Defibrillators and cardiac resynchronization therapy as a bridge to cardiac transplantation

Despite the positive impact of medical therapy, the burden of heart failure persists, with disease progression, frequent hospitalizations, and reduced survival. Mortality related to ventricular tachyarrhythmias and/or pump failure has led to the introduction of device therapy. Implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) have now been established as the standard of care in selected patients with chronic heart failure. CRT and ICDs offer the opportunity to reduce morbidity and increase survival in patients with drug-refractory heart failure, and to retard, if not prevent, development of end-stage heart failure requiring cardiac transplantation.     

Exercise capacity for survivors of cardiac transplantation or sustained medical therapy for stable heart failure

Cardiac transplantation is predicted to improve survival for patients with severe symptoms of heart failure and ejection fraction of 20% or less, but the exercise capacity after cardiac transplantation is less than normal. Patients responding to vasodilators and diuretics have progressive improvement in exercise capacity despite low ejection fraction. We hypothesized that among patients currently considered appropriate for transplantation who could nonetheless subsequently be stabilized on medical therapy tailored to hemodynamic goals, survivors after 6 months of sustained medical therapy would demonstrate exercise capacity comparable to that of survivors of transplantation. Of 146 patients referred, 118 (81%) were discharged on tailored therapy without transplantation, and 88 (60%) were stable for at least 1 month. Stability after discharge was more likely in patients with lower right atrial pressures and better renal function on therapy. Of the 88 stable patients, 45 patients were listed for transplant, and 43 were ineligible or unwilling. From these patients, 42 survivors for more than 6 months follow-up after cardiac transplantation or tailoring of medical therapy underwent exercise testing. Baseline functional and hemodynamic status and left ventricular ejection fraction (15 +/- 4%) were not different between the transplant and sustained medical survivor groups at the time of initial evaluation. After 14 +/- 6 months, left ventricular ejection fraction had increased to 62 +/- 7% after transplantation (p less than 0.01) and only 22 +/- 9% after sustained medical therapy (p less than 0.05). However, there were no significant differences in the maximum workload, oxygen uptake, anaerobic threshold, or maximum oxygen pulse between survivors of cardiac transplantation and survivors on sustained medical therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Current treatment options for patients with endocarditis: The evolving indications for cardiac surgery

Infective endocarditis (IE) is a serious and deadly disease. Despite medical advances over the past half century, more than one half of patients with IE suffer a serious complication, and the mortality rate remains approximately 20% during the initial hospitalization and approaches 40% at 1 year. In patients with documented IE, the treatment centers on two main aspects: effective antibiotic therapy and consideration of surgical therapy. Effective antibiotic therapy is the mainstay of treatment and focuses on sustained bactericidal concentrations tailored specifically to the causative microorganism. Surgical therapy is also an important option for many patients with IE. The goals of surgical therapy are to eradicate the focus of infection, to repair endocardial destruction, and to prevent the development of complications and relapse of infection. Ideally, surgical therapy should offer a survival advantage over medical therapy alone. Recent evidence supports the survival benefit of surgery in patients with IE, specifically in those with heart failure and complicated, left-sided IE. Future therapeutic strategies may include broader indications for surgery, as well as new treatments such as immune-modulating agents.     

Therapeutic prospects of cardiac gene transfer

Cardiovascular diseases remain a major cause of morbidity and mortality. Despite significant gains in medical and surgical treatment of these conditions, the burden imposed continues to increase, particularly as the population ages. Hence, there exists an impetus to explore novel therapeutic approaches. Gene therapy, broadly defined as the use of nucleic acid sequences as medicine, is an example of such a novel approach. The potential of gene therapy has been explored in several models of both inherited monogenic and acquired polygenic cardiovascular diseases, such as heart failure and arrhythmia. Exciting developments in gene transfer technology and important insights into the molecular basis of these common diseases have placed them within reach of gene-based therapy.     

