Risk profiles and incidence of cardiovascular events across different cancer types

BACKGROUND

Cancer survivors are at increased risk for cardiovascular (CV) disease, although additional data are needed to better understand the incidence of CV events across different malignancies. This study sought to characterize the incidence of major adverse CV events [myocardial infarction, stroke, unstable angina (MACE), or heart failure (HF)] across multiple cancer types after cancer diagnosis.

PATIENTS AND METHODS

Patients were identified from a USA-based administrative claims database who had index cancer diagnoses of breast, lung, prostate, melanoma, myeloma, kidney, colorectal, leukemia, or lymphoma between 2011 and 2019, with continuous enrollment for ≥12 months before diagnosis. Baseline CV risk factors and incidence rates of CV events post-index were identified for each cancer. Multivariable Cox hazards models assessed the cumulative incidence of MACE, accounting for baseline risk factors.

RESULTS

Among 839 934 patients across nine cancer types, CV risk factors were prevalent. The cumulative incidence of MACE was highest in lung cancer and myeloma, and lowest in breast cancer, prostate cancer, and melanoma. MACE cumulative incidence for lung cancer was 26% by 4 years (2.7-fold higher relative to breast cancer). The incidence of stroke was especially pronounced in lung cancer, while HF was highest in myeloma and lung cancer.

CONCLUSIONS

CV events were especially increased following certain cancer diagnoses, even after accounting for baseline risk factors. Understanding the variable patient characteristics and associated CV events across different cancers can help target appropriate CV risk factor modification and develop strategies to minimize adverse CV events and improve patient outcomes.

Hypertension is associated with more advanced heart failure in african americans with suspected cardiac amyloidosis

Background

Prior studies have shown worse clinical outcomes for African Americans with transthyretin and light chain cardiac amyloidosis as compared to Caucasians. Hypertensive heart disease is common among African Americans, and a known echocardiographic mimic of cardiac amyloidosis. The association between hypertension and heart failure severity in patients with suspected cardiac amyloidosis has not been well characterized.

Purpose

We sought to identify phenotypic differences between African American and Caucasian patients with suspected cardiac amyloidosis with and without hypertension.

Methods

We retrospectively identified consecutive patients who underwent cardiac biopsy for evaluation of cardiac amyloidosis at our institution between 2000–2018. Clinical and demographic data were obtained from the medical record. Electrocardiograms and echocardiograms performed at the time of cardiac biopsy were interpreted by study personnel.

Results

Among 230 patients with suspected cardiac amyloidosis, 144 (58%) had a prior diagnosis of hypertension. Hypertension was more common among African Americans (71 of 91, 78%) than among Caucasians (73 of 139, 52%). Among African Americans with suspected cardiac amyloidosis, those with hypertension had higher left ventricular mass index (156 versus 119 g/m2), lower left ventricular ejection fraction (47% versus 56%), worse global longitudinal strain (−9.0% versus −11.7%), and higher creatine (1.95 versus 1.43 mg/dL) than those without hypertension (p<0.05 for all). There were no differences in these parameters among Caucasians with and without hypertension.

Conclusions

Among African Americans with suspected cardiac amyloidosis, those with hypertension had worse systolic function and more advanced heart failure than those without hypertension. Targeted screening and/or surveillance strategies are needed to improve early diagnosis of cardiac amyloidosis in African American patients with hypertension.

Funding Acknowledgement

Type of funding sources: None.

1169Interim analysis of data from a long-term, extension trial of tafamidis meglumine in patients with transthyretin amyloid cardiomyopathy

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM), is an underdiagnosed, fatal disease caused by the deposition of transthyretin amyloid fibrils in the heart leading to heart failure. The Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), an international, multi-center, double-blind, placebo-controlled, randomized study, demonstrated the efficacy and safety of tafamidis treatment for patients with ATTR-CM due to variant (ATTRm) or wild-type (ATTRwt) TTR.

Purpose

This is a pooled analysis of data from ATTR-ACT and interim data from the ongoing, long-term, extension study to evaluate longer term data on the efficacy of tafamidis in patients with ATTR-CM.

