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PubMed1993

Approximate entropy of heart rate as a correlate of postoperative ventricular dysfunction.

BACKGROUND: Instantaneous changes in the heart rate, i.e., heart rate variation, traditionally have been quantified by the standard deviation of a series of intervals between successive heart beats. Approximate entropy provides another measure of variability by calculating the logarithmic likelihood that patterns that are similar remain similar on the next incremental comparisons. Approximate entropy is a nonnegative number that will distinguish data sets by their amount of regularity, with larger numbers indicating more randomness. We hypothesized that a decrease in the approximate entropy of heart rate would be associated with postoperative ventricular dysfunction (e.g., myocardial infarction, unstable angina, congestive heart failure, prolonged inotropic support). METHODS: Twenty-three high-risk noncardiac patients were continuously monitored by ambulatory electrocardiographic recorders from the evening before surgery up to 80 h during the postoperative period: 9 demonstrated postoperative ventricular dysfunction, and 14 had an uncomplicated postoperative course. Hourly approximate entropy average values were calculated. RESULTS: Approximate entropy was high (> 0.7) in all but two patients preoperatively. Postoperative approximate entropy <0.55 had a sensitivity of 88% and a specificity of 71% for being associated with postoperative ventricular dysfunction; preoperative approximate entropy values were not significantly different between the two groups. CONCLUSIONS: These results suggest that changes in approximate entropy can distinguish between patients who sustained poor outcome and those who had an uncomplicated course.

Aged↗
PubMed1998

Presence of angiographic coronary collaterals predicts myocardial recovery after coronary bypass surgery in patients with severe left ventricular dysfunction.

BACKGROUND: Patients with coronary artery disease and left ventricular dysfunction (LVD) may have areas of hibernating myocardium that improve functionally after revascularization. Coronary collateral circulation may sustain ischemic, dysfunctional myocardium and favor myocardial recovery after revascularization. We evaluated the effect of angiographic coronary collaterals on myocardial functional recovery after coronary bypass graft (CABG) surgery in a group of patients with severe LVD. METHODS AND RESULTS: Forty-one patients with multivessel coronary artery disease and advanced LVD (left ventricular ejection fraction [LVEF] 25 +/- 5%) undergoing CABG were identified from a prospective database. Preoperative coronary angiograms were evaluated for collaterals, which were graded according to Rentrop's classification (0 to 3), and a collateral index was calculated (collateral sum divided by 3). Preoperative and postoperative radionuclide ventriculograms provided global LVEF and regional ejection fractions. Of 123 regions evaluated, 120 were dysfunctional at baseline. Virtually all (122 of 123) regions were subtended by an artery with > or = 70% stenosis that was bypassed. Thirty-eight (81%) of 47 dysfunctional regions with grade 2 or 3 collaterals improved regional ejection fraction after surgery versus 38 (52%) of 73 dysfunctional regions with grade 0 or 1 collaterals (P = 0.0018). Global LVEF was 34 +/- 10% after surgery (P < 0.001 versus before surgery). Among patients with a global LVEF increase > or = 10%, collateral index was 1.81 versus 0.83 in those with an LVEF increase < 10% (P = 0.005). CONCLUSIONS: In this population of patients with coronary artery disease with severe LVD, the presence of angiographic grade 2 or 3 collaterals predicted recovery of regional and global myocardial function after CABG.

Aged↗
PubMed2002

Efficacy of angiotensin-converting enzyme inhibition in reducing progression from asymptomatic left ventricular dysfunction to symptomatic heart failure in black and white patients.

