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Dive into the research topics where S. Wahi is active.

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Featured researches published by S. Wahi.


Heart | 2009

Evolution and Outcome of Diastolic Dysfunction

Naomi Achong; S. Wahi; Thomas H. Marwick

Background: Diastolic dysfunction (DD) is highly prevalent and associated with increased morbidity and mortality, but its natural history remains poorly defined. Objective: This cohort study sought to characterise the influence of clinical features, medical therapy and echocardiographic parameters on the progression of DD. Methods: We identified 926 consecutive patients (aged 62 (14) years, 221 women) with DD and preserved systolic function. A repeat echocardiogram was performed in 199 patients ⩾1 year after the baseline study (average 3.6 (1.4) years). Follow-up for 4.8 (2.5) years was 97% complete for the major endpoint of all-cause mortality. Cox regression analyses were performed to identify the associations of mortality. Results: Over follow-up, 142 patients died and 22 were admitted with heart failure. The independent predictors of death were age, hyperlipidaemia, co-morbid disease and restrictive filling. The degree of diastolic dysfunction remained stable in 52%, deteriorated in 27% and improved in 21%. There was a greater use of medical therapy in those with stable or worsening diastolic function; when the protective effects of these agents were taken into account in a multivariate model, improvement in diastolic dysfunction was associated with a survival benefit. Conclusion: DD is associated with all-cause mortality, independent of the presence of a major co-morbidity. The degree of DD remains stable in about 50% of patients, the population whose diastolic function improves over time has a more favourable outcome.


International Journal of Cardiac Imaging | 2000

Anatomical M-mode : A novel technique for the quantitative evaluation of regional wall motion analysis during dobutamine echocardiography

Jonathan Chan; S. Wahi; P. A. Cain; Thomas H. Marwick

Recognition of abnormal wall motion during dobutamine echocardiography requires an expert observer. Anatomical M-mode echocardiography may offer a novel quantitative approach to interpretation, amenable to less expert readers. We studied the application of this new modality to 124 patients (80 with known coronary anatomy and 44 patients at low probability of coronary disease) who underwent dobutamine echocardiography, using a standard protocol. Wall motion was interpreted by an experienced reader, using digitally stored 2-dimensional echocardiographic images at rest and peak stress. Percentage of systolic thickening was measured offline using anatomical M-mode echocardiography in the basal and mid segments at rest and peak dose, and compared with wall motion scores and coronary angiography. Of 729 segments, wall motion was identified as normal in 449, ischemic or viable in 171 and showed resting WM abnormalities only in 109 segments. After exclusion of the apex, anatomical M-mode measurements were feasible in 729 of 960 possible basal- and mid-zone segments (76%). Measurement of systolic thickening at peak dose was reproducible within (r2 = 0.83) and between observers (r2 = 0.93). Systolic thickening was significantly greater in segments with normal wall motion (37 ± 2%) compared with ischemic or viable segments (30 ± 2%, p < 0.001), and scar segments (23 ± 3%, p < 0.001). There was an increment of thickening from rest to stress in normal and viable segments, no change in scar, and a decrement in ischemic segments. Significant coronary artery disease (defined by stenoses >70% diameter) was present in 59 patients. Systolic thickening showed significant variation between segments interpreted by wall motion scoring and angiography as true and false positive and true and false negative (p < 0.05). Measurement of systolic thickening using anatomical M-mode echocardiography offers an objective method to quantify systolic thickening at dobutamine echocardiography but has limited clinical feasibility.


Journal of The American Society of Echocardiography | 1999

Aortic Regurgitation Reduces the Accuracy of Exercise Echocardiography for Diagnosis of Coronary Artery Disease

