CYP3A4 genotype is associated with sildenafil concentrations in patients with heart failure with preserved ejection fraction.

Despite its established inter-individual variability, sildenafil has been the subject of only a few pharmacogenetic investigations, with limited data regarding the genetic modulators of its pharmacokinetics. We conducted a pharmacogenetic sub-study of patients randomized to sildenafil (n=85) in the RELAX trial, which investigated the impact of high-dose sildenafil in patients with heart failure with preserved left ventricular ejection fraction (HFpEF). In the overall population, the CYP3A4 inferred phenotype appeared associated with the dose-adjusted peak concentrations of sildenafil at week 12 and week 24 (adjusted P=0.045 for repeated measures analysis), although this P-value did not meet our corrected significance threshold of 0.0167. In the more homogeneous Caucasian subgroup, this association was significant (adjusted P=0.0165 for repeated measures). Hence, CYP3A4 inferred phenotype is associated with peak sildenafil dose-adjusted concentrations in patients with HFpEF receiving high doses of sildenafil. The clinical impact of this association requires further investigation.

A pharmacogenetic investigation of intravenous furosemide in decompensated heart failure: a meta-analysis of three clinical trials.

We conducted a meta-analysis of pharmacogenomic substudies of three randomized trials conducted in patients with decompensated heart failure (HF) that were led by National Heart Lung and Blood Institute (NHLBI)-funded HF Network to test the hypothesis that candidate genes modulate net fluid loss and weight change in patients with decompensated HF treated with a furosemide-based diuretic regimen. Although none of the genetic variants previously shown to modulate the effects of loop diuretics in healthy individuals were associated with net fluid loss after 72 h of treatment, a set of rare variants in the APOL1 gene, which codes for apolipoprotein L1 (P=0.0005 in the random effects model), was associated with this end point. Moreover, a common variant in the multidrug resistance protein-4 coding gene (ABCC4, rs17268282) was associated with weight loss with furosemide use (P=0.0001). Our results suggest that both common and rare genetic variants modulate the response to a furosemide-based diuretic regimen in patients with decompensated HF.

Variations in very preterm birth rates in 30 high-income countries: are valid international comparisons possible using routine data?

OBJECTIVE: Concerns about differences in registration practices across countries have limited the use of routine data for international very preterm birth (VPT) rate comparisons. DESIGN: Population-based study. SETTING: Twenty-seven European countries, the United States, Canada and Japan in 2010. POPULATION: A total of 9 376 252 singleton births. METHOD: We requested aggregated gestational age data on live births, stillbirths and terminations of pregnancy (TOP) before 32 weeks of gestation, and information on registration practices for these births. We compared VPT rates and assessed the impact of births at 22-23 weeks of gestation, and different criteria for inclusion of stillbirths and TOP on country rates and rankings. MAIN OUTCOME MEASURES: Singleton very preterm birth rate, defined as singleton stillbirths and live births before 32 completed weeks of gestation per 1000 total births, excluding TOP if identifiable in the data source. RESULTS: Rates varied from 5.7 to 15.7 per 1000 total births and 4.0 to 11.9 per 1000 live births. Country registration practices were related to percentage of births at 22-23 weeks of gestation (between 1% and 23% of very preterm births) and stillbirths (between 6% and 40% of very preterm births). After excluding births at 22-23 weeks, rate variations remained high and with a few exceptions, country rankings were unchanged. CONCLUSIONS: International comparisons of very preterm birth rates using routine data should exclude births at 22-23 weeks of gestation and terminations of pregnancy. The persistent large rate variations after these exclusions warrant continued surveillance of VPT rates at 24 weeks and over in high-income countries. TWEETABLE ABSTRACT: International comparisons of VPT rates should exclude births at 22-23 weeks of gestation and terminations of pregnancy.

Opinions, hopes and concerns regarding pharmacogenomics: a comparison of healthy individuals, heart failure patients and heart transplant recipients.

