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PubMed1995

Beneficial cumulative role of both nitroglycerin and dobutamine on right ventricular systolic function in congestive heart failure patients awaiting heart transplantation.

End-stage idiopathic dilated cardiomyopathy or ischemic heart disease usually present with very low cardiac output and severe ventricular dysfunction which may require pharmacological support before heart transplantation. Right ventricular ejection fraction might be an important factor of functional capacity and survival in congestive heart failure. In order to test the immediate response of right ventricular hemodynamic parameters to nitroglycerin and dobutamine usually used to treat severe left ventricular dysfunction, we studied 17 congestive heart failure patients (15 men, two women; mean age 55 +/- 13 years) with end-stage idiopathic dilated cardiomyopathy (n = 10) or end-stage ischemic heart disease (n = 7), left ventricular ejection fraction < 35% (mean 22 +/- 8%), and sinus rhythm. A well validated thermodilution technique using a dedicated catheter with a fast catheter-computer response, permitting instantaneous measurements of right ventricular ejection fraction, was used. Right ventricular hemodynamic parameters were recorded at baseline, after an intravenous bolus injection of 3 mg nitroglycerin and after an intravenous infusion of dobutamine administered after nitroglycerin until normalization of cardiac index or a maximal dose of 15 micrograms/kg/min. Pulmonary artery mean pressure significantly decreased after nitroglycerin (43 +/- 9 mmHg at baseline vs. 31 +/- 10 mmHg after nitroglycerin, P < 0.0001) and did not subsequently change after dobutamine (32 +/- 10 mmHg after dobutamine, ns). Cardiac index was not affected by nitroglycerin (1.7 +/- 0. l/min/m2 at baseline vs. 2.0 +/- 0.3 l/min/m2 after nitroglycerin, ns), but dramatically increased after dobutamine (3.0 +/- 1.0 l/min/m2 after dobutamine, P < 0.0001). Concomitantly to the changes of these two parameters, right ventricular ejection fraction progressively increased (14 +/- 8% at baseline vs. 20 +/- 10% after nitroglycerin (P < 0.0006) vs. 28 +/- 13% after dobutamine (P < 0.0001)). Progressive increase of right ventricular ejection fraction after administration of nitroglycerin followed by administration of dobutamine suggests the beneficial cumulative role of both medications on right ventricular systolic function in severe congestive heart failure.

Cardiomyopathy, Dilated↗
PubMed2006

Free amino acids in hearts of pediatric patients with congenital heart disease: the effects of cyanosis, age, and pathology.

BACKGROUND: The immature heart has a much greater dependence than the adult heart on amino acid transamination in determining its ischemic tolerance. Compared with adult hearts, experimental models of the immature heart have quantified higher resting concentrations of free amino acids (AA) which are depleted by acute hypoxia. However, we have found no clinical studies that have looked at the free AA profile of the immature human heart or the effects of cyanosis, age, and pathology upon this. METHODS: One hundred eighty-one pediatric patients (37 cyanotic, 144 acyanotic) undergoing open-heart surgery were recruited. Myocardial biopsies were collected prior to ischemia and analyzed for free AAs (eg, glutamate, aspartate) using high-performance liquid chromatography. The effects of cyanosis, age, and pathology on amino acid concentrations were estimated by multiple regression modeling with and without controlling for diagnosis; the effects of age and pathology were estimated only in acyanotic children. RESULTS: Alanine concentrations were about 20% higher in cyanotic than acyanotic patients (p = 0.04). Cyanosis was not associated with any other amino acid levels. In acyanotic patients, after controlling for diagnosis, concentrations of glutamate, aspartate, and alanine decreased from birth to about 8 to 10 years, then started to increase again (p < 0.05 for both linear and quadratic terms); concentrations of taurine and the branched chain AAs decreased steadily with increasing age (p < 0.05). There were significant effects of pathology on glutamate (p = 0.006), glutamine (p = 0.003), and branched chain AA (p = 0.004) levels. CONCLUSIONS: There is no evidence that chronic hypoxia depletes endogenous AAs. Young age is associated with higher resting AA levels.

Aging↗
PubMed2006

Carvedilol can restore the multifractal properties of heart beat dynamics in patients with advanced congestive heart failure.