Methods

Patients who completed ATTR-ACT (which had a duration of 30 months) were eligible to be enrolled in a long-term, extension study in which patients either continued to receive tafamidis meglumine at the same dose (the tafamidis/tafamidis [T/T] group) or, for patients previously treated with placebo, were randomised (in a 1:2 ratio) to tafamidis meglumine 20 mg or 80 mg (the placebo/tafamidis [P/T] group) for up to 60 months. The primary efficacy outcome was all-cause mortality. This analysis combined data from the completed ATTR-ACT with interim data from the extension study (cut-off date: 15 Feb, 2018), and included patients treated with tafamidis meglumine across the two studies with a median follow up of 36 months.

Results

All-cause mortality was significantly lower in the T/T group (n=264; 88 events, 33.3%) compared with the P/T group (n=177; 88 events, 50.3%); hazard ratio (95% CI), 0.64 (0.47, 0.85); P=0.001. In the subgroup of ATTRwt patients, all-cause mortality was significantly reduced in the T/T group (55/201; 27.4%) compared with the P/T group (60/134; 44.8%); 0.64 (0.44, 0.92); P=0.002. In the 106 (24.0%) ATTRm patients, there was a trend towards a reduction in all-cause mortality in the T/T group (33/63; 52.4%) compared with the P/T group (29/43; 67.4%); 0.66 (0.39, 1.09); P=0.17. In patients who were NYHA Class I or II at baseline, all-cause mortality was significantly reduced in the T/T group (38/186; 20.4%) compared with the P/T group (45/114; 39.5%); 0.49 (0.32, 0.75); P=0.001. In those patients with more severe symptoms at baseline (NYHA Class III), there were fewer deaths in the T/T group (50/78; 64.1%) compared with the P/T group (44/63; 69.8%); 0.80 (0.53, 1.21), but this difference was not statistically significant (P=0.50).

Conclusions

In ATTR-ACT, tafamidis was shown to significantly improve survival, functional capacity, and quality of life in patients with ATTR-CM. This pooled analysis with data from the ongoing extension study further supports the efficacy of tafamidis in patients over a longer period of time and the importance of early diagnosis and treatment.

Acknowledgement/Funding

This study was sponsored by Pfizer.

P2724Diagnosis of transthyretin versus light chain cardiac amyloidosis by apical sparing strain ratio in patients with clinically suspected disease

Background

Apical sparing by longitudinal strain imaging has reported utility for the diagnosis of cardiac amyloidosis. However, potential differences in the apical sparing pattern in light chain (AL) versus transthyretin (ATTR) amyloidosis in patients with high clinical suspicion for cardiac amyloidosis is not clear.

Purpose

Our objective was to test the hypothesis that echocardiographic strain imaging could determine differences in patients with clinically suspected AL and ATTR cardiac amyloidosis.

Methods

We studied 206 patients, aged 64±11, with clinically suspected cardiac amyloidosis. Routine longitudinal strain imaging analyses was performed (EchoPAC, GE Healthcare) with bulls-eye plots. After 27 exclusions (8 arrhythmia/frame rate, 19 missing/poor images), there were 179 patients. Included were 129 patients with cardiac amyloid: 42 by endomyocardial biopsy, 4 by technetium pyrophosphate scan, 65 by non-cardiac biopsy with suggestive cardiac imaging (interventricular septal thickness ≥1.2cm by echocardiography or characteristic cardiac MRI findings), 15 with multiple myeloma and suggestive cardiac imaging, and 3 by autopsy; 50 patients had a negative endomyocardial biopsy or autopsy for cardiac amyloid. The apical sparing ratio by strain imaging was calculated as the (average of apical segments) / (average of mid segments + average of basal segments).

Results

Cardiac amyloidosis patients were 79% with AL and 21% with ATTR. Applying the previously published apical sparing ratio cut-off of 1.0 for longitudinal strain imaging, sensitivity and specificity were 29% and 78%, respectively, for diagnosis of cardiac amyloidosis. Applying a ratio cut-off of 0.81 improved sensitivity to 72% with specificity of 64% and area under the curve (AUC) of 0.66. Positive and negative predictive values were 85% and 46%, respectively, at this ratio cut-off. The apical sparing ratio was significantly higher in AL and ATTR as compared to the biopsy negative group (p<0.001). Furthermore, the apical sparing ratio was significantly higher in ATTR as compared to AL (p<0.05).