It is not yet known whether healthy individuals and patients with a chronic disease have similar attitudes towards pharmacogenomics. Thus we conducted a survey of 175 healthy volunteers, 175 heart failure (HF) patients and 100 heart transplant recipients to compare their opinions on this subject. Most participants (>90%) stated that they would accept pharmacogenomic testing and expressed high hopes regarding its potential applications. Overall, interest for pharmacogenomics was shared equally among the three groups. In contrast, after adjusting for age, gender, education and income, healthy individuals were more likely to voice concerns about potential employment (P=0.008 vs HF, odds ratio (OR)=2.93, confidence interval (CI)=1.33-6.47; P=0.010 vs Transplant, OR=2.46, CI=1.24-4.90) and insurance discrimination (P=0.001 vs HF, OR=5.58, CI=2.01-15.48; P<0.001 vs Transplant, OR=4.98, CI=2.03-12.21) and were possibly more worried by confidentiality issues. These findings highlight the need for strict legislation and proper educational strategies directed at the general population to facilitate the clinical implementation of pharmacogenomics.

Effect of nesiritide in patients with acute decompensated heart failure.

BACKGROUND: Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality associated with this agent. METHODS: We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days. RESULTS: Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P=0.03) and 24 hours (68.2% vs. 66.1%, P=0.007), but the prespecified level for significance (P≤0.005 for both assessments or P≤0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference, -0.7 percentage points; 95% confidence interval [CI], -2.1 to 0.7; P=0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference, -0.4 percentage points; 95% CI, -1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P=0.11). CONCLUSIONS: Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure. (Funded by Scios; ClinicalTrials.gov number, NCT00475852.).

Amniotic fluid embolism: incidence, risk factors, and impact on perinatal outcome.

OBJECTIVE: To extend our previous work on AFE in Canada by including stricter criteria for case identification and by examining risks for stillbirth, neonatal mortality and serious maternal and neonatal morbidity. DESIGN: Population-based cohort study. SETTING: Canada. POPULATION OR SAMPLE: In all, 4,508,462 hospital deliveries from fiscal year 1991/92 to 2008/09. METHODS: To reduce false-positive diagnoses, we restricted our analysis to AFE cases with cardiac arrest, shock or severe hypertension, respiratory distress, mechanical ventilation, coma, seizure, or coagulation disorder. Linkage of maternal and neonatal records, available since 2001/02, enabled us to examine the effects of AFE on neonatal outcomes. Detailed demographic and clinical data facilitated control for a broad array of potential confounding variables. MAIN OUTCOME MEASURES: Amniotic fluid embolism, in-hospital neonatal death, asphyxia, mechanical ventilation, bacterial sepsis, seizure, nonimmune haemolytic or traumatic jaundice and length of hospital stay. RESULTS: A total of 292 AFE cases were identified, of which only 120 (40%) were confirmed after applying our additional diagnostic criteria, yielding an AFE incidence of 2.5 per 100,000 deliveries. Of the 120 confirmed cases, 33 (27%) were fatal. Significant modifiable risk factors included medical induction, caesarean delivery, instrumental vaginal delivery, and uterine or cervical trauma. Amniotic fluid embolism was associated with significantly increased risks of stillbirth and neonatal asphyxia, mechanical ventilation, sepsis, seizures and prolonged length of hospital stay. CONCLUSIONS: Amniotic fluid embolism remains a rare but serious obstetric outcome, with several important modifiable risk factors and major implications for maternal, fetal and neonatal health.

Modulation of nitric oxide affects myocardial perfusion-contraction matching in anaesthetized dogs with recurrent no-flow ischaemia.

