2009

Koh CH, Foo D, Ng KS, Chong CH
Correspondence: Dr Koh Choong Hou, xjunhao@gmail.com

ABSTRACT
A 19-year-old Chinese man presented with tachyarrhythmia during a human centrifuge session while performing a Valsalva manoeuvre at near normal (+1.4 Gz) centripetal forces. It was likely that the hydrostatic effects of sustained centrifugal forces, the distortion of the heart’s shape, as well as swings in the autonomic dominance pre- and post-Valsalva manoeuvre, contributed to the tachyarrhythmia. The 12-lead ECG showed a narrow complex tachycardia with visible P-waves after the QRS complexes consistent with a long R-P’ tachycardia. The intracardiac electrogram demonstrated a concentric retrograde atrial activation during narrow complex tachycardia. The V-A interval was 150 ms which was much longer than in typical atrioventricular nodal reentry tachycardia, which is usually less than 70 ms. The A-H interval was short and the H-A interval was long, indicating that antegrade activation was over the fast pathway and retrograde activation was over the slow pathway. The diagnosis was atypical atrioventricular nodal reentry tachycardia, and radiofrequency ablation was successfully applied to the slow AV nodal pathway.

Keywords: atrioventricular nodal reentry tachycardia, centrifugal forces, narrow complex tachycardia, tachyarrythymia, Valsalva manoeuvre
Singapore Med J 2009; 50(4): 438-441

Koh SLS, Hafizah N, Lee JY, Loo YL, Muthu R
Correspondence: Dr Serena Siew Lin Koh, serena.koh.sl@kkh.com.sg

ABSTRACT
Introduction This study aimed to develop a multifaceted strategy using tailored interventions to implement a fall prevention programme, and to achieve a change in fall prevention practices and a reduction in fall incidence at an acute care hospital in Singapore.
Methods A comparative study was conducted at two acute care hospitals (intervention and control) in Singapore. Pre-intervention, post-intervention and six-month follow-up knowledge assessments of 641 nursing staff, and audits of fall rates and fall prevention practices were performed to determine the effectiveness of a multifaceted strategy with targeted interventions in supporting the implementation of a fall prevention programme.
Results The mean post-knowledge test scores at six months were statistically significantly higher (t[516] is -3.3, p-value is less than 0.01) at the intervention hospital (10.3 +/- 2.3) compared to the scores at the control hospital (9.8 +/- 1.8). Increased compliance with the use of fall risk assessment tools was evident in 99.4 percent and 99.3 percent of all patient records at the control and intervention hospitals, respectively. Following the implementation strategy for a fall prevention programme, there was a non-significant reduction in fall rates from 1.44 to 1.09 per 1,000 patient days at the intervention hospital. No reduction in the fall rate was observed at the control hospital.
Conclusion A multifaceted strategy for the implementation of a fall prevention programme was effective in increasing nurses’ knowledge and the use of the fall risk assessment, but did not have a statistically significant impact on a reduction in the fall rate. The increase in nurses’ knowledge and change in nursing practice were important markers of success in terms of fall prevention at the acute hospitals.

Keywords: clinical practice guidelines, fall incidence, fall prevention programme, fall risk assessment
Singapore Med J 2009; 50(4): 425-432

Bhagwat VR, Yadav AS, Rathod IM
Correspondence: Dr VR Bhagwat, bhagwatvr@yahoo.co.in

