Rapid recovery from acute, potentially lethal myocarditis.

Two cases of acute myocarditis in young men, both with clinical and laboratory criteria indicating poor prognosis, were initially treated with conventional treatment (captopril plus metoprolol). The addition of intravenous immunoglobulin was followed by rapid clinical and laboratory recovery. This observation is considered to support previous but ambiguous evidence that autoimmune treatment may help recovery from acute myocarditis that has evidence of poor prognosis.

Outcome of patients with congestive heart failure treated with standard versus high doses of enalapril: a multicenter study. High Enalapril Dose Study Group.

OBJECTIVES: We sought to prospectively and randomly compare survival with clinical and hemodynamic variables in patients with congestive heart failure (CHF) treated with standard versus high doses of enalapril. BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors produce hemodynamic and symptomatic benefits in patients with CHF, but there is still controversy about the optimal dose in this clinical setting. METHODS: Two hundred and forty-eight patients with advanced CHF (age 56.3+/-12 years) were randomized to receive a maximal tolerated dose of enalapril, up to 20 mg/day in group 1 (mean dose achieved 17.9+/-4.3 mg/day, n = 122) and 60 mg/day in group 2 (mean dose achieved 42+/-19.3 mg/day, n = 126). RESULTS: At enrollment, patients in group 1 were in New York Heart Association (NYHA) functional class 2.6+/-0.7 and had a mean systolic blood pressure (SBP) of 117+/-18 mm Hg, a mean heart rate (HR) of 85+/-16 beats/min and a left ventricular ejection fraction (LVEF) of 20.0+/-9.8%. In group 2, patients were in NYHA class 2.6+/-0.7; their SBP was 118+/-17 mm Hg, HR 83+/-15 beats/min and LVEF 18.8+/-8.1%. There were no significant differences in these characteristics between the two groups of patients at enrollment. After 12 months of follow-up, 22 (18%) of 122 patients in group 1 and 23 (18%) of 126 patients in group 2 had died (p = 0.995, with 80% power of the study to detect a delta difference of 13%). The NYHA class was the same (1.9+/-0.7) in both groups; SBP was 111+/-16 and 111+/-17 mm Hg, HR 77+/-12 and 79+/-13 beats/min and LVEF 31+/-19% and 30+/-12% in groups 1 and 2, respectively. These differences were not statistically significant. The study had a power of 80% to detect (p = 0.05) the following changes: 13% in death rate, 0.25 units in NYHA class, 6 mm Hg in SBP, 5 beats/min in HR and 6% in LVEF. CONCLUSIONS: No significant differences were found in survival and clinical and hemodynamic variables between patients receiving standard and those receiving high doses of enalapril.

Peripheral vascular endothelial dysfunction in patients with angina pectoris and normal coronary arteriograms.

OBJECTIVES: We sought to determine endothelium-dependent vasodilator function in the brachial artery of patients with microvascular angina pectoris. BACKGROUND: Previous studies suggest the presence of endothelial dysfunction of the coronary microcirculation in patients with microvascular angina pectoris. It is not known whether endothelial dysfunction in these patients is a generalized process or whether it is confined to the coronary microcirculation only. METHODS: In 11 women (mean [+/-SD] age 60.1 +/- 7.8 years) with microvascular angina (anginal pain, normal epicardial coronary arteries, positive exercise stress test), endothelium-dependent vasodilation was assessed in the brachial artery by measuring the change in brachial artery diameter in response to hyperemic flow. Results were compared with 11 age- and gender-matched patients with known three-vessel coronary artery disease and 11 age- and gender-matched healthy control subjects. In all subjects, the intima-media thickness (IMT) of the common carotid artery was also measured. RESULTS: Flow-mediated dilation (FMD) was comparable in patients with microvascular angina and coronary artery disease (1.9 +/- 2.5% vs. 3.3 +/- 3.3%, p = NS) but was significantly lower in patients with microvascular angina than in healthy control subjects (1.9 +/- 2.5% vs. 7.9 +/- 3%, p < 0.05). IMT was significantly lower in patients with microvascular angina than in those with coronary artery disease (0.64 +/- 0.08 vs. 1.0 +/- 0.28 mm, p < 0.05) and was comparable between patients with microvascular angina pectoris and healthy control subjects (0.64 +/- 0.08 vs. 0.56 +/- 0.14 mm, p = NS). IMT > or = 0.8 mm was observed in 1 of 11 patients with microvascular angina, 1 of 11 control subjects and 10 of 11 patients with coronary artery disease. CONCLUSIONS: These findings suggest that endothelial dysfunction in microvascular angina is a generalized process that also involves the peripheral conduit arteries and is similar to that observed in atherosclerotic disease. IMT could be helpful in discriminating patients with microvascular angina and atherosclerotic coronary artery disease.