OBJECTIVES: This study was undertaken to determine whether enalapril had comparable efficacy in black and white patients with asymptomatic left ventricular dysfunction (ALVD) in preventing the development of symptomatic heart failure (HF). BACKGROUND: Recent studies have suggested that black patients with HF due to systolic dysfunction may derive less benefit than white patients with HF when treated with the same medication. METHODS: This is a post hoc analysis of the 4,054 black and white participants of the Studies of Left Ventricular Dysfunction Prevention Trial. RESULTS: Randomization to enalapril was associated with a comparable reduction in the relative risk of the development of symptomatic HF in black (relative risk [RR] 0.67, 95% confidence interval [CI] 0.49, 0.92, p = 0.01) and white patients (RR 0.61, 95% CI 0.53, 0.70, p < 0.001). Treatment with enalapril was also associated with a comparable reduction in the risk of the development of HF requiring medical therapy and the composite end point of death or development of HF in black and white patients. Black as compared with white patients with ALVD were at increased risk of the development of symptomatic HF (RR 1.81, 95% CI 1.51, 2.17, p < 0.001) despite adjustment for available measures of disease severity. CONCLUSIONS: Despite the increased absolute risk in black patients compared with white patients for the progression of ALVD, enalapril was equally efficacious in reducing the risk of progression of ALVD in these two ethnic groups.

Black or African American↗
PubMed1996

ACE inhibitor use in elderly patients with systolic left ventricular dysfunction: problems and opportunities.

The ACE inhibitors have been found effective in reducing the morbidity and mortality of both post-infarction patients and those with chronic systolic left ventricular dysfunction. However, their use is limited--particularly in elderly patients because of poor tolerance partly due to bradykinin-induced side-effects such as renal dysfunction, first-dose hypotension, and cough. Thus, the introduction of the angiotensin II type I receptor antagonists--that block the effects of angiotensin II without increasing bradykinin concentration--may be particularly important in the treatment of elderly patients. The role of the angiotensin II type I receptor antagonists in patients with systolic left ventricular dysfunction is currently being explored in direct comparison with and in conjunction with the ACE inhibitors. Furthermore, important questions about the most effective dose of ACE inhibitor and ACE inhibitor use in conjunction with aspirin and the NSAIDs still have to be answered. Thus, although we have learnt much about the role of ACE inhibitors in heart failure treatment, we are still at an early stage in the application of this knowledge, particularly in elderly patients.

Aged↗
PubMed1988

The relation between supraventricular tachyarrhythmias and left ventricular dysfunction after acute myocardial infarction.

The clinical characteristics of supraventricular tachyarrhythmias (SVTA) and their relation to left ventricular dysfunction were assessed in 208 consecutive patients with recent myocardial infarction. Arrhythmias were quantified on hospital discharge by 24 hour electrocardiographic recording. All the variables were evaluated between the second and the fourth week after infarction. SVTA occurred in 113 (54%) patients: Supraventricular premature beats (SVPB) in 49 (24%), frequent or repetitive SVPB in 37 (18%), atrial or junctional tachycardia in 23 (11%), atrial flutter or fibrillation in 4 (2%). Most of these arrhythmias occurred in the absence of symptoms, and the most complex forms were always selflimiting. No relation was found among the presence of different forms of SVTA and sex, coronary risk factors, previous history of ischemic heart disease, type or site of acute myocardial infarction, NYHA functional class. Age, left atrial dimension (LAD), cardio-thoracic ratio (CTR) and left ventricular ejection fraction (LVEF) at rest differed significantly among three groups of patients: those without SVTA, those with SVPB less than 100 per hour and those with frequent-repetitive SVPB or atrial-junctional tachycardia. The more SVTA complexity, the worse LAD, CTR, LVEF and the higher the age. Multivariate discriminant analysis showed that CTR was directly and LVEF inversely related to the occurrence of SVPB less than 100 per hour, while the presence of frequent-repetitive SVPB or supraventricular tachycardia was closely related to increasing age, LAD, CTR and decreasing LVEF. Patients with atrial fibrillation always showed the worst values of LAD, CTR, LVEF and age. The results of the present study show that different types of SVTA occurring at discharge from hospital after myocardial infarction are clinically benign, but always suggestive of different degrees of left ventricular dysfunction.

Adult↗
PubMed2004

The acute administration of trimetazidine modified myocardial perfusion and left ventricular function in 31 patients with ischaemic ventricular dysfunction.

