Hemodynamic effects of intravenous prenalterol in severe heart failure

Nine patients with chronic severe low output heart failure (radionuclide left ventricular ejection fraction 17 +/- 5 percent [mean +/- standard deviation], left ventricular filling pressure 26 +/- 6 mm Hg, cardiac index 1.9 +/- 0.4 liters/min per m2, left ventricular stroke work index 18 +/- 6 g-m/m2) from various causes were treated with intravenous prenalterol (a new catecholamine-like inotropic agent) in doses of 1,4 and 8 mg. Significant hemodynamic improvement occurred as measured by increased left ventricular ejection fraction (to 26 +/- 4 percent), decreased left ventricular filling pressure (to 21 +/- 8 mm Hg) and increased cardiac index (to 2.4 +/- 0.6 liters/min per m2) and left ventricular stroke work index (to 25 +/- 8 g-m/m2). Significant increases in heart rate (from 87 +/- 18 to 91 +/- 18 beats/min) and mean systemic arterial pressure (from 87 +/- 8 to 92 +/- 7 mm Hg) also occurred. Peak hemodynamic response occurred at various doses. Significant adverse effects associated with prenalterol consisted of increased ventricular ectopic beats in two patients and asymptomatic ventricular tachycardia in two patients. Thus, intravenous prenalterol produces hemodynamic improvement in patients with a chronic severe low output state but may be associated with increased ventricular ectopic activity.     

Value of right ventricular ejection fraction in predicting short-term prognosis of patients with severe chronic heart failure

BACKGROUND: The prognosis of chronic heart failure has been studied extensively, but factors predicting short-term outcome in patients with severe chronic heart failure are still poorly defined, and the current indications for heart transplantation as a treatment for end-stage heart failure need on objective analysis. METHODS: Purpose of the study was to identify the determinants of short-term prognosis in a group of 142 consecutive ambulatory patients (mean age 49.8 +/- 11 years). Referred for heart transplantation because of severe chronic heart failure, the patients were admitted with left ventricular ejection fraction markedly depressed and had had symptoms in spite of an optimal standardized medical therapy for at least 1 month. Baseline clinical and instrumental evaluation included right-sided heart catheterization with a flow-directed multilumen thermodilution catheter, which enables determination of pressures, cardiac output, right ventricular volumes, and ejection fraction. RESULTS: Most patients were in New York Heart Association class III (61%) and IV (24%), and the hemodynamic profile was characterized by mean left ventricular ejection fraction of 20.2% +/- 6%, cardiac index of 2.13 +/- 0.6 l/min/m2, pulmonary capillary wedge pressure of 23.1 +/- 11 mm Hg, right atrial pressure of 7.9 +/- 6 mm Hg, right ventricular ejection fraction of 23.2% +/- 12.4%. During a mean follow-up of 11.1 +/- 9.4 months, 33 patients underwent transplantation (23.4%), 41 died (28.8%), and 68 were still alive (47.8%). There was a substantial overlap in left ventricular ejection fraction between patients divided on the basis of outcome, whereas right ventricular ejection fraction was significantly lower in patients who died or underwent transplantation. Cox multivariate analysis showed three independent prognostic variables: cause (p = 0.03), heart failure score (p = 0.001), and right ventricular ejection fraction (p = 0.000). Short-term survival (10 months) was significantly (p = 0.000) different in patients with > or = 24% or < 24% right ventricular ejection fraction. Statistical analysis identified right ventricular ejection fraction as the single variable to be highly correlated with an increased risk of early death. CONCLUSIONS: This study suggests that right ventricular function is a crucial determinant of short-term prognosis in severe chronic heart failure. Statistical analysis identified right ventricular ejection fraction, determined by thermodilution during right-sided heart catheterization, as the single most important predictor of short-term prognosis in a large cohort of patients who had symptoms in spite of a standardized, optimized, multipharmacologic treatment. The variable allows a useful risk stratification in patients with severe chronic heart failure and uniformly depressed left ventricular ejection fraction and provides guidance in the assessment of indications and timing for transplantation.     

