Eric Ahn

Dilated Cardiomyopathy: A review

Dilated cardiomyopathy (DCM) is a common cardiac diagnosis that may result as a consequence of a variety of pathologies. The differential diagnosis remains quite broad since many pathologies can present as DCM, and as a result the approach to diagnosis may, at times, be quite difficult. This review article discusses genetic and acquired causes of DCM, pathophysiology of myocardial damage, pathology, and diagnostic criteria. An approach to management is also included, in the hope of informing physicians of a clinical entity that afflicts a substantial number of people worldwide.

Hypertrophic cardiomyopathy : current understanding and treatment objectives

The understanding of hypertrophic cardiomyopathy (HCM) has changed dramatically over the last few decades, and it is now understood to be caused by a mutation in one of several cardiac sarcomeric genes. Due to complications such as outflow tract obstruction, diastolic dysfunction, arrhythmias, stroke, infective endocarditis and sudden cardiac death, appropriate and early identification of these patients is imperative. This review attempts to summarise the current state of knowledge on HCM, and provide insight of the appropriate investigations needed in patients with HCM. It also outlines treatment strategies for these patients. Much remains unknown about this complex and intriguing disease, and continued research in identifying the genetic basis of HCM, along with the assessment of therapeutic strategies, will help to optimise patient care.

Do clinical diagnoses correlate with pathological diagnoses in cardiac transplant patients? The importance of endomyocardial biopsy

BACKGROUND Heart transplantation remains the last treatment option for patients with end-stage cardiac disease. Such diseases include ischemic cardiomyopathy, nonischemic cardiomyopathy and other conditions such as arrhythmogenic right ventricular dysplasia, cardiac sarcoidosis and cardiac amyloidosis. OBJECTIVE To review the changes that have occurred over time in the etiology of heart disease in patients requiring heart transplantation, and to compare the clinical and histological diagnoses of explanted hearts from patients with progressive cardiac disease. METHODS The pathological findings of 296 surgically excised hearts over a 20-year period (January 1987 to July 2006) at one institution were examined. Patients were separated into groups based on year of heart transplantation. The tissue was examined to determine the underlying cardiac pathology leading to congestive heart failure. Patient records were reviewed for preoperative clinical diagnoses and other relevant data, including pretransplant endomyocardial biopsy (EMB) results, information regarding left ventricular assist devices and, finally, evidence of disease recurrence in the grafted heart. RESULTS A shift in the underlying etiology was found in patients who underwent heart transplantation from 1992 to 1996, and 1997 to 2001. Between 1987 and 1997, the majority of transplant cases consisted of ischemic cardiomyopathies. From 1997 to 2001, the majority of patients had nonischemic cardiomyopathies, and this trend continued to 2006. A majority of patients with ischemic and hypertrophic cardiomyopathy were diagnosed correctly (96.5% and 82%, respectively) before transplantation. Most patients diagnosed post-transplant with lymphocytic (viral, 15%), hypersensitive/ eosinophilic (25%) and giant cell (100%) myocarditis, arrhythmogenic right ventricle dysplasia (100%), cardiac sarcoidosis (83%) and iron overload toxicity- associated cardiomyopathy (100%) had been misdiagnosed in pretransplantation investigations. Investigations before transplantation did not include an EMB. Of all 296 patients, 51 patients (17%) were misdiagnosed. Excluding the patients with ischemic cardiomyopathy, 46 of 152 patients (30%) were misdiagnosed before transplantation. CONCLUSIONS Although cardiac transplantation is a viable treatment option for patients with a variety of cardiac diseases, accurate diagnosis of patients before transplantation remains a priority. Accurate diagnosis of particular diseases (sarcoidosis, myocarditis, iron toxicity-associated cardiomyopathy and others) allows for proper treatment before transplantation, which may slow down disease progression and improve patient outcomes. Furthermore, it is important to accurately diagnose patients with diseases such as sarcoidosis, amyloidosis and particular types of myocarditis because these can readily recur in the grafted heart. The risk for recurrence must be known to practitioners and, most importantly, to the patient. We strongly recommend the use of EMB if a nonischemic cardiomyopathy is suspected, because the results may alter the diagnosis and modify the treatment strategy.