UNLABELLED: Trimetazidine (TMZ) increases the mithocondrial oxidative metabolism and improves Tc-99m sestamibi uptake in myocardial single photon emission tomography (SPECT). The aim of this study was to evaluate whether the acute administration of TMZ improved myocardial perfusion and modified left ventricular ejection fraction (LVEF) in ischaemic left ventricular impairment. METHODS: Thirty-one patients (23 males, age 66 years) with prior myocardial infarction (>6 months) and echocardiographic LVEF < or = 45% underwent coronary angiography, rest basal myocardial SPECT (after 3-day placebo administration) and rest TMZ myocardial SPECT [after 3-day TMZ administration (60mg/die)]. The left ventricle was analysed in 16 segments. The summed placebo score (SPS) and the summed TMZ score (STS) were calculated with a 5-point scale (from 0 = normal uptake to 4 = absent uptake) by two blinded operators. The GATED Tc-99m SPECT was always provided. RESULTS: After TMZ administration GATED LVEF improved from 26.5+/-9.7% to 29.1+/-11.3% (p = 0.04) and left ventricular end-systolic volume (LVESV) was reduced from 90.2+/-40.7 to 85.6+/-39.2 ml/mq (p = 0.006). Similarly the addition of TMZ to myocardial SPECT significantly reduced the STS compared to SPS (21.5+/-11 vs. 26.6+/-10.5 p = 0.0001). Eleven patients (35.5%) had an echocardiographic LVEF < or = 30%; in these patients who had severe ventricular dysfunction, GATED LVEF and LVESV did not change after TMZ (20.2+/-5.7% vs. 21+/-6.9% p =0.6; 116.7+/-35.3 ml vs. 112.6+/-32.3 ml p = 0.08, respectively). CONCLUSION: In comparison with placebo, the addition of TMZ to myocardial Tc-99m tetrofosmin SPECT improved myocardial perfusion and LVEF, reducing LVESV. These effects were lost in patients with more severe ventricular dysfunction.

Adult↗
PubMed1998

Safety and utility of atropine addition during dobutamine stress echocardiography for the assessment of viable myocardium in patients with severe left ventricular dysfunction.

OBJECTIVE: To assess the feasibility safety and side effects of the addition of atropine to dobutamine stress echocardiography for the detection of viable myocardium in patients with left ventricular dysfunction (ejection fraction < or = 35%) prior to coronary revascularization. BACKGROUND: The assessment of viable and/or ischaemic myocardium has high prognostic value as regards improvement of function and survival after coronary revascularization. The addition of atropine to dobutamine during echocardiographic testing for the presence of viable myocardium is not common practice. Consequently, no data exist on the safety and additional diagnostic value of this practice. METHODS: Two hundred patients with left ventricular ejection fraction < or = 35% were studied. RESULTS: Test end-points were: target heart rate in 164 (82%) of the patients, severe angina in 18 (9%), maximum dobutamine-atropine dose in six (3%), severe ST segment changes in five (2%), cardiac arrhythmias in four (2%), and hypotension in three (1%). Viability could be assessed echocardiogaphically in 105/200 (53%) from a biphasic response (improvement of wall motion with low dose dobutamine and worsening with high dose), in 93 from ischaemia and in 12 from sustained or late improvements. In 36/105 (34%) patients, ischaemic myocardium could only be assessed after the addition of atropine. Cardiac arrhythmias occurred in 11/200 (6%) and hypotension (decrease of systolic blood pressure >30 mmHg) in 21/200 (11%). Neither the use of atropine nor the induction of ischaemia were associated with an increased incidence of cardiac arrhythmias or hypotension. CONCLUSIONS: In a large group of patients with severe left ventricular dysfunction, dobutamine stress echocardiography is feasible and safe in 186/200 (93%); the addition of atropine was necessary in 34% to assess myocardial viability. Hypotension and cardiac arrhythmias were the most frequent side effects, but were not related to the induction of ischaemia or addition of atropine.

