Cardiomyocyte stretch mediates the relation between left ventricular amyloid burden and adverse outcomes in light chain amyloidosis: a 18F-florbetapir positron emission tomography study

Background

Patients with light chain (AL) amyloidosis and cardiac involvement have poor prognosis. Mayo stage accounts for severity of plasma cell dyscrasia and cardiac biomarker release, and provides powerful risk stratification. Myocardial amyloid burden can be quantified by 18F-florbetapir positron emission tomography (PET), but its prognostic value is not known.

Purpose

To test our hypothesis that (1) myocardial amyloid burden predicts adverse outcomes and (2) the relationship between amyloid burden and adverse outcomes is mediated by cardiomyocyte stretch and injury. Amyloid burden was estimated by left ventricular 18F-florbetapir retention index (RI) and cardiomyocyte stretch and injury by NT proBNP and troponin T respectively.

Methods

We performed 18F-florbetapir PET (median dose 9.05 mCi) in prospectively enrolled subjects with newly diagnosed AL amyloidosis with abnormal cardiac biomarkers or with normal cardiac biomarkers and normal left ventricular wall thickness (NCT02641145). Left ventricular RI was calculated as the activity concentration between 10 and 30 min. after injection divided by the integral of the left atrial blood time-activity curve from 0 to 20 min. RI was categorized as normal (<0.06/min, based on controls), increased (0.06–0.12/min), or high risk (>0.12/min, based on log-rank statistic maximization). Mayo stages I–IV were based on elevated serum cardiac biomarkers: NT-proBNP ≥1800 pg/ml, troponin T ≥0.025 ng/ml, and difference in free light chains ≥180 mg/l. Adverse outcomes of all-cause death or heart failure hospitalization were evaluated. Survival analysis was performed using Kaplan-Meier and Cox regression including Mayo stage and RI. Mediation analysis was used to elucidate the role of cardiomyocyte stretch (as NT-proBNP) and injury (as troponin T) in the association between amyloid burden estimated by RI and adverse outcomes.

Results

We studied 80 subjects with median age 62 years (IQR 57–67), 46 men (57%), 60 with abnormal cardiac biomarkers (75%), and median RI of 0.10/min (IQR 0.06–0.16). At follow-up (median 15 months), adverse outcomes occurred in 34 subjects (42%), with 17 deaths (21%) and 23 heart failure hospitalizations (29%). The incidence of adverse outcomes increased across Mayo stages from 9% to 44% (log-rank p<0.001), and across RI levels from 29% to 57% (log-rank p=0.037, Figure 1). In multivariable Cox regression, only Mayo stage independently predicted adverse outcomes (HR 2.0 [95% CI 1.4–3.0], p<0.001). Multivariable mediation analysis showed that 83% of the association between RI and adverse outcomes was mediated by NT-proBNP (p<0.001, Figure 2), without contribution from troponin T.

Conclusion

Myocardial amyloid burden estimated by F-18 florbetapir RI predicts adverse outcomes in AL amyloidosis, but not independently of Mayo stage. Cardiomyocyte stretch mediates the relationship between myocardial amyloid burden and adverse outcomes in AL amyloidosis.

Funding Acknowledgement

Type of funding sources: Private company.

Scanning electron microscopy of developing plant organs

Shoot apices and young meristematic leaves can be examined directly with the scanning electron microscope without prior fixation or metal coating. The form of the shoot apex, cellular organization, andleaf arrangement (phyllotaxis) can be observed, perphaps as they have never been visualized before.

The cardiovascular response to sexual activity: do we know enough?

Interest in comprehensive cardiac rehabilitation over the past 25 years spawned a series of small investigations concerning the heart rate, blood pressure, and ischemic response to sexual intercourse. This information was adequate for advising patients about return to sexual activity after a myocardial infarction or cardiac surgery. However, the introduction of medications for erectile dysfunction enabled impotent cardiac patients to engage in sexual activity and has highlighted the need for more detailed information concerning cardiovascular physiology during coitus. Review of the medical literature indicates a remarkable paucity of such data despite dramatic advances in most other aspects of cardiovascular physiology and pathophysiology. This brief paper gives an overview of the current knowledge of the cardiovascular response to sexual activity and, within the framework of advances in cardiology, highlights areas where it appears important to fill in the knowledge gap.

High-dose intravenous melphalan and autologous stem cell transplantation as initial therapy or following two cycles of oral chemotherapy for the treatment of AL amyloidosis: results of a prospective randomized trial

SUMMARY

A prospective randomized trial was conducted to study the timing of high-dose intravenous melphalan and autologous stem cell transplantation (HDM/SCT) in AL amyloidosis. In all, 100 newly diagnosed patients were randomized to receive HDM/SCT, either as initial therapy (Arm-1) or following two cycles of oral melphalan and prednisone (Arm-2). The objectives of the trial were to compare survival and hematologic and clinical responses. With a median follow-up of 45 months (range 24-70), the overall survival was not significantly different between the two treatment arms (P=0.39). The hematologic response and organ system improvements after treatment did not differ between the two groups. Fewer patients received HDM/SCT in Arm-2 because of disease progression during the oral chemotherapy phase of the study, rendering them ineligible for subsequent high-dose therapy. This affected patients with cardiac involvement particularly, and led to a trend for an early survival disadvantage in Arm-2. Hence, newly diagnosed patients with AL amyloidosis eligible for HDM/SCT did not benefit from initial treatment with oral melphalan and prednisone, and there was a survival disadvantage for patients with cardiac involvement if HDM/SCT was delayed by initial oral chemotherapy.

