PubMed Health⌕ Search

Biomedical subjects

F Cobelli

Publications and source records attributed to F Cobelli.

At least 19 recordsLinked to original sources
PubMed2004

Impact of physical training and detraining on endothelium-dependent vasodilation in patients with recent acute myocardial infarction.

BACKGROUND: There is evidence that aerobic exercise improves endothelial function in healthy subjects as well as in patients with chronic heart failure. However, it is unknown whether this effect occurs in patients with recent myocardial infarction (AMI). METHODS: Fifty-two patients with a recent first uncomplicated AMI underwent endothelial function evaluation before and after 3 months of moderate aerobic exercise training. We measured brachial artery vasomotor reactivity using flow-mediated dilation (FMD), a cold pressor (CP) test, and sublingual nitroglycerin. Patients were randomized into 2 groups: 28 patients (G1) underwent training, while 24 patients (G2) served as controls. Brachial artery vasomotor reactivity was reassessed after 1 month of detraining (DT). RESULTS: At baseline the FMD was 1.66% +/- 4.11% in G1 and 2.04% +/- 3.4% in G2 (P = NS) and vasoconstriction was evident after a CP test. The diameter reduction was -4.1% +/- 3.89% in G1 and -4.39% +/- 5.67% in G2 (P = NS). At follow-up the FMD had increased to 9.39% +/- 4.87% in G1 (P <.01) and to 4.4% +/- 3.9% in G2 (P <.01 vs G1). Vasoconstriction during a CP test was observed only in G2. Endothelium-independent vasodilation was unchanged in both groups. Effort tolerance increased by 32% in G1 patients (P <.01 versus G2) and was correlated with FMD change (R = 0.51, P <.01). After detraining the FMD was significantly reduced in G1 (P <.01) and a further vasoconstriction was evident after CP testing. CONCLUSIONS: Exercise training improves endothelium-dependent vasodilation in post-AMI patients. This improvement is associated with a significant increase in exercise tolerance. These benefits disappeared after detraining.

Adult↗
PubMed2002

Left atrial function: bridge to central and hormonal determinants of exercise capacity in patients with chronic heart failure.

UNLABELLED: The stroke volume response to exercise is a critical determinant in meeting peripheral metabolic demands in patients with chronic hear failure. The Left atrium, by its position, is important in coupling right and left ventricles, to left preload reserve and to modulate sympathetic activity. We performed this study to investigate the relationship between exercise capacity and diastolic and systolic left atrium function in patients with chronic heart failure. METHODS: We considered 128 consecutive patients with severe chronic heart failure (EF < 35%) due to ischemic or idiopathic dilated cardiomyopathy. Cardiac output, right atrial pressure, pulmonary artery pressures and mean pulmonary wedge pressure (A, X, V, Y wedge pressures) were determined during right cardiac catheterization. By Echocardiography evaluation, we measured atrial pressures and volume during early and late left atrial systolic filling and we calculated left atrial chamber stiffness by this equation P = A*eKV1. (P = left atrial pressure; A = elastic constant (mmHg*ml); e = the base of the natural logarithm; V1 = left atrial volume (ml); K = left atrial chamber stiffness constant (ml-1) = ln (V/X)/(maximal--minimal left atrial volumes)). All patients performed cardiopulmonary exercise test with modified Noughton protocol. Plasma norepinephrine and Atrial natriuretic factor levels were determined. RESULTS: Maximal and minimal left atrial volumes were inversely related to oxygen consumption (r = -.44, p < .001; r = -.61, p < .001). At rest, no differences were found in plasma norepinephrine concentrations (309 +/- 152 pg/ml vs 309 +/- 394 pg/ml; p = ns) and systemic vascular resistance (1706 +/- 435 vs 1771 +/- 524 dynes/cm sec-5; p = ns) in patients with large or normal left atrial volumes. During exercise the chronotropic response increased less in patients with large atrial volumes (56 +/- 13 vs 45 +/- 14; p = .001). The left atrial chamber stiffness constant was inversely related to peak oxygen consumption and exercise time. Patients with different chamber stiffness showed statistical difference in peak VO2 (16 +/- 4 vs 11 +/- 3 ml/kg/min; p = .0001). Left atrial ejection fraction was directly related to peak oxygen consumption (r = 0.55), but the most strongly correlation was with atrial filling fraction (r = .67). CONCLUSIONS: This study demonstrates a strong relationship between left atrial function and exercise capacity in patients with chronic heart failure.