INTRODUCTION: Human heart beats in an extremely inhomogeneous and non-stationary manner. Recent study has demonstrated that it belongs to a class of signals called multifractal. Loss of multifractality was also uncovered in patients with congestive heart failure. We investigated whether carvedilol could restore the multifractal properties in a group of patients with advanced congestive heart failure. METHODS AND RESULTS: A Holter ECG recording was obtained before and 1 and 3 months after titrated addition of carvedilol therapy in 10 patients with advanced congestive heart failure. Multifractal spectrum, detrended fluctuation analysis (DFA) as well as the traditional time- and frequency-domain heart rate variability (HRV) parameters were compared before and after carvedilol therapy together with those in age and sex-matched normal control. The results showed that the multifractal spectrum tau(q) vs. q of N-N interval time series returned toward normal during carvedilol treatment. All the traditional HRV parameters and the short-term DFA improved significantly after 3 months of carvedilol therapy. CONCLUSION: We concluded that the deteriorated multifractal properties could be reversed by carvedilol treatment in patients with advanced congestive heart failure.

Adrenergic beta-Antagonists↗
PubMed2004

Analysing myocardial tissue from explanted hearts of heart transplant recipients and multi-organ donors for the presence of parvovirus B19 DNA.

BACKGROUND: Parvovirus B19 (PVB19) is an erythrovirus causing diverse clinical manifestations ranging from asymptomatic or mild to more severe outcomes, dependent on the haematological and/or immunological status of the host. Reports of PVB19 infection as a causative agent of paediatric or adult inflammatory cardiac diseases, or of cardiac transplant rejection are rare. OBJECTIVES: To identify PVB19 and other cardiotropic viruses in the myocardium of heart transplant (HTx) recipients and multi-organ donors (MOD). Furthermore, to assess the prevalence of cardiotropic viral infection in inflammatory heart disease. STUDY DESIGN: Heart tissue samples from 110 explants were analysed for PVB19 using primers and a 5'-nuclease probe designed to amplify a 160-basepair PCR product from the VP1/NS1 gene region. Samples tested included those obtained from patients undergoing HTx or from MODs. The findings were correlated with clinical course, histologic analysis and serologic testing. Confirmation of the positive PCR-results was done by sequencing and in situ hybridisation. RESULTS: The new assay described here allows precise quantitation of viral load over 7 orders of magnitude (10(6) to 10(0)IU/assay). Measurable amounts of parvoviral genomes were detected in 4/56 (7%) explanted HTx-hearts and in 5/54 (9%) explanted MOD-hearts. CONCLUSIONS: The newly developed real-time PCR is a rapid, sensitive and specific method to detect PVB19 infection in heart tissue. It will be a useful tool to address important questions regarding viral infections transmitted by transplantation, acute infections, relapses and complications involving late or chronic rejection.

Adolescent↗
PubMed1999

Effects of short-acting and long-acting loop diuretics on heart rate variability in patients with chronic compensated congestive heart failure.

BACKGROUND: We investigated the effects of a short-acting loop diuretic (furosemide) and a long-acting loop diuretic (azosemide) on heart rate variability, fluid balance, and neurohormonal responses in patients with mild to moderate chronic congestive heart failure. METHODS: Nineteen patients with mild to moderate chronic congestive heart failure received furosemide (40 to 60 mg/day) or azosemide (60 to 90 mg/day) for 5 days in a crossover manner. We performed time-domain and frequency-domain analyses of 24-hour Holter electrocardiographic recordings to assess heart rate variability. RESULTS: The 24-hour urinary sodium excretion was similar during the furosemide and azosemide treatment periods but was significantly greater in the first 2 hours after drug administration during furosemide treatment. Plasma renin activity and the hematocrit level increased and high-frequency power significantly decreased 2 hours after the administration of furosemide only. The standard deviation of all normal R-R intervals and the root mean square of successive differences in the R-R interval were lower with furosemide than with azosemide (P <.05). CONCLUSIONS: Furosemide, a short-acting loop diuretic, has a greater influence on heart rate variability and fluid balance than azosemide, a long-acting loop diuretic, in patients with mild to moderate chronic congestive heart failure.