S. Wahi; Thomas H. Marwick

The association of aortic regurgitation with left ventricular size, hypertrophy, and abnormal coronary flow may influence the accuracy of stress testing techniques for the diagnosis of coronary disease. We examined the diagnostic accuracy of treadmill exercise echocardiography to predict coronary artery disease in 76 patients with moderate to severe aortic regurgitation. Rest and poststress images were interpreted by 2 experienced observers, and accuracy was defined by comparison with stenoses >/=50% diameter at coronary angiography. Results were compared with accuracy in a control group of previously published studies in patients without valvular heart disease. After 6 patients were excluded because of a submaximal heart rate response (<85% age-predicted maximal heart rate), 70 patients were included in the final analysis. Patients with aortic regurgitation were of comparable age to the control group and exercised to similar workload. In 16 (23%) patients with significant coronary artery disease and significant aortic regurgitation, the sensitivity of exercise echocardiography was 56% compared with 83% in the control group (P =.03). The specificity in 54 patients with aortic regurgitation but no significant coronary artery disease was 67% compared with 83% in the control group (P =.02). Accuracy was 64% in aortic regurgitation compared with 83% in the control group (P =.02). In patients with aortic regurgitation, accuracy in the left anterior descending artery territory (76%) marginally exceeded that in the posterior (right + circumflex coronary artery) circulation (70%). Thus the presence of significant aortic regurgitation affects the regional wall motion of the left ventricle during exercise and adversely affects the accuracy of exercise echocardiography for the diagnosis of coronary artery disease.


Pacing and Clinical Electrophysiology | 2016

Imaging and Right Ventricular Pacing Lead Position: A Comparison of CT, MRI, and Echocardiography.

Peter T. Moore; John Coucher; Stanley Ngai; Tony Stanton; S. Wahi; Paul A. Gould; C. Booth; Jit Pratap; G. Kaye

Right ventricular nonapical (RVNA) pacing may reduce the risk of heart failure. Fluoroscopy is the standard approach to determine lead tip position, but is inaccurate. We compared cardiac computed tomography (CT), magnetic resonance imaging (MRI), two‐dimensional and three‐dimensional transthoracic echocardiography (TTE), and chest x‐ray (CXR) to assess which provides the optimal assessment of right ventricular (RV) lead tip position.


Echocardiography-a Journal of Cardiovascular Ultrasound and Allied Techniques | 2015

Exploring Noninvasive Tricuspid dP/dt as a Marker of Right Ventricular Function

Yash Singbal; William Vollbon; Luan Tan Huynh; W. Wang; Arnold C.T. Ng; S. Wahi

Right ventricular (RV) function assumes prognostic significance in various disease states, but RV geometry is not amenable to volumetric assessment by two‐dimensional echocardiography. Intra‐ventricular pressure rate of rise (dP/dt) predicts myocardial contractility and adjusting for the maximal regurgitant velocity (Vmax) corrects for preload. We examined the relationship of noninvasive tricuspid dP/dt and dP/dt/Vmax with RV ejection fraction (RVEF) by cardiac magnetic resonance imaging (CMR) as a measure of RV function.


Indian heart journal | 2014

The role of transesophageal echocardiography in aortic valve preserving procedures

T. Hall; Pallav Shah; S. Wahi

In selected cases of aortic regurgitation, aortic valve (AV) repair and AV sparing root reconstruction viable alternatives to aortic valve replacement. Repair and preservation of the native valve avoids the use of long-term anticoagulation, lowers the incidence of subsequent thromboembolic events and reduces the risk of endocarditis. Additionally repair has a low operative mortality with reasonable mid-term durability. The success and longer term durability of AVPP has improved with surgical experience. An understanding of the mechanism of the AR is integral to determining feasibility and success of an AVPP. Assessment of AV morphology, anatomy of the functional aortic annulus (FAA) and the aortic root with transesophageal echocardiography (TEE) improves the understanding of the mechanisms of AR. Pre- and intra-operative TEE plays a pivotal role in guiding case selection, surgical planning, and in evaluating procedural success. Post-operative transthoracic echocardiography is useful to determine long-term success and monitor for recurrence of AR.