Chronic Disease↗
PubMed2002

Relationship between cognitive impairment and clinical status in chronic heart failure patients.

BACKGROUND: In spite of its clinical importance, cognitive functioning is not always taken into account in studies on patients with chronic heart failure. The aim of the present study is to analyse the relationship between cognitive impairment and cardiovascular variables in a sample of patients with chronic heart failure for assessment or candidated for heart transplant. METHODS: Sixty-four male patients with chronic heart failure in NYHA class I-III, in a stable clinical condition, underwent cardiological evaluation and neuropsychological assessment by means of a wide battery of tests: Spinnler and Tognoni's tests and WAIS scale. RESULTS: Compared to the normative group, only 9% of patients did not have impairment in any cognitive function. 26% of patients had impairment of one cognitive function, and 30% of four or more cognitive functions. The cognitive functions that were most often impaired were short-term verbal memory, short-term visual spatial memory, differed verbal memory and verbal learning and visual spatial logical ability. On the whole, no statistical significant relationship was found between cognitive scores and the considered cardiovascular variables. CONCLUSIONS: Our data support the need to take into account the risk of cognitive impairment in CHF patients, regardless of age, disease severity or functional status. The high prevalence of short-term verbal memory impairment has important implications in clinical practice, since CHF patients should be actively involved in the medical management of their disease. Memory deficits could compromise patient's adherence to treatment as well as doctor-patient interactions. The practical consequences of these difficulties require some changes in doctors' behaviour and suggest the need for specific medical staff member training.

Chronic Disease↗
PubMed2001

Echo-Doppler mitral flow monitoring: an operative tool to evaluate day-to-day tolerance to and effectiveness of beta-adrenergic blocking agent therapy in patients with chronic heart failure.

OBJECTIVES: The goals of this study were: 1) to assess the predictive value of baseline mitral flow pattern (MFP) and its changes after loading manipulations as regards tolerance to and effectiveness of beta-adrenergic blocking agent treatment in patients with chronic heart failure (CHF); and 2) to analyze the prognostic implications of chronic MFP modifications after beta-blocker treatment. BACKGROUND: In patients with CHF, carvedilol therapy induces clinical and hemodynamic improvements. Individual management, clinical effectiveness and prognostic implications, however, remain unclear. The MFP changes induced by loading manipulations provide independent prognostic information. METHODS: Echo-Doppler was performed at baseline and after loading manipulations in 116 consecutive patients with CHF (left ventricular ejection fraction: 25 +/- 7%); 54 patients with a baseline restrictive MFP were given nitroprusside infusion; 62 patients with a baseline nonrestrictive MFP performed passive leg lifting. According to changes in MFP, we identified four groups: 17 with irreversible restrictive MFP (Irr-rMFP), 37 with reversible restrictive MFP (Rev-rMFP), 12 with unstable nonrestrictive MFP (Un-nrMFP) and 50 with stable nonrestrictive MFP (Sta-nrMFP). Carvedilol therapy (44 +/- 27 mg) was administered blind to results of loading maneuvers. After six months, MFP was reassessed and patients reclassified according to chronic MFP changes. During follow-up, tolerance to and effectiveness of treatment and major cardiac events (death, readmission and urgent transplantation) were considered. RESULTS: Changes of MFP after loading manipulations were more accurate than baseline MFP in predicting both tolerance to (p < 0.01) and effectiveness of (p < 0.05) carvedilol. After 26 +/- 14 months of follow-up, cardiac events had occurred in 23/102 patients (23%). The event rate in patients with chronic Irr-rMFP or Un-nrMFP was markedly higher than it was in those with Rev-rMFP or Sta-nrMFP. CONCLUSIONS: In our patients, tolerance to and effectiveness of carvedilol was predicted better by echo-Doppler MFP changes after loading manipulations than by baseline MFP. Chronic changes of MFP after therapy are strong predictors of major cardiac events.

Adrenergic beta-Antagonists↗
PubMed2001

Doppler echocardiography reliably predicts pulmonary artery wedge pressure in patients with chronic heart failure even when atrial fibrillation is present.

