Clinical consequences of hospital variation in use of oral anticoagulant therapy after first-time admission for atrial fibrillation.

OBJECTIVE: To analyse how hospital factors influence the use of oral anticoagulants (OAC) in atrial fibrillation (AF) patients and address the clinical consequences of hospital variation in OAC use. DESIGN AND SUBJECTS: By linkage of nationwide Danish administrative registers we conducted an observational study including all patients with a first-time hospitalization for AF between 1995 and 2004 as well as prescription claims for OAC. Multivariable logistic regression analysis was used to evaluate hospital factors associated with prescription of OAC therapy. Cox proportional-hazard models were used to estimate the risk of re-hospitalization for thromboembolism and haemorrhagic stroke with respect to discharge from a low, intermediate, or high OAC use hospital. RESULTS: Overall 40,133 (37%) out of 108,504 patients received OAC; ranging from 17% to 50% between the hospitals with the lowest and highest OAC use, respectively. Cardiology departments had the highest use of OAC, but neither tertiary university hospitals nor high volume hospitals had higher OAC use than local community hospitals and low volume hospitals. Risk of a thromboembolic event was significantly increased amongst patients from hospitals with a low OAC use (hazard ratio 1.16, confidence interval 1.10-1.22). Notably, higher OAC use was not associated with a higher risk of haemorrhagic stroke. CONCLUSION: In Denmark between 1995 and 2004, there was a major hospital variation in AF patients receiving OAC, and consequently, more thromboembolic events were observed amongst patients from low OAC use hospitals. Our study emphasizes the need for a continued vigilance on implementation of international AF management guidelines.

Temporal decline in the prognostic impact of a recurrent acute myocardial infarction 1985 to 2002.

OBJECTIVE: To investigate trends in case-fatality and prognostic impact from recurrent acute myocardial infarction (re-AMI) during 1985-2002. DESIGN: Retrospective cohort study using nationwide administrative data from Denmark. SETTINGS: National registries on hospital admissions and causes of death were linked to identify patients with first AMI, re-AMI and subsequent prognosis. PATIENTS: Patients > or =30 years old with a discharge diagnosis of AMI during 1985-2002 were tracked for first hospital admission for re-AMI 1 year after discharge. MAIN OUTCOME MEASURES: One-year case-fatality. RESULTS: 166 472 patients were identified with a first AMI; 14 123 developed re-AMI. One-year crude case-fatality from first AMI/re-AMI was 39% versus 43% in 1985-1989 and 25% versus 29% in 2000-2002, respectively. In 1985-89, 35 795 patients survived to discharge (71%); of these 2.5% experienced reinfarction within 30 days (early reinfarction) and an additional 9.0% reinfarction within days 31-365 (late re-AMI). Re-AMI carried a poor prognosis in 1985-1989 compared to no re-AMI with age- and sex-adjusted relative risk of 1-year case-fatality of 7.5 (95% CI: 6.9 to 8.5) from early re-AMI and 11.7 (95% CI: 11.0 to 12.4) from late re-AMI. In 2000-2002, 23 552 patients (86%) survived to discharge; 4.4% had early re-AMI and 6.6% late re-AMI. Adjusted relative risk of 1-year case-fatality had declined to 2.1 (95% CI: 1.9 to 2.5) from early re-AMI and 5.6 (95% CI: 5.1 to 6.2) from late re-AMI compared to patients without reinfarction. CONCLUSION: Prognosis after AMI has improved substantially during the latest two decades and extends to patients with re-AMI.

Temporal trends in the prescription of vitamin K antagonists in patients with atrial fibrillation.

OBJECTIVES: Anticoagulation therapy is recommended in patients with atrial fibrillation (AF) and risk factors for stroke. We studied the temporal trends in the prescription of vitamin K antagonists (VKA) in patients with a first hospital diagnosis of AF in Denmark, 1995-2002. DESIGN: The Danish National Hospital Registry was used to identify subjects with a first hospital diagnosis of AF and the Danish Register of Medical Products Statistics to determine the proportion of these patients who claimed a prescription of VKA within 3 months from discharge. RESULTS: Amongst 68 546 patients aged 50-99 years with a diagnosis of AF who survived 3 months following discharge, 24 991 (36%) patients claimed a prescription of VKA within 3 months. In both men and women a gradual increase in the use of VKA with time was observed, the relative increase being largest amongst the 80- to 99-year olds. In all age groups, the prescription of VKA was lower in women than in men, including patients with a prior or concurrent stroke. CONCLUSIONS: From 1995 to 2002 the proportion of AF patients receiving VKA therapy increased significantly but the use of VKA therapy amongst women was lagging behind that of men. Even in patients with AF and prior stroke, the use of VKA seems to be less than optimal.