Adult↗
PubMed1992

Reversibility of left ventricular dysfunction after successful catheter ablation of supraventricular reentrant tachycardia.

Fourteen patients (mean age, 48 +/- 19 years) with left ventricular dysfunction in the absence of underlying organic heart disease underwent catheter ablation (nine with direct-current energy and five with radiofrequency energy) to treat drug-refractory, symptomatic supraventricular reentrant tachycardia (mean duration of tachycardia, 22 +/- 17 years). Clinical tachycardias were accessory pathway-mediated tachyarrhythmia (12 patients) and atrioventricular nodal reentrant tachycardia (two patients). Changes of ventricular function after successful ablation, as assessed by radionuclide ventriculography and echocardiography, showed a decrease in left ventricular end-systolic dimension (39 +/- 6 mm to 34 +/- 6 mm; 32 +/- 6 mm; p < 0.05) and in left ventricular end-diastolic dimension (55 +/- 5 mm to 52 +/- 3 mm; 51 +/- 3 mm; p < 0.05) in the early (2 to 3 months) and late (6 to 8 months) follow-up periods, increase of nuclear ejection fraction (38% +/- 8% to 46% +/- 7%; p < 0.05) and fractional shortening (28% +/- 7% to 36% +/- 8%; p < 0.05) in the late follow-up period. Increase of fractional shortening was mainly due to decrease in the end-systolic dimension. These findings suggest that prolonged attacks of uncontrolled supraventricular tachycardia may result in left ventricular dysfunction, which is reversible after successful catheter ablation of the arrhythmias.

Adult↗
PubMed1985

Acute hemodynamic effects of propranolol, glycerylnitrate, and exercise in coronary patients with left ventricular dysfunction.

Some adverse effects of beta-blockers in heart failure are counteracted by glycerylnitrate. However, the hemodynamics in this condition after giving both drugs are not well known. We examined the drug combination in exercising coronary patients with left ventricular dysfunction. Elevated left ventricular end-diastolic pressure was a measure of dysfunction. A right-heart catheterization with three successive exercise stress tests was done in 40 patients. At repeated exercise without drugs a "warming up" phenomenon was observed, consisting of small but statistically significant reductions in pulmonary capillary wedge pressure, and heart rate. At exercise propranolol reduced heart rate, cardiac output, systemic blood pressure, left ventricular work, and increased arteriovenous oxygen difference. Glycerylnitrate reduced pulmonary capillary wedge pressure at exercise, but, contrary to the findings at rest, it did not increase heart rate or reduce cardiac output. The drug combination resulted in hemodynamics that were similar to those after propranolol alone, except for a lower pulmonary capillary wedge pressure. The drug combination allowed the patients to exercise with the benefits of the beta-blocker, but at a lower ventricular filling pressure. Thus, the potential hazard of giving beta-blockers to patients with left ventricular dysfunction may be reduced by adding glycerylnitrate.

Angina Pectoris↗
PubMed1999

Dobutamine-induced hypotension is an independent predictor for mortality in patients with left ventricular dysfunction following myocardial infarction.

Dobutamine echocardiography was performed on 297 patients after acute myocardial infarction to assess the prognostic value of dobutamine-induced hypotension in patients with left ventricular dysfunction. Patients were divided into two groups according to ejection fraction (group I, ejection fraction <0.45, n = 123; group II, ejection fraction > or =0.45, n = 174) and were followed for 20+/-8 months. Hypotension was defined as a decrease in systolic blood pressure > or =20 mm Hg, compared with baseline values. The incidence of hypotension was similar in groups I and II (23.6% vs. 18.4%, P = 0.28), and the hypotension was not related to positive dobutamine echocardiography. Univariate analysis showed that the development of hypotension was associated with a higher incidence of cardiac death in group I but not in group II. Multivariate analysis showed that dobutamine-induced hypotension was an independent predictor only for cardiac death in group I and was not related to any other cardiac events in either group. In conclusion, the development of hypotension during dobutamine stress can identify a subgroup with poor ventricular functional reserve and at high risk for cardiac death among patients complicated with left ventricular dysfunction.