BACKGROUND AND AIMS: In patients with chronic congestive heart failure a high pulmonary artery wedge pressure (PAWP) is associated with poor prognosis, severe symptoms and low exercise tolerance. When atrial fibrillation is present the non-invasive prediction of PAWP by Doppler echocardiography is generally considered to be not reliable. METHODS: In 51 consecutive patients with chronic heart failure, due to either ischemic and non-ischemic dilated cardiomyopathy, and atrial fibrillation simultaneous Doppler echocardiographic and hemodynamic studies were used to estimate PAWP. The power of the obtained multivariate equation was compared with that of previously developed equations and was then prospectively tested in a group of 15 patients. RESULTS: The deceleration rate (DR) of early diastolic mitral flow, the left ventricular iso-volumic relaxation time (IVRT) and the systolic fraction of pulmonary venous flow (SF) were independent predictors of PAWP and the following multivariable equation was derived: PAWP=24.04 + 1.23 x DR- 0.089 x IVRT - 0.175 x SF. The correlation between invasive PAWP and the PAWP non-invasively estimated by this equation in the testing group was 0.91 (standard error of estimate=3.2 mmHg). The mean difference was 0.93 and the standard error of differences was 2.7 mmHg. CONCLUSION: In patients with chronic heart failure due to dilated cardiomyopathy who are in atrial fibrillation a relatively accurate estimation of PAWP can be obtained by Doppler echocardiography of mitral and pulmonary venous flow.

Aged↗
PubMed2001

Chronic infusion of dobutamine and nitroprusside in patients with end-stage heart failure awaiting heart transplantation: safety and clinical outcome.

BACKGROUND: in patients with severe heart failure additional therapeutic support with intravenous inotropic or vasodilator drugs is frequently employed in an attempt to obtain hemodynamic and clinical control. No data comparing the use and efficacy of chronic intravenous inotropic and vasodilator therapy in patients with advanced heart failure are available. AIMS: we evaluated, in a group of patients with advanced heart failure undergoing chronic infusion with dobutamine or nitroprusside, in addition to optimized oral therapy, (1) the safety of chronic infusion, (2) the efficacy of both drugs in managing unloading therapy and (3) clinical outcome of the two therapeutic strategies. METHODS: one hundred and thirteen patients receiving optimized oral therapy, in functional class III/IV with symptoms and signs of refractory heart failure and requiring additional pharmacological support with either intravenous dobutamine or nitroprusside were evaluated. Clinical and therapeutic management and clinical outcome of the two groups were considered. RESULTS: dobutamine was administered for 12 h/day for 20+/-23 days at a dosage of 7+/-3 microg/kg/min to 43 patients. The mean dose of nitroprusside was 0.76+/-0.99 microg/kg/min. The mean duration of use of this drug, administered as a 12-h/day infusion was 22+/-38 days. Nitroprusside infusion allowed greater doses of short-term ACE-inhibitors to be used compared to pre-infusion (ACE-inhibitor dose: 55+/-30 mg/day vs. 127+/-30 mg/day P<0.0001) and during dobutamine infusion (ACE-inhibitor dose: 85+/-47 mg/day vs. 127+/-30 mg/day P<0.002). Nitroprusside unlike dobutamine significantly improved the NYHA functional class. Of the 113 patients, 109 (97%) had a cardiac event during a mean follow-up of 337+/-264 days. Forty-four patients required hospitalization for worsening congestive heart failure, 45/113 (39%) patients died during the follow-up and 27/113 (24%) patients had a heart transplant in status one. Hospitalization, because of worsening heart failure was less frequent in the nitroprusside than in the dobutamine subgroup [29/51 (57%) vs. 19/22 (86%) P<0.02]. The overall mortality was 28% (20/70) in the nitroprusside group and 58% (25/43) in the dobutamine group (odds ratio 0.33 CI 0.16 to 0.73 P<0.006). In the group treated with nitroprusside, heart transplantation in status one was performed in 16/33 patients (48%), while in the dobutamine group this was done in 11/14 patients (78%) (odds ratio 0.25 CI 0.06-1.02 P<0.06). There was a significant reduction in the combined end-point of mortality/heart transplantation in status one in patients treated with nitroprusside compared to those treated with dobutamine (36/70 (51%) vs. 36/43 (84%) - (odds ratio 0.34 CI 0.14-0.80 P<0.01). The incidence of adverse events in the patients treated with nitroprusside was similar to that in those treated with dobutamine (20% vs. 17% P=ns). CONCLUSIONS: for patients awaiting heart transplantation chronic intermittent nitroprusside infusions are more effective and safer than dobutamine in relieving symptoms, facilitating unloading therapy management and improving survival. Whether chronic intermittent infusion of nitroprusside could represent a feasible medical strategy in out-patients with severe heart failure remains to be investigated.

