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PubMed1994

Native beta-adrenergic support for left ventricular dysfunction in experimental mitral regurgitation normalizes indexes of pump and contractile function.

BACKGROUND: It is generally accepted that the adrenergic nervous system provides inotropic support for the failing heart. However, the magnitude of this support has never been studied extensively. The present study was performed to test the hypothesis that the adrenergic nervous system is capable of maintaining indexes of pump and contractile function in the normal range despite significant innate myocardial depression. METHODS AND RESULTS: We used our model of experimental canine mitral regurgitation, which produces left ventricular dysfunction after 3 months of volume overload. We studied indexes of contractile function on and off beta-blockade at baseline and again on and off beta-blockade 3 months after chronic mitral regurgitation had induced significant contractile dysfunction. At baseline, acute beta-blockade caused insignificant reductions in the mass-corrected slope of the end-ejection stress-volume relation (EESVR), the end-systolic stiffness constant, and the ejection fraction-end-systolic stress and the mean velocity of circumferential fiber shortening (VCF)-end-systolic stress relations. After 3 months of chronic mitral regurgitation, all indexes of contractile function were normal in the unblocked state except for the VCF-stress relation, which was mildly reduced. However, after acute beta-blockade after 3 months of chronic mitral regurgitation, the EESVR fell to 303 +/- 27 versus 443 +/- 24 during acute beta-blockade before mitral regurgitation was created (P < .05), and the end-systolic stiffness constant was reduced to 2.54 +/- 0.15 versus 3.27 +/- 0.11 (P < .05). Only after beta-blockade was the ejection fraction-stress relation significantly reduced for dogs with chronic mitral regurgitation. The VCF-stress relation became markedly more abnormal. The viscosity-velocity relation of myocytes isolated from the ventricles of the dogs with mitral regurgitation confirmed that substantial innate contractile depression was present. CONCLUSIONS: After 3 months of chronic mitral regurgitation, the adrenergic nervous system was able to maintain most indexes of contractile function in the normal range despite significant depression in innate contractile function. Thus, in the absence of beta-blockade, significant innate contractile depression may be obscured by adrenergic support.

Animals↗
PubMed2005

Cost-effectiveness of eplerenone compared with placebo in patients with myocardial infarction complicated by left ventricular dysfunction and heart failure.

BACKGROUND: In the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS), aldosterone blockade with eplerenone decreased mortality in patients with left ventricular systolic dysfunction and heart failure after acute myocardial infarction. The present study was performed to evaluate the cost-effectiveness of eplerenone compared with placebo in these patients. METHODS AND RESULTS: A total of 6632 patients with left ventricular systolic dysfunction and heart failure after acute myocardial infarction were randomized to eplerenone or placebo and followed up for a mean of 16 months. The coprimary end points were all-cause mortality and the composite of cardiovascular mortality/cardiovascular hospitalization. The evaluation of resource use included hospitalizations, outpatient services, and medications. Eplerenone was priced at the average wholesale price, 3.60 dollars per day. Survival beyond the trial period was estimated from data from the Framingham Heart Study, the Saskatchewan Health database, and the Worcester Heart Attack Registry. The incremental cost-effectiveness of eplerenone in cost per life-year and quality-adjusted life-year gained compared with placebo was estimated. The number of life-years gained with eplerenone was 0.1014 based on Framingham (95% CI, 0.0306 to 0.1740), 0.0636 with Saskatchewan (95% CI, 0.0229 to 0.1038), and 0.1337 with Worcester (95% CI, 0.0438 to 0.2252) data. Cost was 1391 dollars higher over the trial period in the eplerenone arm (95% CI, 656 to 2165) because of drug cost. The incremental cost-effectiveness ratio was 13,718 dollars per life-year gained with Framingham (96.7% under 50,000 dollars per life-year gained), 21,876 dollars with Saskatchewan, and 10,402 dollars with Worcester. CONCLUSIONS: Eplerenone compared with placebo in the treatment of heart failure after acute myocardial infarction is effective in reducing mortality and is cost-effective in increasing years of life by commonly used criteria.