Adrenergic beta-Agonists↗
PubMed1990

Right ventricular dysfunction and dilatation, similar to left ventricular changes, characterize the cardiac depression of septic shock in humans.

Septic shock in humans is usually characterized by a high cardiac output, a low systemic vascular resistance, reversible depression of left ventricular ejection fraction, and transient left ventricular dilatation. The relationship of left ventricular to right ventricular function in septic shock is poorly understood. To evaluate right ventricular vs left ventricular performance and to evaluate the relation of biventricular performance to survival, we performed serial hemodynamic and radionuclide angiographic studies in 39 patients with septic shock. Right ventricular ejection fraction was calculated using the two regions of interest method. There were 22 survivors and 17 nonsurvivors. Comparing initial with final (after recovery for survivors; within 24 hours of death for nonsurvivors) studies, each survivor's cardiovascular performance returned toward normal, with significant increases in mean arterial pressure, left and right ventricular ejection fraction, and right ventricular stroke work index. Their profiles also demonstrated significant decreases in central venous pressure, pulmonary artery wedge pressure, pulmonary artery mean pressure, and left and right ventricular end-diastolic volume indices. From initial to final study in the nonsurvivors, there was a statistically significant increase in heart rate but no change in any other cardiovascular parameter, indicating a persistence of the initial cardiovascular dysfunction until death. Comparing serial studies, the pattern of change in right vs left ventricular function was very similar (same direction in 82 percent of patients). Thus, myocardial depression in human septic shock affects both ventricles simultaneously with a similar pattern of dysfunction.

Adolescent↗
PubMed2007

Persistent atrial fibrillation is associated with appropriate shocks and heart failure in patients with left ventricular dysfunction treated with an implantable cardioverter defibrillator.

AIM: The objective of this study was to investigate whether persistent atrial fibrillation (AF) and new-onset AF are associated with appropriate shocks, cardiovascular mortality, chronic heart failure (CHF), and inappropriate shocks in implantable cardioverter defibrillator (ICD) patients with left ventricular dysfunction. METHODS: We included 290 consecutive ICD patients with a documented left ventricular ejection fraction < or = 0.35 and compared outcomes between patients without AF (n = 207), those with persistent AF (n = 64), and those with new-onset AF (n = 19). RESULTS: The patients with persistent AF were older, more frequently had valve disease and cardiac surgery, and less frequently had coronary artery disease as compared with the patients without AF. Patients with persistent AF had a higher New York Heart Association class, however, left ventricular ejection fraction rates between these 2 groups were comparable (0.28 +/- 0.07 vs 0.29 +/- 0.08, P = not significant). No difference was found between patients with new-onset AF and those without AF. During follow-up (2.6 +/- 1.9 years), more patients with persistent AF received appropriate ICD shocks as compared with those without AF (24 [38%] vs 49 [24%], P = .04). Deterioration of CHF occurred more often in patients with persistent AF (19 [30%], P = .001) and those with new-onset AF (9 [47%], P < .001) as compared with patients without AF (31 [14%]). Multivariate analysis revealed that patients with persistent AF had an increased risk for appropriate ICD shocks (adjusted hazard ratio [HR] 1.9, 95% CI 1.2-3.2, P = .009). Persistent AF (adjusted HR 2.1, 95% CI 1.1-3.9, P = .03) and new-onset AF (adjusted HR 2.5, 95% CI 1.1-5.7, P = .02) were found to be independent risk indicators of CHF deterioration. CONCLUSIONS: In ICD patients with left ventricular dysfunction, persistent AF is associated with appropriate ICD shocks and deterioration of CHF. New-onset AF is related to deterioration of CHF.

Aged↗
PubMed1985

Left ventricular dilatation. Prognostic value in severe left ventricular dysfunction secondary to coronary artery disease.