Cardiac Output, Low↗
PubMed2001

Six-minute walking performance in patients with moderate-to-severe heart failure; is it a useful indicator in clinical practice?

AIMS: The 6-min walk test has been incorporated into studies on the efficacy of new therapies and into prognostic stratification for chronic heart failure patients. Firm conclusions on the usefulness of the test in clinical practice are still lacking. The aim of this study was to investigate (1) the correlation between walk test performance and standard indices of cardiac function and exercise capacity, and (2) the prognostic value of the walk test with respect to peak VO2 and NYHA class. METHODS AND RESULTS: Three hundred and fifteen chronic heart failure patients (age: 53+/-9 years, NYHA class: II (182), III (133)) underwent a functional evaluation and a 6-min walk test. Of these, 270 were followed-up for a minimum of 6 months (mean 387+/-177 days). Walked distance was 396+/-92 m. There was no significant correlation between distance walked and central haemodynamic data. Functional capacity, as measured by ergometry, correlated moderately with distance walked (duration: r=0.48, peak VO2: r=0.59, anaerobic threshold: r=0.54; all P<0.001). During follow-up, 46 patients died from cardiovascular causes and 12 were urgently transplanted. Either of these events were considered end points of the study. Survival analysis was performed from a continuous walk test and peak VO2 measurements or after categorization of (a) quartile segmentation, (b) cut-off points from the literature and (c) thresholds from receiver operating characteristic curves. At univariate survival analysis (Cox regression), the association of the walk test with survival was of significance (P=0.03, continuous variable), or borderline significance (0.05< or =P< or =0.1, after categorization). Peak VO2 was always significant, independent of the scale used (0.005< or =P< or =0.03). The strongest association was found for NYHA class (P<0.001), which showed the highest sensitivity and specificity for the prediction of the event (0.64 and 0.65, respectively). When walk test performance, continuous or categorized, was entered into a multivariate model with NYHA class or peak VO2, it lost any significant association with survival (P>0.76 in all models with NYHA class and P>0.27 in all models with peak VO2). CONCLUSION: In moderate-to-severe chronic heart failure patients, the 6-min walk test is not related to cardiac function and only moderately related to exercise capacity. Walking performance does not provide prognostic information which can complement or substitute for that provided by peak VO2 or NYHA class. Hence the test is of limited usefulness as a decisional indicator in clinical practice.

Adult↗
PubMed2001

[Rehabilitation day-hospital of the heart failure unit: structure and functions].

Chronic heart failure has emerged as an important public health problem. The consequent increase in the sanitary services has induced an increased consumption of financial resources and conditioned the need to investigate new sanitary models that guarantee, by integrating the inpatient and outpatient health care delivery, the continuity of health assistance. Cardiac rehabilitation in the context of a day-hospital Heart Failure Unit allows for the organization of a rehabilitation program including various health approaches aimed at guaranteeing a multidisciplinary program and the relief continuity. This article describes the experience developed in the Heart Failure Unit of Montescano.

Algorithms↗
PubMed2000

Nonselective beta-adrenergic blocking agent, carvedilol, improves arterial baroflex gain and heart rate variability in patients with stable chronic heart failure.