Myocardial perfusion and contraction are closely coupled; however, the effect of recurrent no-flow ischaemia on perfusion-contraction matching remains to be established. In the present studies, we examined the influence of modulating nitric oxide availability on perfusion-contraction matching after recurrent no-flow ischaemia in acute open-chest, anaesthetized dogs. The following three groups were studied: (1) saline; (2) L-NAME (10 mg kg(-1) I.V.); and (3) enalaprilat (1.5 mg kg(-1) I.V.). Regional myocardial blood flow was measured with microspheres and contractile function with piezoelectric crystals to determine systolic wall thickening. Dogs underwent four cycles of 5 min acute ischaemia and 5 min coronary reperfusion; area at risk was similar for all groups. In all dogs, ischaemic zone contractile function was depressed after recurrent no-flow ischaemia despite increased myocardial blood flow during reperfusion; contractile function was further depressed during L-NAME and was partly restored with enalaprilat. Within the ischaemic region, blood flow in subendocardial and subepicardial layers increased significantly compared with baseline during each reperfusion period independently of treatment. Our findings suggest that reduced NO availability can significantly impair myocardial perfusion-contraction matching, which is partly restored by administration of an NO donor.

Investigation of an increase in postpartum haemorrhage in Canada.

OBJECTIVE: To investigate the cause of a recent increase in hysterectomies for postpartum haemorrhage in Canada. DESIGN: Retrospective cohort study. SETTING: Canada between 1991 and 2004. POPULATION: All hospital deliveries in Canada as documented in the database of the Canadian Institute for Health Information (excluding incomplete data from Quebec, Manitoba and Nova Scotia). METHODS: Deliveries with postpartum haemorrhage by subtype were identified using International Classification of Diseases codes, while hysterectomies were identified using procedure codes. Changes in determinants of postpartum haemorrhage (all postpartum haemorrhage and that requiring hysterectomy) were examined, and crude and adjusted period changes were assessed using logistic models. MAIN OUTCOME MEASURES: Postpartum haemorrhage, postpartum haemorrhage with hysterectomy, postpartum haemorrhage with blood transfusion and postpartum haemorrhage by subtype. RESULTS: Rates of postpartum haemorrhage increased from 4.1% in 1991 to 5.1% in 2004 (23% increase, 95% CI 20-26%), while rates of postpartum haemorrhage with hysterectomy increased from 24.0 in 1991 to 41.7 per 100,000 deliveries in 2004 (73% increase, 95% CI 27-137%). These increases were because of an increase in atonic postpartum haemorrhage, from 29.4 per 1000 deliveries in 1991 to 39.5 per 1000 deliveries in 2004 (34% increase, 95% CI 31-38%). Adjustment for temporal changes in risk factors did not explain the increase in atonic postpartum haemorrhage but attenuated the increase in atonic postpartum haemorrhage with hysterectomy. CONCLUSIONS: There has been a recent, unexplained increase in the frequency, and possibly the severity, of atonic postpartum haemorrhage in Canada.

Vasopeptidase inhibitors: a new therapeutic concept in cardiovascular disease?

The cardiovascular system is regulated by hemodynamic and neurohumoral mechanisms. These regulatory systems play a key role in modulating cardiac function, vascular tone, and structure. Although neurohumoral systems are essential in vascular homeostasis, they become maladaptive in disease states such as hypertension, coronary disease, and heart failure. The clinical success of ACE inhibitors has led to efforts to block other humoral systems. Neutral endopeptidase (NEP) is an endothelial cell surface zinc metallopeptidase with similar structure and catalytic site. NEP is the major enzymatic pathway for degradation of natriuretic peptides, a secondary enzymatic pathway for degradation of kinins, and adrenomedullin. The natriuretic peptides can be viewed as endogenous inhibitors of the renin angiotensin system. Inhibition of NEP increases levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) of myocardial cell origin, and C-type natriuretic peptide (CNP) of endothelial cell origin as well as bradykinin and adrenomedullin. By simultaneously inhibiting the renin-angiotensin-aldosterone system and potentiating the natriuretic peptide and kinin systems, vasopeptidase inhibitors reduce vasoconstriction, enhance vasodilation, improve sodium/water balance, and, in turn, decrease peripheral vascular resistance and blood pressure and improve local blood flow. Within the blood vessel wall, this leads to a reduction of vasoconstrictor and proliferative mediators such as angiotensin II and increased local levels of bradykinin (and, in turn, nitric oxide) and natriuretic peptides. Preliminary clinical experiences with vasopeptidase inhibitors are encouraging. Thus, the combined inhibition of ACE and neutral endopeptidase is a new and promising approach to treat patients with hypertension, atherosclerosis, or heart failure.