Apical sparing pattern and ratio

Conclusions

Among patients with high clinical suspicion for cardiac amyloidosis, the apical sparing ratio by echocardiographic strain imaging can demonstrate differences for AL and ATTR cardiac amyloidosis and has potential for clinical utility.

1176Hepatocyte growth factor has prognostic utility in light chain and transthyretin cardiac amyloidosis

Background

With the advent of multiple novel therapeutics for light chain (AL) and transthyretin (ATTR) amyloidosis, there is a critical need for validated prognostic markers in cardiac amyloidosis. A discriminatory serum biomarker may improve prognostic and staging systems in AL and ATTR cardiac amyloidosis.

Purpose

Our objective was to test the hypothesis that hepatocyte growth factor (HGF) is associated with clinical outcomes in patients with AL and ATTR cardiac amyloidosis.

Methods

102 patients with AL or ATTR and suspected cardiac involvement were prospectively enrolled. HGF, NT-proBNP, troponin-T, and eGFR were measured upon study enrollment. Cardiac involvement was established by 1) endomyocardial biopsy, or 2) non-cardiac biopsy with concentric hypertrophy on echocardiography, low voltage or pseudo-infarction on ECG, elevated NT-proBNP or troponin-T, or characteristic delayed myocardial enhancement on cardiac MRI. Patients were followed for the occurrence of all-cause mortality, cardiac transplantation, and left-ventricular assist device implantation.

Results

Of the total amyloidosis cohort, 72 had cardiac involvement while 30 had non-cardiac disease. HGF, NT-proBNP, and troponin-T levels were significantly higher in patients with cardiac involvement than in patients with non-cardiac disease (p<0.05 for all comparisons). Over a median follow-up period of 1.9 years there were 20 deaths, 1 cardiac transplant, and 1 left-ventricular assist device implant, all in patients with cardiac involvement. Patient stratification by cut-off levels of NT-proBNP (332 pg/mL), troponin-T (35 ng/L), and eGFR (45 mL/min/1.73m2) used in published staging models for AL and ATTR cardiac amyloidosis showed no association between abnormal biomarker level and adverse clinical outcome (p>0.05). In contrast, stratification by HGF level of 310 pg/mL (identified by the Youden Index for cardiac involvement by AL and ATTR in our cohort) showed that elevated HGF was associated with worse clinical outcomes (p=0.0211). Furthermore, event-free survival was worse in patients with elevated HGF, with survival curves diverging soon after enrollment (p=0.0730).

HGF is Prognostic in Cardiac Amyloidosis

Conclusions

Elevated HGF is associated with worse clinical outcomes in patients with AL and ATTR cardiac amyloidosis and has potential for clinical utility.

High-output heart failure resulting from a remote traumatic aorto-caval fistula: diagnosis by echocardiography

Congestive heart failure (CHF) due to high output states is known to occur in a variety of systemic illnesses and in patients with arterial-venous fistulas. This paper reports the case of a 45-year-old man admitted to the emergency room with a diagnosis of new onset atrial fibrillation and CHF, whose past medical history was not significant except for a gunshot wound to his abdomen 22 years previously. The etiology of his CHF together with the cardiomegaly and hyperdynamic left ventricular systolic function was unknown. A subcostal view routinely done during transthoracic echocardiography revealed a severely dilated inferior vena cava and the presence of an aorto-caval fistula by color doppler. The patient underwent successful corrective repair with dramatic improvement in symptoms and resolution of the atrial fibrillation, and cardiac size returned to normal. This rare case emphasizes that patients with refractory CHF must be closely examined with particular attention to palpation and auscultation over all scars, irrespective of the duration since any traumatic or surgical event.

Ticlopidine-induced neutropenia mimicking sepsis early after intracoronary stent placement

We report a case of ticlopidine-induced profound neutropenia early in the course of therapy, which was manifest as a febrile systemic illness mimicking sepsis. This clinical presentation was potentially indicative of a contaminated intracoronary stent. The patient's signs and symptoms of illness promptly resolved with removal of ticlopidine, and no infection was documented. Review of indications for ticlopidine use, potential adverse effects, and monitoring recommendations are discussed.