Aged↗
PubMed1978

Effect of digoxin and diuretics on high altitude left ventricular dysfunction.

Systolic time intervals, stroke volume, cardiac output and (dZ/dt)/RZ index were serially estimated in 51 normal healthy volunteers at sea level, for ten days after air induction to 3658 m altitude and on return to sea level. The subjects were divided into three groups and were administered a diuretic, beta methyldigoxin and placebo in a double blind protocol. The group on placebo showed an increase in heart rate, reduction in stroke index and cardiac index during high altitude exposure with normalization on return to sea level. A deterioration in left ventricular function as manifested by prolongation of pre-ejection period, increase in PEP/LVET ratio, reduction in (dZ/dt)/RZ index and left ventricular ejection time was also noted at high altitude. The subjects on digoxin maintained normal stroke/cardiac index and did not show any significant changes in the parameters of myocardial function. The diuretic group showed more deterioration in the parameters than the placebo group. No significant side effects were noted. Left ventricular dysfunction and reduction of stroke index at high altitudes may be causually related; digoxin administration may prevent them from occurring.

Adult↗
PubMed1995

Altered vagal and sympathetic control of heart rate in left ventricular dysfunction and heart failure.

We investigated alterations in autonomic control of heart rate in conscious dogs with left ventricular (LV) dysfunction in the presence and absence of heart failure (HF) due to rapid pacing. In dogs with LV dysfunction but no HF, indexes of parasympathetic control decreased significantly after only 4 days of pacing. In dogs with fully developed HF, both vagal and sympathetic contributions were small. Vagomimetic doses of atropine increased both R-R interval (419 +/- 25 to 466 +/- 34 ms, P < 0.05) and standard deviation (SD) of the R-R interval (13 +/- 2 to 34 +/- 9 ms, P < 0.05). The digitalis glycoside deslanoside (Cedilanid-D) alone prolonged R-R interval (420 +/- 33 to 492 +/- 44 ms, P < 0.01) and tended to increase SD (14 +/- 4 to 28 +/- 8 ms, P = 0.08). After Cedilanid-D, low-dose atropine resulted in no significant further change in R-R interval or SD. These data indicate that changes in vagal control of heart rate become apparent at a very early developmental stage of LV dysfunction, and we speculate that this may provide important prognostic information in patients who are at risk for developing progressive myocardial dysfunction and HF.

Animals↗
PubMed1993

[Pathogenic factors of postischemic ventricular dysfunction and effects of magnesium].

To investigate the mechanism of myocardial; tunning, a Langendorff model of rat hearts (n = 18) underwent 15 min ischemia with coronary flow at 0.2 ml/min and 10 min reperfusion with Ringer's solution of 1.06 mmol/L Mg2+. Histological exam revealed no myocardial necrosis. However, the recovery of pressure product (RPP) was only 77% compared with control period. The myocardial Ca2+ content and water content were significantly increased (P < 0.01, vs control hearts). Pretreatment with high concentration of Mg2+ (2.4 mmol/L) improved the recovery of postischemic ventricular function, attenuated the Ca2+ overload and myocardial edema. The results indicated that a brief period of low-flow ischemia could produce a postischemic ventricular dysfunction-the myocardial stunning. Calcium overload and myocardial edema might be two pathogenic factors. An increased Mg2+ had a protective effects on postischemic ventricular dysfunction, which may involve the following mechanisms: reduced Ca2+ overload and attenuated myocardial edema.

Animals↗
PubMed1997

[Clinical, echocardiographic and Doppler outcome in ischemic right ventricular dysfunction associated with inferior wall infarction].