Cardioprotective effects of ramipril and losartan in right ventricular pressure overload in the rabbit: importance of kinins and influence on angiotensin II type 1 receptor signaling pathway.

BACKGROUND: The role of kinins in the cardioprotective effects of ACE inhibitors remains controversial. METHODS AND RESULTS: Right ventricular pressure overload in rabbits was produced by pulmonary artery banding for 21 days. Rabbits were untreated, or they received the ACE inhibitor ramipril with or without bradykinin B(1) and B(2) receptor blockers or the angiotensin (Ang) II type I (AT(1)) receptor blocker losartan. Pulmonary artery banding caused right ventricular hypertrophy, depressed papillary muscle contractility, and loss of Ang II contractile effects because of a signaling defect downstream of AT(1) receptors. Paradoxically, AT(1) receptor density and G protein alpha subunits alphaq and alphai1/2 increased. Inotropic responsiveness to the alpha-receptor agonist phenylephrine was normal. Ramipril preserved cardiac contractility, but this effect was attenuated by simultaneous use of kinin receptor blockers. Ramipril also maintained responsiveness to Ang II and prevented AT(1) receptor and G protein upregulation. The simultaneous use of a kinin receptor blocker attenuated but did not prevent upregulation in the AT(1) receptor and G protein. Losartan had no effect on baseline contractility, but it maintained cardiac inotropic responsiveness to Ang II, prevented upregulation of AT(1) receptors, but did not modify G protein upregulation. CONCLUSIONS: Pressure overload of the right ventricle decreases contractility, uncouples AT(1) receptors to downstream signaling pathways, and changes the expression of components of the AT(1) receptor signaling pathway. Ramipril attenuates these effects via kinins. Interventions that prevent local increases in Ang II or block AT(1) receptors also prevent decreased responsiveness of the AT(1) receptor in this model.

Long-term effects of nonselective endothelin A and B receptor antagonism in postinfarction rat: importance of timing.

BACKGROUND: Some controversy exists as to the effects of endothelin (ET) receptor antagonism on long-term post-myocardial infarction (MI) evolution, particularly as it relates to the timing of the intervention after MI (<24 hours versus 10 days). METHODS AND RESULTS: Sham rats and rats surviving an acute MI for >20 hours (n=301) were assigned to treatment with saline or the nonselective ET(A) and ET(B) receptor antagonist LU 420627 (LU) started <24 hours (early) or 10 days (late) after MI and continued for 100 days. Long-term LU treatment led to increased mortality of rats with large MI, regardless of the timing of initiation of therapy. Early initiation of LU reduced survival from 61% to 16% (P<0.001 versus untreated), and later initiation reduced survival to 36% (P=0.012 versus untreated and P<0.001 versus early initiation). Early initiation of LU led to scar thinning, further left ventricular (LV) dilatation, LV dysfunction, and an excessive rise in right ventricular systolic pressure. Later initiation of LU did not modify scar formation but resulted in LV dilatation and dysfunction compared with the untreated group. Cardiac fibrosis tended to increase in the LU-treated MI groups. LU in the sham group reduced cardiac endothelial constitutive nitric oxide synthase but did not modify the changes that occurred with a large MI. CONCLUSIONS: The use of the nonselective ET(A) and ET(B) receptor antagonist LU results in reduced survival, ventricular dilatation, and dysfunction whether started early or late after MI. Early initiation of LU resulted in scar expansion and a particularly unfavorable outcome.

Improvement of endocardial and vascular endothelial function on myocardial performance by captopril treatment in postinfarct rat hearts.