Amyloidosis

Amyloidosis is not a single disease but a series of diseases in which there is extracellular deposition of a protein which, although it may be derived from different and unrelated sources, folds into a beta pleated sheet. There have recently been significant advances in elucidating the pathogenesis and in the treatment of this group of disorders. By identifying the source of precursor protein, treatment is aimed at eliminating or reducing the extent of deposition and is tailored for each patient. Early diagnosis is required for the optimal effect of treatment on patient survival and quality of life. An increased awareness among physicians of the spectrum of the disease and tools to aid its diagnosis is of increasing importance.

Infusion of light chains from patients with cardiac amyloidosis causes diastolic dysfunction in isolated mouse hearts

BACKGROUND

Primary (AL) amyloidosis is a plasma cell dyscrasia characterized by clonal production of immunoglobulin light chains (LC) resulting in the subsequent systemic deposition of extracellular amyloid fibrils. Cardiac involvement is marked by the hemodynamic pattern of impaired diastolic filling and restrictive cardiomyopathy. Although cardiac death in patients with AL amyloidosis is usually associated with extensive myocardial infiltration, the infiltration alone does not correlated with the degree of heart failure or survival. We hypothesized that circulating monoclonal LC may directly impair cardiac function, in addition to any mechanical effects of amyloid fibril deposition. Therefore, we examined the effects of amyloid LC proteins on diastolic and systolic cardiac function, as measured in an isolated mouse heart model.

METHODS AND RESULTS

LC were obtained from patients with nonamyloid disease or from those with noncardiac, mild cardiac, and severe cardiac involved AL amyloidosis. Saline or LC (100 microgram/mL) was infused into a Langendorff-perfused, isovolumically contracting mouse heart. Saline and control, noncardiac, and mild-cardiac LC infusions did not alter ex vivo cardiac function. In contrast, infusion of sever cardiac LC resulted in marked impairment of ventricular relaxation with preservation of contractile function.

CONCLUSION

These results demonstrate that infusion of LC from patients with AL amyloidosis result in diastolic dysfunction similar to that observed in patients with cardiac involved AL amyloidosis, and they suggest that amyloid LC proteins may contribute directly to the pathogenesis and the rapid progression of amyloid cardiomyopathy, independent of extracellular fibril deposition.

An overview of the use of high-dose melphalan with autologous stem cell transplantation for the treatment of AL amyloidosis

Primary or AL amyloidosis results from a plasma cell dyscrasia in which fibrillar light chain protein deposition leads to organ failure and death. Standard treatment for AL amyloidosis has been oral melphalan and prednisone. However, this form of treatment modifies the natural history of this lethal disease only marginally, extending median survival from 13 months following diagnosis to 17 months. At Boston University Medical Center, we have developed treatment protocols using high-dose intravenous melphalan with autologous peripheral blood stem cell transplantation (HDM/SCT) to treat AL amyloidosis, and we have treated over 200 patients with HDM/SCT during the past six years. This extensive experience has shown that patients with AL amyloidosis, despite multisystem involvement and compromised organ function can tolerate this aggressive form of treatment. Furthermore, HDM/SCT results in durable hematologic responses in a substantial proportion of patients, and such responses are associated with clinical improvement, decreased amyloid-related organ dysfunction, and prolonged survival. However, toxicity from treatment is high (overall peri-transplant mortality, 14%), particularly for those patients with clinically significant cardiac involvement. For this reason, we believe a multidisciplinary management approach is essential when using HDM/SCT for treatment of AL amyloidosis. Based on our experience, we believe that HDM/SCT is the treatment of choice for patients with AL amyloidosis who have a good performance status and limited cardiac involvement at the time of diagnosis. HDM/SCT offers the best chance for hematologic remission, prolongation of survival, and reversal of amyloid-related disease. At the same time, we believe that HDM/SCT should continue to be examined in the context of clinical trials, directed at developing approaches to broaden the applicability of this therapy by minimizing toxicity and to increase the likelihood of complete hematologic responses.

Effect of dose-intensive intravenous melphalan and autologous blood stem-cell transplantation on al amyloidosis-associated renal disease

BACKGROUND

Dose-intensive intravenous melphalan with autologous blood stem-cell transplantation induces remission of the plasma cell dyscrasia in a substantial proportion of patients with AL amyloidosis. The impact of this treatment on associated renal disease is not known.

OBJECTIVE

To determine the effect of dose-intensive intravenous melphalan and autologous blood stem-cell transplantation on AL amyloidosis-associated renal disease.

DESIGN

Prospective cohort study.

SETTING

Academic medical center.

PATIENTS

65 patients with AL amyloidosis and urinary protein excretion greater than 1 g/24 h who received dose-intensive intravenous melphalan and autologous blood stem-cell transplantation between 1 July 1994 and 30 June 1998.