Right ventricular involvement during inferior wall myocardial infarction does not seem to alter long-term clinical prognosis but its specific outcome has not been clearly studied. We have previously demonstrated that pulmonary regurgitant (PR) flow tracings doppler analysis allows the accurate diagnosis of RV involvement, especially when the pressure half-time of PR was < or = 150 ms and the ratio of the minimal velocity to the maximal velocity was < or = 0.5. We studied 40 patients with acute inferior wall myocardial infarction and with PR flow. Doppler echocardiography was obtained during the first day, before discharge (early control) and between 12 and 24 months follow-up (late control). Among 22 patients with RV involvement defined with PR-derived doppler parameters (RVIPR). 8 had right ventricular enlargement and/or wall motion abnormalities, observed in 6 cases at early control and in 4 at late control. Doppler analysis showed remnant RVIPR parameters in 9 patients at early control and 8 among these at late contorl, with no relation with pulmonary artery pressure or other echocardiographic parameters. No clinical, angiographic or therapeutic data predicted these distinct echocardiographic and doppler patterns and the long-term prognosis was not different. At late control, among 12 RVIPR patients which PR-derived doppler parameters were normal at early control, two patients had still RVIPR pattern at late control and described ischemic recurrence. PR flow doppler analysis is a useful tool for diagnosis and outcome evaluation of RV involvement and shows a remnant diastolic dysfunction in half of the patients with acute RV involvement.

Aged↗
PubMed1993

Detection of silent left ventricular dysfunction during daily activities in coronary artery disease patients by the nuclear VEST.

Myocardial ischemia during routine daily activities was studied in patients with known coronary artery disease with an ambulatory radionuclide probe and recording device (VEST) and routine rest and exercise gated blood pool imaging. Seventeen patients were monitored for 60 minutes while sitting (baseline), standing in place, walking, eating (6 patients), and urinating (4 patients). Eleven of them (64%) failed to show an augmentation of at least 5% in the LVEF on an exercise gated blood pool imaging study (Group I) and 6 (36%) showed a normal response (Group II). Three patients (18%) in Group I experienced angina. Transient left ventricular dysfunction was detected by the VEST during walking, urinating or eating in 80% of the patients in Group I and 33% in Group II (p < 0.05). During walking, mean ejection fraction slightly decreased from 45 +/- 12% to 43 +/- 13% in Group I while the ejection fraction increased from 46 +/- 8% to 51 +/- 12% in Group II (p = 0.04 for the difference in responses). Standing in place and eating did not affect the mean ejection fraction. Urination in 4 patients in Group I caused a significant drop in ejection fraction in 3 patients for a mean change from 51 +/- 9% at rest to 42 +/- 15%. By contrast, none of the patients had angina or diagnostic ECG changes during the monitoring period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

Biventricular versus conventional right ventricular stimulation for patients with standard pacing indication and left ventricular dysfunction: the Homburg Biventricular Pacing Evaluation (HOBIPACE).

OBJECTIVES: The Homburg Biventricular Pacing Evaluation (HOBIPACE) is the first randomized controlled study that compares the biventricular (BV) pacing approach with conventional right ventricular (RV) pacing in patients with left ventricular (LV) dysfunction and a standard indication for antibradycardia pacing in the ventricle. BACKGROUND: In patients with LV dysfunction and atrioventricular block, conventional RV pacing may yield a detrimental effect on LV function. METHODS: Thirty patients with standard indication for permanent ventricular pacing and LV dysfunction defined by an LV end-diastolic diameter > or =60 mm and an ejection fraction < or =40% were included. Using a prospective, randomized crossover design, three months of RV pacing were compared with three months of BV pacing with regard to LV function, N-terminal pro-B-type natriuretic peptide (NT-proBNP) serum concentration, exercise capacity, and quality of life. RESULTS: When compared with RV pacing, BV stimulation reduced LV end-diastolic (-9.0%, p = 0.022) and end-systolic volumes (-16.9%, p < 0.001), NT-proBNP level (-31.0%, p < 0.002), and the Minnesota Living with Heart Failure score (-18.9%, p = 0.01). Left ventricular ejection fraction (+22.1%), peak oxygen consumption (+12.0%), oxygen uptake at the ventilatory threshold (+12.5%), and peak circulatory power (+21.0%) were higher (p < 0.0002) with BV pacing. The benefit of BV over RV pacing was similar for patients with (n = 9) and without (n = 21) atrial fibrillation. Right ventricular function was not affected by BV pacing. CONCLUSIONS: In patients with LV dysfunction who need permanent ventricular pacing support, BV stimulation is superior to conventional RV pacing with regard to LV function, quality of life, and maximal as well as submaximal exercise capacity.