Evaluation of a new bipyridine inotropic agent--milrinone--in patients with severe congestive heart failure

Milrinone, a derivative of amrinone, has nearly 20 times the inotropic potency of the parent compound and does not cause fever or thrombocytopenia in normal volunteers or in animals sensitive to amrinone. In 20 patients with severe congestive heart failure, intravenous milrinone resulted in significant decreases in left ventricular end-diastolic pressure (from 27 +/- 2 to 18 +/- 2 mm Hg), pulmonary wedge pressure, right atrial pressure, and systemic vascular resistance, as well as a slight reduction in mean arterial pressure. Significant increases occurred in cardiac index (from 1.9 +/- 0.1 to 2.9 +/- 0.2 liters per minute per square meter) and the peak positive first derivative of left ventricular pressure, with a slight increase in heart rate. Hemodynamic improvement was sustained during a 24-hour continuous infusion. Nineteen of the 20 patients subsequently received oral milrinone (29 +/- 2 mg per day) for up to 11 months (mean, 6.0 +/- 0.8), with sustained improvement in symptoms of heart failure. In 10 patients receiving long-term oral milrinone (greater than or equal to 6 months) radionuclide ventriculography showed continued responsiveness, with a 27 per cent increase in left ventricular ejection fraction after 7.5 mg of the drug. Four patients died after a mean of 4.8 months of therapy, and three patients with severe underlying coronary-artery disease and angina pectoris required additional antianginal therapy. No patient had fever, thrombocytopenia, gastrointestinal intolerance, or aggravation of ventricular ectopy. We conclude that milrinone shows promise for the longterm treatment of congestive heart failure.     

Hemodynamic and physiologic changes during support with an implantable left ventricular assist device

To evaluate hemodynamic effectiveness and physiologic changes on the HeartMate 1000 IP left ventricular assist device (Thermo Cardiosystems, Inc., Woburn, Mass.), we studied 25 patients undergoing bridge to heart transplantation (35 to 63 years old, mean 50 years). All were receiving inotropic agents before left ventricular assist device implantation, 21 (84%) were supported with a balloon pump, and 7 (28%) were supported by extracorporeal membrane oxygenation. Six patients died, primarily of right ventricular dysfunction and multiple organ failure. Nineteen (76%) were rehabilitated, received a donor heart, and were discharged (100% survival after transplantation). Pretransplantation duration of support averaged 76 days (22 to 153 days). No thromboembolic events occurred in more than 1500 patient-days of support with only antiplatelet medications. Significant hemodynamic improvement was measured (before implantation to before explantation) in cardiac index (1.7 +/- 0.3 to 3.1 +/- 0.8 L/min per square meter; p < 0.001), left atrial pressure (23.7 +/- 7 to 9 +/- 7.5 mm Hg; p < 0.001), pulmonary artery pressure, pulmonary vascular resistance, and right ventricular volumes and ejection fraction. Both creatinine and blood urea nitrogen levels were significantly higher before implantation in patients who died while receiving support. Renal and liver function returned to normal before transplantation. We conclude that support with the HeartMate device improved hemodynamic and subsystem function before transplantation. Long-term support with the HeartMate device has a low risk of thromboemboli and makes a clinical trial of a portable HeartMate device a realistic alternative to medical therapy.     

Significance of radiographic cardiomegaly in orthotopic heart transplant recipients

OBJECTIVE: The purpose of this study is to evaluate the clinical significance of radiographic cardiomegaly in orthotopic heart transplant recipients and to identify causative anatomic and physiologic parameters. MATERIALS AND METHODS: We retrospectively compared the cardiothoracic ratio (CTR) measured using standard posteroanterior chest radiography with left ventricular end-diastolic diameter and left ventricular ejection fraction measured on two-dimensional echocardiography; right ventricular systolic pressure; and systolic, diastolic, and mean blood pressure measured at biopsy in 46 heart transplant recipients. RESULTS: Twenty-eight (61%) of the 46 patients had radiographic cardiomegaly. When we compared heart transplant recipients who had a CTR greater than 0.5 with recipients who had a CTR less than or equal to 0.5, we found no significant difference between their respective left ventricular end-diastolic diameters, left ventricular ejection fractions, right ventricular systolic pressures, systolic blood pressures, or mean blood pressures. A statistically significant difference existed between the mean values of diastolic blood pressure for transplant recipients with and without radiographic cardiomegaly. We found no significant correlation between CTR and left ventricular end-diastolic diameter, left ventricular ejection fraction, systolic blood pressure, diastolic blood pressure, or mean blood pressure. CONCLUSION: The statistically significant difference between the mean values of diastolic blood pressure of transplant recipients with and without radiographic cardiomegaly is clinically insignificant and unlikely to account for the finding of radiographic cardiomegaly. We conclude that radiographic cardiomegaly, which occurs frequently in heart transplant recipients, does not correlate with anatomic or physiologic parameters obtained under the same conditions. Radiographic cardiomegaly in heart transplant recipients does not connote allograft dysfunction or heart failure.     