MEASUREMENTS

24-hour urinary protein excretion, serum cholesterol level, serum albumin level, creatinine clearance, urine and serum immunoelectrophoresis, and bone marrow biopsy. Renal response was defined as a greater than 50% reduction in urinary protein excretion in the absence of a 25% or greater reduction in creatinine clearance. Complete hematologic response was defined as absence of detectable monoclonal protein in serum and urine and a bone marrow specimen containing less than 5% plasma cells without clonal dominance of kappa or lambda isotype.

RESULTS

Among the 50 patients who survived for at least 12 months, proteinuria, hypoalbuminemia, and hypercholesterolemia improved during follow-up; 36% met criteria for a renal response. Median 24-hour urinary protein excretion decreased from a baseline value of 9.6 g/24 h to 1.6 g/24 h at 12 months among patients with complete hematologic response, and 71% met criteria for a renal response. Twenty-hour urinary protein excretion did not decrease during follow-up among patients with persistent plasma cell disease, and only 11% had a renal response at 12 months (P < 0.001 for hematologic responders vs. nonresponders).

CONCLUSION

Dose-intensive intravenous melphalan with autologous blood stem-cell transplantation improves the nephrotic syndrome in patients with AL amyloidosis-associated renal disease. The benefit is largely limited to patients achieving eradication of the underlying plasma cell dyscrasia.

Dofetilide: a new pure class III antiarrhythmic agent

BACKGROUND

Although there are a variety of antiarrhythmic agents used for the treatment of atrial fibrillation of flutter, each drug has drawbacks, and room exists for new pharmacologic agents. Dofetilide, a pure class III agent, has recently been approved by the Food and Drug Administration for therapy of these arrhythmias and is reviewed.

METHODS

Data for dofetilide, published in full or in abstract form, were reviewed, concentrating on the properties related to its efficacy for the therapy of supraventricular arrhythmias.

RESULTS

Results from animal and human studies indicate that dofetilide, a renally excreted drug, has pure class III properties related to blockade of the delayed rectifier potassium current. It is effective for the therapy of atrial arrhythmias, particularly atrial fibrillation and flutter, and has no demonstrable negative inotropic effect. Despite an incidence of torsades de pointes of approximately 2% in patients with impaired ventricular function, dofetilide exhibited no association with an increased mortality rate when studied in a large series of patients with a reduced ejection fraction.

CONCLUSIONS

Dofetilide's electrophysiologic and clinical profiles suggest that it will be safe and clinically useful for the termination and prevention of atrial fibrillation or flutter, even in patients with impaired ventricular function.

Positive atrial inotropic effect of dofetilide after cardioversion of atrial fibrillation or flutter

The pure class III agent dofetilide was evaluated to determine its effect on atrial function after cardioversion of atrial fibrillation or flutter. Compared with placebo, dofetilide-treated patients had evidence of better atrial function after cardioversion, indicating that this agent has a positive atrial inotropic effect during the period of postcardioversion atrial stunning.

A new transthyretin variant (Ser23Asn) associated with familial amyloidosis in a Portuguese patient

The detection and characterization of a new transthyretin (ATTR) variant, Ser23Asn, associated with cardiomyopathy in a Portuguese patient with familial amyloidosis is described. Isoelectric focusing (IEF) of serum from the propositus demonstrated heterozygosity for the presence of wild type and variant ATTR. A combination of mass spectrometric (MS) analyses, including electrospray ionization mass spectrometry (ESI MS), high performance liquid chromatography (HPLC)/ESI MS and matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) performed on the serum-derived TTR were used to identify and locate the amino acid replacement in the variant protein. Genetic mutation analysis by DNA sequencing and allele-specific PCR confirmed this finding.

A new amyloidogenic transthyretin variant (Val122Ala) found in a compound heterozygous patient

A new TTR variant, Val122Ala, was characterized in an individual who carried the Gly6Ser polymorphism on the opposite allele. The main clinical feature of this familial transthyretin amyloidosis (ATTR) variant is extensive cardiomyopathy. The detection and characterization of the variant were performed using a combination of isoelectric focusing (IEF), restriction fragment length polymorphism (RFLP), immunoprecipitation, electrospray ionization mass spectrometry (ESIMS), HPLC (high performance liquid chromatography)/ESIMS, and matrix-assisted laser desorption/ionization mass spectrometry (MALDIMS). The results were confirmed by DNA analysis. The propositus has a brother who carries the new variant but not the polymorphism.

Etiology and complications of atrial fibrillation: insights from pathology studies

Atrial fibrillation (AF) is an arrhythmia associated with a wide variety of cardiac conditions, and it carries a risk of thromboembolism which varies with the underlying disease. The prevalence of AF increases markedly with age, and a review of histopathologic studies reveals that normal aging produces histologic changes in atrial conduction that may lead to the development of atrial arrhythmias. The diverse pathologic causes of AF also result in histologic abnormalities, and an examination of the relation of the etiology of the arrhythmia to pathologic changes suggests a possible reason for the varying risk of thrombus formation. The interaction between the histologic abnormalities and the presence of triggers of AF may also play an important role in the onset and maintenance of this common condition.

