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.

Intravenous amiodarone decreases the duration of atrial fibrillation associated with acute myocardial infarction.

PURPOSE: Atrial fibrillation (AF) is a fairly common complication of acute myocardial infarction (AMI). The aim of this study was to examine the safety and efficacy of intravenous amiodarone in converting AF associated with AMI. METHODS: Seventy patients with AMI complicated with AF were prospectively divided into 3 groups: a) In group D (n = 26), 0.75 mg digoxin was administered intravenously and thereafter as needed, b) In group AM (n = 16), 300 mg of amiodarone was infused over 2 hours followed by 44 mg/hour for up to 60 hours or until sinus rhythm was restored, c) In group D + AM (n = 28), 0.75 mg of digoxin was administered (as in group D) for the initial 2 hours followed by amiodarone infusion as in group AM. RESULTS: Sinus rhythm was restored: a) by the end of the 2nd hour in 9/26 patients from group D, 4/16 from group AM, and 10/28 from group D + AM (p = NS), b) by the end of the 96th hour, in 18/26 patients from group D, and in all patients from group AM and groupd D + AM. The corresponding duration of AF was 51 +/- 34 hours, 17 +/- 15 hours and 9 +/- 13 hours, respectively (F = 15.4, p < 0.001). AF recurred in 9/26, 5/16 and 1/28 patients of groups D, AM and D + AM, respectively (p = 0.026). The required dosage of amiodarone was lower in the D + AM group than in the AM group (603 +/- 563 mg versus 1058 +/- 680 mg, p = 0.037). CONCLUSIONS: Intravenous amiodarone was well tolerated in patients with AMI complicated by AF and was effective in decreasing the duration of AF. However, the combination of amiodarone and digoxin was superior to amiodarone alone in restoring sinus rhythm faster, maintaining sinus rhythm longer, and allowing the use of a lower cumulative amount of amiodarone.

Correlation and stability of heart rate and ventricular ectopy variability in patients with congestive heart failure.

The stability of indexes of heart rate variability and their possible association with spontaneous variability of ventricular ectopy was examined in 13 patients with advanced congestive heart failure over 14 consecutive days of 24-hour ambulatory electrocardiographic recording. It was found that time and frequency domain measures of heart rate variability are stable over time and are inversely correlated with spontaneous variability of ventricular ectopy.

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.

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.

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.

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.

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.

Postpericardiotomy syndrome during intensive immunosuppression after cardiac transplantation.

A 15-year-old man with end-stage heart failure due to dilated cardiomyopathy, underwent heart transplantation. In the second postoperative week, while being treated with monoclonal antibodies (OKT3), cyclosporine and azathioprine, he developed a postpericardiotomy syndrome and cardiac tamponade, which necessitated emergency pericardiocentesis. Corticosteroids, administered according to the immunosuppression protocol, resulted in the prompt subsidence of the syndrome. This is the first report of a large pericardial effusion and cardiac tamponade due to a postpericardiotomy syndrome in an adult cardiac recipient.

Congestive heart failure treated by the upgrade from VVI to DDD pacing.

The case is presented of an elderly woman with normal left ventricular (LV) systolic function and VVI pacing complicated by severe congestive heart failure. The symptoms and findings of congestive heart failure became refractory to medical treatment and resolved with the upgrade of the VVI to a DDD system. Right heart catheterization during VVI pacing showed increased mean pulmonary capillary wedge and right atrial pressures both being normalized under DDD pacing. This case report illustrates the need to consider permanent physiological pacing in elderly patients, even in presence of normal LV systolic function, to ensure AV synchrony when the atrium can be paced, since diastolic LV dysfunction is quite common in these subjects.

Amiodarone concentration in human myocardium after rapid intravenous administration.

Intravenous amiodarone has been found useful in the emergent management of life-threatening arrhythmias. Experimental studies have shown that its electrophysiologic effects are proportional to its myocardial concentration. However, early after its intravenous administration, the extent of the concentration of amiodarone in the human myocardium, the site of its action, is not well known. This study was performed to measure the myocardial concentration of amiodarone shortly after rapid intravenous injection. Amiodarone, 150 mg, was injected over 15 seconds intravenously into 9 patients, 52 +/- 9 years of age, weighing between 65 and 98 kg (mean = 81 +/- 15.6). All patients suffered from idiopathic dilated cardiomyopathy, were in NYHA functional class II, and the mean left ventricular ejection fraction was 21 +/- 6%. Right ventricular endomyocardial biopsy, required for the establishment of the diagnosis, was performed 2-5 minutes after drug administration for measurements of its myocardial concentration. Plasma concentrations of amiodarone were also measured at 2, 5, 10, and 60 minutes, and measurements of right heart hemodynamics were made 2 and 10 minutes after the injection. At 2.5 +/- 1.2 minutes after amiodarone administration, the mean myocardial concentration was 95.7 +/- 67.4 micrograms/g (range, 16-175), and the myocardial/plasma amiodarone ratio was 5.05 +/- 5.01. Heart rate increased from 82 +/- 17 to 90 +/- 13 beats/min (P < 0.05), and systolic blood pressure decreased from 132 +/- 19 to 118 +/- 17 mmHg (P < 0.03). The extent of myocardial fibrosis was 5.13 +/- 6.55% (range, 0.3-17.5%). Intravenous amiodarone (150 mg) accumulates rapidly in the human myocardium. This pharmacokinetic characteristic probably explains its acute efficacy in the treatment of life-threatening arrhythmias.