Significance of stress myocardial perfusion scans in predicting cardiovascular events and mortality in cancer patients

17009

Background: Cardiac risk assessment in cancer patients has not extensively been studied. We evaluated the role of stress myocardial perfusion scan (SMPS) in predicting cardiovascular outcomes in cancer patients. Methods: A retrospective chart review was performed on 787 patients who had a SMPS from 01/2002 - 03/2003. All patients were followed for at least 1.5 years. Cox proportional hazard model was used to determine the time-to-first event [cardiac death, myocardial infarction (MI) and coronary revascularization]. Cardiac death was defined as documented cardiac death or sudden unexplained death. Results: A total of 501/787 (64%) patients had normal SMPS, whereas 286/787 (36%) had abnormal SMPS. Adenosine [430/787 (55%)] and dobutamine [144/787 (14%)] were used for chemical stress while 213/787 (23%) patients underwent exercise testing. Mean age was 66±11 years and median follow-up duration was 1.8 years. The 3- year event-free survival rate was 0.71 (0.64–0.78) for abnormal SMPS and 0.87 (0.8–0.94) for normal SMPS (p<0.0001). Of all abnormal scans (n=286), 3-year event free-survival rate based on type of vascular defects varied from 0.79(0.67–0.93) for fixed defects, 0.68 (0.58-.08) for reversible defects and 0.63 (0.5–0.8) for co-existent fixed and reversible defects (p<0.0001). Other factors adversely affecting event-free survival were male gender (p=0.025), cardiomyopathy (p=0.001), coronary artery disease (p<0.0001), previous MI (p<0.0001), congestive heart failure (p=0.001) and hypercholesterolemia (p<0.0001). When we analyzed cardiac death as a separate event, SMPS results still made a significant difference with 3-year cardiac-survival rate of 0.79 (0.69–0.91) for abnormal scan group versus 0.88 (0.81–0.95) for normal scan group (p=0.05). Furthermore, the 3-year cardiac-survival rate in patients with both fixed and reversible defects was 0.4 (0.1–1), which was much worse than those with fixed [0.87 (0.76–0.99)] or reversible [0.85 (0.74–0.99)] defects alone (p=0.028). Conclusions: SMPS is a highly useful modality for predicting cardiac events and mortality in cancer patients. The characteristics of the perfusion defect further stratifies the patients at higher risk.

No significant financial relationships to disclose.

Early detection of cardiotoxicity during chemotherapy using biomarkers

19521

Cancer chemotherapy (CHEMO), especially anthracycline-containing regimens, may result in heart failure and left ventricular dysfunction (LVD) due to cardiotoxicity (CVTx). The ability to detect CVTx currently utilizes techniques to assess LVD, such as MUGA or echocardiography (Echo), which have substantial limitations and only detect LVD well after it occurs. Cardiac biomarkers, troponin (Trop I) and B-Type Natriuretic Peptide (BNP) are well established for detecting myocardial injury and LVD in patients without cancer. Limited evidence suggests that these may be important predictors of subsequent CVTx during CHEMO, but these markers have not been systematically investigated prospectively. Methods: Patients undergoing anthracycline-containing combination CHEMO were evaluated at baseline with: history and physical; electrocardiogram; Echo; and BNP and Trop I. Biomarkers were repeated before and after up to 6 cycles of CHEMO. ECHO was repeated after 6 cycles or at 6 months from baseline. Cardiac events (heart failure, LVD, sudden death, or arrhythmia) were documented, if present. Results: To date, 111 (53M/58F) patients, age 56±14 (mean±SD), with either lymphoma (n=39, 35%), sarcoma (n=60, 54%), or breast cancer (n=12, 11%) were enrolled. At least one traditional cardiac risk factor was identified in 77 (69%) and 2 or more risk factors noted in 46 (41%). Baseline ECHO parameters including ejection fraction (EF) and biomarkers were normal. With CHEMO, the mean post CHEMO BNP value (pg/ml) for the group did not change significantly; however, in the 8 patients with cardiac events, the BNP post CHEMO was elevated. The Trop I values were not abnormal except in 2 patients with events. Conclusion: Preliminary data collected to date indicates that BNP values during CHEMO remain normal unless cardiac events occur. Additionally, elevated BNP levels appear to detect CVTx, but LVEF did not. Furthermore, patients receiving CHEMO frequently have cardiac risk factors that may promote CVTx.