OBJECTIVES: The purpose of this study was to investigate in a case-controlled study whether carvedilol increased baroreflex sensitivity and heart rate variability (HRV). BACKGROUND: In chronic heart failure (CHF), beta-adrenergic blockade improves symptoms and ventricular function and may favorably affect prognosis. Although beta-blockade therapy is supposed to decrease myocardial adrenergic activity, data on restoration of autonomic balance to the heart and, particularly, on vagal reflexes are limited. METHODS: Nineteen consecutive patients with moderate, stable CHF (age 54 +/- 7 years, New York Heart Association [NYHA] class II to III, left ventricular ejection fraction [LVEF] 24 +/- 6%), treated with optimized conventional medical therapy, received carvedilol treatment. Controls with CHF were selected from our database on the basis of the following matching criteria: age +/- 3 years, same NYHA class, LVEF +/- 3%, pulmonary wedge pressure +/- 3 mm Hg, peak volume of oxygen +/- 3 ml/kg/min, same therapy. All patients underwent analysis of baroreflex sensitivity (phenylephrine method) and of HRV (24-h Holter recording) at baseline and after six months. RESULTS: Beta-blockade therapy was associated with a significant improvement in symptoms (NYHA class 2.1 +/- 0.4 vs. 1.8 +/- 0.5, p < 0.01), systolic and diastolic function (LVEF 23 +/- 7 vs. 28 +/- 9%, p < 0.01; pulmonary wedge pressure 17 +/- 8 vs. 14 +/- 7 mm Hg, p < 0.05) and mitral regurgitation area (7.0 +/- 5.1 vs. 3.6 +/- 3.0 cm2, p < 0.01). No significant differences were observed in either clinical or hemodynamic indexes in control patients. Phenylephrine method increased significantly after carvedilol (from 3.7 +/- 3.4 to 7.1 +/- 4.9 ms/mm Hg, p < 0.01) as well as RR interval (from 791 +/- 113 to 894 +/- 110 ms, p < 0.001), 24-h standard deviation of normal RR interval and root mean square of successive differences (from 56 +/- 17 to 80 +/- 28 ms and from 12 +/- 7 to 18 +/- 9 ms, all p < 0.05), while all parameters remained unmodified in controls. During a mean follow-up of 19 +/- 8 months a reduced number of cardiac events (death plus heart transplantation, 58% vs. 31%) occurred in those patients receiving beta-blockade. CONCLUSIONS: Besides the well-known effects on ventricular function, treatment with carvedilol in CHF restores both autonomic balance and the ability to increase reflex vagal activity. This protective mechanism may contribute to the beneficial effect of beta-blockade treatment on prognosis in CHF.

Adrenergic beta-Antagonists↗
PubMed2000

Beta-blockade therapy in chronic heart failure: diastolic function and mitral regurgitation improvement by carvedilol.

BACKGROUND: In patients with chronic heart failure, the use of carvedilol therapy induces clinical and hemodynamic improvement. However, although the benefits of this beta-blocker have been established in patients with chronic heart failure, the mechanisms underlying them and the changes in left ventricular systolic function, diastolic function, and mitral regurgitation during long-term therapy remain unclear. OBJECTIVE: To identify the clinical and functional effects of carvedilol, focusing on diastolic function and mitral regurgitation variations. METHODS: Forty-five consecutive patients with chronic heart failure (ejection fraction 24% +/- 7%), 17 with dilated ischemic and 28 with nonischemic cardiomyopathy, were treated with carvedilol (mean dose 44 +/- 30 mg) and matched for clinical (New York Heart Association functional class and heart failure duration) and hemodynamic (cardiac index and pulmonary wedge pressure) characteristics to a control group. Clinical and echocardiographic variables were measured in the 2 groups at baseline and after 6 months and the results compared. RESULTS: After 6 months of treatment with carvedilol, left ventricular ejection fraction had increased from 24% +/- 7% to 29% +/- 9% (P <.0001); this change was caused by a reduction in end-systolic volume index (106 +/- 41 vs 93 +/- 37 mL/m(2); P <. 0001). Deceleration time of early diastolic filling increased (134 +/- 74 vs 196 +/- 63 ms; P <.0001). Seventeen of the 27 patients with demonstrated improvement of left ventricular diastolic filling moved from having a restrictive filling pattern to having a normal or pseudonormal left ventricular filling pattern. In the control group, no significant changes in deceleration time of early diastolic filling were found (139 +/- 74 vs 132 +/- 45 ms; P = not significant). The effective regurgitant orifice area decreased significantly in the carvedilol group but not in the control group. These changes were associated with a significant reduction of the mitral regurgitant stroke volume in the carvedilol group (50 +/- 25 vs 16 +/- 13 mL; P <.0001) but not in the control group (57 +/- 29 vs 47 +/- 24 mL; P = not significant). These changes of mitral regurgitation were closely associated with significant improvement of forward aortic stroke volume (r = -.57, P <.0001). These findings were not observed in patients in the control group. CONCLUSIONS: The results of this study show that long-term carvedilol therapy in patients with chronic heart failure was able to prevent or partially reverse progressive left ventricular dilatation. The effects on left ventricular remodeling were associated with a concomitant recovery of diastolic reserve and a decrease of mitral regurgitation, which have been demonstrated to be powerful prognostic predictors in such patients. Overall these findings provide important insights into the pathophysiologic mechanisms by which carvedilol improves the clinical course of patients with chronic heart failure.

Adrenergic beta-Antagonists↗
PubMed2000

Invasive and non-invasive determinants of pulmonary hypertension in patients with chronic heart failure.