Pharmacological modulation of the ATP sensitive potassium channels during repeated coronary occlusions: no effect on myocardial ischaemia or function.

BACKGROUND: Repeated episodes of myocardial ischaemia may lead to ischaemic preconditioning. This is believed to be mediated by the ATP sensitive potassium channels. OBJECTIVE: To examine the effect of pharmacological modulation of the ATP sensitive potassium channels during repeated coronary occlusions. DESIGN: Double blind, double dummy study. METHODS: 38 patients with a proximal stenosis of the left anterior descending coronary artery and no visible coronary collateral vessels underwent three identical 90 second balloon occlusions, each followed by five minutes of reperfusion. The patients were randomised to pinacidil 25 mg, glibenclamide 10.5 mg, or matching placebo 90 minutes before the start of the procedure. Myocardial ischaemia was measured by continuous monitoring of ECG ST segment changes. Changes in left ventricular function were recorded with a miniature radionuclide detector, and angina was scored on the Borg scale. RESULTS: In all patients the first balloon occlusion led to significant ST segment elevation, a clear decrease in left ventricular ejection fraction, and angina pectoris. This response was not attenuated at the second or third balloon occlusion, either in the placebo group or in the patients pretreated with pinacidil or glibenclamide. CONCLUSIONS: Under the given experimental conditions, this randomised and double blind study did not support the view that the human myocardium has an intrinsic protective mechanism that is activated by short lasting episodes of ischaemia.

Quality assessment of pacemaker implantations in Denmark.

AIMS: Quality assessment of therapeutic procedures is essential to insure a cost-effective health care system. Pacemaker implantation is a common procedure with more than 500,000 implantations world-wide per year, but the general complication rate is not well described. We studied procedure related complications for all implantations performed in an entire nation over a 3-year period. METHODS AND RESULTS: A prospective study of complications related to 99% of the 5648 primary pacemaker implantations performed in the 12 Danish pacemaker centres in 1997-1999 was carried out. Overall 76% of the patients received a physiological pacemaker system and 91% received the optimal pacing mode according to international guidelines. Perioperative complications requiring reoperation were: haematoma 0.3%, atrial lead related 1.9%, ventricular lead related 1.7%. Late complications requiring reoperation were: infection 02%, atrial lead related 13%, ventricular lead related 1.2%. The complication rate decreased over the study period, but overall the complication rate was higher than expected and showed considerable variation between centres. CONCLUSIONS: Our results demonstrate that sensitive data such as complications related to pacemaker implantations can be collected on a national basis. We suggest that a reoperation rate higher than 3% for atrial as well as ventricular pacing electrodes in the individual implanting centre should cause the centre to evaluate carefully the procedure as well as the performance of the individual implanter.

In-hospital heart failure, first-year ventricular dilatation and 10-year survival after acute myocardial infarction.

BACKGROUND: Little is known about the factors that determine long-term prognosis in patients who have survived the first year after acute myocardial infarction (AMI). AIMS: To study the influence of left and right ventricular (LV and RV) dilatation during the first year after AMI on subsequent 10-year survival in comparison with in-hospital heart failure and other established prognostic indices. METHODS: Radionuclide ventriculography was performed before the era of thrombolysis and post-infarction ACE-inhibition in 57 patients with AMI at hospital discharge and again 1 year later, and compared with survival the ensuing 10 years. RESULTS: After 1 year significant LV-dilatation (>20%) had occurred in 32 (56%) patients. One year after the re-investigation the mortality in these was 19% vs. 0% in patients without dilatation (P=0.02); after 5 years the difference was 38 vs. 12% (P=0.02), whereafter it declined and became insignificant at 10 years. Neither RV-dilatation, nor LVEF determined at discharge or at the 1-year reinvestigation influenced long-term survival. In contrast, clinical heart failure recorded during the hospital stay had a sustained negative influence on long-term survival. CONCLUSION: Progressive LV dilatation after discharge and clinical heart failure during the hospital stay are both determinants of late survival after AMI, whereas LV ejection fraction at hospital discharge or 1 year later has little, if any, effect on survival beyond 1-year post-AMI.