An approach in the assessment of pacing hemodynamics: a comparison of VVI and DDD

Previous methods for assessment of pacemaker hemodynamics have been limited to a rigid hospital environment. An alternative is the ambulatory ventricular function monitor (C-VEST) that, with a single injection of technetium-99m, permits the continuous measurement of relative ejection fraction (EF) and cardiac output (CO) during the activities of daily living. A study of reproducibility and a comparison of dual chamber (DDD) and fixed rate ventricular (VVI) pacing are presented. Reproducibility was assessed in six patients (4 males; mean age 58, range 27-78 years) with a mean EF of 48.5% (range 34%-62%) and DDD pacemakers, implanted for conduction abnormalities. In addition, 11 patients (7 males; mean age 55.5, range 34-75 years) with a mean EF of 48.5% (range 34%-65%), chronic complete heart block, and DDD pacemakers were used for the comparative study. After an initial multigated scan, the monitor was positioned over the left ventricle and kept in place with the plastic C-VEST. The patients undergoing the reproducibility study performed three shuttle walking tests with 20 minutes of rest in between. The patients in the comparative study were randomized to either VVI or DDD mode and performed one shuttle walking test in each pacing mode. The results confirmed that the C-VEST produces reproducible results with no significant difference in peak CO between the three shuttle walks. In addition, it confirmed previous hemodynamic studies showing that DDD pacing was superior to VVI pacing both at rest (P < 0.004) and at exercise (P < 0.002). These findings show the C-VEST to be an extremely useful tool for the hemodynamic assessment of pacemaker patients.     

Long-term (5 year) effects of transient (silent) ischaemia on left ventricular systolic function in stable angina. Clinical and radionuclide study

AIMS: (a) to assess short (1 year) and long-term (5 year) changes in left ventricular ejection fraction in patients with stable coronary disease with or without ECG evidence of transient ischaemia during daily life on routine therapy, and (b) to assess whether patients with recurrent transient ischaemic episodes have a particular propensity to gradual deterioration in left ventricular ejection fraction in the absence of infarction. METHODS AND RESULTS: One hundred and forty eight patients (127 males; mean age 59 years), part of a natural history cohort of 172 patients who had undergone exercise testing, 48 h ambulatory ST monitoring, and resting radionuclide ventriculography at baseline, and who had not suffered any intervening cardiac event, underwent repeat radionuclide ventriculography at 1 year follow-up on identical or very similar medications. Furthermore, 56 patients (50 males; mean age 65 years) of this cohort, who had ischaemia both on exercise testing and ambulatory monitoring at baseline (n=33), or no ischaemia on either test at baseline (n=23), and who had suffered no intervening event, underwent repeat exercise testing, ambulatory monitoring and radionuclide ventriculography at a mean of 61.8 months follow-up. In 38 of these 56 cases, long-term testing mirrored baseline testing in terms of presence or absence of ischaemia (both tests +, n=25; both tests -, n=13). At one year there was no change in left ventricular ejection fraction, either for the whole group (n=148; left ventricular ejection fraction 47=11.6% - 47.13+11.07%, P=ns) or for subgroups with (n=62; left ventricular ejection fraction 48+12.1%-48.5+10.5%, P=ns) and without (n=86; left ventricular ejection fraction 46.2+10.4%-46.2+11.3%, P=ns) evidence of transient ischaemia at baseline. At 61 months, there was a small fall in mean left ventricular ejection fraction for the total study group (n=56; left ventricular ejection fraction 45.8+9.3%-42.1+8.8%, P<0.05); however, this fall was not significant for those patients with both baseline and 5 year evidence of transient ischaemia (n=25; left ventricular ejection fraction 44.9+8.7%-41.3+7.5%, P=0.056). CONCLUSION: In medically treated stable coronary patients who do not suffer any intervening cardiac event, recurrent transient (silent) ischaemic episodes do not, in themselves, lead to gradual deterioration in left ventricular systolic function over a 1-5 year period.     

