Friday, April 3, 2015

DILATED CARDIOMYOPATHY


 
Cardiomyopathy is a term that literally meaning “an ailment of the heart”, used to describe a group of diseases affecting the myocardium, which in response to injury, may undergo dilation or hypertrophy, according to Damjanov (2012),. They are a heterogeneous group of entities affecting the myocardium primarily and not associated with the major causes of cardiac disease, there is now a general agreement on a classification based upon general features of presentation and pathophysiology.  Cardiomyopathy is divided into three forms: Dilated Cardiomyopathy, Hypertrophy Cardiomyopathy, and Restrictive Cardiomyopathy.

Dilated Cardiomyopathy (90% of cases) is considered the most common cardiomyopathy (Le, Bhushan, & Grimm, 2009), also is the third most common cause of heart failure and the most frequent reason for heart transplantation.

It is considered a progressive disease of heart muscle, in which the ventricle are markedly dilated and the heart appears to have a myocardium that is either flabby or thinned and that has been partially replaced  by fibrous tissue, bringing as a  result ventricular chamber enlargement and contractile dysfunction with normal left ventricle wall thickness, the right ventricle may also be dilated (Goswami, 2014). Usually present with symptoms and signs of congestive heart failure, the initial presentation may be severe biventricular failure, accompanied by chest pain and palpitation,  (Tierney, McPhee, & Papadakis, 2005), in the physical examination we find low blood pressure, pulsus alterns, peripheral cyanosis, tachypnea, diffuse apical beat displaced inferolateral and diminished in force, irregularly irregular pulse, as mentioned by Reynolds (2013).

 

Dilated Cardiomyopathy has many causes, but finding a specific cause for an individual case may be difficult, especially as explain Goswami (2014) in patients with multiple risk factors. In many cases (50 % ) of Dilated cardiomyopathy, the cause remains unexplained or idiopathic (Reynolds, 2013). However, some idiopathic causes may result from failure to identify known causes such as infection or toxins, almost a third of cases may result from severe ethanol abuse.

Other causes include:

Genetics, secondary to other cardiovascular diseases, infections, metabolic disorders, nutritional, collagen vascular disease, infiltrative, neuromuscular diseases, primary cardiac tumor, peripartum, and immunologic conditions.

To establish the diagnosis of cardiomyopathy, we must perform a series of complementary studies such as Complete blood count, Metabolic panel, Thyroid function tests, Cardiac biomarkers, B-type natriuretic peptide assay, Chest radiography, Echocardiography, Cardiac magnetic resonance imaging (MRI), and Electrocardiography (ECG) .

As explained by Reynolds (2013) four chamber dilation, decreased global left ventricular systolic and diastolic function, increased left ventricular volumes and left ventricular mass index, with eccentric left ventricular hypertrophy and usually small pericardial effusion are general echocardiographic findings.

Finally the treatment of Dilated cardiomyopathy is essentially the same as treatment of chronic heart failure like a complex clinical syndrome for which many treatment modalities have emerged.

 

Bibliography



Damjanov, I. (2012). Pathology for the Health Professions. Missouri: ELSEVIER Saunders.

Goswami, V. J. (2014, Oct 6). Medscape. Retrieved from emedicine.medscape.com: http://emedicine.medscape.com/article/152696-overview

Le, T., Bhushan, V., & Grimm, L. (2009). FIRST AID for the USMLE step 1. USA: McGraw Hill.

medscape.com. (n.d.). Retrieved from Dilated Cardiomyphaty.

Reynolds, T. (2013). the Echocardiographer's Pocket Reference. Phoenix: Arizona Foundation.

Tierney, L. M., McPhee, S. J., & Papadakis, M. A. (2005). CURRENT Medical Diagnosis & Treatment. New York: McGraw Hill.

TRICUSPID REGURGITATION


           
         
Tricuspid Valve as described by Alexander, Schlant, & Fuster (1998) is a complex structure made up of six major anatomic components such as right atrial wall, annulus, three leaflets, chordae tendineae, papillary muscles, and the right ventricular free wall. The three leaflets are named anterior, posterior, and septal.

            Tricuspid Regurgitation (TR) is a disorder in which this valve doesn’t close tight enough resulting in blood to flow backward into the right upper heart chamber when right ventricle contracts, my be acute, chronic or intermittent.

            This disorder may result from structural alterations of any or all of the components of the valve apparatus. According to Mancini (2014), the lesion may be classified as primary when the Tricuspid Regurgitation is caused by an intrinsic abnormality of the valve structure, or secondary when it is caused by right ventricular dilatation. Most of the TR are functional (primary) and secondary of association with severe mitral valve disease, which triggers a marked dilation of the right ventricle, tricuspid ring, and dysfunction of the subvalvular apparatus due to hypertension. As an isolated lesion, is relatively common and caused by infectious endocarditis, preferably between drugs addicts; other possible causes are Ebstein’s disease, atrial septal defect, carcinoid heart disease, and thoracic trauma with papillary muscle rupture (Roca Goderich, 2002).

            Usually well tolerated in the absence of pulmonary hypertension as described Roca Goderich (2002), when the TR is important symptoms like fatigue or asthenia appear, which are related to the decrease of the cardiac output, other symptoms can be edema, hepatomegaly, abdominal distension, jugular venous distension, weight loss, cachexia, cyanosis, jaundice.

            Color Flow Doppler echocardiography is a mainstay for evaluation of TR, other studies are also used: Chest radiography, serum chemistry, ECG, Cardiac catheterization. (Mancini, 2014).

            Doppler techniques are used to directly visualize regurgitation jets, measure the flow velocities of the regurgitate jets, and accurately estimate right ventricular systolic pressure. In trivial to mild TR, the jet is central and narrow, when it progress to severe the width increases as does the penetration of the jet into the right atrium.

            Other possible findings include: Prolapse of the TV, endocarditis, rheumatic heart disease, or Ebstein anomaly, right ventricle dilated, paradoxical motion of the ventricular septum. Using pulsed wave and continuous wave Doppler, right ventricular and pulmonary arterial systolic pressure can be estimated  by measuring the peak regurgitant flow velocity across the tricuspid valve, converting it to a pressure gradient by use of the modified Bernoulli equation, and then adding the gradient to an estimate of the right atrial pressure as mentioned by Ha, Chung, Jang, & Rim, (2000).

            The TR itself does not require intervention; depending on the etiology and severity of tricuspid regurgitation, treatment may involve medication when the TR is secondary to left side heart failure, mild TR associated with mitral valve disease and pulmonary hypertension; or surgical repair or replacement of the valve in cases like Ebstein anomaly, destruction of the valve by bacterial endocarditis, and severe ventricular dilation that is uncontrolled with medical therapy.

 

 


Bibliography



Alexander, R. W., Schlant, R. C., & Fuster, V. (1998). Hurst's The Heart. United States: Mc-Graw Hill.

Ha, J., Chung, N., Jang, Y., & Rim, S. (2000). Tricusp Stenosis and regurgitation: Doppler and color flow achocardiography and cardiac catheterization findings. Clin Cardiol, ;23(1):51-2.

Mancini, M. C. (2014, Jun 2). emedicine.medscape.com. Retrieved from Medscape: http://emedicine.medscape.com/article/158484-overview#a0101

Roca Goderich, R. (2002). Temas de Medicina Interna. La Habana: Ecimed.