This study determines the noninvasive prognostic predictors (using radionuclide angiography) in patients with severe left ventricular dysfunction (resting ejection fraction less than or equal to 35 percent) secondary to coronary artery disease. We retrospectively evaluated 94 such patients using rest and exercise radionuclide ventriculography. At a mean follow-up of 16 months, cardiac events occurred in 22 patients: ten patients died of cardiac causes, five patients sustained nonfatal myocardial infarction, and seven patients developed severe congestive heart failure (class 4). Results indicate that patients with severe left ventricular dysfunction may be stratified into different risk groups according to left ventricular size. Marked left ventricular dilatation identifies a subgroup at high risk.

Actuarial Analysis↗
PubMed1994

Primary isolated coronary artery bypass in left ventricular dysfunction: survival and predictors of survival.

Coronary angiograms of 462 patients with ejection fractions below 51% who underwent primary isolated coronary artery bypass at the Cleveland Clinic from 1981 to 1985 were available for review. They were divided into two groups: group 1 (n = 166) with severe ventricular dysfunction (ejection fraction less than 30%) and group 2 (n = 296) with moderate ventricular dysfunction (ejection fraction 31 to 50%) at a median follow-up of 5.8 years/patient. The actuarial survival was 64.3% in group 1 and 80.6% in group 2 (P = 0.0001). By multivariate analysis, congestive heart failure (P = 0.0001) was the single most important factor affecting survival for both groups. In addition, in group 1 the preoperative use of inotropes (P = 0.03) and in group 2 the presence of peripheral vascular disease (P = 0.001) affected long term survival.

Actuarial Analysis↗
PubMed2000

Habitual activities and peak aerobic capacity in patients with asymptomatic and symptomatic left ventricular dysfunction.

BACKGROUND: A reduced level of daily activities is thought to be an important determinant of aerobic exercise intolerance in patients with chronic heart failure chronic heart failure; however, few data exist about the relationship between habitual physical activity level and peak aerobic capacity in patients at different clinical stages of left ventricular dysfunction. STUDY OBJECTIVES: The purposes of this study were as follow: (1) to validate a simple interviewer-administered scoring system for evaluation of habitual physical activity level of patients with chronic heart failure and asymptomatic left ventricular dysfunction (ALVD); (2) to determine the relationship between habitual physical activity level and peak aerobic capacity in chronic heart failure and ALVD patients; and (3) to compare habitual activity levels among different New York Heart Association (NYHA) classes in these populations. SETTING: Cardiology division at a tertiary-care hospital. STUDY POPULATION: We studied 167 consecutive patients with chronic heart failure (NYHA class I to III), 40 patients with ALVD, and 52 healthy subjects (HS). MEASUREMENTS AND RESULTS: Habitual physical activity level was evaluated by means of an interview-based activity scoring system considering leisure time and occupational activities and also recent deconditioning events (eg, hospital admissions); a final activity score (AS) ranging from 0.8 to 5 was obtained. All patients and HS performed a symptom-limited cardiopulmonary exercise test up to a respiratory exchange ratio of > or = 1.1. AS was an independent predictor of peak oxygen consumption (VO(2)) in all groups, with a significantly higher VO(2) vs AS relationship slope in the ALVD and HS groups than in the chronic heart failure group. Moreover, AS was found to be significantly lower in chronic heart failure than in ALVD patients and HS (1.6 +/- 0.6 vs 2.2 +/- 0.7 vs 3.5 +/- 1.1, respectively; p < 0.0001), as was peak VO(2) (14.7 +/- 3.7 mL/kg/min vs 20 +/- 4 mL/kg/min vs 33.1 +/- 10 mL/kg/min, respectively; p < 0.0001), but the latter differences were canceled after adjusting for AS values. Significant AS and peak VO(2) reductions were observed in chronic heart failure patients with NYHA class progression from I to III. CONCLUSIONS: Habitual physical activity level is progressively decreased with worsening of heart failure symptoms and is related to peak aerobic capacity in both chronic heart failure and ALVD patients. However, this relationship appears to be weak in patients with chronic heart failure, whereas daily activity is a strong independent predictor of peak aerobic capacity both in ALVD patients and HS. This may be related to the intervention of factors other than skeletal muscle deconditioning in the exercise pathophysiology of chronic heart failure patients.