Prognostic value of plasma catecholamines, plasma renin activity, and plasma atrial natriuretic peptide at rest and during exercise in congestive heart failure: comparison with clinical evaluation, ejection fraction, and exercise capacity

Survival in congestive heart failure is related to plasma catecholamines and atrial natriuretic peptide at rest, but the prognostic importance of changes during exercise is unknown. The aim of this study was to evaluate the prognostic value of catecholamines and atrial natriuretic peptide at rest and during maximal exercise in congestive heart failure, and to compare it to clinical and exercise test variables and left ventricular ejection fraction. One hundred ninety consecutive patients (136 men and 54 women; median age, 66 years; range, 42-75 years) with clinically stable congestive heart failure were included. Sixteen patients were in New York Heart Association class I, 87 in class II, 83 in class III, and 4 in class IV. Left ventricular ejection fraction was 0.30 (range, 0.06-0.74). Total survival after 1 year was 79%, after 2 years, it was 68%. Prognostic variables at univariate analysis were: plasma noradrenaline at rest (P < .0001), plasma adrenaline at rest (P = .049), and atrial natriuretic peptide at rest (P = .016). During exercise, plasma catecholamines and plasma atrial natriuretic peptide increased significantly; the change, however, was not related to survival. Six variables carried significant, independent prognostic information in a multivariate analysis: left ventricular ejection fraction (P = .03), plasma noradrenaline at rest (P = .009), New York Heart Association class III + IV (P = .005), increase in heart rate during exercise < or = 35 min-1 (P < .0001), serum creatinine > 121 mumol/L (P = .004), and serum urea > 7.6 mmol/L (P = .007). Patients with congestive heart failure have a poor survival despite intensive medical treatment. Plasma catecholamines and plasma atrial natriuretic peptide are elevated at rest and rises further during exercise; the increase, however, is not related to mortality. Plasma noradrenaline at rest contributes with further prognostic information despite knowledge of clinical and exercise variables and was the only neurohormonal variable with independent, significant prognostic information on survival.     

Quantitative radionuclide angiocardiography. Determination of left ventricular ejection fraction in children

A method is described for measuring left ventricular ejection fraction which uses high frequency computer recording of gamma scintillation camera data and peripheral venous injectinon of technetium-99m as sodium pertechnetate. Data from mechanical model experiments are used to show feasibility of this method. A phantom experiment is described which was used to develop a technique for accurate delineation of the ventricular outline in the presence of background. The left ventricular ejection was measured in 12 patients by radionuclide angiocardiography and biplane cineangiography. Comparison of these two methods gave a correlation coefficient of 0-91. In addition, left ventricular ejection fraction was measured in 34 patients (aged 7 weeks to 18 years) without evidence of cardiac disease using the radionuclide method alone. Average ejection fractions of 0-66 and 0-70 were found for children over 2 years of age and children 2 years of age or younger, respectively. In addition, an interobseerver comparison study was performed with the data from 10 patients, and only small differences were noted (SD 0-025).     

Impact of size mismatch and left ventricular function on performance of the St. Jude disc valve after aortic valve replacement

