A Beat Too Short: A Narrative Review of Heart Failure
Yogesh Acharya1*, Anastasia  Anoshina1, Daniella Azike1, Ranjan Dahal2
1Avalon University School of Medicine, Willemstad, Curacao,  Netherlands Antilles 
2Saint Peter’s University Hospital, NJ, USA
*Corresponding Author: Yogesh Acharya, Avalon University School of Medicine, Willemstad, Curacao, Netherlands Antilles
Received: 28 October 2018; Accepted: 08 November 2018; Published: 12 November 2018
Article Information
Citation: Yogesh Acharya, Anastasia Anoshina, Daniella Azike, Ranjan Dahal. A Beat Too Short: A Narrative Review of Heart Failure. Cardiology and Cardiovascular Medicine 2 (2018): 156-165.
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Background: Heart failure (HF) is one of the most common global public health concerns and a leading cause of death with the steadily increasing prevalence and substantial impact on quality of life. The objective of the article is to analyze various components of HF and discuss its determinants. 
Materials and Methods: A total of 50 articles was chosen for this literature review from sources such as EBSCO, PUBMED and Google Scholar. 
Results: Risk of developing HF is highest with coronary artery disease, diabetes, obesity, hypertension, and smoking respectively. Regardless of the precipitating factors, many compensatory mechanisms in our body serve only as a temporary fix. Most patients present with volume overload and normal or reduced cardiac output. Evaluation begins with a comprehensive history and examination, supported by the laboratory test. The major goals of treatment are to improve quality of life, alleviate symptoms, and reduce morbidity and mortality by reversing or slowing the cardiac and other vital organ dysfunction. Atrial fibrillation and ventricular arrhythmias are the most dreaded complications, and the prognosis is interlinked with associated comorbidities. 
Discussion: Currently, prescribed medications can improve the signs and symptoms HF. But it is necessary to develop and validate newer treatments, and early diagnostic modalities to enhance the quality of life. More research is needed to better organize and formulate patient-oriented plans when it comes to non-pharmacological treatment approach. A holistic approach is necessary to curb its growing incidence and address comorbidities, starting with health education and general screening.
Keywords
Heart Failure; Epidemiology; Risk Factors; Prevention; Management; Review
Article Details
1. Introduction
Globally, heart failure  (HF) is considered the leading cause of death and the worldwide prevalence  surpasses 37 million [1] with steady growth. Annually, more than 50,000  patients [2] are listed to be candidates for heart transplantation with only as  few as 5,000 cardiac allografts available. Undeniably, HF is a worldwide  dilemma with a substantial impact on human lives and steadily increasing  prevalence [3]. In the US alone, almost 6 million people have HF which will  possibly surpass 8 million by 2030 [4, 5]. An annual estimated cost of $30.7  billion dollars is spent annually, still more than 1/3rd die within  five years of diagnosis [6].
2. Materials & Methods
The objective of the article is to analyze the different components of  HF. A total of 50 articles was chosen for this descriptive review and were  retrieved from sources such as EBSCO, PUBMED and Google Scholar. The  non patterned search terms included keywords like “Heart Failure”,  “Epidemiology”, “Risk Factors”, “Clinical presentation”, “Management” and  “Recent advancements”. The  focus was on recent studies that were peer-reviewed and related to HF in  humans. 
2.1 Risk factors
Ischemic heart disease (IHD) is the commonest cause of HF in western  countries where as male sex, lack of exercise, cigarette smoking, overweight,  diabetes, hypertension, valvular heart disease are all independent risk factors  [7]. The risk of developing HF is highest with coronary artery disease (CAD),  followed by diabetes, obesity, hypertension and smoking. Similarly, the median  time frame (in years) from diagnosis to the development of HF is lowest in CAD  followed by diabetes, hypertension and obesity. Females with CAD develop HF  earlier than the male counterpart [8].