Aspergillus valve endocarditis in patients without prior cardiac surgery

Aspergillus native valve endocarditis in patients who have not had cardiac surgery is uncommon. We report 3 cases and review 58 other adult patients reported in the English-language literature. Sixty-seven percent of the patients had underlying immunosuppression. The clinical features were fever (74%), embolic episodes (69%), a new or changing heart murmur (41%), and sudden visual loss (13%). Patients with mural endocarditis were more often immunosuppressed, especially due to solid organ transplants, but had lower frequency of heart murmurs and embolic episodes. Echocardiography revealed a vegetation in 78% of all the cases in which it was performed. Examination and culture of biopsy material often helped to establish a diagnosis of Aspergillus infection. Twenty-five patients had an antemortem diagnosis. These patients received a mean cumulative amphotericin B dose of 27 mg/kg. Twenty percent (3/15) of patients who received combined surgical and medical therapy survived, compared to none of those who received medical therapy alone (p = 0.08). Patients who survived were not immunosuppressed. We conclude that native valve aspergillus infective endocarditis is uniformly fatal without surgical intervention and antifungal therapy.     

Biventricular cardiac pacing

Chronic heart failure (CHF) is a very frequent condition. Its frequency increases with prolongation of median life expectancy and due to improvements in medical care. However, medical treatment does not allow adequate control of symptoms in many cases. Therefore, various nonpharmacological approaches are being developed. The so-called biventricular pacing is one of them. Its main goal is to restore impaired mechanical cardiac synchrony that is present in patients with prolonged QRS duration due to inter- or intraventricular conduction abnormality. At present, biventricular pacing can be achieved through positioning of a special pacing lead into a branch of the coronary sinus on the surface of the left ventricle and implanting the other lead into the right ventricular cavity, and the third lead into right atrial appendage. Clinical trials and experience from many centres have documented improvements in clinical status in the vast majority of patients. An improvement in functional classification (NYHA) by at least one class, prolongation of the six minute walk distance by 20-40%, increase the maximal oxygen uptake by 10-40% a beneficial effect on quality of life can be expected. Preliminary results of the COMPANION trial have suggested that cardiac resynchronization therapy is associated with prognostic effect, especially in conjunction with implantable cardioverter-defibrillator.     

Nitrates as an integral part of optimal medical therapy and cardiac rehabilitation for stable angina: review of current concepts and therapeutics

The goals of optimal medical therapy in patients with stable angina pectoris are to reduce the risk of cardiovascular mortality and future cardiovascular events, improve exercise capacity, and enhance quality of life. Whereas myocardial revascularization is frequently employed in the management of patients with stable angina, a variety of pharmacologic interventions are recommended as part of optimal medical management. The use of short- and rapidly-acting nitrates (eg, sublingual nitroglycerin spray and tablets) is at the core of the therapeutic armamentarium and should be integrated into optimal medical therapy for stable angina along with exercise therapy. The potential clinical implications from these observations are that prophylactic sublingual nitrates, when combined with cardiac rehabilitation, may allow the patient with angina to exercise to a greater functional capacity than without sublingual nitrates.     

Prevention of sudden cardiac death and diabetes mellitus

Conclusions Appropriate medical therapy and revascularization play a pivotal role in preventing or treating myocardial infarction and left ventricular systolic dysfunction, thereby reducing the incidence of SCD. Nevertheless, the ever-growing population of diabetic patients with coronary artery disease, prior myocardial infarction, and left ventricular systolic dysfunction continue to comprise a high-risk population. Thus, appropriate screening and utilization of ICD therapy will remain essential modalities in the ongoing battle against SCD. The use of devices capable of both biventricular pacing and ICD therapy will continue to grow in the ongoing effort to improve both quality of life and mortality in patients with systolic congestive heart failure.     

Epidemiology of sudden cardiac death in patients with heart failure

Mortality in congestive heart failure (CHF) usually occurs from either progressive worsening of cardiac pump failure or sudden cardiac death (SCD). Medical interventions that counter neurohormonal changes slow the progression of CHF and also prevent SCD. The benefits of medical therapy on SCD prevention have been variable, depending on the type of medical therapy. This article discusses the incidence, prediction, and prevention of SCD in CHF due to ischemic and nonischemic cardiomyopathy.     