Drug-related cardiac pathology

Many commonly used drugs, with each causing changes that may be potentially lethal, can adversely affect the function of the heart. In addition some drugs have synergistic effects that can also damage cardiovascular tissues. The drug-related cardiotoxic effects of antineoplastic agents, psychotropic medications, heavy metals, substances of abuse, promotility agents, antihistamines, antimicrobials and antiarrhythmic agents are discussed. Hypersensitivity myocarditis is also discussed.

Cardiac sarcoidosis: Recurrent disease in a heart transplant patient following pulmonary tuberculosis infection

Cardiac transplantation is indicated for patients with end-stage cardiomyopathy secondary to cardiac sarcoidosis. Although rare, recurrent disease has been reported in two cases. The current report presents a case of recurrent cardiac sarcoidosis in a patient 45 months postorthotopic heart transplantation and 40 months following reactivation of latent Mycobacterium tuberculosis infection. The patient was the first to have recurrent disease following an infection that has been proposed to be involved in its pathogenesis. The patients interval between transplant and recurrence is the longest reported to date.

Early morphological changes of an Amplatzer Septal Occluder explanted at heart transplant.

A 59-year-old male with severe biventricular heart failure presented with worsening dyspnea and angina. Following left ventricular assist device insertion, an Amplatzer Septal Occluder (ASO) was required as the patients patent foramen ovale reopened. Seven months later, the patient underwent heart transplantation. The excised ASO was covered with a thick layer of host tissue on both right and left atrial sides, and organized thrombus was found between the metal wires. The foreign materials, the Nitinol wire and the synthetic (Dacron) fabric, showed a reactive infiltrate of macrophages, multinucleate giant cells, and scattered mononuclear cells.

Recurrent cardiac amyloidosis following previous heart transplantation

Recurrent cardiac amyloidosis has been reported in the literature. We present two cases, one at 41 months after heart transplant and autologous stem cell transplant, and the other, at 83 months following heart transplantation. The former is the first case ever reported of a patient with amyloid light chain amyloidosis with systemic recurrence following these two treatment modalities, and the latter is a patient with hereditary amyloidosis, whose interval to disease recurrence is the longest ever reported for this type.

Cardiac valve repair: novel techniques

Aims Heart valve repair today includes several preclinical and clinical trans-catheter techniques, including the Evalve MitraClip, for mitral valve (MV) regurgitation by approximating the leaflets, creating a double orifice valve. This is undergoing clinical evaluation in the United States and is commercially available in Europe. We report the pathological findings of explanted MitraClip devices following chronic implantation in the porcine model. Methods Twenty-one explanted porcine valves with MitraClip devices (implanted for 4, 12, 17, 24 and 52 weeks) were examined with light (16) and electron microscopy (5). All were examined, and submitted for routine histology and methyl methacrylate embedding. Haematoxylin and eosin, Gram and connective tissue stains were used. Results Tissue in-growth and endothelialisation, proportional to duration of implantation, were found on the flow (atrial) and non-flow (ventricular) surfaces of the device. This tissue ‘encapsulated’ the device and bridged the gap between the mitral leaflets. Adjacent chordae tendinae were progressively incorporated into the fibrous tissue on the device, as early as 4 weeks, and in 100% of clips by 52 weeks. Conclusions (1) The MitraClip device provides functional tissue apposition;(2) host tissue encases the device, but the valve continues to function well;(3) no device thrombosis was seen.

Pericardial patch repair of the left atrioventricular valve in atrioventricular septal defect: long-term changes in the patch

A 31-year-old woman with partial atrioventricular septal defect underwent left atrioventricular valve (LAVV) replacement. Her initial repair was at 8 years of age. At 23 years of age, she underwent reoperation due to a combination of severe left ventricular outlet obstruction and moderate LAVV regurgitation. At that reoperation, she had a Dacron patch enlargement of the infundibular septum and repair of her LAVV with a xenograft (bovine) pericardial patch sutured into the superior bridging leaflet. LAVV replacement was required 8 years later because of valve insufficiency. There was a perforation in the patch with fibrosis, thickening due to pannus, and calcification of the pericardial tissue and the leaflet tissue, leading to stiffening of the tissue.