Mechanical Dyssynchrony Is Not Everything of Substrate but Is Essential for Cardiac Resynchronization Therapy - Is Assessment of Mechanical Dyssynchrony Necessary in Determining CRT Indication? (Pro) -

Abstract

Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp ardiac resynchronization therapy (CRT) is a treatment for refractory heart failure that uses a specialized pacemaker to re-coordinate or resynchronize the contraction of the both ventricles by pacing multisite in the heart. According to the latest guidelines, CRT is recommended for patients with end-stage heart failure (New York Heart Association (NYHA) class III or IV) despite optimal medical therapy, left ventricular (LV) ejection fraction (EF) ≤35% and wide QRS complex. 1,2 The presence of a conduction delay that includes left bundle branch block (LBBB) is a poor prognostic marker in heart failure. 3 Therefore, CRT can be deemed 'electrical bypass' from the rationale.The acute effects of CRT include an increase in blood pressure, LV max dP/dt and cardiac output 4,5 without an increase in O2 consumption, 6 as well as a reduction of mitral regurgitation (MR) immediately after pacing. 7, 8 The chronic effects of CRT include improvements in functional capacity and symptoms in 70% of heart failure patients, an increase in LVEF, and a decrease of LV end-systolic volume at 6 months and a reduction in the death or heart failure re-admission rates by 30% to 40% at a mean follow-up period of 29 months. 9-12However, despite these promising results, 30-45% of patients selected based on the most recent guidelines do not respond to CRT. 13 Because CRT is an invasive treatment, candidates with severe heart failure should be carefully selected to ensure a maximal benefit with minimal risk. Accordingly, a reliable marker is needed for determining CRT indication. Mechanism of CRTCazeau et al reported in 1994 that multisite pacing increased cardiac output and decreased pulmonary capillary wedge pressure in a patient with LBBB (QRS duration of 200 ms and PR interval of 200 ms) and NYHA IV heart failure, who improved to status to NYHA II 6 weeks later. 14 This is the first reported case of CRT and it is important to think about what type of defect was restored by the pacing in this patient.Patients in whom we are sure that CRT will be effective with a high probability have the following factors: apparent motion by which the LV apex is pulled toward the basal lateral Cardiac resynchronization therapy (CRT) improves heart failure symptoms, cardiac function and long-term prognosis. As a result, it has been established as a treatment for refractory heart failure by using a specialized pacemaker to restore coordinated ventricular contractions with pacing. Despite being an invasive treatment, however, the above effects are not observed in 30-45% of patients selected based on the standard criteria that includes New York Heart Association class III or IV heart failure, left ventricular ejection fraction ≤35%, and QRS duration ≥120 or 130 ms. From the fact that quantifiable resynchronization was associated with hemodynamic and clinical improvements, it should follow that mechanical dyssynchrony is a critical substrate for the benefits from CR...

Coronary Venous Retention—A Feature in Heart Failure as Evidenced by Mean of Cardiac Computed Tomography

“…The value of imaging modalities, such as echocardiography or cardiac computed tomography, in patients with heart failure has been the subject of many researches 16 . Most of these have evaluated the coronary arteries, myocardial infarct, and viability assessment or cardiac dyssynchrony 17–19 …”

“…16 Most of these have evaluated the coronary arteries, myocardial infarct, and viability assessment or cardiac dyssynchrony. [17][18][19] The process of heart failure can significantly influence the anatomy of the heart; however, there has been no complex research that compares the anatomy of the coronary venous system according to the ejection fraction. We hypothesized that its influence could be significant.…”

Limitations and Problems of Assessment of Mechanical Dyssynchrony in Determining Cardiac Resynchronization Therapy Indication - Is Assessment of Mechanical Dyssynchrony Necessary in Determining CRT Indication? (Con) -

“…It is advised that the dyssynchrony reporting should not include a recommendation whether a patient should undergo CRT, as this should be a clinical decision on a case-by-case basis for these borderline or challenging cases. 39 Dr Kanzaki 42 shows us promising new methods for detecting mechanical dyssynchrony. Unfortunately, there is no evidence of their superiorities to the conventional ECG criteria for CRT patient's selection, which is determined by the multicenter, randomized, double blind, prospective studies.…”

Two-dimensional Speckle Tracking Imaging as a Novel Strategy for Accurately Identifying the Accessory Pathway

“…nose myocardial deformation and dyssynchrony in some clinical settings (5,6). It has the advantage of angle independence and may be superior to tissue Doppler-based estimation.…”