Jens Berning

Rapid Estimation of Left Ventricular Ejection Fraction in Acute Myocardial Infarction by Echocardiographic Wall Motion Analysis

Echocardiographic estimates of left ventricular ejection fraction (ECHO-LVEF) in acute myocardial infarction (AMI) were obtained by a new approach, using visual analysis of left ventricular wall motion in a nine-segment model. The method was validated in 41 patients using radionuclide ventriculography (RNV) and contrast ventriculography measurements of LVEF for comparison. ECHO-LVEF from the 41 patients correlated well with the reference methods (y = 1.5x - 14.7, r = 0.93; linear regression analysis; 95% confidence limit for a single determination of ECHO-LVEF was 17.2). Interobserver variability by linear regression was r = 0.89, SEE = 7.1 with a mean difference between paired observations of -1.5 +/- 6.9 (SD). In a random sample of 18 patients (45 observations), ECHO-LVEF allowed separation between RNV-LVEF values greater than or equal to 40 and less than 40, representing low and high risk groups following AMI. Thus, the results showed that simple, readily available wall motion-derived estimates of LVEF were as closely associated with LVEF measured by standard reference methods as were previously published, more cumbersome, planimetric echocardiographic methods. Reporting on global LVEF function in LVEF units rather than in nonstandardized wall motion scores of index values may facilitate intra- and interhospital communication and the use of optimized echocardiographic risk stratification after AMI.

Interactions between digoxin and potassium‐sparing diuretics

A kinetic and hemodynamic study of digoxin was performed in six healthy subjects and similar studies were performed during digoxin with spironolactone and with triamterene. Spironolactone reduced renal tubular secretion of digoxin and attenuated its positive inotropic effect (evaluated by systolic time intervals and echocardiography) and triamterene reduced the extrarenal elimination of digoxin, but induced no changes in digoxin‐elicited inotrophy. It is suggested that the renal handling of digoxin is influenced by the intracellular potassium concentration in the renal tubular cell. The results indicate a drug‐receptor interaction between spironolactone metabolites and digoxin at the hypothetical inotropic digitalis receptor. Amiloride has been reported to suppress digoxin inotropism, whereas spironolactone induces minor inhibition and triamterene does not affect digoxin inotropism.

Interobserver Agreement and Accuracy of Bedside Estimation of Right and Left Ventricular Ejection Fraction in Acute Myocardial Infarction

Ninety-eight patients with acute myocardial infarction were examined by 3 clinicians who, independently of each other, gave an estimate of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) in each patient. Their estimates were based on physical examination, chest x-ray, electrocardiogram, patient history and clinical course during admission. Ejection fractions were estimated as belonging to 1 of 4 categories: normal (LVEF greater than or equal to 0.53, RVEF greater than or equal to 0.57), mildly reduced (LVEF 0.40 to 0.52, RVEF 0.45 to 0.56), moderately reduced (LVEF 0.30 to 0.39, RVEF 0.35 to 0.44) or severely reduced (LVEF less than 0.30, RVEF less than 0.35). Radionuclide ventriculography was carried out immediately after the physical examination. LVEF was correctly estimated in 43% of all examinations, deviated from radionuclide LVEF by 1 LVEF category in 45% and by 2 LVEF categories in 12%. The 3 clinicians agreed on estimated LVEF in only 32% of the patients. RVEF was correctly estimated in 67% of the examinations, but none of the clinicians identified greater than 43% of the relatively few patients with reduced radionuclide RVEF and they greatly disagreed as to who among the patients had a reduced RVEF. Previous myocardial infarction, electrocardiographic infarct location, Killip class, physical signs of left- and right-sided heart failure, radiographic pulmonary congestion and cardiomegaly were analyzed to determine which were the most helpful in predicting LVEF and RVEF. The results disclosed that several variables, traditionally believed to be reliable indexes of reduced ventricular function, were surprisingly poor predictors of LVEF and RVEF.

