Evaluation of QT parameters in patients of thalassaemia major with iron overload.

OBJECTIVE: To study QT parameters in Thalassaemia Major patients and their association with serum ferritin levels. METHODS: This cross-sectional study was conducted at Ziauddin University, Karachi, from February 2013 to September 2014, and comprised patients of Thalassaemia Major. Participants' serum ferritin levels were determined and electrocardiography was performed. Data was analysed using SPSS 20. RESULTS: Of the 135 participants, 68(50.4%) were in the 7-14 years age group and 69(51%) were males. Significant prolongation of QT, corrected QT interval and increased QT dispersion was observed in patients with serum ferritin levels more than 2,500 nanogram/millilitre (p<0.001 each). These measurements of corrected QT and QT dispersion had a positive linear correlation with serum ferritin levels (r=0.760 and 0.786). CONCLUSIONS: Electrocardiography could be a useful means for the pre-clinical detection of cardiac involvement due to iron overload in Thalassaemia Major patients.

Liquid chromatography tandem mass spectrometry method for the simultaneous stereoselective determination of venlafaxine and its major metabolite, O-desmethylvenlafaxine, in human plasma.

A sensitive, accurate and highly stereoselective assay for the simultaneous determination of venlafaxine (VEN) and its equipotent metabolite, O-desmethyl venlafaxine (ODV), in human plasma was developed and validated. Analytes were simultaneously extracted from plasma using solid-phase extraction and detected by tandem mass spectrometry in positive ion mode with a turbo ion spray interface. Deuterium-labeled VEN and ODV were used as internal standards. Chromatographic separation was performed on a Chiral AGP column, using a time programmed gradient flow with a total run time of 16 min. The method has a lower limit of quantitation of 0.60 ng/mL. The assay was linear over a range 0.60-300.00 ng/mL for both the enantiomers of VEN and ODV, respectively, with coefficient of correlation > 0.99. The extraction recoveries were >77.0% on an average for all the four analytes. The analytes were found stable in plasma through three freeze (-15 °C) and thaw cycles and under storage at room temperature for 8 h, and also in mobile phase at 10 °C for 54 h. The method has shown good reproducibility, with intra- and inter-day variation coefficients < 9%, for all the analytes, and has proved to be very reliable for analysis of VEN and its metabolite in clinical study samples.

The intercept and slope of breathlessness/chest pain-heart rate relationship in patients with coronary artery disease using exercise tolerance test.

The most common cause of morbidity and mortality all over the world is Coronary artery disease. The traditional risk factors for Coronary artery disease are hypertension, diabetes mellitus, family history, smoking, dyslipidaemia and obesity. Chest pain and dyspnoea are the two common complaints of patients with Coronary artery disease. The CAD patients are the largest to be recruited in exercise testing. Bruce protocol is most commonly used in exercise testing. Patients developing chest pain and ECG changes are considered ETT positive. Heart rate determines myocardial oxygen demand. The heart rate increases during exercise due to sympathetic activation and parasympathetic withdrawal. Dyspnoea and pain result from interactions between multiple physiological, psychological, social and environmental factors. Both these sensations strongly motivate adaptive behaviour to regain homeostasis, and patients often experience both conditions. Anterior insula has a strong role that activates in pain and dyspnoea. Pain and dyspnoea which are the major complaints of CAD, can be measured using verbal descriptor or VAS. There is a need of simultaneous recording of chest pain and dyspnoea in patients with CAD. This review includes the studies done previously to record dyspnoea, through VAS and to measure intercept and slope in healthy volunteers and in patients with CAD.

The relationship between exertional chest pain/dyspnoea--heart rate in patients with coronary artery disease using Exercise ToleranceTest.

OBJECTIVES: To observe the relationship between chest pain/dyspnoea-heart rate during exertion in patients with angiographically proved Coronary artery disease compared to patients having negative Exercise Tolerance Test in a private and public sector hospital. METHODS: This is an observational two centre study from Karachi in which 150 patients referred for Exercise ToleranceTest (ETT) at Ziauddin University Hospital, Clifton campus and National Institute of Cardiovascular Diseases Karachi were included. The period of study extended from September 2008 to March 2010. All patients performed a maximal progressive exercise on Bruce protocol. Age, Body Mass Index, target heart rate and risk factors of Coronary artery disease were noted for each patient. The resting heart rate and resting systolic Blood Pressure (BP) were noted. The maximum systolic BP, maximum heart rate, total exercise time and Multiples of resting oxygen consumption (METS) were recorded at the end of exercise. The chest pain and dyspnoea score were plotted against maximum heart rate. RESULTS: Out of 136, 51 were ETT positive and 76 were ETT negative. The ETT positive were older in age, had lesser maximal heart rate, lesser total exercise time and lesser METS than ETT negative. Out of 51 ETT positive patients, 20 had chronotropic incompetence. CONCLUSION: In patients having positive ETT and referred for angiography, the chest pain-heart rate relationship correlated well with number of vessel disease. The dyspnoea-heart rate relationship was not different in the two groups.