2.2 Pathophysiology 
An understanding of the progression of the disease is essential to  understand HF. Regardless of the precipitating factors, many compensatory  mechanisms in our body serve only as a temporary fix. Decreased cardiac output (CO)  represents the initial change, causing inadequate circulation to the peripheral  tissues. Blood pressure (BP) subsequently drops activating the sympathetic  nervous system to increase the contractility and heart rate (HR). Release of  hormones like norepinephrine and the atrial natriuretic peptide is responsible  for primary mediators. Increase in contractility is governed by the  Frank-Starling’s mechanism which states that the force of ventricular  contraction is a function of the end diastolic volume (EDV) and muscle length.  A subsequent expansion in the length of the sarcomere causes ventricle to  dilate. Furthermore, hypertrophy is noted with an increase in the muscular  stress leading to apoptosis of the cardiac muscle. This is complicated by  activation of the renin-angiotensin-aldosterone system (RAAS), which in turn  retain sodium and fluid. This increased reabsorption is meant to correct the  venous and arterial pressure and clinically present as edema. Unfortunately,  these compensatory modification increase the blood volume and preload further  exacerbating the HF.
2.3 Signs and Symptoms
Most patients present  with volume overload and normal CO. Symptoms of volume overload include cough,  shortness of breath, leg swelling, increased abdominal girth, orthopnea and  paroxysmal nocturnal dyspnea (PND). Healthcare providers use common presenting symptoms  for diagnosis; however, atypical presentations at times can be challenging.  Many patients may also present with the reduced CO. Symptoms include exertional  dyspnea, fatigue, reduced cognition and cold extremities. Typically, patients  develop exertional dyspnea followed by orthopnea and PND. Other signs may be  evident only at more preceding stages due to compensatory mechanisms. They  include tachycardia, weak pulse, pedal edema, raised jugular venous pressure,  S3 gallop, crackles, ascites, anasarca and hepatojugular reflux.
2.4 Diagnosis
Evaluation begins with  a comprehensive medical history and clinical examination, supported by a  complete blood count, metabolic profile including serum electrolytes, blood  urea nitrogen (BUN), glucose, lipid profile, liver, and thyroid function tests  [9]. Other tests include brain natriuretic peptide (BNP) and N-terminal proBNP  (NT-proBNP). These neuro-hormones can be utilized as diagnostic and prognostic  markers of HF [10,11]. More than 90% of patients diagnosed with HF present with  an abnormal ECG finding [12]. ECG also helps to evaluate ventricular  hypertrophy, axis deviation, bundle branch blocks, and atrial enlargements.  Arrhythmias are common and include ventricular extra systoles, atrial  fibrillations (A-Fib) and ventricular tachycardia (V-Tach). Likewise, chest  x-ray (CxR) and echocardiography (ECHO) can be used to evaluate cardiomegaly.  Although ECHO provides greater diagnostic utility, CxR is widely accessible and  offer significant cost-benefit [13]. Additionally, measurement of lung function  is used to exclude respiratory causes of breathlessness, although the presence  of pulmonary disease does not rule out co-existent HF. Epidemiological studies  suggest a strong association between obstructive airways and IHD, which is one of  the principal causes of HF [14]. Lastly, stress-test and cardiac  catheterization can be used for predictive diagnosis, assessing severity and  finding underlying etiology.
2.5 Management
The major  goals of treatment are to improve quality of life, alleviate symptoms and  reduce morbidity and mortality by reversing or slowing the cardiac and other  major organs dysfunction. Comorbidities contribute to poor prognosis and  addressing them with effective management strategies still remains a major  challenge. It is important to determine the cause of a targeted therapeutic  approach. CAD is the leading cause and after revascularization therapy  ventricular function usually improves. Current medical care includes  pharmacological & non-pharmacological approaches, including more invasive  practices to limit and if possible reverse the manifestations.
Non pharmacological approaches encompass diet and nutritional control, as well as adequate rest and appropriate exercises. Pharmacological treatment is based on the broad classification into two groups: HF with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). Acute exacerbations are treated mainly by diuretics, which includes furosemide, bumetanide or torsemide. However, the medical regimen differs significantly based on the etiologies, complications and related comorbidities. Therefore, it is imperative to understand the type of HF before starting the precision based treatment.