Risk Stratification after Acute Myocardial Infarction by Means of Echocardiographic Wall Motion Scoring and Killip Classification

In order to perform risk stratification, 195 consecutive, unselected patients with acute myocardial infarction (AMI) underwent independent echocardiographic and clinical evaluation of their left ventricular function by means of the wall motion index (WMI) and Killip classification 5 days after AMI. The patients were prospectively allocated to a low, medium or high risk class depending on WMI alone, and the 1-year mortality in these classes was 2, 34 and 37%, respectively (p < 0.0001). The 1-year mortality of the patients in Killip class I, II, or III and IV was 6, 26 and 48%, respectively (p < 0.00001). The number of patients allocated to the low risk group by means of WMI was 87, and the number of patients in Killip class I was 86. Since these groups were not identical, a total of 103 patients, i.e. 53% of the study population, could be identified as low risk patients regarding 1-year mortality 5 days after AMI, when WMI and Killip classification were used in combination. We conclude that the combination of echocardiographic and clinical evaluation of left ventricular function after AMI provides a strong and yet very simple procedure to identify low risk patients, which could be easily implemented in the routine work of coronary care units.

Echocardiographic Algorithms for Admission and Predischarge Prediction of Mortality in Acute Myocardial Infarction

To develop improved prognostic algorithms for routine bedside use in acute myocardial infarction (AMI), the prognostic value concerning 2- and 12-month mortality of an early (within 72 hours after AMI) resting echocardiogram was defined in 201 consecutive patients. The relation between (1) the clinical variables (age, sex, prior and repeat AMI, arrhythmias, cardiac arrest, early [less than 72 hours after AMI] and late heart failure, early and maximal in-hospital Killip class, and maximal creatine kinase-MB isoenzyme), (2) early myocardial performance by echocardiography, and (3) mortality was characterized by Kaplan-Meier survival curves and receiver-operating characteristic curves based on Cox regression model. Only age and clinical heart failure in terms of the maximal in-hospital Killip class had independent predictive value of death (p less than 0.05) when an early echocardiographic estimate of left ventricular ejection fraction (LVEF) was included in the multivariate statistical models. The following 2 optimized algorithms for admission and predischarge calculation of risk of mortality at 2 and 12 months were developed based on the Cox model, using combinations of age, maximal Killip class and early echocardiographic LVEF: mortality at 2 months = 1 - exp - [0.051 x exp [0.044 x (age -60) - (0.117 x (LVEF - 40)]]; and mortality at 1 year = 1 - exp - [0.101 x exp [0.408 x (maxKillip - 1) - (0.061 x (LVEF - 40)]]. Discriminative power for prediction of mortality of the predischarge algorithm in an independent population of 195 patients 5 days after AMI compared favorably with that obtained in the original population, confirming the validity of the proposed method of prognostication.

Benefit of converting enzyme inhibition on left ventricular volumes and ejection fraction in patients receiving β-blockade after myocardial infarction

β-blockers reduce infarct size and improve survival after acute myocardial infarction (MI). Post-MI angiotensin-converting enzyme inhibition also improves survival and may attenuate left ventricular (LV) dilatation. We evaluated the effect of early enalapril treatment on LV volumes and ejection fraction (EF) in patients on concomitant β-blockade after MI. Intravenous enalaprilat or placebo was administered <24 hours after MI and was continued orally for 6 months. LV volumes were assessed by echocardiography 3 ± 2 days, 1 and 6 months after MI. Change in LV diastolic volume during the first month was attenuated with enalapril (2.7 vs placebo 6.5 ml/m2 change; p < 0.05), and significantly lower LV diastolic and systolic volumes were observed with enalapril treatment compared with placebo at 1 month (enalapril 47.223.9 vs placebo 53.129.2 ml/m2; p < 0.05) and at 6 months (enalapril 47.924.8 vs placebo 53.829.6 ml/m2; p < 0.05). EF was also significantly higher 1 month after MI in these patients (enalapril 50.4% vs placebo 46.4%; p < 0.05). Our data demonstrate that early enalapril treatment attenuates LV volume expansion and maintains lower LV volumes and higher EF in patients receiving concurrent β-blockade after MI. A possible additive effect of combined therapy should be evaluated prospectively.