Bridging patients to cardiac transplantation

Potential recipients of heart transplants have the most advanced form of congestive heart failure, in which standard therapy fails to maintain clinical stability. In the absence of guidelines derived from evidence obtained in clinical trials, caring for these patients becomes a challenge. A successful approach requires the proper coordination of surgical and nonsurgical strategies, including revascularization and valvular surgery as well as mechanical ventricular support and medical strategies. Intensive medical therapy is the most commonly used approach for prolonged bridging to transplantation. Although carefully individualized regimens are necessary to achieve desired goals, most centers adopt a fairly standardized approach involving vasodilators, diuretics, and inotropic support. Bridging patients with cardiac decompensation to transplantation presents a major therapeutic challenge. Appropriate strategies will maximize patients' chances that the bridge from decompensation to transplantation remains intact. (c)2000 by CHF, Inc.     

Assessment of cardiac risk in noncardiac surgery

Surgical techniques have been refined so that complications directly resulting from surgical procedures are relatively small. However, with the high prevalence of coronary artery disease in the United States, many surgical patients have concomitant coronary artery disease. Anesthesia as well as the surgical procedure induce stresses on the heart and circulatory system which could result in perioperative cardiac morbidity and mortality. Assessing patients prior to surgical procedures by history, physical examination, laboratory data, and newer cardiovascular diagnostic procedures can stratify the cardiac risk and help to predict the incidence of perioperative cardiac morbidity and mortality. If great risk exists, an alternative therapy or cancellation of the surgical procedure may be considered. In certain subgroups of patients, coronary artery revascularization, valvular heart surgery, or beginning medical therapy of the underlying cardiac pathology could be performed prior to the surgical procedure. If this cannot be arranged for the high-risk patients, more intensive and invasive hemodynamic monitoring and optimal medical management perioperatively might reduce cardiac complications.     

New horizons: infant cardiac transplantation

Cardiac transplantation has become firmly established as a modality of therapy for end-stage heart disease. Application of this procedure to the neonatal and infant age group is a relatively recent innovation. In this article we describe nursing experience with neonates and infants under 6 months of age who have undergone cardiac transplantation at one university-affiliated medical center. Preparation for infant cardiac transplantation, donor and recipient selection criteria, donor resources, and the transplant process are discussed. Issues in postoperative management are reviewed.     

Constrictive pericarditis after cardiac surgery

Forty-five patients were identified as having constrictive pericarditis after cardiac surgery. The mean patient age was 61 years (range, 40 to 77 years). Twenty-three of 37 patients with adequate clinical information were reported to have had a diagnosis of postpericardiotomy syndrome after the original surgery. The mean interval from original surgery to presentation with constriction was 23.4 months (range, 1 to 204 months). Computerized tomography was helpful in establishing a diagnosis of constriction in 23 of 29 patients (79%). Bypass graft patency was 93% (85 of 91 grafts). Severe pulmonary hypertension (pulmonary artery systolic pressure greater than or equal to 60 mm Hg) was present in nine patients; 8 had coexistent valvular disease (seven cases of mitral valve disease, and aortic valve disease in one). Thirty-seven of the 45 patients underwent pericardial stripping, 28 of whom experienced marked symptomatic improvement. One patient had persistent right heart failure, which was not documented to be secondary to constriction. Four patients had persistent constrictive physiologic conditions. Three of these patients had more extensive pericardial stripping and showed clinical improvement. Four patients (11%) died within 30 days of stripping. Eight patients received medical therapy alone. The decision to treat patients medically was based either on favorable response to medical therapy (five patients), or poor general clinical status.     

Pre-operative cardiac risk assessment and perioperative cardiac management in non-cardiac surgery

More than 230 million surgical operations are performed yearly in the world and this number is continually growing. Thirty days mortality in moderate and high risk non-cardiac surgery is about 2% and exceeds 5% in patients with high cardiac risk. European Society of Cardiology (ESC) issued specific guidelines in 2009. ESC experts created clear stepwise algorithm for assessment of risk of cardiac complications in preoperative period and use of diagnostic and curative procedures aimed at its lowering. This allows to avoid unjustified investigations and drug therapy in operations with low cardiac risk and stresses significance of perioperative medical treatment. This review contains an analysis questioning some statements of the novel ESC guidelines such as reduction of preoperative cardiac tests and prophylactic revascularization of coronary arteries before operations with intermediate and high risk of cardiac complications.     

Effect of an irregular ventricular rhythm on cardiac output

The results of this study suggest that a third mechanism for the reduction of cardiac output in patients with AF is irregularity of the ventricular rhythm. Catheter ablation of the AV junction and implantation of a rate-responsive pacemaker in patients with AF may offer hemodynamic benefit beyond rate control by eliminating the irregularity that is present with medical therapy or after radiofrequency modification of the AV node.     