HFrEF is treated with beta blockers and/or enzyme inhibitors angiotensin converting enzyme inhibitors (ACEI)/angiotensin II receptor blocker (ARB) and/or mineralocorticoid receptor antagonists (MRA) and/or digoxin and/or angiotensin receptor- neprilysin inhibitors (ARNI) and/or Ivabradine. Beta-blockers with mortality benefits are metoprolol succinate [15], carvedilol [16] and bisoprolol [17]. ARB is used if ACEI is not tolerated due to intractable cough. Digoxin is typically used in patients with AF which reduces the risk of hospitalization and improves overall symptoms. MRA is used with NYHA class II-IV after titrating up the doses of ACEI and beta blockers to the maximal level. Based on RALES (Randomized Aldactone Evaluation Study) and Ephesus (Eplerenone post-acute myocardial infarction heart failure and survival study), an addition of the low dose MRA is considered in all patient with moderate to severe chronic HF in the absence of hyperkalemia or significant renal dysfunction or both [18]. Hydralazine- isosorbide dinitrate combination is used in patients with chronic kidney disease and those, who are intolerant to ACEI/ARB. In addition, ARNI (Valsartan-sacubitril) can be used in the patient with chronic HFrEF. Pharmacological agents which offer morality benefits are beta- blockers, ACEI or ARB, ANRI, MRA, ivabradine and dinitrate [19]. However, patients with HFpEF are mainly treated with diuretics and antihypertensives. Combination therapy is mainly directed towards improving overall symptoms, and decreasing morbidity and mortality.
When it comes to invasive therapies, an electrophysiologic intervention such as cardiac resynchronization therapy-defibrillator (CRT-D) and implantation of cardioverter-defibrillators (ICD) are common. ICD is used for primary prevention of sudden cardiac death in HF. It should only be considered after guideline directed optimized medical therapy for 40 days’ post MI and 3 months after revascularization. ICD is recommended for ischemic cardiomyopathy with EF ? 35%, and associated HF with NYHA II or III status or EF ? 30 % and NYHA I [20]. ICD is recommended for primary prevention of sudden cardiac death in patients with non-ischemic cardiomyopathy with NYHA II-III symptoms, EF ? 35 %, and failure of guideline-directed medical therapy. Combined CRT-D is recommended for patients with an EF ? 35 %, HF with NYHA III or IV status, and a QRS duration ? 120 ms [21, 22].
Heart transplantation is the standard therapy. Mechanical circulatory devices such as ventricular assist devices and total artificial hearts can help bridge the patient till transplantation [23, 24] However, drugs adherence is challenging and poor adherence is mainly contributing to worsening or re-occurrence in most patients [25].
2.6 Prevention
There are both pharmacological and non pharmacological preventive  modalities. Patients are required to modify the risk factors by changing their  lifestyles, diet, weight, stress as well as be physically active, limit alcohol  intake and be abstinent from smoking [26]. Based on the comorbid conditions,  patients are also placed on specific regimens to improve their health status.  For instance, patients who suffer from hypertension and are at high risk for HF  can be treated with a thiazide-like diuretic like indapamide, as well as ACEI.  Patients unable to tolerate ACEI due to a dry cough, headaches, and  hyperkalemia are switched to ARB. These drugs profoundly decrease the patient’s  potential for developing HF, decrease mortality, and can prevent  hospitalizations [27]. Beta blockers are other agents with well known  beneficial effect. They are useful in patients who experience HFrEF in  comparison to those with HFpEF, unstable severe acute HF, and right ventricular  failure [28]. Some drugs such as thiazolidinediones and metformin in DM can  exacerbate the symptoms of HF, primarily due to fluid retention and lactic  acidosis. However, new drugs are being tested, and one of such is a  sodium?glucose co-transporter inhibitor (SGLT2). Empagliflozin, a SGLT2, have  shown decrement in incidence of cardiovascular events and improvement in patients  with type 2 DM and HF [29].
2.7 Complications
Arrhythmias,  including AF and ventricular arrhythmias, are the most dreaded complications.  AF can be seen in about one-fourth of patients that present with chronic HF,  but overall ventricular arrhythmias are more common [30]. It can also lead to  thromboembolism, which can potentially cause PE, systemic embolization, DVT,  stroke, and MI. Gastrointestinal complications like hepatic congestion and  hepatic dysfunction are common and muscle weakness or wasting are seen in many  patients. HF is frequently associated with impaired kidney function, given  their adjoining risk factors of increasing age and associated comorbidities  [31]. Similarly, pulmonary edema is seen in more than 3/4th of  patients with acute HFrEF [32, 33].