BACKGROUND: The hemodynamic function of the St. Jude valve may change relative to changes in left ventricular function after aortic valve replacement for aortic stenosis. From theoretical reasons one may hypothesize that prosthetic valve hemodynamic function is related to left ventricular failure and mismatch between valve size and patient/ventricular chamber size. METHODS: Forty patients aged 24 to 82 years who survived aortic valve replacement for aortic stenosis with a standard St. Jude disc valve (mean size, 23.5 mm; range, 19 to 29 mm) were followed up prospectively with Doppler echocardiography and radionuclide left ventriculography preoperatively and 9 days, 3 months, and 18 months after the operation with assessment of intravascular hemolysis at 18 months. Follow-up to a maximum of 7.4 years (mean, 6.3 years) was 100% complete. RESULTS: Left ventricular muscle mass index decreased from 198 +/- 62 g.m-2 preoperatively to 153 +/- 53 g.m-2 at 18 months (p < 0.001), paralleled by a significant increase in left ventricular ejection fraction, peak ejection rate, and peak filling rate; only 18% of the patients had normal left ventricular muscle mass index and only 32% normal ventricular function (normal left ventricular ejection fraction, peak ejection rate, peak filling rate, early filling fraction, and late filling fraction during atrial contraction) at 18 months. Prosthetic valve peak Doppler gradient dropped from 20 +/- 6 mm Hg at 9 days to 17 +/- 5 mm Hg at 18 months (p < 0.05). Reduction of left ventricular muscle mass index was unrelated to peak gradient and size of the valve. Peak gradient at 18 months rose with valve orifice diameter of 17 mm or less (by 6 mm Hg), orifice diameter/body surface area of 9 mm.m-2 or less (by 5 mm Hg), left ventricular enddiastolic dimension (by 23 mm Hg per 10 mm increase), and impaired ventricular function (by 3 mm Hg). All but 2 patients (5%) had intravascular hemolysis; none had anemia. Two patients with moderate paravalvular leak had the highest serum lactic dehydrogenase levels; 4 patients with trivial leak had higher serum lactic dehydrogenase levels than those without leak. Serum lactic dehydrogenase levels rose with moderate paravalvular leak, impaired ventricular function, and valve orifice diameter. Six patients with trivial or moderate paravalvular leak had a cumulative 7-year freedom from bleeding and thromboembolism of 44% +/- 22% compared with 87% +/- 5% for those without leak (p < 0.05). CONCLUSIONS: The peak gradient of the St. Jude aortic valve dropped marginally over the first 18 postoperative months in association with incomplete left ventricular hypertrophy regression and marginal improvement of ventricular function. Mismatch between valve size and ventricular cavity size or patient size and impaired function of a dilated ventricle significantly compromised the performance of the St. Jude valve. Probably explained by platelet destruction or activation, paravalvular leak was related to bleeding and thromboembolic complications.     

Safety and efficacy of epoprostenol in patients with severe congestive heart failure. Epoprostenol Multicenter Research Group

Patients with advanced heart failure often remain severely symptomatic and have a high mortality rate despite currently available therapy. We studied the safety and efficacy of a new approach to the patient with refractory heart failure: continuous intravenous treatment via a portable infusion pump with epoprostenol (prostacyclin), a potent pulmonary and systemic vasodilator. A group of 33 patients with severe heart failure (64% New York Heart Association class IV and 36% class III) and profound ventricular dysfunction (median left ventricular ejection fraction, 0.15)--despite prior treatment with diuretics (100%), digitalis (91%), angiotensin-converting enzyme inhibitors (85%), and dobutamine (30%)--underwent a baseline 6-minute walk test prior to dose titration with epoprostenol during invasive hemodynamic monitoring. Subjects responding during the dose titration were randomized, on an open basis, to receive either continuous epoprostenol infusion via an indwelling central venous catheter plus conventional therapy or conventional therapy alone for 12 weeks. The initial dose-ranging study with epoprostenol produced a significant decline in systemic and pulmonary vascular resistance and a substantial increase in cardiac index despite a fall in pulmonary capillary wedge pressure. Symptoms related to vasodilation were noted within the first week after randomization to epoprostenol in 9 of 16 patients but resolved with adjustment of the infusion and concomitant medications in all but one subject. Dose adjustments during the chronic epoprostenol infusion were infrequent after the first week and complications related to the drug delivery system were rare. The change in distance walked from baseline to the last available 6-minute walk test was significantly greater in patients who received epoprostenol compared with patients assigned to standard therapy (72 +/- 40 vs -39 +/- 32 m, mean +/- SEM; p = 0.033). Our study suggests that long-term intravenous infusion of epoprostenol is feasible in patients with severe heart failure and our hemodynamic and functional results suggest clinical benefit as well. However, until recent results indicating an adverse effect of epoprostenol on survival are fully evaluated, the role of this drug in the treatment of advanced heart failure will remain uncertain.     

Echocardiography-guided ethanol septal reduction for hypertrophic obstructive cardiomyopathy