ABSTRACT
Introduction Geographical and ethnic factors have recently been shown to have a significant role to play in cardiovascular diseases. The exact relationship between nutritional and geographical factors in cardiovascular diseases is not very clear. This study examined the relationship of hyperhomocysteinaemia with lipid profile and antioxidants in patients with ischaemic heart disease from rural areas in Maharashtra, India.
Methods Blood cholesterol (total, high- and low-density lipoproteins cholesterol), triglycerides along with thiobarbituric acid reactive substances (TBARS), superoxide dismutase, glutathione peroxidase and catalase activities were measured in acute coronary syndrome (ACS) and chronic stable angina (CSA) patients from rural areas and in normal healthy controls from the same area. Plasma total homocysteine was measured by high pressure liquid chromatography with fluorescence detection. Folic acid and vitamin B12 were measured by chemiluminescence immunoassay.
Results The relative lipid ratios were higher in the patients and had a poor correlation with antioxidants. Total homocysteine levels were significantly higher by almost three times more than the controls. TBARS levels also showed a similar pattern, whereas antioxidant enzymes showed a significantly greater fall in ACS than CSA. There was a definite inverse relationship between total homocysteine, TBARS and antioxidants in the patients. The levels of folic acid and vitamin B12 were 3–4 times higher in the patients compared to the controls. There was a poor correlation between the total homocysteine and vitamin levels in the patients.
Conclusion Blood homocysteine is a very important biomarker of cardiovascular diseases and must be evaluated along with other risk factors. There is a higher prevalence of hyperhomocysteinaemia in rural Indian patients. There appears to be a strong association of genetic factors in the development of ischaemic heart disease in Indian patients.

Keywords: antioxidants, folic acid, homocysteine, ischaemic heart disease, lipids, vitamin B₁₂
Singapore Med J 2009; 50(4): 418-424

Jamshidi N, Rostami M, Najarian S, Menhaj MB, Saadatnia M, Firooz S
Correspondence: Dr Mostafa Rostami, nima_jamshidi@yahoo.com

ABSTRACT
Introduction This paper deals with the dynamic modelling of human walking. The main focus of this research was to optimise the function of the orthosis in patients with neuropathic feet, based on the kinematics data from different categories of neuropathic patients.
Methods The patient’s body on the sagittal plane was modelled for calculating the torques generated in joints. The kinematics data required for mathematical modelling of the patients were obtained from the films of patients captured by high speed camera, and then the films were analysed through a motion analysis software. An inverse dynamic model was used for estimating the spring coefficient.
Results In our dynamic model, the role of muscles was substituted by adding a spring-damper between the shank and ankle that could compensate for their weakness by designing ankle-foot orthoses based on the kinematics data obtained from the patients. The torque generated in the ankle was varied by changing the spring constant. Therefore, it was possible to decrease the torque generated in muscles which could lead to the design of more comfortable and efficient orthoses.
Conclusion In this research, unlike previous research activities, instead of studying the abnormal gait or modelling the ankle-foot orthosis separately, the function of the ankle-foot orthosis on the abnormal gait has been quantitatively improved through a correction of the torque.

Keywords: ankle-foot orthosis, gait analysis, Guillan-Barré syndrome, steppage gait
Singapore Med J 2009; 50(4): 412-417

Vandevenne JE, Lincoln T, Butts Pauly K, Rinsky L, Lang PK
Correspondence: Dr Jan E Vandevenne, vdvennej@hotmail.com

ABSTRACT
Introduction This study aimed to describe the radiological aspects and procedural steps of magnetic resonance (MR) imaging-guided closed reduction for the treatment of developmental dysplasia of the hip (DDH).
Methods Infants were positioned on a custom-made hip spica table attached to a vertically open double doughnut-shaped MR imaging unit (GE Signa SP, 0.5T) affording access to one orthopaedic surgeon and one radiologist. Standard MR imaging sequences and rapid dynamic MR imaging sequences, including fast spin-echo, fast gradient-echo and a fluoroscopic echo-planar sequence, were available. Procedural steps were described and illustrated as a guide for the radiologist actively collaborating with the orthopaedic surgeon.
Results Five separate procedural steps were defined, describing the imaging action and the radiologist’s focus related to the clinical action. These procedural steps included patient positioning, static imaging to evaluate hip congruency and factors impeding reduction, dynamic stress testing and reducing the hip while using dynamic motion MR imaging sequences to visualise reduction or dislocation, cast application with intermittent imaging confirmation of the femoral head position, and postprocedural static imaging.
Conclusion The role of the radiologist was well-defined during each procedural step of the MR imaging-guided closed reduction focusing on the use of specific sequences and image interpretation. Knowledge of these procedural steps may be helpful for efficient collaboration with the orthopaedic surgeon and successful MR imaging-guided treatment of DDH.