Impaired endothelium-dependent vasodilatation in women with previous gestational diabetes.

OBJECTIVE: To assess whether otherwise healthy women with a history of gestational diabetes mellitus (GDM) may have abnormalities in endothelial function at a very early stage, before glucose intolerance occurs. RESEARCH DESIGN AND METHODS: A total of 33 women with previous GDM (17 nonobese [BMI < 27] and 16 obese [BMI > or = 27]) and 19 healthy nonobese women were examined. A 75-g oral glucose tolerance test was performed, and insulin levels and biochemical parameters were also measured. Using high-resolution ultrasound, we measured vasodilatory responses of the brachial artery during reactive hyperemia (endothelium-dependent vasodilatation), and after nitroglycerin administration, an endothelium-independent vasodilator. RESULTS: Flow-mediated dilatation (FMD) was significantly and equally decreased in both groups of women with previous GDM, compared with control subjects (1.6 +/- 3.7% in the nonobese GDM group and 1.6 +/- 2.5% in the obese GDM group vs. 10.3 +/- 4.4% in control subjects, P < 0.001). FMD correlated inversely with serum uric acid levels, BMI, serum total cholesterol, and basal insulin resistance (homeostasis model assessment). Nitrate-induced dilatation was significantly decreased only in the obese GDM group compared with control subjects, (21.4 +/- 5.1 vs. 27.9 +/- 9.5, P < 0.05). CONCLUSIONS: Endothelial dysfunction, which is considered as a very early index of atherogenesis, is already present in both obese and nonobese women with a history of GDM, even when they have normal glucose tolerance.

A pressure-time index' for assessing the severity of essential hypertension.

OBJECTIVE: A new derivative of 24 h ambulatory blood pressure monitoring (ABPM) is introduced and its association with left ventricular mass index (LVMI) in essential hypertension is examined. PATIENT: population One hundred and fifty-three previously untreated essential hypertension patients. METHODS: Patients underwent casual blood pressure (BP) readings, 24 h ABPM and left ventricular echocardiographic assessment The following 24 h awake and sleep ABP variables were calculated: mean systolic and diastolic BP, systolic and diastolic BP loads (percentage of systolic readings > 140/120 mmHg (day/ night) and diastolic readings > 90/80 mmHg (day/night)), standard deviation of systolic and diastolic ABP and nocturnal fall of systolic BP, as well as the integrated areas under the ABP curve. The area under the BP curve divided in horizontal slices was accurately modelled by a sigmoid curve. The parameters controlling the shape of the curve and in particular that regarding its 'slope' is hereafter called the 'pressure-time index'. RESULTS: 'Systolic pressure-time index 24 h' (SPTI24) is related to left ventricular mass index (multivariate analysis, P= 0.008). Using either partial correlation coefficients or a multivariate analysis, SPTI24 is related to left ventricular mass index, independently of age, casual blood pressure, mean systolic and diastolic ABP, systolic and diastolic BP loads, BP variability (standard deviation (SD), nocturnal fall of systolic BP) and integrated area under the curve (multivariate analysis, P= 0.004). CONCLUSIONS: In essential hypertension, the SPTI24 is related to LVMI independently of age, casual blood pressure, integrated area under the curve or any other derivative of 24 h ABPM, and might be used to assess the extent of hypertensive load.