Aged↗
PubMed2003

Aortic valve replacement for aortic regurgitation and stenosis, in patients with severe left ventricular dysfunction.

OBJECTIVE: Aortic valve replacement for aortic valve stenosis (AS) and regurgitation (AR) in patients with severe left ventricular (LV) dysfunction contains an increased risk. Few data are available on the outcome of such patients. METHODS: Fifty-five consecutive patients with severe LV dysfunction (ejection fraction, EF; <30%) and aortic valve replacement for AS (n=35) or AR (n=20) were investigated between 1994 and 2001. EF was 25+/-5%, mean transvalvular gradient 26+/-6mmHg (AS), aortic valve area 0.66+/-0.18cm(2) (AS), cardiac index (CI) 2.4+/-0.9l/min/m(2), enddiastolic LV diameter (LVEDD) 64+/-8mm and endsystolic LV diameters (LVESD) was 55+/-3mm. Ninety percent of patients were in New York Heart Association (NYHA) functional class III/IV at admission to the hospital. Concomitant coronary artery bypass grafts (CABG) were performed in 14 patients. Follow-up examinations including chest X-ray, echocardiography, exercise testing, were performed among survivors. RESULTS: The survival rates for AS were: 1-year 76%, 2-year 68.8%, 5-year 64.2%; for AR: 1-year 94.4%, 2-year 86.5%, 5-year 74.2%. NYHA functional class improved from 90% in class III/IV to 45 (AR group) and 24% (AS group) at follow-up (P<0.02). The LVEDD decreased to 54+/-8mm after 1 year. The EF improved to 38+/-4 (AR group) and 40+/-5% (AS group) at follow-up. CONCLUSIONS: Despite severe LV dysfunction, increased 1-year mortality especially in the AS group, aortic valve replacement was associated with improved functional status, symptoms and EF in both groups and in most patients. We, therefore, conclude that aortic valve replacement in patients with severe LV dysfunction can be performed with acceptable risk.

Aortic Valve↗
PubMed1999

Functional remodelling and left ventricular dysfunction after repeated ischaemic episodes. A chronic experimental porcine model.

This experimental study was set up to investigate left ventricular function and remodelling after repeated ischaemic episodes using magnetic resonance imaging (MRI). A significant reduction in mortality due to coronary heart disease (CHD) has been explained by both a decline in the incidence of acute myocardial infarction (AMI) and an improved post-AMI survival rate, suggesting a change in the natural history of CHD. Experimental intracoronary microembolization can induce different ischaemic patterns and the functional impact of repeated ischaemic episodes different from occlusion of central epicardial arteries can be studied. In this study repeated intracoronary microembolizations were performed in 20 domestic pigs. After 129 d, MRI was performed for assessment of left ventricular volume, mass and wall stress. Six pigs underwent serial MRI at baseline, immediately after embolization and at the end of the observation period. Microembolizations induced acute myocardial infarct expansion and increased left ventricular wall stress preceding chronic remodelling. End systolic and end diastolic volumes increased from 15.1 +/- 2.7 cm3 to 41.3 +/- 11.5 cm 3 (p < 0.002), and from 52.0 +/- 6.7 cm3 to 81.1 +/- 9.2 cm3 (p < 0.0007), respectively. End systolic wall stress increased from and 17.5 +/- 2.7 to 29.7 +/- 6.2 N/m2 (p < 0.001). Left ventricular filling pressures and cardiac index were unchanged. Histological examination revealed a diffuse pattern of perivascular fibrosis covering 12 +/- 3% of the left ventricular wall. This study demonstrates that repeated ischaemic episodes different from confined regional myocardial infarctions induce acute infarct expansion and chronic left ventricular remodelling in pigs. Serial assessment of absolute left ventricular volumes and mass is important during acute/chronic remodelling.