BACKGROUND: In patients with chronic heart failure, pulmonary hypertension is an important predictive marker of adverse outcome. Its invasive and non-invasive determinants have not been evaluated. OBJECTIVE: This study was performed to evaluate hemodynamic determinants of pulmonary hypertension in chronic heart failure and to compare the predictive value of Doppler indices with that of invasively measured hemodynamic indices. METHODS: Right heart catheterization and transthoracic echo-Doppler were simultaneously performed in 259 consecutive patients with chronic heart failure (ejection fraction 24% +/- 7%) who were in sinus rhythm and receiving optimized medical therapy. Systolic pulmonary artery pressure (sPAP), cardiac index, transpulmonary gradient pressure, and pulmonary wedge pressure (PWP) were measured invasively. Left atrial and ventricular systolic and diastolic volumes, the ratio of maximal early to late diastolic filling velocities (E/A ratio), deceleration time (DT) and atrial filling fraction (AFF) of transmitral flow, systolic fraction of forward pulmonary venous flow (SFpvf), and mitral regurgitation were quantified by echo-Doppler. RESULTS: Patients with pulmonary hypertension had greater left atrial systolic and diastolic dysfunction, more left ventricular diastolic abnormalities, and greater hemodynamic impairment. The correlations between systolic left ventricular indices, mitral regurgitation, and sPAP were generally poor. Among invasive and non-invasive measurements, PWP (r = 0.89, p < 0.0001) and SFpvf (r = -0.68, p < 0.0001) showed the strongest correlation with sPAP. When we compared all patients with those without mitral regurgitation, the correlations between E/A ratio (r = 0.56 vs r = 0. 74, p < 0.002), SFpvf (r = -0.68 vs r = -0.84, p < 0.03), and systolic pulmonary artery pressure were significantly stronger. Multivariate analysis revealed that PWP was the strongest invasive independent predictor of systolic pulmonary artery pressure in patients with (R(2) = 0.87, p < 0.0001) and without (R(2) = 0.90, p < 0.0001) mitral regurgitation. A PWP > or= 18 mm Hg (odds ratio [95% CL], 142 (41-570) was strongly associated with systolic pulmonary hypertension. Among non-invasive variables DT, SFpvf, and AFF were identified as independent predictors of sPAP in patients with (R(2) = 0.56, p < 0.0001) and without (R(2) = 0.78, p < 0.0001) mitral regurgitation. A DT < 130 (odds ratio [95% CL], 3.5 (1.3-8.5), SFfvp < 40% (odds ratio [95% CL], 333 (41-1,007), and AFF < 30% (odds ratio [95% CL], 2 (1.3-7) most strongly predicted systolic pulmonary hypertension. CONCLUSIONS: The results of this study indicate that in patients with chronic heart failure, venous pulmonary congestion is an important determinant of systolic pulmonary artery hypertension. Hemodynamic and Doppler determinants showed similar predictive power in identifying systolic pulmonary artery hypertension.

Blood Flow Velocity↗
PubMed2000

Does in-patient ECG monitoring have an impact on medical care in chronic heart failure patients?

BACKGROUND: Heart failure patients' management in non-intensive care units might be improved by telemetry monitoring. However, telemetry adds the cost and evidence of this effectiveness is not available. AIM: To evaluate the utility of the ECG monitoring in chronic heart failure patients admitted to a non-intensive care unit. METHODS: A prospective analysis of the utility of telemetry in 711 patients admitted to a Heart Failure Unit from March 1996 to September 1997. RESULTS: One hundred and ninety-nine patients underwent telemetry; 108 telemetry findings were recorded, in 35% of NYHA class II, in 46% in NYHA class III-IV and 43% in unstable patients. Reasons for telemetry were: known arrhythmia (n=82), electrolytes disturbances (n=20), atrial fibrillation (n=12), symptoms (n=48), i.v. dobutamine (n=13), drugs control (n=16), devices control (n=8). Crossing reasons for telemetry and detected events we had, respectively, 63, 11, 2, 17, 5, 6, and 0 telemetry findings. Treatment was guided by telemetry results in only 33 cases (respectively in 18, 0, 4, 5, 5, 1, and 0 cases). Physicians perceived telemetry as unhelpful in 30% of cases; as helpful in 70%. The percentage of inutility, usefulness with and without related medical intervention were similar between stable and unstable patients (30, 18, 51% and 31, 15, 54%, respectively). CONCLUSION: In a heart failure unit ECG monitoring is mostly used in severe and unstable patients. However, medical decisions are rarely guided by the telemetry findings. The usefulness of telemetry might be underestimated because one of the uncounted results might be the avoidance of inappropriate intervention.