BACKGROUND: Left ventricular outflow tract (LVOT) obstruction is frequently responsible for symptoms in hypertrophic obstructive cardiomyopathy (HOCM). Medical therapy is often not sufficient to control these symptoms, and surgical myotomy-myomectomy is required. METHODS AND RESULTS: We enrolled 33 symptomatic patients with HOCM and obstruction (>/=40 mm Hg gradient at rest or >/=60 mm Hg dobutamine-provoked). By contrast echocardiography, the bulging septum was localized and infarcted by injection of 2 to 5 mL of absolute ethanol into the septal artery(ies) supplying the hypertrophied area. Baseline echocardiograms with Doppler, myocardial perfusion tomograms, and treadmill exercise or pharmacological testing were compared with those at 6 weeks and 6 months. The mean rise in creatine kinase was 1964+/-796 U. All patients experienced symptomatic relief; NYHA class decreased from 3. 0+/-0.5 to 0.9+/-0.6 (P<0.001). Exercise time increased from 286+/-193 to 421+/-181 seconds (P=0.03). The resting and dobutamine-provoked gradient decreased from 49+/-33 and 96+/-34 mm Hg to 9+/-19 (P<0.001) and 24+/-31 mm Hg (P<0.001), respectively. Echocardiograms repeated at 6 weeks after the procedure showed a 28% reduction in septal thickness and 17% reduction in left ventricular mass. Myocardial perfusion imaging showed a "septal amputation pattern," with scarring in the upper and middle septal areas. Complete heart block developed in 11 patients, who then required permanent pacemaker implantation. CONCLUSIONS: Echocardiography-guided ethanol septal reduction in patients with HOCM is a safe, minimally invasive procedure that provides symptomatic relief with improved hemodynamic and left ventricular parameters.     

Impairment of exercise capacity and peak oxygen consumption in patients with mild left ventricular dysfunction and coronary artery disease

AIMS: Most studies in chronic heart failure have only included patients with marked left ventricular systolic dysfunction (i.e. ejection fraction < or =0.35), and patients with mild left ventricular dysfunction are usually excluded. Further, exercise capacity strongly depends on age, but age-adjustment is usually not applied in these studies. Therefore, this study sought to establish whether (age-adjusted) peak VO2 was impaired in patients with mild left ventricular dysfunction. METHODS: Peak VO2 and ventilatory anaerobic threshold were measured in 56 male patients with mild left ventricular dysfunction (ejection fraction 0.35-0.55; study population) and in 17 male patients with a normal left ventricular function (ejection fraction >0.55; control population). All patients had an old (>4 weeks) myocardial infarction. By using age-adjusted peak VO2 values, a 'decreased' exercise capacity was defined as < or = predicted peak VO2 - 1 x SD (0.81 of predicted peak VO2), and a severely decreased exercise capacity as < or = predicted peak VO2 - 2 x SD (0.62 of predicted peak VO2). RESULTS: Patients in the study population (age 52+/-9 years; ejection fraction 0.46+/-0.06) were mostly asymptomatic (NYHA class I: n=40, 76%), while 16 patients (24%) had mild symptoms, i.e. NYHA class II. All 17 controls (age 57+/-8 years) were asymptomatic. Mean peak VO2 was lower in patients with mild left ventricular dysfunction (23.6+/-5.7 vs 27.1+/-4.6 ml x min(-1) x kg(-1) in controls, P<0.05). In 75% of the study population patients (n=42) age-adjusted peak VO2 was decreased (NYHA I/II: n=29/13) and in 18% of them severely decreased (n=10; NYHA I/II: n=6/4). In contrast, only three patients (18%) in the control population had a decreased and none a severely decreased age-adjusted peak VO2. CONCLUSION: In patients with mild left ventricular dysfunction, who have either no or only mild symptoms of chronic heart failure, a substantial proportion has an impaired exercise capacity. By using age-adjustment, impairment of exercise capacity becomes more evident in younger patients. Patients with mild left ventricular dysfunction are probably under-diagnosed, and this finding has clinical and therapeutic implications.     

Attitudes toward sex in the aged

Right ventricular systolic sub-periods were examined in the group of 18 healthy subjects, basing on simultaneous electrocardiographic, phonocardiographic and pulmonary artery pressure tracings. The values established were compared with corresponding left ventricular systolic periods and correlated with selected hemodynamic parameters. Following mean values of the right ventricular systolic sub-periods were found: Q -- 1. sound interval = 0.051 sec., systolic time = 0.404 sec., ejection period = 0.319 sec., pre-ejection period = 0.085 sec., and isovolumetric contraction time = 0.034 sec. Both the right ventricular systolic and ejection periods were significantly longer than the corresponding left ventricular systolic ones. The ratio: right ventricular pre-ejection period to ejection period was lower than that calculated for the left ventricle. Both the right ventricular systolic and ejection periods negatively correlated with heart rate, whereas the ratio: right ventricular isovolumetric contraction time to ejection period depended on pulmonary artery pressure, pulmonary resistance and right ventricular work index.     