Cost-effectiveness of therapies for patients with nonvalvular atrial fibrillation

BACKGROUND

The most appropriate treatment(s) for patients with atrial fibrillation remains uncertain.

OBJECTIVE

To examine the cost-effectiveness of anti-thrombotic and antiarrhythmic treatment strategies for atrial fibrillation.

METHODS

We performed decision and cost-effectiveness analyses using a Markov state transition model. We gathered data from the English-language literature using MEDLINE searches and bibliographies from selected articles. We obtained financial data from nationwide physician-fee references, a medical center's cost accounting system, and one of New England's larger managed care organizations. We examined strategies that included combinations of cardioversion, antiarrhythmic therapy with quinidine, sotalol hydrochloride, or amiodarone, and anticoagulant or antiplatelet therapy.

RESULTS

For a 65-year-old man with nonvalvular atrial fibrillation, any intervention results in a significant gain in quality-adjusted life years (QALYs) compared with no specific therapy. Use of aspirin results in the largest incremental gain (1.2 QALYs). Cardioversion followed by the use of amiodarone and warfarin together is the most effective strategy, yielding a gain of 2.3 QALYs compared with no specific therapy. The marginal cost-effectiveness ratios of cardioversion followed by aspirin, with or without amiodarone, are $33800 per QALY and $10800 per QALY, respectively. Cardioversion followed by amiodarone and warfarin has a marginal cost-effectiveness ratio of $92400 per QALY compared with amiodarone and aspirin. Strategies that include cardioversion followed by either quinidine or sotalol are both more expensive and less effective than competing strategies.

CONCLUSIONS

Cardioversion of patients with nonvalvular atrial fibrillation followed by the use of aspirin alone or with amiodarone has a reasonable marginal cost-effectiveness ratio. While cardioversion followed by the use of amiodarone and warfarin results in the greatest gain in quality-adjusted life expectancy, it is expensive (ie, has a high marginal cost-effectiveness ratio) compared with aspirin and amiodarone. Finally, for patients who are bothered little by symptoms of atrial fibrillation, cardioversion followed by either aspirin or warfarin without subsequent antiarrhythmic therapy is the treatment of choice.

Dose-intensive melphalan with blood stem-cell support for the treatment of AL (amyloid light-chain) amyloidosis: survival and responses in 25 patients

AL (amyloid light-chain) amyloidosis is an uncommon plasma cell disorder in which depositions of amyloid light-chain protein cause progressive organ failure and death in a median of 13 months. Autologous stem-cell transplantation is effective therapy for multiple myeloma and therefore, we evaluated its efficacy for AL amyloidosis. Patients with adequate cardiac, pulmonary, and renal function had stem cells mobilized with granulocyte-colony stimulating factor and were treated with dose-intensive intravenous melphalan (200 mg/m2). Response to therapy was determined by survival and improvement of performance status, complete response or persistence of the clonal plasma cell disorder, and change in the function of organs involved with amyloid at baseline. We enrolled 25 patients with a median age of 48 years (range, 29-60), all of whom had biopsy-proven amyloidosis with clonal plasma cell disorders. Twenty-two (88%) were Southwest Oncology Group performance status 1 or 2 within a year of diagnosis, and 16 (64%) had received no prior therapy. Predominant amyloid-related organ involvement was cardiac (n = 8), renal (n = 7), hepatic (n = 6), neuropathic (n = 3), and lymphatic (n = 1). Fifteen patients had one or two organ systems involved, whereas 10 had three or more involved. With a median follow-up of 24 months (12-38), 17 of 25 patients (68%) are alive, and the median survival has not been reached. Thirteen of 21 patients (62%) evaluated 3 months posttransplant had complete responses of their clonal plasma cell disorders. Currently, two thirds of the surviving patients (11 of 17) have experienced improvements of amyloid-related organ involvement in all systems, whereas 4 of 17 have stable disease. The improvement in the median performance status of the 17 survivors at follow-up (0 [range, 0-3]) is statistically significant versus baseline (2 [range, 1-3]; P < . 01). Significant negative prognostic factors with respect to overall survival include amyloid involvement of more than two major organ systems and predominant cardiac involvement. Three patients have experienced relapses of the clonal plasma cell disorder at 12 and 24 months. Dose-intensive therapy should currently be considered as the preferred therapy for patients with AL amyloidosis who meet functional criteria for autologous transplantation.

Effect of orthotopic liver transplantation on the progression of familial amyloidotic polyneuropathy

BACKGROUND

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant inherited disease associated with a mutant form of the protein transthyretin (TTR). It is characterized clinically by the systemic deposition of amyloid fibrils resulting in organ dysfunction and, ultimately, death. The majority of TTR is produced in the liver, and transplantation of the liver has been shown to ameliorate this source of mutant TTR, arresting the progression of this fatal disease.

METHODS

Thirteen patients with FAP have undergone successful liver transplant surgery at our center since 1992. The impact of liver transplantation on amyloid-related polyneuropathy, cardiovascular, and gastrointestinal dysfunction is reported in this study. Three patients who died before cardiovascular and neurological follow-up are excluded from the analysis.