Indium-111 monoclonal antimyosin cardiac scintigraphy in men with idiopathic dilated cardiomyopathy.

This study examined the prognostic value and the evolution of the heart-to-lung ratio of monoclonal antimyosin antibody (MAA) uptake in patients with a diagnosis of idiopathic dilated cardiomyopathy (IDC). Uptake of indium-111-labeled MAA occurs when the myocytes become irreversibly damaged. The study included 29 men with IDC followed up for 3 years. The diagnosis was verified by endomyocardial biopsy in all patients. Patients who survived beyond 1 year were restudied. Baseline heart-to-lung ratio of MAA was 1.74+/-0.22. Multivariate Cox regression analysis revealed that MAA and New York Heart Association class were independent predictors of late mortality, with a hazard ratio of 4.4 (95% confidence interval 1.1 to 17.9, p = 0.036) and 7.5 (95% confidence interval 2.0 to 28.4, p = 0.003), respectively, when heart-to-lung ratio of MAA uptake was > 1.74 and New York Heart Association class was >11. When these patients were divided into those with chronic IDC (group I [n = 19]) and those with subacute IDC (group II [n = 10]), baseline heart-to-lung ratio was 1.7+/-0.2 and 1.86+/-0.25, respectively (p = NS). In the surviving patients, on restudy, the heart-to-lung ratio of MAA uptake was unchanged in group I (1.64+/-0.20, p = NS), but had decreased to the level of group I (1.66+/-0.21 [p = 0.008]) in group II. Thus, men with IDC and a high heart-to-lung ratio of MAA uptake have a worse long-term prognosis than patients with a lower ratio. The heart-to-lung ratio of MAA decreases comparably over time in subacute IDC and remains stable in chronic IDC.

Ankle-brachial index as a predictor of the extent of coronary atherosclerosis and cardiovascular events in patients with coronary artery disease.

Resting ankle-brachial pressure index (ABI) is a noninvasive method to assess the patency of the lower extremity arterial system. This study aimed to examine the relation between ABI and the extent of coronary atherosclerosis, the extracoronary atherosclerosis lesions, and the prognosis of patients referred for elective coronary angiography. One hundred sixty-five consecutive patients underwent coronary angiography, ultrasound imaging for intima-media thickness measurement of carotid and femoral arteries and ABI evaluation; subjects were followed up for 14.5 +/- 2.4 months. With regard to vascular risk factors, only smoking (p = 0.025) and diabetes (p = 0.01) were related to ABI in the multiple regression analysis. ABI was independently and inversely related to carotid bifurcation (p = 0.0002) and common femoral artery intima-media thickness (p = 0.018). ABI was related to the extent of coronary artery disease as measured by number of coronary arteries diseased (analysis of variance, p = 0.04) and Gensini angiographic score (p = 0.01). In the follow-up study ABI < 0.90 was a univariate predictor of cardiovascular events (cardiac death, nonfatal myocardial infarction, unstable angina) and revascularization procedures. The estimated cumulative rate free of cardiovascular events was 90% for ABI > 0.90 and 73% for ABI < 0.90 (p = 0.02). In logistic regression analysis, ABI < 0.90 was an independent predictor for cardiovascular events after adjustment for age, low-density lipoprotein cholesterol, carotid and femoral intima-media thickness, and Gensini score. Further adjustment for the confounding effect of insulin weakened the relation between ABI and cardiovascular events (p = 0.1). In conclusion, ABI is a simple index related to the extent of atherosclerosis in coronary and noncoronary arterial beds, reflecting generalized atherosclerosis. ABI could be useful in assessing the risk for cardiovascular events in patients with coronary artery disease.