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.

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.

Right and left ventricular interaction in ventricular fibrillation with mechanical maintenance of the circulation.

OBJECTIVE: To investigate the possible mechanisms of right and left ventricular interaction during ventricular fibrillation (VF) with mechanical maintenance of the circulation. EXPERIMENTAL DESIGN: In this experimental study, two para-aortic counterpulsation devices (PACDs) were implanted in 14 mongrel dogs. SETTING: The PACD is a spheroid, valveless, with one opening, 100 ml stroke volume assisting device. After midsternotomy and pericardiotomy, two PACDs were implanted on the ascending aorta and the pulmonary artery, respectively. Catheters were placed into the aortic arch, and the left and right ventricles. An electromagnetic probe was placed on the descending aorta. INTERVENTIONS: After the completion of the experimental preparation, VF was induced and the two devices were synchronized and pumped simultaneously for 10 minutes (A). Subsequently, the left sided PACD pumped alone for the same period of time (B). This sequence was repeated 1-10 times in each experiment. MEASURES: The aortic pressures, the left and right ventricular pressures and the cardiac index were obtained at the end of each intervention. RESULTS: The simultaneous pumping of the two devices (A) compared with the pumping of that implanted on the ascending aorta (B) resulted in: higher peak aortic pressure 119.1+/-32.1 mmHg (A) vs 105.7+/-36.4 mmHg (B), p<0.001, mean aortic pressure 42.1+/-13.2 mmHg vs 27.8+/-10.5 mmHg, p<0.001, mean left ventricular pressure 18.4+4.0 mmHg vs 11.7+/-3.6 mmHg, p<0.001, and cardiac index 105.7+/-40.1 ml/kg/min vs 82.0+/-39.9 ml/kg/mm, p<0.001, and lower right ventricular pressure 10.1+/-3.2 mmHg vs 13.3+/-2.6 mmHg, p<0.001. CONCLUSIONS: Maintenance of the circulation during VF with the PACD implanted on the ascending aorta results in equalization of the right and left ventricular pressures. In contrast, when both devices are pumping simultaneously, the left ventricular pressure is significantly higher than the right one and the assistance is more effective.

Reversible symmetric polyneuropathy with paraplegia after heart transplantation.

BACKGROUND: Neurotoxicity is a well-recognized side effect of cyclosporine therapy in transplant recipients. Cyclosporine can cause a wide range of adverse effects on both the central and peripheral nervous systems. METHODS: We present a case history of symmetric polyneuropathy with flaccid paraplegia, a rare neurological complication of cyclosporine administration. RESULTS: Blood levels of the drug above the therapeutic range accompanied the neurological manifestations. The syndrome subsided fully with dose reduction. Patients' symptoms were attributed to axonal degeneration of the peripheral nerves, according to electromyography findings. CONCLUSIONS: Cyclosporine neurotoxicity should always be considered in patients with neurological complications following transplantation. The case presented in this article illustrates an additional potential mechanism of this adverse effect, namely, axonal degeneration of the peripheral nerves, causing symmetric polyneuropathy.

Itraconazole for the treatment of pulmonary aspergillosis in heart transplant recipients.

The objective of this study was to evaluate the effects of itraconazole as a first choice drug in the treatment of pulmonary aspergillosis in heart transplant recipients. Heart transplant recipients suffering from invasive pulmonary aspergillosis were included in this study. Group 1 included 4 patients treated with i.v. itraconazole (Janssen Pharmaceutica) 400 mg daily, as a first choice drug for 28 d. Itraconazole was discontinued and amphotericin-B was started before the 28th day if clinical or radiographic worsening was observed. Group 2 included 3 patients treated with amphotericin-B as a first choice drug. Itraconazole was discontinued in all patients of Group 1 after 12-26 d of treatment because of radiographic worsening (n = 3) or combined clinical and radiographic worsening (n = 1). Subsequent treatment with amphotericin-B resulted in improvement of all patients. On a 5-yr follow-up period no relapse of aspergillosis was observed in 3 of them. The fourth patient expired from cerebral hemorrhage. The 3 patients of Group 2 treated with amphotericin-B showed a gradual improvement, and all were doing well on a 2-yr follow-up. In conclusion, in our study population consisted of heart transplant recipients amphotericin-B was superior to itraconazole in the treatment of invasive pulmonary aspergillosis.