RESULTS

Ten of 13 patients (77%) remain alive an average of 49 months (range, 17-64 months) after transplantation. Three patients suffered sudden death, with autopsy documentation of amyloid deposits involving the conduction system of the heart. Liver transplantation was performed more quickly, required less blood, and a shorter postoperative hospital stay in these patients, compared with patients with cirrhosis. Neurological and nutritional symptoms improved in the majority of affected patients. Those patients with echocardiographic evidence of ventricular wall and valve thickening before transplantation progressed postoperatively despite neurologic improvement.

CONCLUSIONS

Liver transplantation offers the only cure for the genetic defect causing FAP and appears to result in subjective and objective improvement in neurological dysfunction. Patients with preexisting cardiovascular abnormalities progress despite transplantation; therefore, consideration for combined heart-liver transplantation may be warranted in this subset of patients.

The clinical features of immunoglobulin light-chain (AL) amyloidosis with heart involvement

We reviewed clinical presentation, investigations, therapy, prognosis and outcome of 232 patients with primary (AL) cardiac amyloidosis. There were 142 men and 90 women. Median age at presentation was 59 years (range 29-85). AL heart disease was unusual both in patients under the age of 40 (3.0%) and in non-Caucasians (6.5%). Fatigue and weakness were the commonest presenting symptoms. Hallmark features of periorbital ecchymoses and macroglossia were present in 12.5% and 27.2%, respectively. AL cardiac amyloidosis was unusual in isolation (3.9%), and most frequently patients had features of multiorgan dysfunction; heavy proteinuria and features of malabsorption predominating in this respect. Heart involvement represents the worst prognostic indicator, with a median survival from diagnosis of 1.08 years, falling to 0.75 years with the onset of heart failure. Current therapeutic procedures appear to prolong survival, with left ventricular wall thickness, mass and ejection fraction on echocardiography and late potentials on signal averaged electrocardiography of use in prognostic stratification. Cardiac involvement from AL amyloidosis is rapidly fatal. It should be suspected in all patients with heart failure who have wall thickening on echo, normal chamber sizes, low EKG voltages and evidence suggesting a multisystem disease.

Signal-averaged electrocardiography in patients with AL (primary) amyloidosis

One hundred thirty-three patients with biopsy-proven AL amyloidosis were studied with echocardiography, Holter recording, 12-lead electrocardiography, and signal-averaged electrocardiograms. Features from these tests were analyzed in relation to their effect on mortality. Late potentials were more frequent in patients with echocardiographic evidence of cardiac amyloidosis (31%) compared with patients with normal echocardiograms (9%, p < 0.003). One hundred six of the 133 patients died during follow-up, of which 34 were nonsudden cardiac deaths and 33 were sudden deaths. Abnormal echocardiograms and signal-averaged electrocardiograms were each predictive of all-cause cardiac death (p < 0.0001 ) and sudden cardiac death (p < 0.0001). Abnormal signal-averaged electrocardiograms were also independently predictive of sudden death in the subgroup of patients with an abnormal echocardiogram (p < 0.05). Thus late potentials are predictive of sudden death in patients with AL amyloidosis and provide independent prognostic information in patients with echocardiographic evidence of amyloid involvement.

Features and prognosis of exertional syncope in light-chain associated AL cardiac amyloidosis

Syncope is common in AL amyloid heart disease and in almost 1/3 of our patients who experienced syncope, it was precipitated by physiologic stress. Stress-precipitated syncope was associated with a poor prognosis in such patients, both in terms of their median survival of 2 months and was frequently a precursor of sudden cardiac death.

Electrophysiologic abnormalities in AL (primary) amyloidosis with cardiac involvement

OBJECTIVES

This study sought to determine the spectrum of electrophysiologic abnormalities found in patients with cardiac involvement due to AL (primary) amyloidosis and to evaluate the prognostic implications, particularly in relation to subsequent sudden death.

BACKGROUND

Only case reports, but no series of invasive electrophysiologic studies, exist in patients with cardiac AL.

METHODS

Twenty-five patients with biopsy-proven AL and cardiac involvement underwent standard invasive electrophysiologic studies.

RESULTS

The function of the sinus and the atrioventricular node was preserved in most patients, but the infra-His (HV) conduction times were usually abnormal. The mean (+/-SD) HV interval for the 25 patients was 79 +/- 18 ms (range 50 to 110), and 23 patients (92%) had an abnormally prolonged interval (> 55 ms). Marked HV prolongation (> or = 80 ms) occurred in 12 patients, 6 of whom had an interval > or = 100 ms. Among the 23 patients who died during follow-up, HV prolongation was the sole independent predictor of sudden death by multivariate analysis (p = 0.05).

CONCLUSIONS

Patients with cardiac AL are prone to disease in the His-Purkinje system. Prolongation of the HV interval is common and may not be suspected from the surface electrocardiogram in the presence of a narrow QRS complex. These patients have a high prevalence of sudden death, of which the HV interval is an independent predictor. The association of HV prolongation and sudden death is probably multifactorial, representing either a marker of severe myocardial infiltration with an increased propensity to lethal ventricular arrhythmias or electromechanical dissociation, or indicating severe conduction system disease eventually leading to complete atrioventricular block and bradycardic death.