Anti-Arrhythmia Agents↗
PubMed2000

Dobutamine stress echocardiography and thallium-201 SPECT for detecting ischaemic dilated cardiomyopathy in patients with heart failure.

AIMS: A diagnosis of ischaemic aetiology of a dilated cardiomyopathy has important therapeutic and prognostic implications. In such patients, abnormal ECG and atypical symptoms limit the usefulness of standard ECG-ergometry in detecting myocardial ischaemia. To assess the values of high-dose dobutamine stress echocardiography and of Thallium-201 SPECT (exercise-reinjection-rest protocol) in differentiating between ischaemic and non-ischaemic dilated cardiomyopathy, 37 patients with suspected myocardial ischemia, low ventricular ejection fraction (23 +/- 5%) and heart failure were studied. METHODS AND RESULTS: Coronary artery disease was defined as >50% coronary stenosis in at least one coronary artery. By dobutamine stress echocardiography, ischaemic dilated cardiomyopathy was considered present when either an ischaemic response (biphasic response or direct deterioration) or a scar (fixed dyssynergy) was documented in at least two segments. By Thallium-201 SPECT, severe perfusion defects, either reversible (ischaemia) or fixed (scar), in at least two segments were considered markers of ischaemic dilated cardiomyopathy. Twenty-three patients had ischaemic dilated cardiomyopathy, while 14 had normal coronary arteries. The presence of myocardial ischaemia and/or scar by dobutamine stress echocardiography identified patients with ischaemic dilated cardiomyopathy with a sensitivity of 100% and a specificity of 86%. The sensitivity of Thallium-201 SPECT was 92%, its specificity was 69%. Three of the four false positive results occurred in patients with left bundle branch block. Thirty-two patients were concordantly classified by the two techniques (agreement=86%, k=0.73). CONCLUSION: Both dobutamine stress echocardiography and Thallium-201 SPECT are sensitive techniques for detecting the ischaemic aetiology of dilated cardiomyopathy. The specificity is lower, particularly by SPECT, when left ventricular branch block is present.

Cardiomyopathy, Dilated↗
PubMed2000

[The use of beta blockers in heart failure: clinical studies].

Although inhibitors of angiotensin-converting enzyme (ACE) have improved the treatment of chronic heart failure (CHF), mortality related to this disorder remains unacceptably high. Results from studies started more than 25 years ago in Sweden suggested that long-term therapy with beta-blockers could improve hemodynamics and increase survival in patients with CHF; this hypothesis is confirmed by the results of six double-blind, randomized, placebo-controlled trials (MDC, CIBIS, ANZ, US Carvedilol Study, CIBIS II and MERIT-HF) who enrolled about 9000 patients with CHF. In these trials beta-blockers (metoprolol, bisoprolol or carvedilol) where added to the stable usual treatment of each patient (ACE-inhibitors, diuretics, digoxin). Baseline characteristics of patients enrolled into the beta-blocker or placebo arm were similar in all these studies. Specifically the mean patient's age was < 60 years, with a mean left ventricular ejection fraction of 25-26%, 30% of enrolled patients were in NYHA functional class II and 60% in NYHA functional class III, CHF was due to ischemic heart disease in about 60% of patients. The average follow-up for all the trials was 14.5 +/- 5.6 months. On the whole in patients on beta-blocker treatment there is a 33.3% reduction in total mortality rate, a 34.2% reduction in cardiac death rate, a 37.7% reduction in sudden death rate, and a 41.7% reduction in worsening heart failure mortality rate. Moreover, in beta-blocker patients there is a 31.7% reduction in all-cause readmissions to hospital and a 26% reduction in the combined end point (total mortality and hospital readmission). Beta-blockers improved ventricular function but there was no significant improvement in functional capacity. In conclusion, the results of the six trials considered indicate that there is convincing evidence supporting a favorable effect of beta-blockade on the risk of death and readmission to hospital in patients with dilated cardiomyopathy with systolic dysfunction, aged < 70 years, in NYHA functional class II-III. The effects of these drugs in CHF patients a) with normal left ventricular ejection fraction, b) aged > 65-70 years, c) in NYHA functional class IV, and d) with comorbilities such as obstructive lung disease, diabetes, peripheral arterial diseases, require additional study.

