, these patients had a higher incidence of single-vessel coronary disease and less left ventricular dysfunction. These results emphasize the adverse prognostic significance of complex ventricular arrhythmias in the year after myocardial infarction and their association with extensive coronary artery disease and left ventricular damage.

Arrhythmias, Cardiac↗

PubMed2005

[Pharmacological stress echocardiography for diagnosing of viable myocardium in severe left ventricular dysfunction].

OBJECTIVE: To compare the safety, sensitivity, specificity and accuracy of low dose dobutamine (Dob), isosorbide dinitrate and their combination in stress echocardiography to predict regional movement recovery after coronary revascularization (CRV) in patients with old myocardial infarction (OMI) and severe left ventricular dysfunction. METHODS: Fourty patients (mean age 52 +/- 8 years, male 39, female 1) with OMI waiting for CRV with mean left ventricular ejection fraction (LVEF) (39.4 +/- 5.1)%, underwent Dob (3, 5 and 10 microg.kg(-1).min(-1)), isosorbide dinitrate (270 +/- 56) microg/min and their combination (nitrate plus Dob 3, 5 microg.kg(-1).min(-1)) stress echocardiography. Twenty-six patients completed follow-up rest two dimension echocardiography (2DE) (6.8 +/- 2.9) months after CRV. RESULTS: During Dob 2DE, side effects rates increased by dosage, the drug even induced ischemia at a dosage of 10 microg.kg(-1).min(-1). When Dob was combined with nitrate, no ischemia happened. Among 272 abnormal segments in 26 patients after CRV, 156 segments showed contractile improvement. In Dob 2DE, both the sensitivity (46.8% to 88.6%) and accuracy (64.1% to 77.9%) increased by dosage gradient, while the specificities decreased from 87.1% to 64.2%. When combined with nitrate, the sensitivities and accuracy were higher than either drugs used alone (P < 0.05). The detecting effect in isosorbide dinitrate + Dob 5 microg 2DE was comparable to that of Dob 10 microg.kg(-1).min(-1) 2DE. CONCLUSIONS: In identifying myocardial viability in patients with OMI and severe left ventricular dysfunction, Dob 5-10 microg.kg(-1).min(-1) 2DE have good detecting effects, but could induce ischemia. When nitrate was combined with Dob, no ischemia happened, and the sensitivity and accuracy improved significantly. Isosorbide dinitrate + Dob 5 microg.kg(-1).min(-1) 2DE has identifying effect comparable to Dob 10 microg.kg(-1).min(-1) 2DE.

Cardiotonic Agents↗