Right ventricular dilation in primary amyloidosis: an independent predictor of survival

This study was designed to characterize the geometry and function of the right ventricle and its prognostic significance in patients with primary (AL) cardiac amyloidosis. AL amyloidosis is an infiltrative systemic disease that can result in thickening of heart structures and rapidly progressive congestive heart failure due to restrictive ventricular physiology and eventual systolic dysfunction. Thirty-seven patients with AL amyloid heart involvement and 20 normal control subjects were evaluated using 2-dimensional and Doppler echocardiography. Based on the ratio of left-to-right end-diastolic ventricular chamber areas, patients were classified into 2 groups: 25 patients with disproportionate right ventricular (RV) dilation (left ventricular to RV ratio < or = 2) and 12 with a ventricular area ratio > 2. Patients with a relatively dilated right ventricle (ratio < or = 2) had a shorter median survival (4 months) compared with patients with an area ratio > 2 (10 months, p <0.003). Of multiple clinical, echocardiographic, and Doppler features entered into a multifactorial model, a ventricular area ratio < or = 2 remained the only independent predictor of survival. Patients with AL amyloid heart disease represent a heterogeneous population with regard to both prognosis and the relative degree of right to left ventricular dilation. RV dilation in patients with amyloid heart disease appears to be associated with more severe involvement and is associated with a very poor prognosis with a median survival of only 4 months.

Progression of ventricular wall thickening after liver transplantation for familial amyloidosis

BACKGROUND

Familial amyloidosis (FAP) is characterized by the progression of neurologic and cardiac impairment ultimately leading to death within 7 to 15 years after the onset of the disease. Liver transplantation represents the only definitive therapy for this disease and has been performed since 1990.

METHODS

To determine the effect of liver transplantation on disease progression, electrocardiography and Doppler echocardiography were performed and blindly analyzed on 11 patients with FAP who were followed 0.8 to 8.6 years before liver transplantation and 0.8 to 4.1 years after liver transplantation. RESULTS; After liver transplantation, five patients showed progression of left ventricular wall thickening with increased left ventricular mass, and three of these five showed a reduction in electrocardiographic voltage despite abolition of the mutant protein from the serum. Of the five patients showing progressive wall thickening, four had the transthyretin variant Glu 42 Gly and one patient had the Ala 36 Pro variant; none of the remaining six patients, all of whom possessed the Val 30 Met variant, showed echocardiographic changes. Although 9 of the 11 patients have shown symptomatic improvement in neurologic symptoms, 1 patient has developed heart failure and a second patient has suffered a sudden cardiac death.

CONCLUSIONS

After liver transplantation, patients with FAP should have regular clinical evaluations including electrocardiographic and echocardiographic examinations to look for continued deterioration in heart structure or function.

Familial and primary (AL) cardiac amyloidosis: echocardiographically similar diseases with distinctly different clinical outcomes

OBJECTIVE

To determine whether patients with myocardial amyloidosis due either to AL (primary) amyloid or familial amyloid have distinguishing echocardiographic or electrocardiographic features; and to compare the prevalence of heart failure and survival in the two types of amyloidosis in relation to echocardiographic findings.

DESIGN

Blinded group comparison of randomly selected cases of cardiac amyloidosis.

SETTING

International referral centre for amyloid research and treatment.

PATIENTS

36 patients with cardiac amyloid heart disease, of whom 12 had familial and 24 had primary AL amyloidosis.

RESULTS

Familial and AL echocardiograms were morphologically indistinguishable, with similar left ventricular wall thickness, mean (SD) 15.4 (2.3) nu 15.8 (2.5) mm, respectively; right ventricular wall thickness was also similar between amyloid types: 9.6 (2.8) nu 9.7 (6.5) mm, respectively. Doppler indices of left and right ventricular function, left ventricular volume, and ejection fraction were also similar. Low voltage electrocardiograms (< 0.5 mV) were more common in the AL (16/24, 67%) than in the familial group (4/12, 25%), P < 0.05. The one year survival for familial and AL forms was 92% (11/12) nu 38% (6/24), respectively, with virtually all deaths due to cardiac causes.

CONCLUSIONS

Although cardiac involvement is echocardiographically indistinguishable, cardiac mortality is very different between the two forms of amyloidosis. Preservation of electrocardiographic voltage in familial amyloidosis suggests that the particular biochemical characteristics of distinct types of amyloid fibril have different pathological effects on the myocardium. This distinction becomes critical in the evaluation, treatment, and management of patients who have a diagnosis within the spectrum of the protein deposition diseases.

Intravenous dofetilide, a class III antiarrhythmic agent, for the termination of sustained atrial fibrillation or flutter. Intravenous Dofetilide Investigators

OBJECTIVES

This study sought to determine the safety and efficacy of a single bolus of intravenous dofetilide, a pure class III antiarrhythmic agent, for the termination of sustained atrial fibrillation or flutter.

BACKGROUND

Dofetilide is a highly selective blocker of the rapid component of the delayed rectifier current causing action potential prolongation. These effects, and preliminary clinical data, suggest that it may be effective in the treatment of atrial fibrillation and flutter.