Atherosclerotic changes of extracoronary arteries are associated with the extent of coronary atherosclerosis.

The aim of the present study was to examine the association between carotid and femoral artery intima media thickness (IMT) and the extent and severity of coronary artery disease (CAD) as well as the effects of traditional vascular risk factors on the atherosclerotic changes in the carotid and femoral arteries. Two hundred twenty-four patients who underwent coronary angiography for suspected CAD were evaluated by B-mode ultrasound imaging of the common carotid, internal carotid, carotid bifurcation, and femoral artery for measurement of IMT; traditional vascular risk factors were also evaluated in these patients. CAD extent was evaluated by the number of diseased vessels and by Gensini score. Age, male gender, and diabetes were common risk factors for higher CAD extent and higher carotid and femoral IMT. Insulin levels were correlated with femoral IMT and CAD extent, whereas blood lipids were correlated predominantly with carotid IMT. IMT from carotid and femoral arteries increased significantly with an increase in CAD extent. Using multiple stepwise regression analysis, the following parameters were found to be independent predictors of CAD extent: male gender (p<0.0001), common femoral artery IMT (p = 0.0028), common carotid artery IMT (p = 0.015), age (p = 0.02), diabetes mellitus (p = 0.035), and carotid artery bulb IMT (p = 0.04). Common femoral IMT was the only independent parameter for predicting Gensini score (p<0.0001). In conclusion, there are territorial differences in the various arterial beds regarding their response to risk factors. Femoral artery and carotid bulb are independent predictors of CAD extent and the inclusion of these measurements would add information to that provided by the common carotid artery.

Relation of dispersion of QRS and QT in patients with advanced congestive heart failure to cardiac and sudden death mortality.

This study examined the usefulness of 01 and QRS dispersion in the prognosis of patients with advanced congestive heart failure (CHF). One hundred four patients in New York Heart Association functional classes II to IV, with a left ventricular ejection fraction of <35%, and untreated with antiarrhythmic drugs, were followed prospectively. QRS and QT dispersion were defined as the maximum difference in QRS and QT interval duration, respectively, measured on all leads of standard 12-lead electrocardiograms. The end points of the study were non-sudden and sudden cardiac mortality. During an average follow-up of 20 months, there were 13 non-sudden and 10 sudden deaths. The average QRS duration was significantly longer in nonsurvivors than in survivors (125 ¿ 34 vs 113 ¿ 34 ms, respectively, p <0.04). Similar results were obtained with 01 dispersion (95 ¿ 48 ms vs 78 ¿ 31 ms, respectively, p <0.03) and QRS dispersion (54 ¿ 17 ms vs 46 16 ms, respectively, p <0.02). Furthermore, patients who died suddenly had significantly greater QRS dispersion than patients who survived (56 ¿ 13 vs 46 ¿ 16 ms, respectively, p <0.02). In a multivariate analysis, QT and QRS dispersion were both independent predictors of non-sudden cardiac death (p = 0.01 and p = 0.001, respectively), and QRS dispersion was also an independent predictor of sudden cardiac death (p = 0.04). Death rate in patients with 01 dispersion >90 ms was 2.8-fold higher than those with 01 dispersion 90 ms (95% confidence intervals [CI] 1.2 to 6.4). Similarly, the death rate in patients with QRS dispersion >46 ms was 3.9-fold higher than in those with QRS dispersion 46 ms (95% Cl 1.6 to 9.5). These findings suggest that QT and QRS dispersion are useful predictors of mortality in patients with advanced CHF. ¿2000 by Excerpta Medica, Inc.

Long-term intermittent dobutamine infusion combined with oral amiodarone improves the survival of patients with severe congestive heart failure.