Blood Pressure↗
PubMed1999

Lung membrane diffusing capacity, heart failure, and heart transplantation.

The pulmonary diffusing capacity for carbon monoxide (DLCO) is reduced in chronic heart failure and remains decreased after heart transplantation. This decrease in DLCO may depend on a permanent alteration after transplantation of one or the other of its components: diffusion of the alveolar capillary membrane or the pulmonary capillary blood volume (Vc). Therefore, we measured DLCO, the membrane conductance, and Vc before and after heart transplantation. At the time of hemodynamic measurements, the Roughton and Forster method of measuring DLCO at varying alveolar oxygen concentrations was used to determine the membrane conductance, Vc, DLCO/alveolar volume (VA), the membrane conductance/VA and thetaVc/VA (theta = carbon monoxide conductance of blood, VA = alveolar volume) in 21 patients with class III to IV heart failure before and after transplantation, and in 21 healthy controls. Transplantation normalized pulmonary capillary pressure and increased cardiac index. DLCO was decreased before transplantation (7.11 vs 10.0 mmol/min/kPa in controls), but DLCO/VA was normal (1.67+/-0.44 vs 1.71+/-0.26 mmol/min/kPa/L in controls). DLCO/VA remained unchanged after transplantation, because the decrease in Vc (82+/-30 vs 65+/-18 ml before and after transplantation) and thetaVc/VA was not compensated by the changes in membrane conductance (11+/-4 vs 12+/-5 mmol/min/kPa before and after transplantation, respectively) and membrane conductance/VA. We conclude that the decrease in DLCO in patients with chronic heart failure is due to a restrictive ventilatory pattern because their DLCO/VA remains normal; the decrease in the membrane conductance is compensated by the increase in Vc. After transplantation, the decrease in Vc due to normalization of pulmonary hemodynamics is not completely compensated for by an increase in membrane conductance. Because the membrane conductances, measured before and after transplantation, are negatively correlated with duration of heart failure, its abnormal pulmonary hemodynamics may have irreversibly altered the alveolar capillary membrane.

Adult↗
PubMed2003

Third heart sound and elevated jugular venous pressure as markers of the subsequent development of heart failure in patients with asymptomatic left ventricular dysfunction.

PURPOSE: To determine the independent prognostic value of a third heart sound (S(3)) and elevated jugular venous pressure in patients with asymptomatic left ventricular dysfunction. METHODS: We performed a post hoc analysis of 4102 participants from the Studies of Left Ventricular Dysfunction (SOLVD) prevention trial. In that trial, participants with asymptomatic or minimally symptomatic left ventricular dysfunction (New York Association class I or II, left ventricular ejection fraction < or =0.35, no treatment for heart failure) were allocated randomly to enalapril or placebo and followed for a mean (+/- SD) of 34 +/- 14 months. The presence of an S(3) and elevated jugular venous pressure was ascertained by physical examination at study enrollment. We used multivariate proportional hazards models to determine whether these physical examination findings were associated with the development of heart failure, a prespecified endpoint of the SOLVD prevention trial. RESULTS: At baseline, 209 subjects (5.1%) had an S(3) and 70 (1.7%) had elevated jugular venous pressure. Heart failure developed in 1044 subjects (25.5%). After adjusting for other markers of disease severity, an S(3) was associated with an increased risk of heart failure (relative risk [RR] = 1.38; 95% confidence interval [CI]: 1.09 to 1.73; P = 0.007) and the composite endpoint of death or development of heart failure (RR = 1.34; 95% CI: 1.09 to 1.64; P = 0.005). Elevated jugular venous pressure was also associated with these outcomes in multivariate models. CONCLUSION: The physical examination provides prognostic information among patients with asymptomatic or minimally symptomatic left ventricular dysfunction.

Analysis of Variance↗
PubMed1985

The effect of hypothermic preservation of the heart and lungs on cardiorespiratory function following canine heart-lung transplantation.