Effects of early enalapril treatment on global and regional wall motion in acute myocardial infarction

Angiotensin-converting-enzyme inhibitor therapy can preserve left ventricular (LV) function and geometric features and improve survival in subsets of patients with acute myocardial infarction (AMI). We investigated the effect of enalapril treatment initiated < 24 hours after AMI on global and regional echocardiographic wall motion indexes obtained at 2 to 5 days and at 1 and 6 months in 428 consecutive patients enrolled in the randomized, placebo-controlled Cooperative New Scandinavian Enalapril Survival Study II. In anterior AMIs, the non-infarct-zone index deteriorated in the placebo group but remained unchanged in the enalapril-treated group (0.18 vs 0.02; p < or = 0.05), an effect related to attenuated LV volume expansion. No treatment effects were observed in nonanterior AMIs or in the entire unselected population. Thus in an unselected population with AMI, early enalapril treatment had no effect on LV function; yet in patients with anterior infarcts, LV function was maintained through preservation of function in the noninfarcted myocardium.

Sensitivity and specificity of echocardiographic identification of patients eligible for safe early discharge after acute myocardial infarction

In a prospective clinical trial of 195 consecutive unselected patients with acute myocardial infarction (AMI), systematic blinded clinical and echocardiographic examinations were performed by two observers on day 5. The purpose was to define low-risk patients with regard to in-hospital and 2-month mortality and predict the potential costs (lost patient lives) and benefits (saved in-patient days) if as a routine procedure these low-risk patients were discharged earlier. By design, low-risk patients as defined by clinical criteria were allocated to discharge on days 7 to 10 and by echocardiographic criteria on days 5 to 7 after AMI. The sensitivity of the echocardiographic low-risk identification procedure was more than twofold higher than the sensitivity of clinical low-risk identification (49% vs 24%). Both procedures were safe with a specificity of 100% for cardiac mortality. Optimal identification of low-risk patients was provided by combining data from echocardiographic and clinical evaluations (sensitivity 59%). Results of the study suggest that a bedside echocardiographic approach to estimation of global left ventricular function is more sensitive and equally specific and therefore more efficient for risk stratification on post-AMI day 5 than clinical examination alone. Thus echocardiographic examination allows identification of a larger subset of patients with AMI (greater than 40% of the population alive on day 5) who can be discharged earlier and safely, with a potential saving of in-patient days of 436 days in 87 low-risk patients minus the cost of echocardiographic studies in 195 patients. However, the best prediction was obtained by combining clinical and echocardiographic examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Systolic time intervals during spironolactone treatment of digitalized and non-digitalized patients with ischaemic heart disease

SummaryThe effect of spironolactone on cardiac contractility indices was studied by externally recording systolic time intervals in four digitalized and four non-digitalized patients with ischaemic heart disease. A negative inotropic effect was found after spironolactone 100mg b.i.d. in all eight patients, as measured by an increase in pre-ejection period index PEPI (p<0.01), and the ratio between pre-ejection period and left ventricular ejection time PEP/LVET (p<0.001), while pre- and afterload remained constant. As expected, digoxin exerted a positive inotropic effect, as a decrease was observed in PEPI (p<0.01), and PEP/LVET (p<0.001). It was not possible to ascertain whether the observed effect was caused by a pharmacological interaction at receptor level between spironolactone and digoxin, or indirectly to changes in endogenous substances e.g. aldosterone. The results suggest that spironolactone may have unintended side effects in patients with severe heart failure and that its use be reevaluated.

Relative Prognostic Value of Clinical Heart Failure and Early Echocardiographic Parameters in Acute Myocardial Infarction

The relative prognostic value of clinical heart failure and early M-mode and 2-dimensional echocardiographic indexes of left ventricular performance was compared in a study of 205 consecutive patients with acute myocardial infarction (AMI). Statistical analysis showed that an early wall motion score was a stronger predictor of 1-year mortality than the occurrence of clinical heart failure early, late or at any time during the hospital course of AMI. The finding of clinical heart failure had an independent prognostic value of intermediate strength. M-mode echocardiographic parameters only had a weak independent prognostic value, possibly related to their content of information on left ventricular end-systolic dimension.