Keywords: closed hip joint reduction, developmental dysplasia of the hip, hip dislocation, imaging-guided closed reduction, magnetic resonance imaging-guided procedure
Singapore Med J 2009; 50(4): 407-411

Eng CW, Wansaicheong G, Goh SKJ, Earnest A, Sum C
Correspondence: Dr Eng Chee Way, engcheeway@yahoo.com.sg

ABSTRACT
Introduction The aim of our study was to determine the accuracy of the D-dimer test in the exclusion of pulmonary embolism.
Methods In 2006, 446 patients at our hospital underwent computed tomography pulmonary angiogram (CTPA) for the exclusion of pulmonary embolism. We selected patients with a clinical suspicion of pulmonary embolism, and who underwent both a CTPA examination and a D-dimer test performed within a period of five days. Pregnant women, patients with an allergy to intravenous contrast and those who were on anticoagulant therapy were excluded. Based on our criteria, 219 cases were selected. D-dimer test was performed using an immunoturbidimetric assay. A cut-off value of 500 ng/ml was selected as the upper limit to exclude thrombosis.
Results There were 42 patients positive for pulmonary embolism on CTPA and all had elevated D-dimer values. There were 177 patients negative for pulmonary embolism on CTPA and 49 of them had normal D-dimer values. The sensitivity and specificity of the D-dimer test was 100.0 percent (95 percent confidence interval [CI] 91.6–100.0) and 27.7 percent (95 percent CI 21.2–34.9), respectively. The likelihood ratio for a positive test and negative test was 1.38 and 0, respectively.
Conclusion The D-dimer test is suitable for screening patients with a clinical suspicion of pulmonary embolism. The indiscriminate use of CTPA results in unnecessary testing and elevates healthcare costs. Clinicians are urged to give due consideration to a D-dimer test result prior to requesting a CTPA examination.

Keywords: computed tomography pulmonary angiogram, D-dimer, pulmonary angiogram, pulmonary embolism
Singapore Med J 2009; 50(4): 403-406

Kazerani H, Hajimoradi B, Amini A, Naseri MH, Moharamzad Y
Correspondence: Dr Yashar Moharamzad, yasharpop@hotmail.com

ABSTRACT
Introduction This study aimed to evaluate the response rate, clinical efficacy and onset of action of sublingual captopril in patients diagnosed with hypertensive urgency.
Methods In this cross-sectional study, 101 (67 female and 34 male) patients with a diagnosis of hypertensive urgency (systolic pressure greater than or equal to 180 mmHg and/or diastolic pressure greater than or equal to 110 mmHg, and no findings of target organ damage) were included. Sublingual captopril (25 mg) was administered and the blood pressure was measured during a follow-up period of 120 minutes.
Results After 60 minutes, an ideal decrease (25 percent of the initial blood pressure) was detected in 54 patients (53.5 percent). An additional 25 mg of sublingual captopril was administered to the remaining 47 patients (46.5 percent). Of these, 19 (18.8 percent) did not respond even to the second dose of sublingual captopril. These non-responders consisted of patients who were taking multidrug antihypertensive regimens before presentation due to hypertensive urgency. No serious side effect was recorded during the study period.
Conclusion Sublingual captopril can be used as an effective, easily applicable and safe treatment in the management of hypertensive urgency for 120 minutes for those who do not receive multidrug antihypertensive regimens.

Keywords: captopril, hypertension, hypertensive urgency, sublingual captopril
Singapore Med J 2009; 50(4): 400-402