[Is digoxin effective in the treatment of heart insufficiency in patients with sinus rhythm?]. / Er digoxin virksomt til behandling af hjerteinsufficiens hos patienter med sinusrytme?

Since its introduction in 1785, digitalis has been the cornerstone in the treatment of heart failure, although there during the last 20 years have been an increasing number of critical voices questioning its use in patients with sinus rhythm. In 1997 the Digitalis Investigation Group published the so far largest randomized trial on the use of digoxin in patients with heart failure (DIG-trial). All the included patients had sinus rhythm, and all received an ACE-inhibitor. Digoxin had no effect on mortality, but caused a decrease in hospitalizations. Based on the DIG-study, several minor clinical trials and two large withdrawal studies (RADIANCE and PROVED) it now seems clear that digoxin still has a role in the management of heart failure, not only in patients with atrial fibrillation, but also in patients with sinus rhythm.

Bronchial artery perfusion scintigraphy to assess bronchial artery blood flow after lung transplantation.

UNLABELLED: The bronchial arterial system is inevitably interrupted in transplanted lungs when removing the organs from the donor, but it can be reestablished by direct bronchial artery revascularization (BAR) during implantation. The purpose of this study was to visualize and quantify the distribution of bronchial artery perfusion after en bloc double lung transplantation with BAR, by injecting radiolabeled macroaggregated albumin directly into the bronchial artery system. METHODS: BAR was performed using the internal mammary artery as conduit. Patients were imaged 1 mo (n = 13) or 2 y (n = 9) after en bloc double lung transplantation with BAR. Immediately after bronchial arteriography, 100 MBq macroaggregated albumin (45,000 particles) were injected through the arteriographic catheter. Gamma camera studies were then acquired in the anterior position. At the end of imaging, with the patient remaining in exactly the same position, 81mKr-ventilation scintigraphy or conventional intravenous pulmonary perfusion scintigraphy or both were performed. Images were evaluated by visual analysis, and a semiquantitative assessment of the bronchial arterial supply to the peripheral parts of the lungs was obtained with conventional pulmonary scintigraphy. RESULTS: The bronchial artery scintigraphic images showed that the major part of the bronchial arterial flow supplied central thoracic structures, but bronchial artery perfusion could also be demonstrated in the peripheral parts of the lungs when compared with conventional pulmonary scintigraphy. There were no differences between scintigrams obtained from patients studied 1 mo and 2 y post-transplantation. CONCLUSION: Total distribution of bronchial artery supply to the human lung has been visualized in lung transplant patients. This study demonstrates that this nutritive flow reaches even the most peripheral parts of the lungs and is present 1 mo as well as 2 y after lung transplantation. The results suggest that bronchial artery revascularization may be of significance for the long-term status of the lung transplant.

Divergent cardiac response to exercise in essential hypertension vs. normotension and the effect of enalapril.

The aims of this study were to examine (1) the cardiac response to exercise in essential hypertension and (2) the effect of long-term enalapril treatment on cardiac reserve. Ten normotensive control subjects and 15 patients with moderate, essential hypertension underwent radionuclide ventriculography during graded, supine exercise (0 W-50 W-100 W). The hypertensive patients were studied during monotherapy using hydrochlorothiazide and 3 and 12 months after supplementation with enalapril 10-40 mg o.d. During exercise, the control subjects demonstrated a 17% increase in left ventricular ejection fraction (LVEF) mediated by a 30% decrease in end-systolic volume, a small increase in stroke volume and a minor biphasic (increase-decrease) change in end-diastolic volume. In the hypertensive patients, both the end-diastolic and the end-systolic volume increased substantially with no increase in LVEF, although stroke volume increased by 33%. Long-term therapy with enalapril induced only a minor change towards a more normal pattern of cardiac response to exercise. The hypertensive patients increased their stroke volume during exercise by recruiting preload reserve instead of increasing contractility. Long-term treatment with enalapril had little, if any, effect on this abnormal cardiac response.

