Category: Volume 1

Inherited Wolff‐Parkinson‐White Syndrome

Inherited Wolff‐Parkinson‐White Syndrome

Authors: Liu, Yang; Xue, Yumei; Wu, Shulin; Hu, Dan

Wolff‐Parkinson‐White (WPW) syndrome is a congenital disorder of cardiac conduction system characterized by electrocardiographic preexcitation and episodes of paroxysmal supraventricular tachycardia. It is caused by a cardiac developmental defect in the electrical insulation between the atria and the ventricles due to the presence of an accessory pathway. WPW syndrome is a common cause of supraventricular tachycardia with benign prognosis. However, this clinical entity also predisposes patients to an increased risk of sudden cardiac death, especially in the setting of preexcited atrial fibrillation. WPW syndrome is usually sporadic and of unknown etiology in most cases. During the past 10 years, a significant heritable factor is increasingly recognized. Identification of the genetic basis among patients with WPW syndrome has important implications for understanding the molecular mechanism of ventricular preexcitation and the development of therapeutic strategies for risk stratification and management. The goal of this review is to examine the previous studies on hereditary variants, as well as to outline potential future avenues toward defining the heritability of WPW syndrome.

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Subcutaneous Implantable Cardioverter-Defibrillator

The Subcutaneous Implantable Cardioverter-Defibrillator: A Practical Review and Real-World Use and Application

Authors: Panna, Mark E.; Miles, William M.

The subcutaneous implantable cardioverter-defibrillator (ICD) is a novel technology using a subcutaneous (extrathoracic) system for treatment of potential lethal ventricular arrhythmias. It avoids many of the risks of transvenous ICD implantation. It may be considered in patients having an ICD indication who do not have a pacing and/or cardiac resynchronization therapy indication, and who are unlikely to benefit from antitachycardia pacing therapy. We review patient selection, system components, the implantation technique, and screening considerations for subcutaneous ICD implantation. Its uses in specific patient populations, including children, patients with congenital heart disease, hypertrophic cardiomyopathy, or end-stage renal disease, and patients with preexisting pacemakers, are highlighted. Areas of future investigation are reviewed, including potential use with leadless pacing and magnetic resonance imaging.

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Athletes and Arrhythmias

Athletes and Arrhythmias

Authors: Jansen, Michael J.; Burke, Floyd W.

Sudden cardiac death related to athletic competition is a rare but tragic event. The victims are typically young with no previous cardiovascular symptoms or limitations. The majority of sudden cardiac death events in athletes are due to ventricular arrhythmias as a result of underlying molecular and/or structural level pathologic substrate. In this article, we will review the physiologic cardiac adaptations to exercise along with arrhythmias seen in athletes with a focus on those commonly associated with sudden cardiac death.

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Implantable Cardiac Defibrillators: Who Needs Them and Who Does Not?

Implantable Cardiac Defibrillators: Who Needs Them and Who Does Not?

Author: Conti, C. Richard

Cardiologists who see patients on a general cardiology service are beginning to see an increasing number of patients who have received a primary prevention implantable cardiac defibrillator (ICD) but have never had it fire. There are additionally a number of patients who have inappropriate firing of ICDs. Inappropriate shocks occur in up to 40% of patients with an ICD. The main cause is supraventricular tachyarrhythmia , including sinus tachycardia, atrial fibrillation, and other rapid supraventricular arrhythmias. Read More

Key Words: implantable cardiac defibrillator (ICD); supraventricular tachyarrhythmia; rapid supraventricular arrhythmias;

Document Type: Commentary

 

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Mechanical Circulatory Support for the Failing Heart

Mechanical Circulatory Support for the Failing Heart: Which Device to Choose

Authors: Ahmed, Mustafa; Alvarez, Rene

Critical cardiogenic shock remains a problem with staggering mortality, with the best hope of survival depending on timely and aggressive intervention. This often requires the use of extracorporeal mechanical support in addition to vasoactive medications to manage patients through their initial insult. The decision to use such support must be made early in the clinical presentation, and is best done in a multidisciplinary fashion. In this article, we review the literature and provide an algorithm for the treatment of cardiogenic shock.

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Continuous Flow Left Ventricular Assist Device Therapy

Continuous Flow Left Ventricular Assist Device Therapy: A Focused Review on Optimal Patient Selection and Long-Term Follow-up Using Echocardiography

Authors: Vilaro, Juan R.; Szady, Anita; Ahmed, Mustafa M.; Dawson, Jacqueline; Aranda, Juan M.