2.8 Prognosis
The prognostic factors  in HF are tightly interlinked with associated comorbidities. In particular,  cardiomyopathies with the poor prognosis include low LVEF, secondary MR and HF  precipitated by an IHD [34-36]. Studies suggest [37] implementing reverse cardiac  remodeling in enhancing cardiac functions leading to a much better outcome.  Patients with an increased EF after receiving this procedure had a better  quality of life and 3% decrease in mortality when compared with the placebo.  
2.9 Recent Advancement
Sacubitril/Valsartan, previously known as  LCZ696, is a neprilysin inhibitor and an ARB, widely used in the treatment of  HF at present. Neprilysin normally degrades natriuretic peptide (NP), ergo its  inhibition with sacubitril increases the levels of NP and causes vasodilation,  the effects of which are counteracted with the valsartan component. In July  2015, Food and Drugs (FDA) approved sacubitril/valsartan for patients with  chronic and stable symptomatic HF and who have an EF <40% [38-40].  Furthermore, these agents should be used with other HF treatment modalities but  in place of ACEIs or ARBs. Ivabradine is another drug, which decreases HR  through the inhibition of funny channels in sinoatrial node. When used in  addition to optimal HF medications including beta-blockers it has shown to  reduce cardiovascular mortality, hospitalizations and improve quality of life.  Based on SHIFT trial [41], it is recommended in patients with HFrEF (EF ?35%),  HR ? 70 bpm and persisting symptoms, despite optimal medications.  
Regarding diagnosis, cardiovascular magnetic resonance (CMR) has become a powerful technique in the preclinical as well as the clinical diagnosis of IHD, CAD, HF, cardiac sarcoidosis, myocardial fibrosis, pericardial sickness, congenital heart problems. It is also helpful to distinguish between acute and chronic MI, is clinically safe, and provides an excellent non-invasive diagnostic modality [42-45].
3. Discussion
New method of  prevention, diagnosis, treatment, and rehabilitation of HF is necessary owing  to an increase in the prevalence. Patients with associated comorbidities and  pathologies should require specific-to-case therapies, given that certain  non-cardiac comorbidities are associated with higher mortality [46, 47]. In  addition, physicians are required to correct any treatments based on patient  response and potential side effects of certain medications, specifically in  elderly, and consider the best options for improvement of life [48].
Furthermore, novel drugs must also be explored to fill the void in treatment modalities. Similarly, more research is required to better organize and create patient-oriented plans when it comes to non-pharmacological treatment approach. The specificity of exercises, proper diet, and meal plans should be established as both preventative and treatment measures [49]. More specific and sensitive tests are needed for early diagnosis before patients succumb to fatal complications.
Newer techniques for imaging and localization of HF, such as the use of Positron Emission Tomography ? Cardiac Magnetic Resonance (PET-CMR), has a promising utility but is restricted due to its availability and economic feasibility [50]. It is necessary to develop diagnostic modalities that are economically viable and widely available. Similarly, advancements in stem cell therapy and its utility have many unexplored angles and there are rooms to determine its clinical effectiveness moving forward with the transition from clinical trials into clinical practice [51, 52]. It is utmost important to develop and validate new treatments and diagnostic methods before it's too late. A holistic approach is necessary to curb its growing incidence, starting with health education and general screening.
4. Conclusion
Although cardiac  pathophysiology, including diagnosis and treatment of HF has become more  straightforward, its growing incidence has become a global public health  nuisance. Besides the pharmacological treatments, a more holistic approach must  be taken into consideration to prevent and treat the patients to decrease the  incidence of these varieties of cardiomyopathies. Newer screening and risk  assessment modalities should be developed that can be widely applied to the  general population. A vigorous initiative is needed to educate people and more  resources should be directed towards prevention.
Acknowledgement 
None
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Citation: Yogesh Acharya, Anastasia Anoshina, Daniella Azike, Ranjan Dahal. A Beat Too Short: A Narrative Review of Heart Failure. Cardiology and Cardiovascular Medicine 2 (2018): 156-165.

 
				 