The Co-relations between Electrocardiographic QRS Duration with Several Clinical Findings among Healthy People

Background: The QRS duration signifies the time for ventricular depolarization. Normally, the QRS duration is 0.06 to 0.10 seconds. The measurement of left ventricular dimensions and the changes of left ventricular dimensions are important to assess cardiac as well as the cardiovascular conditions of patients. Co-relations between electrocardiographic QRS duration with other clinical findings among healthy people may help in assessing the cardio-vascular condition of cardiac patients.

Aim of the Study: The aim of this study was to assess the co-relation between electrocardiographic QRS duration with other clinical findings among healthy people.

Methods: This was an observational cross-sectional study which was conducted in the Department of Cardiology, University Cardiac Centre, Bangabandhu Sheikh Mujib Medical University, Dhaka over a period of 2 years from July 2008 to June 2010. In total 92 apparently healthy people without heart failure (HF) or myocardial infarction (MI) were included as the study population. Among them, 22 were in Referent (QRS duration <100 ms), 40 in Incomplete BBB (QRS duration 100 - 119), and 30 in Complete BBB (≥ 120 ms) groups. Proper written consent was taken from all the participants and this study was approved by the ethical committee of the mentioned university. All data were processed, analyzed, and disseminated by MS Office and SPSS version 11.5.

Results: In analyzing the clinical findings of all the participants we observed, the mean systolic and diastolic blood pressure were almost identically distributed among the three groups (125.8 ± 27.7 mmHg vs. 130.1 ± 12.3 mmHg vs. 129.8 ± 14.5. p = 0.652 and 77.9 ± 6.4 mmHg vs. 79.1 ± 6.7 mmHg vs. 76.3 ± 6.7 mmHg, p= 0.225 respectively). The frequency of diabetic patients and antihypertensive drug users was found highest in complete BBB group than those in referent and incomplete BBB group, although the difference was not statistically significant (p=0.262 and p =0.104 respectively).

Conclusion: As a clinical status, systolic blood pressure, diastolic blood pressure and diabetes may be some potential concern in people with complete and incomplete BBB. Besides these, the present study revealed that longer electrocardiographic QRS duration was correlated with an increase in LV mass, LV diastolic dimensions, septal wall thickness, posterior wall thickness, and left atrial size. With complete BBB compared with a normal QRS duration, the association was most striking in individuals. Meanwhile, the presence of prolonged QRS in a patient’s ECG can serve as a bedside clue to the presence of decreased fractional shortening and left ventricular ejection fraction.