Background-Endocardial (EE) and myocardial capillary vascular endothelial (myocap VE) cells have been shown to modulate the contractile characteristics of myocardium in a calcium-dependent manner. We evaluated the endothelial-myocardial interaction in the rat postinfarction myocardial infarction (MI) model and the effects of captopril. Methods and Results-Wistar rats were divided into 4 groups treated for 4 weeks: (1) control; (2) infarcted controls (left anterior coronary artery ligation); (3) infarcted+captopril 2 g/L in drinking water; and (4) infarct+captopril+triton intracoronary injection. Coronary VE function was evaluated by infusion of serotonin in Langendorff preparations (n=31), and the myocardial contractile characteristics were investigated by use of isolated papillary muscles (n=44). Cardiac mRNA for endothelial constitutive nitric oxide synthase (ecNOS) was measured, and its cellular location was evaluated by immunohistochemistry. Serotonin-induced increase in coronary flow was decreased in infarct controls compared with controls (4.6% versus 53.4%, P<0.01) but not in the 2 infarct+captopril groups. Intracoronary triton injection decreased serotonin-induced coronary flow in the infarct+captopril+triton group. All MI groups had decreased total tension in isolated papillary muscles. EE removal by triton immersion decreased total tension in all groups except for infarct controls (3.3 versus 3.2 g/mm(2)). Cardiac ecNOS mRNA decreased in the control infarct group but remained normal in the infarct+captopril group. Conclusions-Chronic postinfarction endothelium-induced coronary vasodilatation is impaired, and both EE and myocap VE dysfunction contribute to myocardial depression. Captopril use prevents these abnormalities and the reduction of cardiac ecNOS mRNA.

Reduction of stroke incidence after myocardial infarction with pravastatin: the Cholesterol and Recurrent Events (CARE) study. The Care Investigators.

BACKGROUND: The role of lipid modification in stroke prevention is controversial, although increasing evidence suggests that HMG-CoA reductase inhibition may reduce cerebrovascular events in patients with prevalent coronary artery disease. METHODS AND RESULTS: To test the hypothesis that cholesterol reduction with pravastatin may reduce stroke incidence after myocardial infarction, we followed 4159 subjects with average total and LDL serum cholesterol levels (mean, 209 and 139 mg/dL, respectively) who had sustained an infarction an average of 10 months before study entry and who were randomized to pravastatin 40 mg/d or placebo in the Cholesterol and Recurrent Events (CARE) trial. Using prospectively defined criteria, we assessed the incidence of stroke, a prespecified secondary end point, and transient ischemic attack (TIA) over a median 5-year follow-up period. Patients were well matched for stroke risk factors and the use of antiplatelet agents (85% of subjects in each group). Compared with placebo, pravastatin lowered total serum cholesterol by 20%, LDL cholesterol by 32%, and triglycerides by 14% and raised HDL cholesterol by 5% over the course of the trial. A total of 128 strokes (52 on pravastatin, 76 on placebo) and 216 strokes or TIAs (92 on pravastatin, 124 on placebo) were observed, representing a 32% reduction (95% CI, 4% to 52%, P=0.03) in all-cause stroke and 27% reduction in stroke or TIA (95% CI, 4% to 44%, P=0.02). All categories of strokes were reduced, and treatment effect was similar when adjusted for age, sex, history of hypertension, cigarette smoking, diabetes, left ventricular ejection fraction, and baseline total, HDL, and LDL cholesterol and triglyceride levels. There was no increase in hemorrhagic stroke in patients on pravastatin compared with placebo (2 versus 6, respectively). CONCLUSIONS: Pravastatin significantly reduced stroke and stroke or TIA incidence after myocardial infarction in patients with average serum cholesterol levels despite the high concurrent use of antiplatelet therapy.

Comparison of candesartan, enalapril, and their combination in congestive heart failure: randomized evaluation of strategies for left ventricular dysfunction (RESOLVD) pilot study. The RESOLVD Pilot Study Investigators.