Journal of The American Society of Echocardiography | 2017

Afterload dependence of right ventricular myocardial strain

Leah Wright; Kazuaki Negishi; Nathan Dwyer; S. Wahi; Thomas H. Marwick

Background: Right ventricular (RV) free wall strain (RVFWS) is a feasible method for quantitation and follow‐up of RV function and may have benefits over traditional markers such as fractional area change. However, like all ejection phase parameters, RVFWS is difficult to assess in the presence of changing afterload. The aim of this study was to compare RVFWS and traditional RV function parameters for tracking progress of RV function in patients with pulmonary arterial hypertension (PAH) over a range of pulmonary artery systolic pressure (PASPs). Methods: Sequential echocardiograms were collected retrospectively at two time points between 2005 and 2015 in 187 patients (71% women; mean age, 63 ± 14 years) undergoing pulmonary vasodilator therapy for group 1 PAH. Patients were either studied during PAH therapy (n = 111) or before and after treatment initiation (n = 76). Standard measurements of RV and left ventricular function and PASP were performed, and speckle‐tracking strain was used to calculate RVFWS. The linear response of RVFWS to afterload (PASP) was assessed using a standard regression equation. Because it is unclear if the response might be nonlinear, a quadratic association (PASP squared) was also used in the regression model. Results: At visit 1, patients with PAH showed impaired functional capacity (mean 6‐min walk distance, 371 ± 131 m), increased PASP (mean, 54 ± 26 mm Hg), and borderline RVFWS (mean, 18 ± 6%). Patients before PAH therapy showed more pronounced reduction in 6‐min walk distance (mean, 302 ± 136 m) and RVFWS (mean, 16 ± 5%). RVFWS at baseline was associated with PASP (R2 = 0.25, P = .001), RV end‐diastolic area (R2 = 0.36, P < .001), and fractional area change (R2 = 0.21, P < .001). Change in RVFWS was more strongly associated with &Dgr;PASP (std &bgr; = −0.20, P = .02) than &Dgr;PASP squared (std &bgr; = 0.11, P = .20). RVFWS showed strength over fractional area change for sequential RV assessment over a range of PASP changes. Conclusions: Afterload changes should be taken into account in the evaluation of RVFWS during PAH follow‐up, with the relationship to PASP likely to be linear. HighlightsThere is a significant linear correlation between changes in RVFWS and changes in PASP during follow‐up of PAH.RVFWS was significantly better than FAC at tracking changes in function over varying ranges of &Dgr;PASP.RVFWS should be a used to track RV function in patients receiving PAH therapy.


Indian heart journal | 2013

Clinical application and laboratory protocols for performing contrast echocardiography.

Adrian Chong; Brian Haluska; S. Wahi

Technically difficult echocardiographic studies with suboptimal images remain a significant challenge in clinical practice despite advances in imaging technologies over the past decades. Use of microbubble ultrasound contrast for left ventricular opacification and enhancement of endocardial border detection during rest or stress echocardiography has become an essential component of the operation of the modern echocardiography laboratory. Contrast echocardiography has been demonstrated to improve diagnostic accuracy and confidence across a range of indications including quantitative assessment of left ventricular systolic function, wall motion analysis, and left ventricular structural abnormalities. Enhancement of Doppler signals and myocardial contrast echocardiography for perfusion remain off-label uses. Implementation of a contrast protocol is feasible for most laboratories and both physicians and sonographers will require training in contrast specific imaging techniques for optimal use. Previous concerns regarding the safety of contrast agents have since been addressed by more recent data supporting its excellent safety profile and overall cost-effectiveness.


CASE | 2017

Left Ventricular Aneurysm Perforating into the Right Ventricle: A Rare Complication of a Small Side Branch Occlusion after Elective Percutaneous Coronary Intervention

Peter Moore; Matthew Burrage; Julie Mundy; S. Wahi; Arun Dahiya; Stephen Cox

Graphical abstract


Asian Cardiovascular and Thoracic Annals | 2014

An unusual cause of pulmonary edema

Adrian Chong; S. Wahi; Ryan Harvey; Chris Finn; Pallav Shah; Paul A. Gould

Primary cardiac tumors are rare malignancies. Patients may present with congestive cardiac failure due to intracavitary obstruction to blood flow, valvular dysfunction, embolic phenomena, local invasion resulting in arrhythmias, pericardial involvement, constitutional symptoms, or paraneoplastic syndromes. We describe the case of a previously fit 79-year-old woman who presented with acute pulmonary edema due to a large left atrial pleomorphic sarcoma causing severe functional mitral stenosis. She underwent palliative debulking surgery with good symptomatic relief.

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Thomas H. Marwick

Baker IDI Heart and Diabetes Institute

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Rodel Leano

University of Queensland

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Arnold C.T. Ng

University of Queensland

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T. Hall

Princess Alexandra Hospital

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Brian Haluska

University of Queensland

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W. Wang

Princess Alexandra Hospital

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Pallav Shah

Princess Alexandra Hospital

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Y. Singbal

Princess Alexandra Hospital

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