[Table: see text]

No significant financial relationships to disclose.

Long term cardiac tolerability of trastuzumab in HER-2-overexpressing metastatic breast cancer (MBC)

629

Background: The use of trastuzumab is associated with an increased risk of cardiotoxic events such as congestive hearth failure (CHF) and decline in the left ventricular ejection fraction (LVEF). Our objectives were to evaluate the incidence of cardiac dysfunction, to identify risk factors and to evaluate the outcome of patients with MBC treated with trastuzumab for one year or longer. Methods: Among 218 MBC patients treated with trastuzumab-based therapy for at least one year, 173 patients were evaluable for cardiac toxicity. Cardiac events (CE) were defined as follows: 1) asymptomatic drop of LVEF below 50%; 2) drop of 20 percentage points in LVEF compared to the baseline; 3) signs or symptoms of CHF. The cardiac toxicity was graded according the NCI-CTCAE, version 3.0. Results: Median age at the start of trastuzumab therapy was 50 years (range, 26–79), median cumulative time on trastuzumab was 21.3 months (range, 11.6–77.6), and median follow-up was 32.2 months (range, 9.7–79.0). Eighty-five percent of patients received prior anthracyclines (median cumulative doxorubicin dose: 300 mg/m2). Forty-nine patients (28%) experienced a CE: 3 patients (1.7%) had an asymptomatic drop in the LVEF of 20 percentage points; 27 patients (15.6%) experienced grade 2 cardiac toxicity; and 18 patients (10.4%) experienced grade 3 cardiac toxicity. There was one cardiac related death (0.5%). Cardiac event-free survival was 87.3% at 1 year. All but four patients had improved LVEF or symptoms of CHF after stopping trastuzumab or with appropriate therapy. After complete recovery, 26 patients were re treated with trastuzumab; 16 patients did not experience further CE. Concomitant taxane use was the only factor significantly associated with a CE (HR: 4.37, 95%CI 1.06–17.98, p:0.04).Prior anthracycline exposure was not associated with increased risk of CE. Conclusions: The risk of cardiac toxicity of long-term trastuzumab-based therapy is acceptable in this population, and this toxicity is reversible in the majority of the patients. In patients who have experienced a CE, additional treatment with trastuzumab can be considered after recovery of cardiac function. The increased risk of cardiotoxicity associated with taxane administration needs to be further investigated.

No significant financial relationships to disclose.

Military graduate medical education in internal medicine: an outcomes study

Military graduate medical education has come under increasing scrutiny in recent years as the size of the military medical force declines. To document the outcomes of military graduate medical education in internal medicine, a cohort of Air Force internal medicine residency graduates from Wright-Patterson Medical Center were studied and their residency performance, staff performance, and active duty retention recorded. The study cohort had an outstanding residency performance, as measured by research experience and board certification rate. They also performed well as military staff physicians, receiving numerous individual military medals while holding important administrative and supervisory positions in the military. Finally, the study cohort had a higher than expected active duty retention rate. These findings support the notion that military graduate medical education in internal medicine produces outstanding military internists.

Native valve infective endocarditis: what is the optimal timing for surgery?

IE remains a dreaded disease masquerading under a myriad of presentations in an evolving epidemiological environment. In our continuing endeavor against this deadly disease, echocardiography has evolved into an indispensable diagnostic tool to define structural complications and guide therapy. Timing of surgical intervention for IE remains a subject of intense debate and depends on the cardiac and systemic complications of the infection, the virulence of the organism, and the responsiveness to medical therapy. A judicious agreement among cardiologist, cardiovascular surgeon, and infectious disease specialist should define whether surgical intervention is warranted and, if so, the optimal timing. Further optimization of guidelines will help in the diagnosis and treatment of endocarditis but will never be a substitute for sound judgment and experience.