Perioperative conduction and rhythm disturbances after the Ross procedure in young patients

BACKGROUND: The Ross procedure is performed for a variety of left ventricular outflow tract diseases in children. The preoperative hemodynamic burden of pressure or volume overload and associated ventricular hypertrophy can predispose to ventricular arrhythmias. Additional procedures performed with the Ross procedure (eg, Konno) may damage the conduction system. METHODS: Between January 1995 and February 1997, the Ross procedure was performed in 42 patients, 31 (74%) of whom had 71 prior interventions. Concomitant procedures (n = 42 in 23 patients) included 17 annular-enlarging procedures. Screening was performed for perioperative conduction and rhythm abnormalities. RESULTS: There was one postoperative death. Perioperative ventricular tachycardia occurred in 12 patients (29%), with 2 receiving antiarrhythmic medication for ventricular tachycardia at discharge. Transient complete heart block occurred in 3 patients, all of whom had concomitant procedures performed in the subaortic area; all patients were discharged in sinus rhythm and no patient received a permanent pacemaker. CONCLUSIONS: The Ross procedure can be performed successfully in children with complex cardiac disease with low mortality and perioperative morbidity. The incidence of perioperative ventricular tachycardia is high (29%), suggesting the need for vigilant perioperative monitoring and long-term surveillance.     

Hypercholesterolemia enhances oxidant production in mesenteric venules exposed to Ischemia/Reperfusion

BACKGROUND: Three-dimensional echocardiography allows calculation of left ventricular ejection fraction without geometric assumption on the ventricular shape. Our aim was to validate this technique in a paediatric population with distorted ventricles. METHODS: Twenty-one patients aged 6 months to 17 years underwent equilibrium radionuclide angiography and three-dimensional echocardiography. Fourteen patients had dilated cardiomyopathy and seven had univentricular hearts. A new, easy to handle, transthoracic rotational probe was used and motion artefacts were limited during the rotation (3 degrees intervals with ECG and respiratory gating). Left ventricular volumes and ejection fraction were calculated using the Simpson's rule with 12 slices. RESULTS: Three-dimensional echocardiography correlated well with equilibrium radionuclide angiography for ejection fraction measurement (r = 0.90; the mean difference between the two methods being 3.8 +/- 6%). Intra-observer and inter-observer variabilities for 3D echocardiography were 2.4% and 4.5%. CONCLUSIONS: Three-dimensional echocardiography is an accurate, non-invasive, and reproducible methods to measure left ventricular ejection fraction in children.     

Effects on cardiac performance of atrioventricular node catheter ablation using radiofrequency current for drug-refractory atrial arrhythmias

Patients with atrial fibrillation or atrial flutter (AF) are candidates for radiofrequency (RF) catheter ablation of the atrioventricular (AV) node with the aim being to control heart rate. As patients with AF can have markedly impaired ventricular function, information concerning the hemodynamic effects of AV node ablation using RF current would be valuable. Fourteen consecutive patients (mean age 65 +/- 3 years) with drug-resistant AF underwent AV node catheter ablation with RF current and had permanent pacemaker implantation. The mean left ventricular ejection fraction (EF) by two-dimensional echocardiography immediately before ablation was 42 +/- 3% (range 14%-54%) and their mean exercise time was 4.4 +/- 0.4 minutes. Complete AV block was achieved in all 14 patients with 6 +/- 2 RF applications (range 1-18). There was no evidence of any acute cardiodepressant effect associated with delivery of RF current, and EF 3 days after ablation was 44 +/- 4%. By 6 weeks after ablation, the left ventricular EF was significantly improved compared to baseline (47 +/- 4% postablation vs 42 +/- 3% preablation; P < 0.05), and this modest increase in EF was accompanied by an improvement in exercise time (5.4 +/- 0.4 min). In conclusion, delivery of RF current for AV node catheter ablation in patients with AF and reduced ventricular function is not associated with any acute cardiodepressant effect. On the contrary, improved control of rapid heart rate following successful AV node ablation is associated with a modest and progressive improvement in cardiac performance.     