Permanent cardiac pacing to prevent vasovagal syncope.

Patients with frequent vasovagal syncope have a poor quality of life and often resist treatment with standard pharmacologic approaches. Although the evidence is weak, clinical vasovagal syncope is probably associated with some degree of bradycardia. Studies of temporary pacing during tilt table tests showed that pacing prevented syncope in a little over half of patients who developed a vasovagal response. Six open-label studies of permanent pacing show that permanent pacemaker therapy is associated with substantial improvement over medical therapy. The roles of specific pacemaker modes have not been determined, although there is some evidence that rate-drop responsiveness helps. The second Vasovagal Pacemaker Study will quantify the true benefits of pacing for vasovagal syncope and assess the role of rate-drop response algorithms.     

Fatal cardiac arrhythmias and shock following yew leaves ingestion

A 40-year-old woman presented with vomiting and abdominal pain following voluntary ingestion of 150 yew leaves. She developed ventricular conduction defects and arrhythmias unresponsive to medical treatment after admission. She expired five hours after yew ingestion from irreversible cardiogenic shock. More attention should be given to this rare but severe intoxication for which no effective therapy is known.     

Indications and selection criteria for cardiac transplantation

Assessment of indications for cardiac transplantation is a complex process including first a comparison of expected survival of a patient with end-stage heart disease, mostly ischemic or dilative cardiomyopathy, allocated either to conventional medical or surgical therapy or to cardiac transplantation, second the expected increase in exercise tolerance and quality of life after transplantation. Furthermore the exclusion of contraindications is required: severe irreversible secondary organ damage (especially of kidneys and liver), malignant tumors and systemic malignancies, severe pulmonary hypertension, florid infections, unstable psychosocial conditions of the patient and his surrounding. Although a considerable number of clinical, electrocardiographic, echocardiographic and hemodynamic factors have been defined as indicating very poor prognosis, there exists no prognostic index combining all these factors into a precise prediction of survival of an individual patient with end-stage cardiac failure. Whereas high survival rates have been concordantly documented for the first years after transplantation, the long-term prognosis cannot be estimated as yet with equally sufficient certainty, due to increasing observation of vasculopathies and of progressive myocardial (mostly diastolic) dysfunction of transplanted hearts. These problems suggest to continue with very careful selection of candidates for transplantation. Even in the case of cardiac decompensation and poor prognostic factors, usually a single examination of the patient is not sufficient, but rather a thorough observation of the patient over a period of time including an evaluation of the rate of clinical and hemodynamic decline and of the response to medical therapy.     

Current and novel cardiac support therapies

Despite optimal medical therapy, many heart failure patients progress to end-stage disease associated with reduced quality of life and poor outcome. However, these patients can benefit from current novel cardiac support strategies, including ventricular assist devices (VADs), cardiac support devices (CSDs), and future cell- and/or matrix-based therapies. The most exciting goal in using VADs and CSDs is to achieve reverse remodeling, suppression of remodeling gene programs, and activation of myocardial recovery programs, which will improve left ventricular shape, size, and function. Long-term left VADs are effective, but recovery upon removal is uncommon. Passive CSDs (eg, Acorn devices) are very promising as long-term devices for therapy of end-stage heart failure and reversal of structural and biochemical remodeling. Expanding CSD use to include preventing progressive adverse left ventricular remodeling after ST-segment elevation myocardial infarction requires further study. The combination of cell- and/or matrix-based therapies with CSDs is under investigation.     

Heart failure and cardiac hypertrophy

Opinion statement Left ventricular failure is the final common pathway for a wide spectrum of myocardial insults, including systemic hypertension and myocardial infarction. Although left ventricular hypertrophy is an adaptive response to pressure and volume overload, this process becomes maladaptive if left untreated and pathologic cardiac hypertrophy then becomes an important and independent risk factor for the development of heart failure. Despite its importance, the transition from hypertrophy to heart failure in humans is poorly understood. The focus of treatment should be prevention of heart failure and other cardiovascular events, such as stroke and atrial fibrillation. When heart failure is present, treatment with medical and device therapy is then focused on improving functional capacity, increasing survival, and preventing progression to end-stage heart failure.