Adrenergic beta-Antagonists↗
PubMed2000

Non-invasive estimation of right atrial pressure by combined Doppler echocardiographic measurements of the inferior vena cava in patients with congestive heart failure.

BACKGROUND: In patients with congestive heart failure, evaluation of right atrial pressure (RAP) provides useful therapeutic, functional and prognostic information. The aim of this study was to investigate whether a combination of inferior vena cava variables measured by Doppler echocardiography could provide a reliable non-invasive estimate of RAP. METHODS: One hundred consecutive patients with severe congestive heart failure (ejection fraction 24 +/- 6%) due to dilated cardiomyopathy were evaluated by simultaneous Doppler echocardiography and hemodynamic studies. RAP, end-expiratory (IVCDmax) and end-inspiratory (IVCDmin) diameters of the inferior vena cava, its collapse index [CIIVC = (IVCDmax - IVCDmin/IVCDmax)*100] and systolic fraction of forward inferior vena cava flow were measured and correlated by both single and multilinear regression analysis. The accuracy of generated equations was tested in a separate testing group of 61 patients at baseline and a subgroup of 20 patients after loading manipulations, prospectively studied in the same methodological setting. RESULTS: All Doppler echocardiographic variables were correlated with RAP. The IVCDmin showed the strongest correlation (r = 0.84, p < 0.0001). Stepwise regression analysis identified two equations for predicting RAP: 1) RAP = (6.4*IVCDmin + 0.04*CIIVC - 2) (r = 0.82, p < 0.0001, SEE 1.7 mmHg) in all patients, and 2) RAP = (4.9*IVCDmin + 0.01*CIIVC - 0.2) (r = 0.92, p < 0.0001, SEE 1.2 mmHg) in patients without tricuspid regurgitation. In the testing group estimated and measured RAP was strongly correlated at baseline (r = 0.95, SEE 1.3 mmHg, p < 0.00001) and after loading manipulations (r = 0.96, SEE 1.2 mmHg, p < 0.00001). The agreement between invasive and non-invasive measurements of RAP in identifying patients with normal (< or = 5 mmHg), moderately increased (< 5 RAP < 10 mmHg) and markedly increased (> or = 10 mmHg) RAP was 81 or 93% using equation 1 or 2, respectively. CONCLUSIONS: Our results provide evidence that in patients with congestive heart failure indices derived from Doppler measurements of the inferior vena cava can be used to produce an accurate, strong and non-invasive estimate of RAP. This is another example of the usefulness of Doppler echocardiography in evaluating hemodynamic profile and its changes in patients with congestive heart failure. Echocardiographic assessment of the inferior vena cava should be included in the evaluation of patients with congestive heart failure.

Analysis of Variance↗
PubMed1999

Association between hemodynamic impairment and Cheyne-Stokes respiration and periodic breathing in chronic stable congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

Irregular breathing occurs frequently in patients with congestive heart failure (CHF) both during daytime and nighttime. Many factors are involved in the genesis of these breathing abnormalities, but the role of the hemodynamic impairment remains controversial. This study investigated the relation between worsening ventricular function and the frequency of respiratory disorders in patients with mild to severe CHF. One hundred fifty patients with CHF (mean age 53 +/- 8 years, left ventricular (LV) ejection fraction 26 +/- 7, in New York Heart Association [NYHA] classes II to IV, and who underwent stable therapy for > or =2 weeks) were studied. Analysis of instantaneous lung volume signal and arterial oxygen saturation during awake daytime revealed a normal respiratory pattern in 63 patients, whereas 87 had a persistent alteration of breathing, with a typical Cheyne-Stokes respiration (CSR) in 42 and periodic breathing (PB [oscillation of tidal volumes without apnea]) in 45 patients. Patients with PB and CSR showed a more pronounced hemodynamic impairment with a significantly reduced cardiac index, an increased pulmonary arterial wedge pressure, and a longer lung-to-ear circulation time (LECT) compared with patients with normal respiratory patterns. In a logistic regression model that included all of the variables significantly associated with breathing disorders, cardiac index and LECT emerged as the major determinants of CSR. In those patients with LECT > or =30 seconds (upper quartile) and cardiac index < or =1.9 L/min/m2 (lower quartiles), the incidence of CSR was significantly higher (69%) than in patients with lower LECT and higher cardiac index (14%, p <0.001). In conclusion, abnormalities of breathing activity during daytime are significantly associated with a prolonged circulation time and a more severe impairment of systolic and diastolic LV indexes.

Analysis of Variance↗