AIMTo investigate the relationship of inferior wall ischemia on myocardial perfusion imaging in patients with non-dominant right coronary artery anatomy.METHODSThis was a retrospective observational analysis of consecutive patients who presented to the emergency department with primary complaint of chest pain. Only patients who underwent single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) were included. Patients who showed a reversible defect on SPECT MPI and had coronary angiography during the same hospitalization was analyzed. Patients with prior history of coronary artery disease (CAD) including history of percutaneous coronary intervention and coronary artery bypass graft surgerys were excluded. True positive and false positive results were identified on the basis of hemodynamically significant CAD on coronary angiography, in the same territory as identified on SPECT MPI. Coronary artery dominance was determined on coronary angiography. Patients were divided into group 1 and group 2. Group 1 included patients with non-dominant right coronary artery (RCA) (left dominant and codominant). Group 2 included patients with dominant RCA anatomy. Demographics, baseline characteristics and positive predictive value (PPV) were analyzed for the two groups.RESULTSThe mean age of the study cohort was 57.6 years. Sixty-one point seven percent of the patients were males. The prevalence of self-reported diabetes mellitus, hypertension and dyslipidemia was 36%, 71.9% and 53.9% respectively. A comparison of baseline characteristics between the two groups showed that patients with a non-dominant RCA were more likely to be men. For inferior wall ischemia on SPECT MPI, patients in study group 2 had a significantly higher PPV, 32/42 (76.1%), compared to patients in group 1, in which only 3 out of the 29 patients (10.3%) had true positive results (P value < 0.001 Z test). The difference remained statistically significant even when only patients with left dominant coronary system (without co-dominant) were compared to patients with right dominant system (32/40, 76.1% in right dominant group, 3/19, 15.8% in left dominant group, P value < 0.001 Z test). There was no significant difference in mean hospital stay, re-hospitalization, and in-hospital mortality between the two groups.CONCLUSIONThe positive predictive value of SPECT MPI for inferior wall ischemia is affected by coronary artery dominance. More studies are needed to explain this phenomenon.

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Objectives To determine association between physical activity and hours of physical activity and stress levels in medical students  Methods A cross sectional study was conducted at a private medical college in Karachi, during April and May 2015. Convenience sampling was used to identify the study participants. The subjects were medical students from year one through five. We interviewed 235 students. A pre-tested, self-administered three-part questionnaire was used to collect the data. The first part of the questionnaire inquired about the subjects’ demographics and exercise habits, the second part of the questionnaire was adapted from the Perceived Stress Scale (PSS) to determine stress scores within participants, and the third part of the questionnaire asked about other stress relieving factors. Results According to the PSS, 30.3% of the participants were moderately stressed. The mean PSS was found to be 16.95 ± 5.72. 2A significant correlation was found between physical activity and stress levels; those involved in physical activity were 52 percent less likely to be moderately stressed (OR 0.48, p-value = 0.015) as compared to those who had not partaken in physical activity. Furthermore, studentswho performed physical activity for >4 hours per week had a lower mean PSS score (16.2) when compared to those who exercised for <2 hours per week. (18.2). Post-hoc statistical testing revealed the difference to be significant (p=0.028). Conclusion Based on the findings of our study, we conclude that physical activity of any form is associated with significantly decreased stress levels in medical students.

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