Animals↗
PubMedDate not supplied

Prediction of left ventricular dysfunction in coronary artery disease from clinical and exercise test findings.

We studied the ability to predict depressed left ventricular ejection fraction (LVEF) from clinical and exercise test findings prior to surgery in consecutive patients who underwent coronary artery bypass grafting (CABG) from 1988 to 1991 (n = 663). Multivariate analysis showed a history of myocardial infarction, pathological Q-wave in resting ECG, systolic blood pressure at maximal exercise and the degree of mitral regurgitation as significant independent predictors of impaired LVEF. The relative risk (RR) of depressed LVEF was markedly increased for a previous history of myocardial infarction (RR 3.3, p < 0.0001) and a pathological Q-wave in resting ECG (RR 2.4, p < 0.0001). All associations found between depressed LVEF and exercise test results were poor, and of little value for discriminating patients with depressed LVEF. Thus, clinical data appear to be better markers of low LVEF than the information obtained from the exercise test.

Adrenergic beta-Antagonists↗
PubMed2000

Cardiac troponin I elevation in acute pulmonary embolism is associated with right ventricular dysfunction.

OBJECTIVES: The purpose of this study was to evaluate the prevalence and diagnostic utility of cardiac troponin I to identify patients with right ventricular (RV) dysfunction in pulmonary embolism. BACKGROUND: Right ventricular overload resulting from elevated pulmonary resistance is a common finding in major pulmonary embolism. However, biochemical markers to assess the degree of RV dysfunction have not been evaluated so far. METHODS: In this prospective, double-blind study we included 36 study patients diagnosed as having acute pulmonary embolism. RESULTS: Among the whole study population, 14 patients (39%) had positive troponin I tests. Ten of 16 patients (62.5%) with RV dilatation had increased serum troponin I levels, while only 4 of 14 patients (28.6%) with elevated troponin I values had a normal RV diameter as assessed by echocardiography, indicating that positive troponin I tests were significantly associated with RV dilatation (p = 0.009). Patients with positive troponin I tests had significantly more segmental defects in ventilation/perfusion lung scans than patients with normal serum troponin I (p = 0.0002). CONCLUSIONS: Our data demonstrate that more than one-third of patients clinically diagnosed as having pulmonary embolism presented with elevated serum troponin I concentrations. Troponin I tests helped to identify patients with RV dilatation who had significantly more segmental defects in lung scans. Thus, troponin I assays are useful to detect minor myocardial damage in pulmonary embolism.

Acute Disease↗
PubMed2006

Medical treatment of patients with heart failure or left ventricular dysfunction undergoing percutaneous coronary intervention.

Management of ischemic patients with pre-existing or new-onset left ventricular (LV) dysfunction poses a special challenge in terms of the timing of percutaneous coronary intervention (PCI) and appropriate adjunctive medications to optimize outcome while minimizing risk. In a systematic fashion, this review attempts to provide a management scheme for patients with heart failure or LV dysfunction that present with stable angina, ST-segment elevation myocardial infarction, or unstable angina/non-ST-segment elevation myocardial infarction. By addressing therapeutic approaches to acute or decompensated heart failure and timing of coronary angiography based on severity of ischemia, we provide evidence-based recommendations for medications to initiate before, during, and following PCI.

Angina Pectoris↗
PubMed1992

[Combined surgical-interventional procedure in congenital heart defects with postoperative, left ventricular dysfunction].