STUDY OBJECTIVE: To evaluate the effects of long-term intermittent dobutamine infusion (IDI) with concomitant administration of low-dose amiodarone in patients with congestive heart failure (CHF) refractory to standard medical treatment. DESIGN: Prospective, interventional clinical trial. SETTING: Inpatient and outpatient heart failure clinic in a university teaching hospital. PATIENTS AND INTERVENTIONS: Twenty-two patients with CHF refractory to standard treatment who could be weaned from dobutamine therapy after an initial 72-h infusion were included in this study. The first 11 patients (group 1) were treated with IDI, 10 micromin, as needed (mean, once every 16 days, lasting for 12 to 48 h); the next 11 patients (group 2) received oral amiodarone, 400 mg/d, and IDI, 10 microg/kg/min, for 8 h every 7 days. MEASUREMENT AND RESULTS: There were no differences in baseline clinical, hemodynamic, and five biochemical characteristics between the two groups. The left ventricular ejection fraction was 13.5 +/- 4.5% in group 1 vs 15.5 +/- 4.9% in group 2 (mean +/- SD; p = 0.451); mean pulmonary capillary wedge pressure was 31.3 +/- 4.4 mm Hg vs 29.4 +/- 3.3 mm Hg (p = 0.316); serum creatinine was 1.9 +/- 0.4 mg/dL vs 1.6 +/- 0.5 mg/dL (p = 0.19); and serum Na was 139.6 +/- 6.2 mEq/L vs 138.4 +/- 3.1 mEq/L (p = 0.569). At 12 months of follow-up, 1 of 11 patients (9%) was alive in group 1 vs 6 of 11 patients (55%) in group 2 (p = 0.011). Furthermore, in group 2, the functional status improved significantly within the first 3 months of treatment, from New York Heart Association functional class IV to 2.63 +/- 0.5 (p = 0.0001). CONCLUSION: Long-term IDI in conjunction with amiodarone, added to conventional drugs, improved clinical status and survival of patients with severe CHF.

Pulse pressure in normotensives: a marker of cardiovascular disease.

The purpose of the present study was to evaluate the relation of the systemic arterial pulse pressure and other parameters derived from the 24-h arterial blood pressure (BP) monitoring to the severity of coronary artery disease, carotid lesions, and left ventricular (LV) mass index in patients without arterial hypertension. One hundred ten patients with known coronary artery disease underwent coronary arteriography, 24-h arterial BP monitoring, and ultrasound imaging of the carotid arteries and the myocardium. Measurements of 24-h arterial BP monitoring (systolic, diastolic, and average BP, pulse pressure, abnormal values of systolic and diastolic BP, and heart rate), the severity of coronary heart disease (Gensini score), intima-media thickness (IMT) of the common carotid artery and LV mass index were determined in all patients. By univariate analysis, only 24-h pulse pressure was significantly related to the severity of coronary artery disease (P < .01), carotid IMT(P < .01), and LV mass index (P < .01). In a multivariate analysis, 24-h pulse pressure was also the best predictor of the severity of coronary lesions (P = .009), carotid IMT (P = .003), and LV mass index (P = .009). Gensini score was related (P < .01) to LV mass index and not to carotid IMT. In conclusion, systemic arterial pulse pressure derived from 24-h arterial BP monitoring is related to coronary artery disease, carotid IMT, and LV mass index independently of age or any other derivative of 24-h arterial BP monitoring, indicating that this parameter could be a marker of global cardiovascular risk.

Mechanical ventilation in conjunction with the intra-aortic balloon pump improves the outcome of patients in profound cardiogenic shock.