BACKGROUND: We investigated the effects of candesartan (an angiotensin II antagonist) alone, enalapril alone, and their combination on exercise tolerance, ventricular function, quality of life (QOL), neurohormone levels, and tolerability in congestive heart failure (CHF). METHODS AND RESULTS: Seven hundred sixty-eight patients in New York Heart Association functional class (NYHA-FC) II to IV with ejection fraction (EF) <0.40 and a 6-minute walk distance (6MWD) <500 m received either candesartan (4, 8, or 16 mg), candesartan (4 or 8 mg) plus 20 mg of enalapril, or 20 mg of enalapril for 43 weeks. There were no differences among groups with regard to 6MWD, NYHA-FC, or QOL. EF increased (P=NS) more with candesartan-plus-enalapril therapy (0.025+/-0.004) than with candesartan alone (0.015+/-0.004) or enalapril alone(0.015+/-0.005). End-diastolic (EDV) and end-systolic (ESV) volumes increased less with combination therapy (EDV 8+/-4 mL; ESV 1+/-4 mL; P<0.01) than with candesartan alone (EDV 27+/-4 mL; ESV 18+/-3 mL) or enalapril alone (EDV 23+/-7 mL; ESV 14+/-6 mL). Blood pressure decreased with combination therapy (6+/-1/4+/-1 mm Hg) compared with candesartan or enalapril alone (P<0.05). Aldosterone decreased (P<0.05) with combination therapy (23.2+/-5.3 pg/mL) at 17 but not 43 weeks compared with candesartan (0.7+/-7.8 pg/mL) or enalapril (-0.8+/-11. 3 pg/mL). Brain natriuretic peptide decreased with combination therapy (5.8+/-2.7 pmol/L; P<0.01) compared with candesartan (4. 4+/-3.8 pmol/L) and enalapril alone (4.0+/-5.0 pmol/L). CONCLUSIONS: Candesartan alone was as effective, safe, and tolerable as enalapril. The combination of candesartan and enalapril was more beneficial for preventing left ventricular remodeling than either candesartan or enalapril alone.

Tolerance to intravenous nitroglycerin in patients with congestive heart failure: role of increased intravascular volume, neurohumoral activation and lack of prevention with N-acetylcysteine.

To better understand the mechanism of nitrate tolerance in patients with congestive heart failure, 13 patients received a 24 h infusion of nitroglycerin (1.5 micrograms/kg body weight per min) with or without N-acetylcysteine (225 mg/kg per 24 h). The infusions were separated by a 24 h nitrate-free interval. By the end of the nitroglycerin infusion, mean arterial pressure had returned to baseline values and there was a significant increase in ventricular filling pressures and systemic vascular resistance compared with values after 1 h of treatment. The simultaneous infusion of N-acetylcysteine had no effect on these changes. Although a strict fluid restriction of 1.5 liters/day was maintained for 1 week before and throughout the study, after 24 h of nitroglycerin infusion there was a significant and similar degree of hemodilution whether nitroglycerin was infused alone (9.1 +/- 4.3%) or with N-acetylcysteine (8.7 +/- 4.1%). This hemodilution corresponded to an increase in intravascular volume of 745 +/- 382 ml, most of which occurred during the 1st h. Plasma renin activity increased and plasma atrial natriuretic peptide decreased during the infusion. The results of this study suggest that nitrate tolerance is multifactorial. In addition to the previously described pharmacologic tolerance to the effect of nitroglycerin on vascular smooth muscle, a capillary fluid shift from the extravascular to intravascular space appears to be involved, especially during the 1st h of the infusion. A third mechanism, reflex neurohumoral activation, also seems to contribute to the genesis of nitroglycerin tolerance.

Prognostic value of neurohumoral activation in patients with an acute myocardial infarction: effect of captopril.