Continuous monitoring of global left ventricular ejection fraction during percutaneous transluminal coronary angioplasty.

Continuous monitoring of left ventricular (LV) function during percutaneous transluminal coronary angioplasty (PTCA) was performed in 40 patients (53 +/- 2 years) with a miniature, nuclear detector system after labeling the patients' red blood cells with technetium-99m. Balloon dilation (113 seconds, range 60 to 240) induced on average a 0.12 ejection fraction (EF) unit (19%) decrease in the LVEF, which was explained by a 34% increase in end-systolic counts. Balloon dilation of the left anterior descending artery (n = 23) produced a decrease in the LVEF of 0.17 +/- 0.13 EF units compared with the decrease of 0.06 +/- 0.07 EF units in patients undergoing dilation of the left circumflex artery (n = 9) and 0.05 +/- 0.04 EF units in patients treated for a stenosis of the right coronary artery (n = 8), (p = 0.02). Balloon deflation was associated with an immediate return to pre-PTCA levels. In 10 patients with 2 identical balloon occlusions, the second occlusion led to a significantly less decrease in the LVEF (0.41 +/- 0.14 vs 0.44 +/- 0.15) and electrocardiographic ST-segment deviation (88 +/- 54 microV vs 65 +/- 42 microV) than the first. We conclude that PTCA is associated with an abrupt transient decrease in the LVEF. The effect of balloon occlusion of the left anterior descending artery is more pronounced than balloon occlusion of the left circumflex and the right coronary arteries. Neither single nor multiple balloon occlusions were associated with post-PTCA global LV dysfunction, whereas the lesser degree of LV dysfunction and electrocardiographic signs of myocardial ischemia during the second of 2 identical balloon occlusions suggests that preconditioning can be induced during PTCA.

Monitoring of left ventricular ejection fraction with a miniature, nonimaging nuclear detector: accuracy and reliability over time with special reference to blood labeling.

BACKGROUND: The purpose of this study was to determine the accuracy of determinations of left ventricular ejection fraction (LVEF) by a nonimaging miniature nuclear detector system (Cardioscint) and to evaluate the feasibility of long-term LVEF monitoring in patients admitted to the coronary care unit, with special reference to the blood-labeling technique. METHODS AND RESULTS: Cardioscint LVEF values were compared with measurements of LVEF by conventional gamma camera radionuclide ventriculography in 33 patients with a wide range of LVEF values. In 21 of the 33 patients, long-term monitoring was carried out for 1 to 4 hours (mean 186 minutes), with three different kits: one for in vivo and two for in vitro red blood cell labeling. The stability of the labeling was assessed by determination of the activity of blood samples taken during the first 24 hours after blood labeling. The agreement between Cardioscint LVEF and gamma camera LVEF was good with automatic background correction (r = 0.82; regression equation y = 1.04x + 3.88) but poor with manual background correction (r = 0.50; y = 0.88x - 0.55). The agreement was highest in patients without wall motion abnormalities. The long-term monitoring showed no difference between morning and afternoon Cardioscint LVEF values. Short-lasting fluctuations in LVEFs greater than 10 EF units were observed in the majority of the patients. After 24 hours, the mean reduction in the physical decay-corrected count rate of the blood samples was most pronounced for the two in vitro blood-labeling kits (57% +/- 9% and 41% +/- 3%) and less for the in vivo blood-labeling kit (32% +/- 26%). This "biologic decay" had a marked influence on the Cardioscint monitoring results, demanding frequent background correction. CONCLUSION: A fairly accurate estimate of LVEF can be obtained with the nonimaging Cardioscint system, and continuous bedside LVEF monitoring can proceed for hours with little inconvenience to the patients. Instability of the red blood cell labeling during long-term monitoring necessitates frequent background correction.

Technetium-99m sestamibi and tetrofosmin myocardial single-photon emission tomography: can we use the same reference data base?