OBJECTIVE: To examine the effects of mechanical ventilation with positive end-expiratory pressure (PEEP), in conjunction with the intra-aortic balloon pump (IABP), on the outcome of patients in profound cardiogenic shock. PATIENTS: Twenty-eight consecutive patients presenting with myocardial infarction complicated by cardiogenic shock refractory to medical therapy, including dobutamine, dopamine and fluid administration. Eighteen patients were assisted by the IABP alone (IABP group), and ten patients by the IABP plus controlled mechanical ventilation with PEEP set at 10 cmH(2)O (IABP + CMV group). RESULTS: Weaning from mechanical assistance was accomplished in 8 out of 18 patients in the IABP group versus 9 out of 10 patients in the IABP + CMV group (p = 0.04). Ultimately, 5 of 18 patients in the IABP group were discharged from the hospital versus 8 of 10 patients in the IABP + CMV group (p = 0. 01). CONCLUSION: Mechanical ventilation with PEEP at 10 cmH(2)O supplements the IABP and may improve the survival rates of patients suffering from cardiogenic shock.

Treating severe cardiogenic shock by large counterpulsation volumes.

BACKGROUND: Intraaortic balloon pumping is known to be ineffective in severe cardiogenic shock. The efficacy of balloon volumes larger than those commonly used is examined. METHODS: In 18 dogs with severe experimental cardiogenic shock (systolic aortic pressure < 60 mm Hg, aortic flow < 45 mL.min-1.kg-1) the effect of three intraaortic balloon volumes (15, 30, and 45 mL) and a 60-mL paraaortic pump was examined. RESULTS: The 45-mL balloon covering the full length of the aorta induced the highest (+ 12.4 +/- 2.2 mL.min-1.kg-1; mean +/- standard error of the mean) and the 15-mL balloon the lowest increase in aortic flow (F = 14.6, p < 0.0001). Only the 45-mL balloon increased (p < 0.05) urine output and renal artery flow. The 60-mL paraaortic pump induced the highest (F = 10.72, p < 0.002) increase (+ 36.6 +/- 6.5 mL.min-1.kg-1) in aortic flow compared to the three balloons. An 80- to 100-mL paraaortic pump maintained the life of 3 patients in severe cardiogenic shock for 4 hours, 8 days, and 54 days, whereas a 40-mL conventional balloon was completely ineffective. CONCLUSIONS: Experimental and clinical data indicate that the effectiveness of intraaortic balloon pumping in severe cardiogenic shock may be improved by increasing the volume of the balloon (i.e., until it fully occupies the aorta).

Detection of coronary artery disease in the presence of left ventricular atrophy.

To evaluate the accuracy of exercise echocardiography for the recognition of coronary artery disease in the presence of left ventricular hypertrophy 70 patients were studied. Significant coronary artery disease was present in 25 patients and left ventricular hypertrophy had 29 patients. All patients underwent an exercise ECG and echocardiographic test during which cine-loop digitized echocardiography was obtained. Wall motion was analyzed and a regional wall motion score index was calculated. The overall sensitivities of exercise ECG and echocardiography for detecting coronary artery disease were 60% and 64%, respectively, and the specificities were 49% and 78%, respectively. In patients with left ventricular hypertrophy the specificity of exercise echocardiography was higher (71%) compared to exercise ECG (21%) while in patients without hypertrophy the sensitivity was higher (70% vs. 40%, respectively). Of the 19 patients with a non-diagnostic stress ECG, echocardiography correctly identified 100% of those with coronary artery disease but only 53% of those without disease. It is concluded that exercise digital echocardiography represents a good diagnostic alternative to the exercise ECG for identifying coronary artery disease in the presence of left ventricular hypertrophy and should be useful in patients with a non-diagnostic exercise ECG.

Reproducibility of ambulatory blood pressure measurements in essential hypertension.