OBJECTIVES: This study attempted to evaluate whether neurohumoral activation at the time of hospital discharge in postinfarction patients helps to predict long-term prognosis and whether long-term therapy with the angiotensin-converting enzyme inhibitor captopril modifies this relation. BACKGROUND: Neurohumoral activation persists at the time of hospital discharge in a large number of postinfarction patients. The Survival and Ventricular Enlargement (SAVE) study demonstrated that the angiotensin-converting enzyme inhibitor captopril improves survival and decreases the development of severe heart failure in patients with left ventricular dysfunction (left ventricular ejection fraction < or = 40%) but no overt postinfarction heart failure. METHODS: In 534 patients in the SAVE study, plasma neurohormone levels were measured a mean of 12 days after infarction. Patients were then randomized to receive captopril or placebo and were followed up for a mean (+/- SD) of 38 +/- 6 months (range 24 to 55). The association between activation of plasma neurohormones at baseline and subsequent cardiovascular mortality or the development of heart failure was assessed with and without adjustment for other important prognostic factors. RESULTS: By univariate analysis, activation of plasma renin activity and aldosterone, norepinephrine, atrial natriuretic peptide and arginine vasopressin levels were related to subsequent cardiovascular events, whereas epinephrine and dopamine levels were not. By multivariate analysis, only plasma renin activity (relative risk 1.6, 95% confidence interval [CI] 1.0 to 2.5) and atrial natriuretic peptide (relative risk 2.2, 95% CI 1.3 to 3.8) were independently predictive of cardiovascular mortality, whereas the other neurohormones were not. Only plasma renin activity and aldosterone, atrial natriuretic peptide and arginine vasopressin were independent predictors of the combined end points of cardiovascular mortality, development of severe heart failure or recurrent myocardial infarction. Except for 1-year cardiovascular mortality, the use of captopril did not significantly modify these relations. CONCLUSIONS: Neurohumoral activation at the time of hospital discharge in postinfarction patients is an independent sign of poor prognosis. This is particularly true for plasma renin activity and atrial natriuretic peptide. Except for 1-year cardiovascular mortality, captopril does not significantly modify these relations.

A reappraisal of exercise electrocardiographic indexes of the severity of ischemic heart disease: angiographic and scintigraphic correlates.

OBJECTIVES: We explored how the exercise electrocardiographic (ECG) indexes generally presumed to signify severe ischemic heart disease (IHD) correlate with coronary angiographic and scintigraphic myocardial perfusion findings. BACKGROUND: In exercise testing, it is generally assumed that the early onset of ST segment depression and its occurrence at a low rate-pressure product (ischemic threshold); the amount of maximal ST segment depression; and a horizontal or downsloping ST segment and its prolonged recovery after exercise signify more severe IHD. However, the relation of these indexes to coronary angiographic and exercise myocardial perfusion findings in patients with IHD is unclear. METHODS: We prospectively carried out a symptom-limited 12-lead Bruce protocol thallium-201 single-photon emission computed tomographic (SPECT) exercise test in 66 consecutive subjects with stable angina, > or = 70% stenosis of at least one coronary artery, normal rest ECG and left ventricular wall motion and a prior positive exercise ECG. The above ECG indexes, vessel disease (VD), a VD score and the quantitative thallium-SPECT measures of the extent, maximal deficit and redistribution gradient of the perfusion abnormality were characterized. RESULTS: Maximal ST segment depression could not differentiate the number of diseased vessels; was not related to VD score, maximal thallium deficit or redistribution gradient; but was related to the extent of perfusion abnormality (r = 0.29, 95% confidence interval [CI] 0.08 to 0.52, p = 0.02). Time of onset of ST segment depression correlated inversely only with VD (r = -0.22, 95% CI -0.44 to -0.05, p < 0.05), whereas the ischemic threshold had low inverse correlation only with VD score (r = -0.25, 95% CI -0.47 to -0.01, p < 0.05) and the redistribution gradient (r = -0.33, 95% CI -0.53 to -0.10, p < 0.01). A horizontal or downsloping compared with an upsloping ST segment did not demonstrate more severe angiographic and scintigraphic disease. Recovery time did not correlate with angiographic and scintigraphic findings, and correlations between angiographic and scintigraphic findings were also low or absent. CONCLUSIONS: In this homogeneous study group, the exercise ECG indexes did not necessarily signify more severe IHD by angiographic and scintigraphic criteria. Lack of concordance between the exercise ECG, angiography and myocardial scintigraphy suggests that these diagnostic modalities examine different facets of myocardial ischemia, underscoring the need for caution in the interpretation of their results.

Chronic renal and neurohumoral effects of the calcium entry blocker nisoldipine in patients with congestive heart failure.