The aim of this study was to compare technetium-99m labelled tetrofosmin and sestamibi myocardial perfusion single-photon emission tomography (SPET) with one common sestamibi reference file for bull's eye imaging, with quantitation of the extent and severity of perfusion defects. Twenty patients suspected or known to have coronary artery disease participated in the study. Patients first underwent routine sestamibi myocardial SPET over 2 days, receiving doses of 400-600 MBq at stress and 600-800 MBq at rest. Then within the same week a 1-day tetrofosmin myocardial SPET study was performed, with a dose of 300 MBq at stress, followed 2.5 h later by a dose of 750 MBq at rest. Bull's eye images were generated for visual evaluation. Black-out defects according to the Cequal software analysis were only recorded if they comprised more than 10 pixels in men and 20 in women. According to the Cequal program, extent score and severity scores were expressed as number of pixels and deviations below reference limits. Five patients had normal myocardial SPET imaging with both radiotracers, while 15 had reversible, irreversible or partially reversible defects. The concordance of the results was high. The only two significant differences were that one patient had a reversible defect which appeared to be located in different myocardial regions (LAD vs RCA), and another patient had a defect that was partially reversible with sestamibi but irreversible with tetrofosmin. The results showed very high correlation coefficients for the extent and severity scores (linear correlation coefficient values of 0.99 and 0.94, respectively). In conclusion, it appears that changing between sestamibi and tetrofosmin has little influence on the interpretation of bull's eye images from the data file of a common reference population using one of the tracers.

Clinical characteristics, left and right ventricular ejection fraction, and long-term prognosis in patients with non-insulin-dependent diabetes surviving an acute myocardial infarction.

Patients with diabetes mellitus have a high morbidity and mortality from acute myocardial infarction, the reason for which is not fully understood. The relationship between congestive heart failure symptoms, left ventricular ejection fraction, and long-term mortality was examined in 578 hospital survivors of acute myocardial infarction, 47 of whom had Type 2 (non-insulin-dependent) diabetes mellitus. None of the patients were treated with insulin. The prevalence of congestive heart failure during hospitalization was similar in patients with and without diabetes, although mean diuretic dose was higher in the former patients. Left and right ventricular ejection fraction was measured with radionuclide ventriculography in the second week after acute myocardial infarction. At discharge from the coronary care unit, patients with and without diabetes had similar left ventricular ejection fraction (with diabetes: median 46% vs without diabetes: median 43%; p = 0.89). Median right ventricular ejection fraction (62%) was within normal limits in both groups and did not differ statistically. Survival data were obtained for all patients. The 5-year mortality was increased in patients with diabetes compared with non-diabetic patients independent of left ventricular ejection fraction. Univariate analysis showed that the cumulative 5-year mortality rate was 53% in the group with diabetes compared with 43% in the non-diabetic group (p = 0.007). Using multivariate regression analysis presence of diabetes was found to have a significant association with long-term mortality after myocardial infarction, that was independent of age, history of hypertension, congestive heart failure symptoms during hospitalization or of either left or right ventricular ejection fractions at discharge. We conclude that the excess mortality in patients with non-insulin-dependent diabetes mellitus is not explained by available risk markers after myocardial infarction. Even though left ventricular ejection fraction and serum creatinine did not differ significantly, the apparent higher dose of Frusemide in patients with than without non-insulin-dependent diabetes mellitus might indicate that heart failure, it present, is more severe in patients with than in those without diabetes. The importance of diastolic dysfunction in this context needs to be determined.

Changes in left and right ventricular performance and volumes in seven-year survivors of acute myocardial infarction.