BACKGROUND: Data on the reproducibility of serial measurements of ambulatory blood pressure in hypertensive patients are lacking. The purpose of this study was to examine (1) the reproducibility of four consecutive ambulatory blood pressure measurements, and (2) the reproducibility of nocturnal falls in blood pressure in hypertensive patients. METHODS: Twenty patients with mild to moderate essential hypertension underwent four separate ambulatory blood pressure monitorings, on the same day of the week, at 30-day intervals. Antihypertensive therapy was discontinued for 2 weeks before each recording. Comparing the mean values of blood pressure over 24h, as well as diurnal, nocturnal and hourly periods, among the four recordings determined the reproducibility of blood pressure measurements. A day/night difference in mean systolic and in mean diastolic blood pressure defined the nocturnal fall in blood pressure. RESULTS: No significant differences were observed in either hourly, 24-h, diurnal or nocturnal systolic blood pressure, diastolic blood pressure and heart rate, or in the nocturnal fall in systolic and diastolic blood pressure among the four recordings. CONCLUSIONS: Hourly systolic blood pressure, diastolic blood pressure, heart rate, and nocturnal fall in blood pressure were reproducible in four ambulatory blood pressure monitorings recorded over 4 months. These findings suggest that ambulatory blood pressure monitoring is a reliable tool to monitor blood pressure changes.

The efficacy of the high volume counterpulsation technique at very low levels of aortic pressure.

BACKGROUND: The objective of the present study was to identify the hemodynamic variables, that preclude the effectiveness of the counterpulsation technique. METHODS: In order to achieve high counterpulsation volume two devices were used simultaneously. The para-aortic counterpulsation device pumping 60-70 ml was implanted on the ascending aorta, and the intra-aortic balloon (20 ml) was placed in the descending aorta of 14 dogs with severe cardiogenic shock. Both devices were synchronized to provide aortic diastolic augmentation. The mechanical assistance provided by these devices was considered adequate when the mean aortic pressure during the supportive period was at least 50 mmHg, a pressure compatible with life. RESULTS: The mechanical assistance provided by the two devices was adequate in none (0%) of the cases with a systolic aortic pressure below 30 mmHg (Group I), in 71% of the cases with a systolic aortic pressure between 30-56 mmHg (Group II), and in 100% of the cases with a systolic aortic pressure above 56 mmHg (Group III). In group II the left ventricular end-diastolic pressure was higher in the cases responding adequately to mechanical assistance (Subgroup IIa) than in the ones where no adequate response was obtained (Subgroup IIb). CONCLUSIONS: The very low levels of the systolic aortic pressure was the most important factor precluding the adequate effectiveness of the counterpulsation technique.

Limitation of infarct size by fixed coronary arterial stenosis maintained during reperfusion.

BACKGROUND: The effect on infarct size of a pre-infarction high-grade, fixed coronary arterial stenosis maintained during reperfusion, was evaluated. METHODS: This experimental study was carried out in the research laboratory of a University Hospital. A canine occlusion-reperfusion model was used. Twenty-eight dogs underwent proximal left anterior descending (LAD) coronary artery occlusion (O). In Group 1 (n=6) the O lasted for 6 hours. In Group 2 (n=6) the O lasted for 2 hours followed by 4 hours of reperfusion (R). In Group 3 (n=3), LAD was stenosed for 30 minutes followed by O for 6 hours. In Group 4 (n=7) LAD was stenosed for 30 minutes followed by O for 2 hours and then 4 hours of R during which the artery was kept stenosed at the same degree (fixed) as the initial one. In Group 5 (n=6) the protocol was identical to Group 4 with the additional use of the intra-aortic balloon pump during R. RESULTS: The infarcted myocardium was almost the same in Groups 1 and 3 (80.0+/-10.6% vs 77.3+/-3.8%, respectively, p=NS), but less in Group 2 (59.0+/-19.9%, p=0.046 vs Group 1). There were no hemodynamic differences between Groups 4 and 5 and the infarcted myocardium was almost identical in both groups (37.7+/-18.8% and 38.7+/-19.1%, respectively, p=NS). The combined results of Groups 4 and 5, regarding the infarcted myocardium, was 38.1+/-18% (p=0.037 vs Group 2). CONCLUSIONS: In this acute coronary occlusion model, a pre-existing high-grade stenosis that maintained during reperfusion increased the amount of salvaged ischemic myocardium.

Left intraventricular balloon pump optimization during intractable cardiac arrest.