Creation of a communication between the left and right atrium to decompress the left ventricle can be life-saving after corrective surgery in some patients with congenital heart disease and small left ventricle. After adaptation of the left ventricle, surgical closure of this anastomosis becomes mandatory. We report four patients (2.9 to 8.2 kg) where non-surgical, transcatheter-closure was performed in the first year of life using the Rashkind-PDA-Occluder System (USCI). In a newborn with d-transposition of the great arteries (2.9 kg), in a patient with atrial septal defect (5.1 kg), and in a patient with tetralogy of Fallot with atrial septal defect (4.9 kg) atrial septal defects were not completely closed during correction because of left-ventricular dysfunction. Five to 12 days postoperatively transcatheter closure was performed utilizing the 8F-Rashkind-PDA-Occluder System in the first two patients (2.9 kg and 4.9 kg) and by use of the 11F-Rashkind-PDA-Occluder System in the third patient (4.9 kg). In the patient with supracardiac total anomalous pulmonary venous drainage via a vertical vein, the vertical vein was not closed during surgical correction at the age of 2 months. Transcatheter closure was performed 6 months later using the 11F-Rashkind-PDA-Occluder-System. It is concluded that small, defined atrial septal defects can be closed, even in newborns, using the Rashkind-PDA-Occluder System (USCI) and, furthermore, that large vessels, even without luminal narrowing can be occluded completely. Thus, this combined "surgical-interventional approach" is not limited by age and could reduce the risk of surgical correction in patients with congenital heart disease and small left ventricle.

Cardiac Catheterization↗
PubMed2004

Biventricular implantable cardioverter defibrillators improve survival compared with biventricular pacing alone in patients with severe left ventricular dysfunction.

INTRODUCTION: Biventricular cardiac pacemakers provide important hemodynamic benefit in selected patients with heart failure and severe left ventricular (LV) dysfunction. Nevertheless, these patients remain at high mortality risk. To address this issue, we examined mortality outcome in patients with heart failure treated with biventricular pacemakers alone and those treated with biventricular implantable cardioverter defibrillators (ICDs). METHODS AND RESULTS: The study population consisted of 126 consecutive patients with LV dysfunction and heart failure who received either a biventricular ICD (n = 62) or a biventricular pacemaker (n = 64) between January 1998 and December 2002. A minimum 12 months of follow-up was obtained in all survivors. ICD indications were conventional in all patients. Kaplan-Meier actuarial method and log rank statistics were used to calculate and compare survival rates in both groups. Comparison of mortality rates utilized Chi-square test. The two groups had similar clinical and demographic features, LV ejection fraction, and medication use. Average follow-up times were 13 +/- 11.8 months (range 4-60) and 18 +/- 13.2 months (range 0.5-53) for biventricular ICD and pacemaker groups, respectively. Overall mortality rate was significantly lower in the biventricular ICD group (13%, 8 deaths) compared to the pacemaker group (41%, 26 deaths) (P = 0.01). Further, the predominant survival benefit for ICD-treated patients becomes evident after the first 12 months of follow-up. CONCLUSION: The findings in this study, although necessarily limited in their interpretation by the absence of treatment randomization, suggest that biventricular ICDs offer a survival benefit compared to biventricular pacing alone. Furthermore, this benefit may be most apparent if other clinical factors do not preclude patient survival >1 year postimplant.

Aged↗
PubMed2000

Normalization of left ventricular dysfunction in systemic hypertension.

BACKGROUND: In hypertensive heart disease, it is uncertain whether the impairment of left ventricular (LV) systolic function might be reverted by antihypertensive treatment. HYPOTHESIS: This study was undertaken to address the likelihood of recovery of LV dysfunction and to identify factors potentially related. METHODS: Twenty-six patients with primary (n = 16) and renovascular (n = 10) hypertension participated in the study and were classified into Groups A (n = 12) and B (n = 14) according to normalization or persistent left ventricular dysfunction (fractional shortening < 0.30) after 36 weeks of follow-up. All patients received standard medical therapy and appropriate procedures for renovascular disease correction. Logistic regression analysis was used to identify variables associated with recovery. RESULTS: Patients in Group A compared with those in Group B were younger (41 +/- 14 vs. 52 +/- 10 years; p < 0.05), had a greater frequency of renovascular hypertension (8 vs. 2; p < 0.05), showed shorter LV end-diastolic (54 +/- 5 vs. 61 +/- 8 mm; p < 0.05) and end-systolic dimensions (41 +/- 6 vs. 49 +/- 9 mm; p < 0.05), and lower mass index (215 +/- 64 vs. 261 +/- 47 g.m-2; p < 0.05) before treatment, whereas fractional shortening (0.24 +/- 0.4 vs. 0.20 +/- 0.5; p > 0.05) and diastolic blood pressure (116 +/- 12 vs. 122 +/- 19 mmHg; p > 0.05) were similar. On follow-up, Group A patients showed lower diastolic blood pressure (89 +/- 15 vs. 105 +/- 20 mmHg; p < 0.05) and mass index (142 +/- 34 vs. 222 +/- 40 g.m-2; p < 0.05). Logistic regression analysis identified systolic dimension and renovascular hypertension as factors associated with fractional shortening normalization. CONCLUSION: The recovery of LV dysfunction is expected to occur most likely in patients with renovascular hypertension and the shortest systolic dimensions.

