Background: Despite the existence of significant correlation between the mechanical and electric dissynchronism, it is widely known that these two types of dissynchronisms are quite different and there are a number of reasons why mechanical dyssynchronism might be an important variable to measure in addition to electrical dyssynchronism.
Objective: The objective of study was to highlight a group of patients with impaired systolic function who suffer from mechanical dissynchronismin in absence of evident electric dissynchronism (narrow QRS) and who might represent a target group for cardiac resynchronization therapy (CRT).
Materials and methods: We enrolled in study patients with heart failure, NYHA class II-IV and ejection fraction (EF) under 35%, admitted to the Cardiology Department of Internal Medicine Clinic IV. Patients were divided in two groups, according to the duration of QRS complex – one group with wide (≥120 ms) and another one with narrow QRS complex (<120 ms).
Results: Overall, 73.7% of patients had positive criterias for intraventricular dissynchronism – appreciated with ultrasound measurment of septal-to-posterior wall motion delay (SPWMD >130 ms). 10 patients had narrow QRS and 28 had wide QRS. In the wide QRS complex group we found intraventricular dissynchronism at 85.7% of patients, while 14.28% had normal SPWMD. 40% of patients with EF < 35% and narrow QRS had intraventricular dissynchronism.
Conclusions: The duration of QRS complex seems to be an insensitive indicator of ventricular dissynchronism, hence the ultrasound evaluation is recommended for better selection of candidates for CRT.