Nonpharmacologic treatment of heart failure in the elderly

Nonpharmacologic therapy is an integral part of the management of elderly patients with heart failure. Reinforcement of dietary sodium restriction and other nutritional concerns are critical features of therapy. Quality standards for the management of patients with heart failure are being developed, and the implementation of these standards is a goal of clinicians. A multidisciplinary approach to elderly patients with heart failure is beneficial.

Prediction of human transplantation arteriopathy and coronary events with lung/heart count ratios during intravenous dipyridamole thallium-201 imaging

BACKGROUND

Cardiac allograft arteriopathy often limits long-term survival in transplantation recipients but has been difficult to detect by standard diagnostic methods. Because of the diffuse nature of transplantation coronary disease, we postulated that a lung/heart ratio during dipyridamole thallium imaging might better predict arteriopathy-related complications than diagnostic methods that detect discrete luminal stenoses.

METHODS AND RESULTS

Sixty-six unselected heart transplantation recipients were evaluated with annual coronary arteriograms, endomyocardial biopsy, and intravenous dipyridamole thallium testing (initial study group). The mean lung/heart ratio on an anterior planar image was 0.40 for all patients; therefore <0.40 was arbitrarily defined as normal. After October 1992, 98 patients were tested (validation study group) and a lung/heart ratio cutoff of 0.40 was evaluated prospectively. Coronary end points were defined as (1) at least 1 coronary artery stenosis >/=50% of the luminal diameter, (2) sudden cardiac death, and (3) acute myocardial infarction. Stepwise logistic regression analysis was performed to identify independent predictors of future coronary end points. For the initial study group, the lung/heart ratio on the first annual thallium study was the only independent predictor of subsequent cardiac end points (0.47 +/- 0.13 [SD] with end points vs 0.38 +/- 0.11 without end points, P <.05). For the validation study group, independent predictors of subsequent coronary events included the lung/heart ratio and the radionuclide left ventricular ejection fraction. No patient with a lung/heart ratio <0.40 and a left ventricular ejection fraction >/=0.50 developed a cardiac event during 21 +/- 11 months of follow-up.

CONCLUSIONS

A lung/heart ratio >/=0.40 on dipyridamole thallium testing is a sensitive predictor of coronary events after heart transplantation. Patients with heart transplantion who have a lung/heart ratio <0.40 and normal systolic left ventricular function are at low risk for subsequent coronary events and may not require annual surveillance by coronary arteriography.

Reliability of technetium-99m Q12 and thallium-201 myocardial activity measurements after triphenyl tetrazolium chloride myocardial staining by perfusion

RATIONALE AND OBJECTIVES

Investigations in animal models of severe myocardial ischemia or infarction use triphenyl tetrazolium chloride (TTC) staining to document infarction size histologically and to correlate these data with uptake measurements of radiolabeled tracers. Previously published data suggest that TTC staining itself has an important impact on myocardial tracer activity measurements. The authors hypothesized that TTC staining by perfusion has no significant effect on relative regional myocardial activity measurements of technetium-99m Q12 and thallium-201 in an open-chest canine model.

METHODS

Eight dogs underwent left anterior descending artery occlusion for 2 hours with 30 minutes of reperfusion, followed immediately by injection of technetium-99m Q12 (n = 4) or thallium-201. Total myocardial activity was recorded in a dose calibrator, and regional myocardial samples were obtained by Cope needle biopsies from the ischemic and normal zones, both before and after TTC staining.

RESULTS

The mean percent activity retention for the whole heart after perfusion staining with TTC was significantly reduced when compared to the preperfusion value for both technetium-99m Q12 and thallium-201. Regional measurements revealed no significant difference between the mean percent retention of technetium-99m Q12 in the ischemic and normal zones. After TTC perfusion, regional mean percent retention of thallium-201 was similar in the ischemic and normal zones.

CONCLUSIONS

In a canine model of myocardial ischemia and infarction with reperfusion, TTC staining can be performed by coronary artery perfusion without significantly affecting comparative regional measurements of either technetium-99m Q12 or thallium-201. Whole heart tracer retention is significantly reduced by TTC perfusion staining, but thallium-201 is more affected than technetium-99m Q12.

