All about cardiac resynchronisation therapy in patients with heart failure

Cardiac resynchronisation therapy (CRT) has emerged as a transformative treatment for patients with heart failure, particularly those suffering from moderate to severe symptoms and a poor response to conventional therapies. One of the most significant benefits of CRT is its impact on exercise capacity, a critical factor in the overall quality of life for heart failure patients. 

Here to explain more about CRT and heart failure is esteemed consultant cardiologist, Dr Ashish Patwala. 

Heart failure often results in impaired ventricular contraction, leading to dyssynchrony between the left and right ventricles. This dyssynchrony exacerbates the heart's inefficiency, reducing the stroke volume and limiting the amount of blood pumped with each contraction. As a result, patients experience symptoms such as fatigue, shortness of breath, and a reduced ability to perform physical activities, which significantly limits their exercise capacity.

How does CRT work exactly?

CRT works by delivering synchronized electrical impulses to the left and right ventricles, improving the timing of their contractions. This resynchronisation enhances the heart's pumping efficiency, reduces mitral regurgitation, and optimizes ventricular filling. The improved coordination of the heart's function translates directly into increased exercise tolerance and capacity.

Several studies have highlighted the positive impact of CRT on exercise capacity. One notable study found that patients undergoing CRT demonstrated a significant improvement in peak oxygen consumption (VO2 max), a key indicator of exercise capacity. VO2 max is directly correlated with the body's ability to utilise oxygen during intense exercise, and its enhancement is a strong predictor of better exercise performance and survival in heart failure patients.

Moreover, CRT has been shown to improve the New York Heart Association (NYHA) functional classification in many patients, moving them from class III or IV (indicating severe limitations) to class II or even class I (indicating mild or no limitations). This improvement is reflected in increased walking distances in the six-minute walk test, a standard measure of functional exercise capacity in clinical settings.

In addition to physical improvements, the enhancement of exercise capacity through CRT has significant psychological benefits. Patients who can engage in more physical activity often report better overall well-being, reduced anxiety and depression, and an improved sense of autonomy in daily life.

In conclusion, CRT has a profound impact on the exercise capacity of heart failure patients. By improving the synchronization of ventricular contractions, CRT enhances the heart's efficiency, leading to better physical performance and overall quality of life. As research and technology advance, the role of CRT in managing heart failure is likely to become even more pivotal, offering hope and improved outcomes for countless patients worldwide.