METHODS

Ninety-one patients with sustained atrial fibrillation (75 patients) or flutter (16 patients) were entered into a double-blind, randomized multicenter study of one of two doses of dofetilide (4 or 8 micrograms/kg body weight) or placebo.

RESULTS

Dofetilide effectively terminated the arrhythmia in 31% of patients receiving 8 micrograms/kg, a statistically significant difference from those receiving 4 micrograms/kg (conversion rate 12.5%, p < 0.05) or placebo (no conversion, p < 0.01). Patients with atrial flutter had a greater response to dofetilide (54% conversion rate) than those with atrial fibrillation (14.5% conversion rate, p < 0.001).

CONCLUSIONS

Intravenous dofetilide can convert sustained atrial fibrillation or flutter to sinus rhythm. However, its efficacy is greater in flutter--a response that contrasts with the poorer response seen with class I agents. This finding potentially represents an important advance in the pharmacologic termination of atrial flutter.

Optimal number of beats for the Doppler measurement of cardiac output in atrial fibrillation

This study was undertaken to determine the optimum number of Doppler velocity waveforms required to calculate cardiac output in atrial fibrillation with the same degree of accuracy as that for sinus rhythm. Twenty-one patients in atrial fibrillation underwent calculations of cardiac output derived from aortic Doppler waveform velocity time integrals and RR intervals. The variability in estimates of the cardiac output was calculated with the successive addition of sequential beats and compared with that determined in a control group of 12 subjects in sinus rhythm. For the group in atrial fibrillation, a mean of 13 beats (range 4 to 17 beats) was required to achieve an estimation of cardiac output with a variability of less than 2%, compared with a mean of four beats in sinus rhythm. In atrial fibrillation, the mean number of beats required to determine cardiac output was approximately three times that necessary in sinus rhythm.

Pharmacologic control of heart rate in atrial fibrillation

Atrial fibrillation is associated with a resting heart rate in excess of age-matched subjects in sinus rhythm, and there is an additional steep rise in rate during exertion. This article reviews the factors responsible for this tachycardia, the pharmacologic agents commonly used for heart rate control, and the effects of atrial antiarrhythmic agents on the heart rate during paroxysmal atrial fibrillation.

Dose-intensive melphalan with blood stem cell support for the treatment of AL amyloidosis: one-year follow-up in five patients

The morbidity and lethality of AL amyloidosis is caused by the deposition of lg light chains as fibrillar amyloid protein in vital organs, disrupting their function, and not by the generally low burden of clonal plasma cells that produce the paraproteins. Survival of patients with AL amyloidosis is no more than 1 to 2 years from the time of diagnosis with current management approaches. Clearly, more effective therapies are needed for this rapidly lethal disease. Five patients were treated with dose-intensive melphalan and blood stem cell support and followed for a period of 1 year. Patients were diagnosed with AL amyloidosis by tissue biopsy and categorized by performance status and organ involvement. Their plasma cell dyscrasias were evaluated with immunofixation electrophoresis of serum and urine specimens, quantitative serum lgs, and immunohistochemical staining of bone marrow biopsy specimens. After treatment with dose-intensive intravenous melphalan followed by infusion of autologous growth-factor-mobilized blood stem cells, clinical evaluations and plasma cell studies were repeated at 3 and 12 months. Three men and 2 women aged 38 to 53 years were treated. Median performance status (SWOG) was 2 (1 to 3), and clinical presentations included nephrotic syndrome (n = 1), symptomatic cardiomyopathy (n = 1), gastrointestinal involvement with polyneuropathy (n = 2), and hepatomegaly (n = 1). With a median follow-up of 13 months (12 to 17 months), all five patients are well and have shown stable or improved performance status and clinical remission of organ-related dysfunction, including a 50% reduction in daily proteinuria with no change in creatinine, reversal of symptoms of cardiomyopathy and reductions of posterior wall and septal thickening, reversal of polyneuropathy and gastric atony, and resolution of hepatomegaly by computed tomographic scan. In 3 of the 5 patients (60%) at 12 months after treatment, plasma cell dyscrasias could not be detected. Dose-intensive chemotherapy with intravenous melphalan and growth-factor-mobilized blood stem cell support is feasible therapy for patients with AL amyloidosis, even when there is clinical evidence of cardiac involvement. At least some patients with AL amyloidosis achieve complete remission of their plasma cell dyscrasia, improvement in performance status, and clinical remission of organ-specific disease after this form of treatment.

Resolution of heart failure in patients with AL amyloidosis

BACKGROUND

Patients with AL amyloidosis and congestive heart failure have a very poor prognosis. To date, the recovery of these patients has not been described in detail.

OBJECTIVE

To determine the frequency and characteristics regression of disease in patients with congestive heart failure due to AL amyloidosis.

DESIGN

Review of patients with systemic AL amyloidosis.

SETTING

An international referral center for amyloidosis in the United States.

PATIENTS

140 patients with congestive heart failure due to Al amyloidosis who were seen between 1983 and 1994.

MEASUREMENTS

Functional status, Doppler echocardiography, and objective measurements of disease activity.