Effects of changes in atrioventricular gradient and contractility on left ventricular filling in human diastolic cardiac dysfunction

The factors responsible for abnormalities in diastolic filling indexes as assessed by noninvasive testing in human beings have been extensively studied but are not completely understood. We therefore investigated left ventricular diastolic filling indexes by radionuclide angiography during right atrial pacing simultaneously with assessment of a directly measured left atrioventricular gradient and a time constant of isovolumic relaxation in 11 patients with hypertension and diastolic dysfunction. Loading conditions were altered with nitroprusside and phenylephrine, and contractility was improved by dobutamine infusion. The maximum left atrioventricular gradient at constant heart rates was determined by loading conditions and was not significantly affected by increases in contractility or an improvement in isovolumic relaxation rate. The peak filling rate according to radionuclide angiography was highly dependent on the atrioventricular gradient and was not affected by enhancement of the isovolumic relaxation rate.

Mechanisms, diagnosis, and treatment of diastolic heart failure

Diastolic heart failure, in the absence of LV systolic dysfunction, is a common clinical condition that can be demonstrated in as many as one third of patients with congestive heart failure. Diastolic dysfunction caused by abnormalities in LV filling can be a result of many pathologic conditions, including hypertrophy, infiltrative cardiomyopathies, or myocardial ischemia. The major physiologic determinants of LV filling can be divided into cellular mechanisms, hemodynamic characteristics, and hormonal influences. Cellular mechanisms for impaired LV inactivation are determined by the handling of calcium within the myocyte during excitation-contraction-relaxation coupling. The hemodynamic characteristics of LV diastolic filling are determined by loading conditions, the time constant of isovolumic relaxation, heart rate, ventricular nonuniformity, pericardial restraint, myocardial elasticity, chamber compliance, and coronary blood flow. The sympathetic nervous system and the renin-angiotensin system are important modulators of diastolic filling, directly or indirectly. The diagnosis of heart failure is confirmed by a combination of clinical tests including invasive and noninvasive techniques, each of which has advantages and disadvantages. Treatment of medical conditions in which diastolic heart failure is a prominent component include pharmacotherapy with calcium channel antagonists, beta-adrenergic blocking agents, diuretic agents, and angiotensin-converting-enzyme inhibitors. Certain conditions associated with diastolic filling abnormalities such as pericardial disease or severe ischemic heart disease may be best managed by surgical or percutaneous intervention. Future research will include further delineation of the cellular mechanisms of active myocardial relaxation and clinical investigation into treatment directed at improving outcome.

Frequency of late potentials on signal-averaged electrocardiograms during thallium stress testing in coronary artery disease

Late potentials detected by signal-averaged electrocardiography (SAECG) are an important noninvasive indicator identifying patients with previous myocardial infarction at risk for developing ventricular tachycardia. The role of myocardial ischemia in the development of late potentials is undefined. This study attempts to determine if late potentials on SAECG can be produced during scintigraphically proven ischemia. A signal-averaged electrocardiogram was obtained before and immediately after single-photon emission computed tomography thallium exercise testing in 51 patients. Reversible ischemia was documented in 25 cases with no significant changes in the parameters of SAECG; patients with previous myocardial infarction (n = 10) also had no significant changes from baseline. Multivariate analysis with respect to reversible ischemia and previous myocardial infarction was unrevealing. Patients with late potentials at baseline (n = 10) who developed reversible ischemia (n = 5) had a shorter QRS duration than those with late potentials at baseline and no reversible ischemia. The data indicate that exercise-induced scintigraphically proven ischemia does not alter SAECG even in the presence of previous myocardial infarction. Patients with late potentials at baseline may actually have a shortened QRS duration during reversible ischemia as opposed to the expected lengthening of the QRS.

Left main coronary artery aneurysm in association with severe atherosclerosis: a case report and review of the literature

Aneurysms of the coronary arteries occur in from 0.3% to 4.9% of angiograms. Only 12 cases of left main artery (LMA) aneurysms have been reported. Of these, seven were associated with atherosclerosis in patients more than 56 years old. This report details the case of a 39-year-old patient with a large LMA aneurysm associated with atherosclerosis.