We describe the spontaneous long-term changes in right (RV) and left (LV) ventricular performance during a 7-year period after acute myocardial infarction (AMI). Radionuclide ventriculography was performed in the second week after AMI in 201 patients. RV and LV ejection fractions, and LV end-diastolic and end-systolic volumes were determined. A follow-up after 7 years was performed in 55 survivors. Of these, 16 patients were also examined after 1 year. During the 7-year follow-up period, LV ejection fraction decreased from 0.49 to 0.45 (p < 0.01). LV end-diastolic volume increased from 161 to 210 ml (30%) (p < 0.01), and LV end-systolic volume from 83 to 123 ml (48%) (p < 0.01). In patients without recurrent AMI, coronary artery bypass grafting surgery, or angiotensin-converting enzyme inhibitor therapy (n = 37) during follow-up, no change in average LV ejection fraction was observed. Nevertheless, this subgroup had substantial increases in LV end-diastolic volume, from 157 to 190 ml (21%) (p = 0.002) and in LV end-systolic volume, from 80 to 105 ml (31%) (p < 0.001). In a subgroup of patients also reinvestigated after 1 year (n = 16), there was a 15% increase in LV end-diastolic volume the first year after AMI with an additional 10% increase in LV end-diastolic volume between years 1 and 7. Corresponding figures for LV end-systolic volume were 20% and 12%, respectively. Hardly any association was apparent between LV ejection fraction, LV end-diastolic volume, and LV stroke volume at discharge for subsequent LV dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricle haemodynamics and vaso-active hormones during graded supine exercise in healthy male subjects.

Left ventricle systolic and diastolic functional parameters were measured by gated equilibrium radionuclide cardiography in 12 healthy men (age 33-51 years) at rest and during graded supine exercise. The leftventricle end-diastolic volume showed an initial small (11%) increase during low submaximal exercise [from mean 163 (SD 40) at rest to mean 181 (SD 48) ml], while left ventricle end-systolic volume decreased successively [from mean 59 (SD 19) to mean 39 (SD 21) ml] with increasing exercise. Stroke volume was therefore elevated at all exercise levels compared with rest [mean 104 (SD 23) ml], and the peak value [mean 128 (SD 33) ml] was found at the lowest exercise level, contributing 40% to the initial increase in cardiac output. Cardiac output increased from mean 6.2 (SD 1.4) at rest to mean 20.2 (SD 5.0) l.min-1 at maximum. Left ventricle peak ejection and peak filling rates increased from mean 449 (SD 89) and mean 442 (SD 85) ml.s-1 at rest to mean 996 (SD 227) and mean 1255 (SD 333) ml.s-1, respectively, at maximum. The myocardium oxygen consumption, assumed to be proportional to the sum of the stroke work and the potential energy, increased fourfold, but absolute values were twice as high as expected, indicating that extrapolation from data obtained in dog hearts (as we have done) cannot be directly applied to humans. Selected vaso-active hormones were measured at all exercise intensities. Noradrenaline (NA), adrenaline (A) and angiotensin II (AII) concentrations showed a very pronounced increase at maximal exercise compared with the preceding lower intensites, while atrial natriuretic factor (ANF) and cyclic guanosinemonophosphate (cGMP) concentrations showed a more continuous increase, and dopamine (DA) remained almost unchanged. This speaks in favour of a crucial role for NA, A and AII in preserving blood pressure at maximum exercise, while DA probably has no importance for the cardiovascular homeostasis during exercise. Increases in concentrations of ANF and cGMP were highly correlated (r = 0.86). Our data supported the opinion that there is a cardiac limitation to maximal performance connected to the cardiac pumping capacity.

Is digoxin an independent risk factor for long-term mortality after acute myocardial infarction?

The safety of treatment with digoxin in patients with acute myocardial infarction (MI) was investigated in 584 hospital survivors of MI. All patients were examined by radionuclide ventriculography, with determination of left ventricular ejection fraction (LVEF), close to the time of discharge. Clinical data were collected on admission. All patients were followed up with regard to death (median 6.2 years, range 3.9-7.8 years). Patients treated with digoxin (N = 172 (29%) were older (median 66 vs 59 years; (P < 0.001), had a higher incidence of diabetes (13% vs 7%; P = 0.025), and a lower LVEF (0.33 vs 0.49; P < 0.001). As expected, clinical heart failure was more frequent among them (84% vs 14%; P < 0.001), than in patients not receiving digoxin. The 1- and 5-year mortality of patients treated with digoxin was 38% and 74% compared to 8% and 26% in patients not receiving digoxin (P < 0.001). The increased risk associated with digoxin therapy remained statistically significant when patients were stratified according to the presence or absence of heart failure or atrial fibrillation/flutter during hospitalization, or to LVEF above or below 0.45 at discharge. In a proportional hazard model including age, LVEF, diabetes mellitus, heart failure, atrial fibrillation or flutter, ventricular fibrillation, gender, dose of furosemide at discharge and calcium antagonists and digoxin treatment as covariates, digoxin was independently associated with an increased risk of death (relative risk 1.8 (95% confidence limit 1.2-2.5)). We conclude that administration of digoxin may be harmful in hospital survivors of MI.

