New-onset left bundle branch block–associated idiopathic nonischemic cardiomyopathy and left ventricular ejection fraction response to guideline-directed therapies: The NEOLITH study

New‐onset left bundle branch block‐associated idiopathic nonischemic cardiomyopathy and time from diagnosis to cardiac resynchronization therapy: The NEOLITH II study

“…The CRT waiting period for those with LBBB‐associated idiopathic NICM would likely not be of great importance if GDMT was highly effective in promoting cardiac remodeling and if delaying CRT was not harmful. Unfortunately, GDMT has demonstrated only a limited ability to improve LVEF and we have now demonstrated a potential adverse impact of CRT delay . Most CRT is implanted >9 months after initial diagnosis .…”

“…The lackluster benefit of GDMT in the setting of new‐onset LBBB‐associated idiopathic NICM may be partially due to inability to reach target doses due to hypotension and/or persistent hypervolemia. Most are diagnosed in the setting of HF hospitalization where the presence of LBBB confers a worse postdischarge prognosis . β‐blocker initiation is only recommended once euvolemia is achieved .…”

“…Antiarrhythmic medications were all class III. Percent target doses achieved for subjects on treatment for ACEIs/ARBs, β‐blockers, and aldosterone antagonists were calculated for descriptive purposes only as previously described . ΔQRS duration was the change in QRS duration and defined as the difference between the CRT‐paced QRS duration and the LBBB QRS duration.…”

“…In the NEw‐Onset LBBB‐Associated Idiopathic Nonischemic CardiomyopaTHy (NEOLITH) study, LVEF improvement after 3 months of GDMT in subjects with LBBB was very modest . We conducted the NEOLITH II study to address two hypotheses: (1) long‐term clinical outcomes would differ between those implanted with CRT ≤9 months versus >9 months after initial HF diagnosis, and (2) long‐term echocardiographic outcomes would differ between those implanted with CRT ≤9 months versus >9 months after initial HF diagnosis.…”

Electro-echocardiographic Indices to Predict Cardiac Resynchronization Therapy Non-response on Non-ischemic Cardiomyopathy

“…S wave indicating the maximal velocity of mitral annulus motion revealed cardiac systolic function1819. CRT response was defined as relative increase (≥15%) or absolute increase (≥10%) of LVEF after 1 year2021. And if it didn’t meet the CRT response criteria, CRT non-response was defined.…”