Despite widespread awareness and use of scientifically proven life-prolonging medical and device-based therapies over the last two decades, heart failure remains a leading cause of morbidity, mortality, and health care expenditure in the United States. Mechanical circulatory support with a continuous-flow left ventricular assist device (CF-LVAD), either as a bridge to heart transplantation or as destination therapy, is an increasingly used treatment modality for patients with advanced heart failure syndromes that worsen despite their receiving standard therapies. CF-LVAD support creates unique hemodynamic alterations that must be understood to provide appropriate care for these patients before and after implantation. Echocardiography is essential in the evaluation of patients who are being considered for or are mechanically supported by CF-LVADs. Here we provide a focused clinical review on the use of echocardiography in two main aspects of the evaluation of these patients: (a) optimal patient selection for CF-LVAD support and (b) follow-up assessment of optimal pump function.

Document Type: Research Article

DOI: http://dx.doi.org/10.15212/CVIA.2015.0013

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Cardiac Resynchronization Therapy

Cardiac Resynchronization Therapy in 2015: Lessons Learned

Authors: Ketha, Siva; Kusumoto, Fred M.

Over 20 years of research has led to the now widely accepted role of cardiac resynchronization therapy (CRT) in medically refractory, mild to severe systolic heart failure (HF) with increased QRS duration. In addition to conferring a mortality benefit, CRT has been shown to reduce HF hospitalization rates and improve functional status in this population. However, not all patients consistently demonstrate a positive response to CRT. Efforts to improve response to CRT have focused on improving patient selection and optimizing device implantation and follow-up, thereby correcting electrical and mechanical dyssynchrony. In this article we review the pathobiology of cardiac dyssynchrony, the rationale for the use of CRT, the history and the state of the art of CRT, and guidelines and recommendations for CRT, while also focusing on the areas of controversy and potential future applications.

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Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension and the Failing Ventricle: Getting It Right

Authors: Mandras, Stacy A.; Oleck, Sylvia; Ventura, Hector O.

Right ventricular failure (RVF) remains the primary cause of death in patients with pulmonary arterial hypertension. We review the pathophysiology of RVF, including the remodeling and ventriculoarterial uncoupling that occurs when the failing right side of the heart is unable to compensate for a rising afterload. Secondly, the noninvasive imaging techniques used in the assessment of RVF are explored, including echocardiography, cardiac magnetic resonance imaging, computed tomography, and positron emission tomography. Third, we describe how these imaging techniques and a patient’s clinical characteristics may be used to determine prognosis. Lastly, we explore the medical and surgical/interventional treatment options for RVF. Despite these treatment options, morbidity and mortality remain high in this patient population. The discovery of new prognostic indicators, use of hybrid imaging for early detection of RVF, and strategies to prevent the development of RVF will be important if outcomes in this patient population are to improve.

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Evaluation of the Heart Failure Patient by Echocardiography

The Evaluation of the Heart Failure Patient by Echocardiography: Time to go beyond the Ejection Fraction

Authors: Dowe, Jacqueline Dawson; Vilaro, Juan; Hamilton, Karen; Szady, Anita; Aranda, Juan M.

Heart failure is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood. The echocardiogram is the single most performed and useful study in these patients. This article reviews the role of the echocardiogram in the evaluation of the heart failure patient, without focusing on the left ventricle. The discussion includes the use of the echocardiogram in the assessment of the right ventricle and diastolic function and in detecting hemodynamic and morphologic changes in heart failure over a period of time. In addition, we highlight some of the limitations of echocardiography in the assessment of these patients.

Document Type: Research Article

DOI: http://dx.doi.org/10.15212/CVIA.2015.0008

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Noninvasive Hemodynamic Monitoring for Heart Failure

Noninvasive Hemodynamic Monitoring for Heart Failure: A New Era of Heart Failure Management

Authors: Hernandez, Gabriel A.; Navas, Viviana; Chaparro, Sandra

Despite the development of noninvasive tools as echocardiography, right-sided heart catheterization remains an integral part of the cardiovascular evaluation. In the last decade, better understanding of the hemodynamic process before heart failure decompensation led to improvement of outpatient strategies to prevent it. Advances in implantable wireless technology now allow frequent and direct measurement of intracardiac filling pressures, which can be monitored by health care providers to help tailor therapy to reduce filling pressures and hospital readmission rates.

Document Type: Research Article

DOI: http://dx.doi.org/10.15212/CVIA.2015.0009

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