The effect of hypothermic preservation of the heart and lungs with a crystalloid solution was evaluated in 12 mongrel dogs receiving heart-lung allografts. Six animals served as controls and received an immediate heart-lung transplant. Six animals were in the experimental group and received a heart-lung transplant after 5 hours of preservation at 4 degrees C following perfusion of both organs with a crystalloid solution. Physiological function of the heart and lungs was studied for 20 hours after transplantation. While cardiac function was minimally depressed following preservation, pulmonary function testing demonstrated significantly greater increases in extravascular lung water in experimental animals, suggesting that an ischemic lung injury occurred with this preservation technique. The model allows for future evaluation of other methods of combined preservation of both the heart and lungs for transplantation.

Airway Resistance↗
PubMed2001

Circadian variation in the effects of aldosterone blockade on heart rate variability and QT dispersion in congestive heart failure.

OBJECTIVES: The study was designed to comprehensively evaluate the circadian effects of aldosterone blockade on autonomic tone and QT dispersion in chronic heart failure (CHF). BACKGROUND: Spironolactone therapy given in addition to angiotensin-converting enzyme inhibitors improved survival in CHF, but the mechanism of its benefit is uncertain. Experimental evidence suggests that aldosterone may have detrimental effects on the autonomic nervous system, especially during the morning hours. METHODS: Twenty-eight patients with New York Heart Association class II to IV CHF received spironolactone 50 mg daily and placebo for four weeks each in a double-blind crossover fashion. After each treatment phase, a full circadian assessment was undertaken of spironolactone's autonomic effects. The assessment included monitoring heart rate, QT dispersion, continuous Holter recordings, heart rate variability (HRV) and norepinephrine kinetics. RESULTS: Spironolactone significantly reduced all indices of QT dispersion. The reductions in QTcmax, QTd and QTcd were greatest at 6 AM. In addition, spironolactone had favorable autonomic effects, which were limited to the morning (6-10 AM), including heart rate reduction and an improvement in HRV. CONCLUSIONS: Spironolactone reduced heart rate and improved HRV and QT dispersion in CHF. Its effects were particularly prominent during the morning hours.

Circadian Rhythm↗
PubMed1999

Chronotropic competence in endurance trained heart transplant recipients: heart rate is not a limiting factor for exercise capacity.

OBJECTIVES: The purpose of this study was to show that the chronotropic potential of the well trained heart transplant recipient (HTR) does not limit exercise capacity. BACKGROUND: Chronotropic incompetence is considered to be the main limiting factor of the functional capacity of heart transplant recipients. However, no systematic study had been published on patients who had spontaneously undergone heavy endurance training for several years. METHODS: Heart rate (HR) and respiratory gas exchanges (VO2, VCO2, VE) were measured in 14 trained HTRs (T-HTRs) during exercise tests on a bicycle, on a treadmill and by Holter electrocardiography during a race. RESULTS: Peak values observed in T-HTRs during the treadmill test were higher than those reached during the bicycle test (VO2peak: 39.8+/-6.9 vs. 32.5+/-7.8 ml x kg(-1) x min(-1), p < 0.001; HRpeak: 169+/-14 vs. 159+/-16 bpm, p < 0.01). During treadmill exercise VO2peak and HRpeak values observed were very close to the mean predicted VO2pmax and HRpmax. The maximum heart rate during the race (HRrace) was greater than HRpeak values during the treadmill test (179+/-14 vs 169+/-14 bpm, p < 0.01) and slightly above the mean predicted values (HRrace/HRpmax X 100 = 101+/-10%). The treadmill exercise test yields more reliable data than does the bicycle test. CONCLUSIONS: Extensive endurance training enables heart transplant recipients to reach physical fitness levels similar to those of normal sedentary subjects; heart rate does not limit their exercise capacity.

Adult↗
PubMed1997

Effect of ramipril on heart rate variability in digitalis-treated patients with chronic heart failure.