This work aims to determine optimal balloon shape and volume during left intraventricular balloon pumping (IABP) in the fibrillating dog heart. A balloon volume equal to the left ventricular end-diastolic volume (LVEDV) maintained a higher systolic aortic pressure and flow (106.4 +/- 2.7 mmHg and 84.7 +/- 2.35 ml/kg/min, x +/- SEM, respectively) than a 25% smaller (97.8 +/- 3.3 mmHg, P = 0.002 and 63.7 +/- 4.1 ml/kg/min, P = 0.002, respectively) or a 25% larger balloon (87.4 +/- 2.3 mmHg, P = 0.002 and 70.9 +/- 3.4 ml/kg/min, P = 0.002, respectively). Among 5 different balloon shapes tested, a pear-shaped balloon inflated from the apex to the base of the left ventricle induced the highest (P varying from 0.042 to 0.01, compared to the remaining balloon shapes) systolic aortic pressure and flow (104.6 +/- 4.5 mmHg and 77.9 +/- 1.7 mg/kg/min, respectively). In conclusion, a pear shaped balloon, inflated to a volume equal to the LVEDV, from the apex to the base of the left ventricle, induced an optimal hemodynamic effect during LVBP.

Heart rate effect on hemodynamics during mechanical assistance by the intra-aortic balloon pump.

UNLABELLED: Heart rate (HR) has been characterized as an important cardiovascular parameter that affects acute hemodynamic performance of intra-aortic balloon counterpulsation (IABC). However, the effect of HR on hemodynamics during mechanical assistance by the IABC has neither been clarified nor quantified. We sought to evaluate the relationship between IABC and HR and also to examine whether there is a range of HR with optimum hemodynamic response to IABC. METHODS: 20 patients (14 males--6 females, mean age 64.4 +/- 11.4 years) with post-infarction cardiogenic shock undergoing IABC treatment were evaluated. Hemodynamics were recorded for each patient once per day during the assistance period; 131 measurements were taken and thus a wide range of heart rates was obtained (64-141 bpm). The following changes in aortic pressures were used to evaluate acute IABC performance on: a) the maximal increase of diastolic aortic pressure induced by IABC and b) the reduction in systolic and end-diastolic aortic pressure. RESULTS: Non-linear regression analysis and analysis of variance revealed that a significant correlation exists between IABC performance indices and heart rate. At HR<80 bpm, IABC performance tended to be reduced, whereas the increase in HR above 110 bpm resulted in a significant reduction of all IABC performance indices. In contrast, IABC operating at 80-110 bpm resulted in optimum hemodynamic performance. In conclusion, the effect of heart rate on IABC performance is non-linear indicating that IABC may be more effective when operating within 80-110 bpm.

Arterial compliance is an independent factor predicting acute hemodynamic performance of intra-aortic balloon counterpulsation.

Data concerning the effect of arterial compliance (AC) on hemodynamics during intraaortic balloon counterpulsation (IABC) are lacking. This study examines the effect of AC on acute hemodynamics induced by IABC in 15 patients with post-infarction cardiogenic shock. AC was estimated by aortic pulse wave analysis using the reflection time index (RTI). Measurements were obtained once per day during IABC. The % reduction in systolic aortic pressure (ASAP), end-diastolic aortic pressure (AEDAP) and the peak aortic diastolic augmentation (PADA) were used as performance indices of IABC; 107 sets of measurements were obtained. Multivariate analysis indicated an independent association of each IABC performance index with AC (p<0.05). A high AC group (RTI< or =20.6%, n=40) and a low AC group (RTI>20.6%, n=67) were obtained. DeltaSAP deltaEDAP and PADA were significantly higher in the low AC group by almost 75%, 54.6% and 11.3% (p<0.03), while arterial blood pressure did not significantly differ. Arterial compliance is an independent factor affecting hemodynamics during IABC. RTI values higher than 20.6% may predict a better acute hemodynamic response to IABC.