Determinants of Response to Cardiac Resynchronization Therapy
John D Allison1, Yitschak Biton2, Theofanie Mela1
1The Demoulas Center for Cardiac Arrhythmias, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
Summary
Cardiac resynchronization therapy (CRT) improves heart failure (HF) outcomes in select patients. Optimizing patient selection and device parameters can enhance CRT response rates, improving treatment efficacy for HF management.
Area of Science:
- Cardiology
- Medical Devices
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is a standard treatment for heart failure (HF) patients with specific electrocardiographic and functional criteria.
- CRT effectively promotes reverse left ventricular (LV) remodeling and improves HF symptoms and clinical outcomes.
- A significant proportion of patients (approximately one-third) do not respond adequately to CRT.
Purpose of the Study:
- To review the key factors influencing patient response to CRT.
- To identify patient selection criteria and device-related parameters that optimize CRT efficacy.
- To provide insights into improving CRT response rates for better heart failure management.
Main Methods:
- Literature review of studies investigating CRT response.
- Analysis of factors including patient selection, LV lead placement, and device programming.
- Synthesis of evidence on optimizing atrioventricular and ventriculo-ventricular intervals.
Main Results:
- Patient selection is crucial for successful CRT outcomes.
- Left ventricular (LV) lead location and selection significantly impact CRT response.
- Optimization of pacing intervals (atrioventricular and ventriculo-ventricular) is associated with improved CRT response rates.
Conclusions:
- Several factors determine the success of CRT in heart failure patients.
- Careful patient selection and precise device optimization are essential for maximizing CRT benefits.
- Further research into refining CRT strategies can improve outcomes for non-responders.
Related Concept Videos
01:30Cardiomyopathy II: Dilated Cardiomyopathy
34
Dilated cardiomyopathy, or DCM, is a progressive myocardial disorder characterized by ventricular chamber dilation and contractile dysfunction.EtiologyVarious factors can cause DCM, including hypertension and heavy alcohol intake, which contribute to the weakening and enlargement of the heart muscle. Viral infections, such as Coxsackievirus B, adenoviruses, and influenza, can lead to DCM by causing inflammation and damage to heart tissue. Certain chemotherapeutic agents, including daunorubicin,...
34
01:22Heart Failure VI: Adjunct Therapies
40
Additional therapies for treating patients with heart failure (HF) may include procedural interventions, supplemental oxygen, the management of sleep disorders, and nutritional therapy.Procedural InterventionsImplantable Cardioverter-Defibrillator: For patients at risk of life-threatening arrhythmias due to severe left ventricular dysfunction, an Implantable Cardioverter-Defibrillator (ICD) can detect and terminate these arrhythmias, preventing sudden cardiac death and improving survival rates.
40
01:26Heart Failure Drugs: Inhibitors of Renin-Angiotensin System
527
The activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system (RAAS) contributes to cardiac remodeling, and inhibiting the RAAS is a pharmacological target in heart failure management. As a result, neurohumoral modulation is a crucial treatment principle for managing heart failure. This approach involves using medications like ACE inhibitors (ACEIs), angiotensin receptor blockers (ARBs), β-blockers, mineralocorticoid receptor antagonists (MRAs), and neutral...
527
01:29Pathophysiology of Cardiac Performance
816
Typical heart performance is influenced by heart rate, rhythm, myocardial contraction, and metabolism or blood flow. The cardiac muscle exhibits distinct electrophysiological features, including pacemaker activity and calcium channel control, which play a vital role in the heart's response to various drugs. The autonomic nervous system, comprising the sympathetic and parasympathetic branches, regulates heart rate. Sympathetic activation increases heart rate, while parasympathetic activation...
816
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
69
Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...
69
01:26Heart Failure Drugs: Inotropic Agents
750
Positive inotropic agents are commonly used as the first line of treatment for heart failure. One such agent is digoxin, derived from the genus Digitalis, which has been known for centuries but effectively utilized since 1785. However, these cardiac glycosides can have potentially toxic effects due to their mechanism of action, which involves inhibiting Na+/K+-ATPase and increasing contractility. Digoxin is absorbed orally and distributed in various tissues, including the CNS. It has a long...
750