Involvement of platelet activating factor in physiological stress in the lizard, Anolis carolinensis

Platelet activating factor (PAF) and 1-O-alkyl-linked choline-containing phosphoglycerides have been identified in the blood of the lizard, Anolis carolinensis. The level of PAF in the blood of chronically stressed lizards is 250% higher than in that of controls; the blood contains sufficient 1-O-alkyl-linked choline-containing phosphoglycerides to support the synthesis of PAF. Incorporation of PAF is higher in the liver than in the blood; control animals incorporate more PAF than chronically stressed animals. "Lyso"-PAF is the major metabolite in the blood; whereas, in the liver both "lyso"-PAF and "acyl"-PAF are predominant products. 1-Alkyl-2-acetyl-sn-glycero-3-phosphocholine:acetylhydrolase activity in the chronically stressed or corticosterone-implanted lizards is increased 2- to 3-fold over the control. Involvement of PAF in the physiological response to psychological stress is indicated.

Regulation of platelet activating factor synthesis: modulation of 1-alkyl-2-lyso-sn-glycero-3-phosphocholine:acetyl-CoA acetyltransferase by phosphorylation and dephosphorylation in rat spleen microsomes

1-Alkyl-2-lyso-sn-glycero-3-phosphocholine:acetyl-CoA acetyltransferase plays an important regulatory role in the biosynthesis of platelet activating factor, a potent bioactive mediator. We tested the hypothesis that the activity of acetyltransferase may be modulated by enzymatic phosphorylation and dephosphorylation. The results showed that acetyltransferase activity in rat spleens was 2- to 3-fold higher in microsomes isolated in the presence of F-than in those isolated in the presence of Cl-. The microsomal acetyltransferase could be activated by preincubation of microsomes, isolated in the presence of Cl-, with ATP, Mg2+, and the soluble fraction from rat spleen. Addition of phosphatidylserine, diacylglycerols, plus Ca2+ further enhanced the activity. The increase in the activity of acetyltransferase was abolished by treatment of the activated microsomes with alkaline phosphatase. Conversely, the activity of acetyltransferase can be reactivated in the alkaline phosphatase-treated microsomes with incubation conditions that favor phosphorylation. Therefore, our findings suggest that acetyltransferase activity is regulated by reversible activation/inactivation through phosphorylation/dephosphorylation.

Increased biosynthesis of platelet-activating factor in activated human eosinophils

1-Alkyl-2-lyso-sn-glycero-3-phosphocholine:acetyl-CoA acetyltransferase catalyzes the conversion of biologically inactive lysophospholipid to bioactive platelet-activating factor (1-alkyl-2-acetyl-sn-glycero-3-phosphocholine, PAF) by an acetylation reaction. The activity of this enzyme in eosinophils isolated from patients with eosinophilia is stimulated (up to 4-fold) in a dose-, time-, and Ca2+/Mg2+-dependent manner after exposure to the eosinophil chemotactic factor of anaphylaxis (ECF-A), C5a, formyl-methionylleucylphenylalanine (fMLP), or ionophore A23187. The three naturally occurring chemotactic factors (ECF-A, C5a, and fMLP) cause a rapid and transient increase of enzyme activity, with a maximum at 1 or 3 min, whereas ionophore A23187 maintains an elevated level for up to 15 min. The activity of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetylhydrolase, an enzyme that catalyzes the breakdown of PAF to lyso-PAF, is not affected by C5a, fMLP, or ionophore A23187. The presence of PAF in eosinophils was established by demonstrating the lipid nature of the compound, the RF value being identical with that of synthetic 1-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine on thin layer chromatograms, and by its ability to induce serotonin release from rabbit platelets. Furthermore, ECF-A, C5a, fMLP, and ionophore A23187 all induce the secretion of PAF from eosinophils. These findings suggest that the generation and release of PAF could be a consequence of eosinophil chemotactic activation and may thus function in inflammatory and allergic reactions in which eosinophils participate.