Nisoldipine, a calcium entry blocker, was given to 10 patients with congestive heart failure. During a 2 month follow-up period, 7 of the 10 patients were readmitted with pulmonary edema; daily furosemide doses were increased (128 +/- 87 to 192 +/- 135 mg/day, p less than 0.01), and plasma creatinine increased (1.5 +/- 0.5 to 1.8 +/- 0.6 mg/dl, p less than 0.05) (all values mean +/- SD). Despite this unfavorable clinical course, nisoldipine caused some beneficial chronic (1 month) hemodynamic effects. It decreased systemic vascular resistance (from 1,781 +/- 229 to 1,306 +/- 345 dynes X s X cm-5, p less than 0.01), decreased mean arterial pressure (from 88 +/- 0 to 74 +/- 4 mm Hg, p less than 0.001) and increased stroke volume index (from 27 +/- 6 to 33 +/- 9 ml/min per m2, p less than 0.02). Heart rate, pulmonary capillary wedge pressure and stroke work index did not change. However, nisoldipine's chronic renal and neurohumoral effects were not as favorable. These were assessed during a 5 hour water load (15 ml/kg body weight of 5% dextrose in water) and compared with the effects of a water load before therapy. Nisoldipine did not change creatinine clearance or sodium excretion, but decreased water excretion (from 58 +/- 35 to 46 +/- 40% of water load in 5 hours). Over this 5 hour study, mean plasma vasopressin was also higher with nisoldipine (1.9 +/- 2.3 versus 2.7 +/- 3.2 pg/ml, p less than 0.05), but mean plasma aldosterone was lower (67 +/- 31 to 47 +/- 27 mg/dl, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Markedly different effects on ventricular remodeling result in a decrease in inducibility of ventricular arrhythmias.

OBJECTIVES: The purpose of this study was to determine whether the type and extent of ventricular remodeling after infarction influence inducibility of ventricular arrhythmias after infarction. BACKGROUND: Although serious ventricular arrhythmias after infarction are related to ventricular dysfunction, the relation between inducibility of ventricular arrhythmias and ventricular remodeling remains incompletely understood. METHODS: Rats that survived ligation of the left anterior descending coronary artery (n = 218) were randomized to receive placebo (saline solution) or captopril or propranolol therapy and were followed up for 5 weeks. Hemodynamic and neurohumoral blood measurements were obtained, and therapy was stopped. Two days later, susceptibility to ventricular arrhythmias was assessed by programmed electrical stimulation, and hearts were prepared for pathologic studies. RESULTS: Placebo-treated rats with a large myocardial infarction had ventricular dysfunction, marked neurohumoral activation, ventricular enlargement (endocardial circumference 16 +/- 3 [mean +/- SD] to 20 +/- 4 mm, p < 0.05) and increased cardiac fibrosis (volume density of collagen 2.3 +/- 0.8% to 5.6 +/- 2.4%, p < 0.05). In many rats this resulted in easily inducible ventricular arrhythmias (inducibility quotient 4.9 +/- 2.2). Captopril attenuated the development of ventricular dysfunction, neurohumoral activation, ventricular hypertrophy and dilation (endocardial circumference 18 +/- 3 mm) and cardiac fibrosis (3.1 +/- 0.8%, p < 0.05). These modifications were accompanied by decreased inducibility of ventricular arrhythmias (inducibility quotient 1.1 +/- 2.0, p < 0.05). Propranolol did not prevent ventricular dysfunction, had variable effects on neurohumoral activation and led to increased ventricular dilation (endocardial circumference 25 +/- 4 mm, p < 0.05) and cardiac fibrosis (7.7 +/- 1.2%, p < 0.05). Nevertheless, these morphologic changes led to decreased inducibility of ventricular arrhythmias (inducibility quotient 2.2 +/- 2.5%, p < 0.05). CONCLUSIONS: This study indicates that the inducibility of ventricular arrhythmias can be reduced as a result of markedly different effects on ventricular remodeling, indicating that the relation between ventricular remodeling, arrhythmias and survival is more complex than previously thought.