The aim of this study was to evaluate the effect of an angiotensin-converting enzyme (ACE) inhibitor, ramipril, on heart rate variability in patients with heart failure simultaneously treated with digitalis. This study was a multicentric, randomized, double-blind, placebo-controlled study including 50 patients with chronic heart failure (CHF). All patients were in NYHA functional class II and III. The etiology of CHF was mainly idiopathic dilated cardiomyopathy and ischemic heart disease. After a 4-week placebo run-in period with digoxin and diuretics, patients were randomized to receive additional ramipril or placebo. To assess heart rate variability (HRV) and arrhythmias, 24-hour ECGs were recorded at the end of the placebo run-in period, 8 and 24 weeks after randomization. Spectral analysis of HRV was performed during one diurnal and one nocturnal 5-minute time period. No statistically significant differences in HRV within low-, high-, and total-frequency bands were induced by ramipril in either the diurnal or nocturnal periods, both at 8 and 24 weeks after randomization. Ramipril produced a significant decrease in nonsustained ventricular tachycardia at 24 weeks of treatment (p = 0.01). These results run against previous observations showing an increase in parasympathetic tone with ACE inhibitors in heart failure. The present study thus suggests that the effects of ACE inhibitors in CHF are variable and depend on the patient and concomitant treatment that might influence HRV such as digoxin treatment.

Adult↗
PubMed2001

Simultaneous heart and kidney transplantation in patients with end-stage heart and renal failure.

Combined simultaneous organ transplantation has become more common as selection criteria for transplantation have broadened. Broadening selection criteria is secondary to improved immunosuppression and surgical techniques. The kidney is the most common extrathoracic organ to be simultaneously transplanted with the heart. A series of 13 patients suffering from both end-stage heart and renal failure underwent 14 simultaneous heart and kidney transplantations at Temple University Hospital between 1990 and 1999. This is the largest series reported from a single center. Three patients died during the initial hospitalization for an in-hospital mortality of 21%. Of 10 patients who left the hospital, 1-year survival was 100% and 2-year survival 75%. One patient required retransplant for rejection within the first year. Overall mortality at 1 and 2 years was 25 and 41%, respectively. Four out of nine (44%) patients greater than 5 years post-transplant were alive. Of the 10 patients who left the hospital, 66% were alive at 5 years. One patient succumbed to primary nonfunction of the cardiac allograft, while the four other deaths were secondary to bacterial or fungal sepsis. The patient's racial backgrounds were equally divided between African-American and white. These results are similar to those reported in a United Network of Organ Sharing Database (UNOS) registry analysis of 84 simultaneous heart and kidney transplants that found 1- and 2-year survival to be 76 and 67%, respectively. Simultaneous heart and kidney transplantation continues to be a viable option for patients suffering from failure of these two organ systems, although the results do not match those of heart transplant alone.

Cause of Death↗
PubMed1996

Physical training enhances sympathetic and parasympathetic control of heart rate and peripheral vessels in chronic heart failure.

1. Physical training has been proposed to increase vagal control of heart rate in chronic heart failure. We studied the effects of physical training on cardiovascular control in 6 moderate to severe heart failure (NYHA II-III) patients and 6 age matched normal controls in a randomized controlled cross over trial (Training vs Detraining). 2. Five weeks training (20 min/day, 5 days/week bicycle exercise) increased peak VO2 in both C (from 31.2 +/- 1.4 to 37.7 +/- 2.4 ml/kg/min p < 0.01) and CHF patients (from 12.16 +/- 2.2 to 14.13 +/- 2 ml/kg/min p < 0.05). The sympathovagal control of heart rate and sympathetic control of the resistance vessels was assessed by the power of the oscillations (LF:0.03-0.15 Hz index of sympathetic activity, HF: 0.18-0.35 Hz index of vagal activity) in RR interval, blood pressure (systolic and diastolic by Finapres) and respiration by autoregressive spectral analysis, during free and controlled breathing (15b/min), in order to increase vagal activity. 3. T increased heart rate vagal control both in C (LF/HF ratio fb to cb: (D) 1.73 +/- 0.35 to 1.19 +/- 0.43 p = NS: (T) 2.9 +/- 1.2 to 1.13 +/- 0.3 p < 0.05) and in CHF patients (LF/HF ratio fb to cb: (D) 2.05 +/- 0.56 to 1.24 +/- 0.21 p = NS; (T) 2.6 +/- 0.89 to 0.87 +/- 0.15 p < 0.05; and in cb HF%: 36.2 +/- 2.7 (D) to 46.2 +/- 4.8 (T) p < 0.05). Before T, the sympathetic modulation of peripheral vessels (% LF compared to total variability) was depressed in CHF vs C (SBP: 9 +/- 2 vs 42 +/- 12% p < 0.05; DBP: 29 +/- 7 vs 55 +/- 31%, p < 0.05), and increased significantly after T in CHF (SBP from 9 +/- 2 (D) to 19 +/- 5% (T) p < 0.05; DBP from 29 +/- 7 to 41 +/- 11% (T) p < 0.05). This suggests an overall increase of autonomic control, both vagal on the heart and sympathetic on the peripheral vessels, in CHF by physical training.