Antitumor activity of human umbilical cord blood cells: A comparative analysis with peripheral blood and bone marrow cells

OBJECTIVES: To determine the predictive value of quantitative evaluation of myocardial viability on changes in left ventricular function, exercise capacity, and quality of life after coronary artery bypass grafting in patients with ischemic heart failure (congestive heart failure, New York Heart Association class > or = III) with and without angina. METHODS: Thirty-five patients, 14 with congestive heart failure and angina (CHF-angina) and 21 with congestive heart failure without angina (CHF-no angina) were studied at baseline and 6 months after coronary bypass grafting. Left ventricular function was evaluated with transthoracic echocardiography and radionuclide ventriculography. Myocardial viability was assessed with [18F]-2-fluoro-2-deoxy-D-glucose using positron emission tomography. Peak aerobic capacity (peak oxygen consumption) and anaerobic threshold were assessed with treadmill exercise test and quality of life with a questionnaire. RESULTS: A total of 286 of 336 dysfunctional left ventricular segments were viable. There were two perioperative deaths (5.7%) and three late deaths. Left ventricular ejection fraction increased from 23% +/- 7% to 32% +/- 9% (p < 0.0001), and a linear correlation was found between the number of viable segments and the changes in ejection fraction (r = 0.65; p = 0.0001). Receiver operating characteristics curve identified eight viable segments as the best predictor for increase of ejection fraction more than 5 percentage points. Peak oxygen consumption increased from 15 +/- 4 to 22 +/- 5 ml/kg per minute (p < 0.0001). Preoperatively, anaerobic threshold was identified in one patient from the CHF-angina group and in all from the CHF-no angina group and increased from 13 +/- 4 to 19 +/- 4 ml/kg per minute (p < 0.0001). Quality of life scores improved significantly in both groups. No correlation was found between the amount of viable dysfunctional myocardium and changes in exercise capacity or quality of life. CONCLUSIONS: In patients with postischemic congestive heart failure the amount of viable myocardium dictates the degree of improvement in left ventricular function after revascularization.     

Effects of valve replacement on ventricular mechanics in mitral regurgitation and aortic stenosis

BACKGROUND: This study in humans assessed changes in left ventricular function early and late after correction of mitral regurgitation (MR) (n = 9) or aortic stenosis (AS) (n = 10). METHODS: Ventricular function was measured with radionuclide and micromanometer-derived pressure-volume loops during preload manipulation, thermodilution cardiac outputs, and echocardiograms. Late radionuclide and echocardiographic data were acquired at 24 hours and 20 months. RESULTS: Perioperative left ventricular performance (stroke work-end-diastolic volume relationship) did not change for patients with MR or AS. Significant changes in afterload occurred: ejection fraction (MR, 0.49 to 0.37; AS, 0.54 to 0.60; both, p = 0.013), mean left ventricular ejection pressure (MR, 73 to 91 mm Hg; AS, 138 to 93 mm Hg; both, p < 0.01), and end-systolic wall stress (MR, 26 to 42 x 10(3) dynes/cm2; AS, 37 to 22 x 10(3) dynes/cm2; both, p < 0.01). Ejection efficiency improved for MR patients (0.69 +/- 0.26 to 1.0 +/- 0.15; p < 0.05). The 20-month data showed improved New York Heart Association functional class, normal resting ejection fraction, and normal exercise response for both groups. CONCLUSIONS: Early after operation, a significant change in left ventricular load was seen with correction of MR and AS. Data obtained late after operation showed improvement consistent with ventricular remodeling.     

Heart rate changes during the Valsalva maneuver in patients with isolated aortic insufficiency

To determine the possible relationship between left ventricular dilatation and heart rate changes provoked by the Valsalva maneuver (Valsalva ratio), we studied 9 patients with isolated chronic aortic insufficiency. Left ventricular systolic function was assessed by two-dimensional echocardiography and cardiac catheterization. All patients were asymptomatic (functional class I of the New York Heart Association). The left ventricular internal diameters and volumes were significantly increased in all patients. The asymptomatic patients had either normal or slightly depressed ejection fraction (EF > 0.40). The Valsalva ratio of these asymptomatic patients showed no significant correlation with the left ventricular volumes or with the left ventricular ejection fraction. In other words, parasympathetic heart rate control, as expressed by the Valsalva ratio, was normal in the asymptomatic patients with left ventricular dilatation and preserved left ventricular ejection fraction. Therefore, left ventricular dilatation may not be the major mechanism responsible for the abnormal parasympathetic heart rate control of patients with acquired heart disease.