Adult↗
PubMed1992

Ascending aortic Doppler velocity and the prediction of exercise capacity in post-infarction left ventricular dysfunction.

A system to improve analysis of the aortic pulsed Doppler velocity signal has been developed and used to study cardiac performance during a 4 min, 25 W incremental stage supine bicycle exercise to exhaustion. Twenty-two male subjects with stable chronic ischaemic heart disease were studied (15 with NYHA class II/III heart failure, and seven age-matched class I subjects). None had evidence of reversible ischaemia. Peak velocity (PV) from the intensity weighted mean velocity profile, early acceleration (eA) and stroke distance (SD) were all significantly lower at rest in class II/III compared to class I. For the change from rest to 50 W, PV did not alter, eAC increased significantly (P less than 0.05) and to a similar extent in both groups (18.6% class II/III vs 16.4% class I) and SD was reduced from 7.8 to 5.9 in class II/III (P less than 0.01) but did not change in class I (12.4 vs 11.8, ns). There was also a greater increase in heart rate (HR) in class II/III subjects (P less than 0.05). The duration of exercise was correlated with resting PV (r = 0.48, P less than 0.025) but was correlated best with the change in blood momentum (PV x Stroke volume x HR) between rest and peak exercise (r = 0.80, P less than 0.001). Thus Doppler velocimetry can give quantitative information on the response to exercise which discriminates between grades of ventricular dysfunction and is predictive of exercise capacity.

Adult↗
PubMed1994

Relationship of renin, angiotensin II and atrial natriuretic factor to clinical status in the early post-infarct period in patients with left ventricular dysfunction.

The vasoconstrictor and cardiotoxic effects of angiotensin II may be particularly harmful in the early post-infarct period, but could be partially offset by the release of atrial natriuretic factor. We studied the relationship of renin, angiotensin II and atrial natriuretic factor to clinical status in the first 72 h after infarction in 36 patients not requiring treatment with diuretics on clinical grounds. Since these patients were treated with streptokinase, 16 non-thrombolysed patients were included to control for the acute effects of streptokinase on plasma hormones. Streptokinase caused transient fluctuations in plasma renin and atrial natriuretic factor but did not limit the subsequent development of supranormal hormone levels. Streptokinase-treated patients were divided on the basis of the highest recorded Killip class. Activation of the renin angiotensin system occurred only in those patients in Killip class 2 (n = 11), was maximal at 24-72 h and was proportional to the extent of left ventricular dysfunction. Plasma levels of atrial natriuretic factor were elevated on admission, even in patients in Killip class 1 (n = 25), but declined within an hour before rising again to supranormal levels at 24-72 h. Cumulative release of renin and angiotensin II, but not atrial natriuretic factor, were significantly greater in patients in Killip class 2. Heart rate was greater in Killip class 2 at 24 and 72 h but there was no difference in mean arterial pressures. We conclude that the renin angiotensin system is activated in the early post-infarction phase, but only in patients in Killip class 2, possibly as a result of increased sympathetic activity and reduced renal perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Natriuretic Factor↗