Activities of Daily Living↗
PubMed2005

CRT-D therapy in patients with left ventricular dysfunction and atrial fibrillation.

The number of patients with atrial fibrillation and congestive heart failure has steadily increased in the United States. The presence of atrial fibrillation increases morbidity and mortality for patients with left ventricular dysfunction. The emergence of cardiac resynchronization therapy to improve symptoms and survival from congestive heart failure may provide benefits for those with atrial fibrillation; we review the pathophysiology of atrial fibrillation in the presence of left ventricular dysfunction and the promise of cardiac resynchronization therapy to improve symptoms for the for these patients.

Atrial Fibrillation↗
PubMed1997

Assessment of viable myocardium and prediction of postoperative improvement in left ventricular function in patients with severe left ventricular dysfunction by quantitative planar stress-redistribution-reinjection 201-T1 imaging.

A noninvasive approach to determine viable but asynergic myocardium will be clinically significant in identifying patients with coronary artery disease and severe left ventricular dysfunction who will benefit most from coronary bypass surgery. Accordingly, 12 patients (mean ejection fraction 0.32 +/- 0.03) underwent quantitative planar stress-redistribution-reinjection thallium scintigraphy and radionuclide ventriculography before and 8 weeks after revascularization for viability and segmental and global left ventricular function assessment, respectively. Reinjection scan showed new fill-in in 63% of segments without redistribution. Postoperative improvement in perfusion and function of asynergic segments were significantly better in viable compared to nonviable segments (P < 0.001, P < 0.01, respectively) with a strong correlation between improvement in 201-T1 uptake and function (P < 0.001). When adequacy of revascularization was considered, the predictive value of a positive preoperative viability test for functional improvement was 83%. Finally, mean ejection fraction and global wall motion score increased significantly after revascularization for the group as a whole (0.32 +/- 0.03 to 0.44 +/- 0.04, P < 0.001 and 24.08 +/- 2.90 to 33.16 +/- 3.32, P < 0.001, respectively). Thus, preoperative quantitative planar stress-redistribution-reinjection thallium imaging detects viable but asynergic segments which improve function postoperatively and may be valuable in selection of patients with severe left ventricular dysfunction for revascularization.

Chi-Square Distribution↗
PubMed1997

Right ventricular dysfunction in patients with obstructive sleep apnoea syndrome.

There is conclusive evidence that obstructive sleep apnoea syndrome (OSAS) influences right heart haemodynamics and can also induce pulmonary hypertension. It is not known, however, whether right ventricular dysfunction can occur in patients with OSAS in the absence of lung disease. We studied 107 patients (94 males, 13 females, mean age 55 +/- 11 yrs) with polysomnographically verified OSAS in whom clinically significant lung disease was excluded. Right ventricular ejection fraction (RVEF) was determined by radionuclide ventriculography. In addition, pulmonary function tests, arterial blood gas analysis and right heart catheterization were performed. RVEF was impaired in 19 patients (18%). Eighteen (95%) had signs or symptoms consistent with mild right ventricular failure. Patients with or without impaired RVEF did not differ with respect to body mass index, age or lung function. Stepwise multiple logistic regression analysis revealed that RVEF was significantly associated with the apnoea/hypopnoea index (r = -0.68; p = 0.0009) and the extent of nocturnal oxyhaemoglobin saturation (r = 0.42; p = 0.035), but not with age, body mass index, blood gas analysis, gender, lung function, pulmonary artery pressure and left ventricular ejection fraction. We conclude that in patients with otherwise unexplained right ventricular failure, obstructive sleep apnoea syndrome may underlie the right ventricular dysfunction.

Adult↗