Autonomic Nervous System↗
PubMed1989

Interstitial myocardial lipomatosis: a morphological study on endomyocardial biopsies and diseased hearts surgically removed for heart transplantation.

A morphological study was designed to assess on histological grounds the frequency and degree of interstitial adipose tissue in the myocardium of diseased and transplanted hearts. A review was conducted on 144 right ventricular histological sections (RVs) from hearts surgically resected for heart transplantation, 115 endomyocardial biopsies (EMB) from 100 patients investigated for dilated cardiomyopathy (DCM), and 309 biopsies from 26 heart-transplant patients. Interstitial lipomatosis (IL) was the preferred term to describe the mere presence of adipose tissue in the myocardium, and the arbitrary classification of grade 0, 1, and 2 IL was devised to collect data. Only grade 2 IL was considered as potentially pathological. Morphometric analysis was adopted on the 144 RVs from surgical hearts; only a morphological approach was preferred for the EMB. Grade 2 IL was observed in 58/144 RVs (40.27%), in 5/365 (1.3%) myocardial samples from 115 EMB in patients with DCM, and in 5/1296 (0.38%) myocardial samples from 309 biopsies of 26 transplants. Morphometric analysis of the surgical hearts revealed a case in which a significant grade 2 IL of the RV was associated with life-threatening ventricular arrhythmias.

Adult↗
PubMed1995

Circadian pattern of heart rate variability in chronic heart failure patients. Effects of physical training.

The effect of physical training on the circadian pattern of heart rate variability (recorded over 24 h in relation to both time and frequency) was assessed in 12 chronic heart failure patients randomized, in a cross-over design, to 8 weeks training or detraining, and compared with 12 age-matched normals. Training improved heart rate variability indices: all R-R interval 5 min standard deviations increased by 17.6%, the root mean square of the differences of successive R-R intervals by 34.9%, the percentage difference between adjacent normal R-R intervals > 50 ms by 112.5%, total power by 58.3%, high frequency by 128.5% and low frequency by 65.0%. Compared with controls, circadian variations in autonomic parameters were maintained in chronic heart failure. Training-induced changes were observed at different time intervals throughout the day: the highest values were at 0100 h-0700 h (detraining: low frequency 361 +/- 83 ms2, high frequency 126 +/- 47 ms2; training: low frequency 535 +/- 202 ms2, high frequency 227 +/- 115 ms2, P < 0.01) and the lowest at 1300 h-1900 h (detraining: low frequency 91 +/- 23 ms2, high frequency 39 +/- 14 ms2; training: low frequency 154 +/- 42 ms2, high frequency 133 +/- 67 ms2, P < 0.05). In chronic heart failure, training maintains and improves circadian variations in heart rate variability measures.

Aged↗
PubMed2002

The relationship of heart rate reserve to VO2 reserve in patients with heart disease.