Cardiac function and maximal exercise capacity early after acute myocardial infarction.

The purpose of the study was to assess the relationship between left and right ventricular function measured at rest and maximal exercise capacity in patients with recent acute myocardial infarction (AMI). Forty-three male patients (Killip Class I, n = 36; Killip Class II, n = 7) with a wide range of left ventricular (LV) function and size underwent graded bicycle exercise testing less than 4 weeks after AMI (mean 21 days, 17-27). None of the patients had exercise limiting factors other than dyspnoea and fatigue. Left and right ventricular ejection fractions were determined by a radionuclide ventriculographic method which also allowed determination of absolute LV volumes and actual LV peak filling rate. LV ejection fraction had a weak association to estimated maximal oxygen uptake (VO2 max) (r = 0.37). No association was found between LV size, LV stroke volume, or LV peak filling rate and estimated VO2 max. Similarly, right ventricular ejection fraction showed no correlation to estimated VO2 max. Patients with well preserved LV function had a higher exercise induced increase in systolic blood pressure than patients with reduced LV function, but the increase in systolic blood pressure could not be used to estimate LV function with any reasonable accuracy. We conclude that the maximal exercise capacity of patients with recent AMI is virtually independent of their left and right ventricular function determined at rest, and that exercise testing and radionuclide ventriculography should be regarded as complementary procedures in the evaluation of patients with AMI.

Left ventricular peak filling rate, heart failure and 1-year survival in patients with acute myocardial infarction.

Radionuclide left ventricular (LV) peak filling rate (PFR) was determined in 185 survivors of acute myocardial infarction (AMI) and expressed in units of (1) end-diastolic volume per second (EDV s-1). (2) stroke volume per second (SV s-1), or (3) actual millilitres of blood filled into the left ventricle per second (ml s-1). The purpose of the study was to assess the interrelationship between the three expressions of PFR, and to analyse their significance with regard to signs of congestive heart failure and 1-year survival in patients with AMI. PFR EDV s-1, PFR SV s-1 and PFR ml s-1 had a poor relationship to each other, were all influenced by LV volumes and ejection fraction, and supplied contradictory information with regard to LV filling in patients with heart failure. None of the three expressions of LV peak filling rate had an association to heart failure that was independent of LV volume and ejection fraction. A low PFR EDV s-1 in contrast to a high PFR SV s-1 was associated with a high 1-year cardiac mortality, suggesting that these 'normalized' indices of LV peak filling rate signalled LV size and stroke volume rather than actual LV filling behaviour. No association was present between PFR ml s-1 and 1-year mortality. We conclude that the clinical use of radionuclide LV PFR in patients with AMI may lead to spurious results, unless the influence of LV size and ejection fraction is taken into consideration.

Left ventricular volumes in the recovery phase after myocardial infarction: relation to infarct location, left ventricular function and one-year cardiac mortality.

Absolute left ventricular volumes, normalized to body surface area, were determined by a count-based radionuclide technique in 189 patients with myocardial infarction (MI). All examinations were performed in the second week after MI. Fifty-three percent of the patients had an increased end-diastolic volume index (EDVI) and 72% an increased end-systolic volume index (ESVI). Patients with anterior MI had the same median EDVI as patients with inferoposterior MI, but significantly higher median ESVI and significantly lower median stroke volume index (SVI). SVI was subnormal in 19% of the 189 patients and left ventricular ejection fraction (LVEF) was subnormal in 67%. A non-linear, inverse relationship was present between EDVI and LVEF and between ESVI and LVEF, but LVEF varied greatly for any degree of ventricular dilatation. During a 1-year follow-up period, death from cardiac causes occurred in 29 patients. A strong relationship was present between the degree of ventricular dilatation and 1-year mortality, as well as between the degree of SVI or LVEF reduction and 1-year mortality but, next to clinical heart failure, LVEF was the single most powerful predictor of cardiac death, and various combinations of EDVI, ESVI and SVI did not add more prognostic information to that obtained by heart failure than did LVEF.