RESULTS

3 of 140 patients (2.1%) had marked resolution of congestive heart failure and evidence for remission of disease activity. All 3 had been treated with melphalan.

CONCLUSIONS

Melphalan appears to have had a favorable effect in 3 patients with AL amyloidosis and heart failure. The abolition of light chains that was seen in these 3 patients suggests that light-chain toxicity may play a role in the genesis of heart failure in patients with AL amyloidosis.

Should all patients with atrial fibrillation receive warfarin? Evidence from randomized clinical trials

Anticoagulants should be used more widely in patients with atrial fibrillation. Legitimate concerns exist about the risk/benefit ratio in younger patients with no risk factors and in patients over the age of 75 years. Use of lower doses of anticoagulation (potential target range INR of 1.5-2.5) than used heretofore is probably the solution to most of the problems associated with anticoagulation, but conclusive proof of the efficacy of this strategy is needed. Although aspirin may reduce the risk of stroke the effect may be no more than among patients with a similar level of cardiovascular risk factors and in sinus rhythm. As such, aspirin is a valid alternative for patients with atrial fibrillation at a low risk of stroke but should not be used as an excuse to withhold anticoagulants in patients at greater risk. Several larger studies investigating the effects of different intensities of anticoagulation and the use of aspirin-warfarin combinations are underway. Indeed SPAF-III, comparing a combination of low dose warfarin and aspirin with formal anticoagulation has been stopped and reported in March 1996. A summary of the results will appear in the July issue. Identification of the minimum effective dose of warfarin and effective monitoring systems remain a priority.

Electrocardiography and Doppler echocardiography in secondary (AA) amyloidosis

The fibrils in AL and AA amyloidosis, although similar in appearance, have different biochemical composition and staining characteristics. Whereas electrocardiographic and echocardiographic features of heart involvement in AA amyloidosis resemble those for AL amyloidosis, our findings support the concept that the constituent amyloid fibrils may play a decisive role in the clinical pattern and significance of heart infiltration.

Atrial thrombi occurring during sinus rhythm in cardiac amyloidosis: evidence for atrial electromechanical dissociation

Thrombus formation in the left atrium is rare in patients in sinus rhythm. In three patients with extensive cardiac amyloidosis transthoracic echocardiography showed large atrial thrombi in or protruding into the body of the left atrium during sinus rhythm. Doppler studies showed no A wave on mitral inflow. Severe atrial and ventricular infiltration by amyloid may have resulted in mechanical atrial standstill with resultant thrombus formation. These findings suggest that patients with severe cardiac amyloidosis may require anticoagulation when atrial function is impaired.

Recurrence of primary (AL) amyloidosis in a transplanted heart with four-year survival

Cardiac amyloidosis has a poor prognosis, with a median survival of approximately 6 months once symptoms develop. This patient had a markedly improved quality of life with cardiac transplantation. We would suggest that with refinement of pretransplant chemotherapy, prolonged survival may be possible in carefully selected cases.

Aggravation of postcardioversion atrial dysfunction by sotalol

OBJECTIVES

This study determined the effect of sotalol on atrial function after electrical cardioversion of atrial fibrillation.

BACKGROUND

After electrical cardioversion of atrial fibrillation, the Doppler mitral A wave is often diminished, representing impaired atrial contractile function. Sotalol is an effective atrial antiarrhythmic drug with class III and beta-adrenergic blocking properties. Although the negative inotropic effect of sotalol on the ventricle is minimal in patients with normal ventricular function, it may manifest negative inotropy when ventricular function is impaired. We postulated that after cardioversion, when intrinsic atrial function is impaired, sotalol may have an adverse effect on the atrium.

METHODS

Thirty-seven patients enrolled in a randomized, double-blind study of sotalol for maintenance of sinus rhythm were studied by quantitative Doppler echocardiography within 24 h of electrical cardioversion and, for those still in sinus rhythm, again at 1 month. Doppler variables (E and A wave velocities and integrals) in patients receiving sotalol were compared with those in patients receiving placebo.

RESULTS

After electrical cardioversion, peak A wave velocity and A wave time-velocity integral in the 20 patients receiving placebo were reduced compared with normal values. In the 17 patients receiving sotalol (median dose 320 mg twice daily) these variables were further reduced (mean [+/- SD] peak A wave velocity 19.4 +/- 5.5 vs. 38.4 +/- 14.7 cm/s, p < 0.001 and mean A wave time-velocity integral 1.7 +/- 0.6 vs. 3.4 +/- 1.4 cm, p < 0.001, in sotalol- vs. placebo-treated patients, respectively). Early diastolic filling (E wave variables) did not differ between sotalol- and placebo-treated groups. At 1 month, five sotalol- and six placebo-treated patients remained in sinus rhythm, and A wave variables had increased for the whole group, with a greater increase in sotalol-treated patients.

CONCLUSIONS

After electrical cardioversion, when atrial stunning is prominent, sotalol has a negative atrial inotropic effect. This effect may be temporary, as suggested by resolution at 1 month. Negative inotropic effects of antiarrhythmic drugs on the atrium should be considered in assessing Doppler variables of left ventricular filling.