UNLABELLED: Recent reports indicate that among healthy adults, % heart rate reserve (HRR) is more closely related to %VO2 reserve (VO2R) than it is to %VO2max. This finding, in addition to the disparity between %HRR and %VO2max which is greater at low intensities and among low fit individuals, led the American College of Sports Medicine to adopt the use of %VO2R in place of %VO2max when prescribing exercise intensity among healthy adults and persons with heart disease. However, the relationship of %HRR to %VO2R among persons with heart disease has not been described. PURPOSE: Among patients with a myocardial infarction (MI) and patients with chronic heart failure (HF), test the hypothesis that %VO2R is equivalent to %HRR, while %VO2peak is not. METHODS: Using a clinical cardiology outcomes database, symptom-limited treadmill tests from 65 patients with MI and 72 patients with HF were identified. Heart rate and VO2 data were measured continuously and averaged every 15 s. For each subject, linear regression was used to calculate the slope and y-intercept of %HRR versus %VO2R (assuming rest VO2 = 3.5 mL x kg(-1) x min(-1)) and %HRR versus %VO2peak. Mean slope and y-intercept were calculated for each group and compared with the line of identity (slope = 1, y-intercept = 0). RESULTS: For the MI and HF groups, the slope of %HRR versus %VO2R was 0.96 +/- 0.02 (+/-SE; P = NS, slope vs 1) and 0.97 +/- 0.02 (P = NS), respectively. And the y-intercept was -1.9 +/- 2.1% (P = NS, y-intercept vs 0) and -5.9 +/- 2.1% (P < 0.05) for MI and HF, respectively. For both patient groups, the regression of %HRR versus %VO2peak resulted in a line that differed (P < 0.001) in both slope and y-intercept from the line of identity. CONCLUSIONS: In patients with heart disease, %HRR is a better estimate of %VO2R than %VO2peak. This finding does not affect the current recommended use of %HRR. However, when prescribing exercise based on VO2, relative intensity should be expressed as %VO2R.

Aged↗
PubMed1992

Blood cyclosporin concentrations but not doses correlate with acute changes in renal function following heart and heart-lung transplantation.

The relationship between changes in cyclosporin (CyA) dose or CyA blood concentration and the reciprocal creatinine concentration was investigated by cross-correlation analysis over the first 3 postoperative months in 32 consecutive heart and heart-lung recipients. Exploratory analysis suggested that early changes in renal function, probably attributable to recovery from preoperative cardiac failure, obscured later underlying correlations. Therefore, all data up to the first nadir in plasma creatinine following transplantation were excluded from the analysis. Five-day mean CyA doses or blood concentrations were cross-correlated with 5-day mean reciprocal creatinine concentrations measured either in the same 5-day period or with the creatinine measured up to two 5-day periods later. Although a significant correlation was found between CyA dose and blood concentration (the 95% confidence interval of the population correlation coefficient did not overlap zero), there was no relationship between dose and changes in renal function. The blood CyA concentration, however, correlated significantly with the reciprocal creatinine concentration measured in the same 5-day period and was also predictive of changes in creatinine measured in the subsequent 5-day period. Thus, a major criterion for therapeutic drug monitoring had been fulfilled: CyA dosage adjustment based on blood CyA concentrations, as the intermediate therapeutic end point, is helpful in the management of acute nephrotoxicity in heart and heart-lung transplant recipients because of the lack of a dose-effect relationship. Regular CyA monitoring and appropriate dosage adjustment is essential for the management of acute nephrotoxicity in the first 3 months following heart or heart-lung transplantation.

Creatinine↗
PubMed1996

The effect of lazaroid (U74500A), a novel inhibitor of lipid peroxidation, on 24-hour heart preservation. A study based on a working model using cross-circulated blood-perfused rabbit hearts.

Lazaroid, an inhibitor of iron-mediated lipid peroxidation, has been shown to reduce free radical-mediated injury after ischemia and reperfusion. We thus examined the efficacy of pretreatment with lazaroid (U74500A) in enhancing functional recovery after 24-hr heart preservation. An isolated rabbit heart model perfused with the blood from a support rabbit was used. Before preservation, either U74500A (4 mg/kg, group L; n = 6) or solvent (group S; n = 7) was given to the donor rabbit. After 24-hr preservation with UW solution at 0 degrees C, all hearts were perfused with cross-circulated blood for 60 min with the Langendorff mode followed by 40 min of the working mode. In group S, ventricular fibrillation (Vf) after reperfusion was observed in all hearts, whereas no Vf was observed in the U74500A-pretreated group. In group L, the serum creatine phosphokinase; its isozyme, troponin-T; and serum lipid peroxide levels after 10 min of reperfusion were all significantly (P < 0.05) lower than those in group S. The Frank-Starling curve (indicating the left atrial pressure-aortic flow relationship) showed a significant left and upward shift in group L compared with that in group S (P < 0.0001). The heart pretreated with U74500A showed less ischemia-reperfusion injury, better ventricular function, and a lower lipid peroxide level. We thus conclude that the inhibition of lipid peroxidation with lazaroid appears to offer some potential benefits for long-term heart preservation.

Animals↗