Publications by authors named "Arun Narayan"

The Himalayas are one of the most mystical, yet least studied terrains of the world. One of Earth's greatest multifaceted and diverse montane ecosystems is also one of the thirty-four global biodiversity hotspots of the world. These are supposed to have been uplifted about 60-70 million years ago and support, distinct environments, physiography, a variety of orogeny, and great biological diversity (plants, animals, and microbes).

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Background The clinical significance of the duration of inducible ventricular tachycardia (VT) at electrophysiology study (EPS) in patients soon after ST-segment-elevation myocardial infarction and its predictive utility for VT recurrence are not known. Methods and Results Consecutive ST-segment-elevation myocardial infarction patients with day 3 to 5 left ventricular ejection fraction ≤40% underwent EPS. A positive EPS was defined as sustained monomorphic VT with cycle length ≥200 ms.

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Background: Recent studies suggest an obesity paradox in individuals with myocardial infarction with better outcomes in obese relative to normal weight patients. We assessed the influence of body mass index (BMI) on early and long-term outcomes in patients with ST elevation myocardial infarction (STEMI) and left ventricular (LV) dysfunction.

Methods: Outcomes were assessed according to BMI status in 478 consecutive patients with STEMI and LV dysfunction (ejection fraction [EF]<40%) admitted to Westmead Hospital between 1 January 2004 and 16 April 2014.

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Background: Obesity is associated with increased risk of cardiovascular disease. There is little known, however, about the influence of body mass index (BMI) on spontaneously occurring ventricular arrhythmias in patients with ischaemic heart disease. We sought to examine the effect of BMI on the ventricular arrhythmia (VA) recurrence and mortality in defibrillator recipients with ischaemic cardiomyopathy.

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A quadrivalent split-virion inactivated influenza vaccine (IIV4; Fluzone® Quadrivalent, Sanofi Pasteur) has been available in the US since 2013 for individuals aged ≥ 6 months. Here, we describe the results of an open-label, multicenter trial (WHO Universal Trial Number U1111-1143-8370) evaluating the immunogenicity and safety of IIV4 in Indian children aged 6-35 months and 3-8 years, adolescents aged 9-17 years, and adults aged ≥ 18 years (n = 100 per group). Post-vaccination hemagglutination inhibition titers for all strains in all age groups were ≥ 8 fold higher than at baseline (range, 8-51).

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Background: There is limited data regarding long-term survival in patients who present with STEMI and out of hospital cardiac arrest (OHCA).

Methods: We prospectively analysed outcomes in 3521 consecutive patients who were diagnosed with STEMI and underwent primary percutaneous coronary intervention (PPCI) or coronary artery bypass surgery from 2004 to 2017. They were divided into two groups according to the presence of cardiac arrest (group I, patients with cardiac arrest;  = 156 group II, patients without cardiac arrest;  = 3365).

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Background: Internationally, a growing number of studies has identified race-related disparities in the presentation, treatment and outcomes of patients with ST-elevation myocardial infarction (STEMI). With a large migrant population, Australia presents a unique microcosm in which to study the impact of migrant status and ethnicity in STEMI patients.

Aim: To investigate if first-generation migrants differed in presentation, treatment or outcomes following STEMI compared with the Australian-born population.

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Article Synopsis
  • The study investigates how body mass index (BMI) affects electrical changes in the heart and overall mortality after a heart attack in patients with severe heart dysfunction.
  • It involved 380 patients, showing that normal-weight individuals had a higher likelihood of experiencing dangerous heart rhythms (inducible-VT) and a greater risk of all-cause mortality compared to overweight and obese patients.
  • Findings support the "obesity paradox," suggesting that being overweight or obese may confer some protective effects in the context of heart attacks and cardiac dysfunction.
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Dengue is a mosquito-borne viral disease that is endemic in India. We evaluated the immunogenicity and safety of recombinant, live-attenuated, tetravalent dengue vaccine (CYD-TDV) in Indian adults. In this observer-blind, randomized, placebo-controlled, Phase II study, adults aged 18-45 years were randomized 2:1 to receive CYD-TDV or placebo at 0, 6 and 12 months in sub-cutaneous administration.

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Background: Inducible ventricular tachycardia (VT) is a strong predictor of spontaneous ventricular tachyarrhythmia following ST-segment-elevation myocardial infarction. Reduced left ventricular ejection fraction (EF) predisposes patients to inducible VT after ST-segment-elevation myocardial infarction. However, the role of right ventricular (RV) dysfunction in predisposing to inducible VT has not been described previously.

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Background: The prognostic significance of a second programmed ventricular stimulation (PVS) at electrophysiology study (EPS), when the first PVS is negative for inducible ventricular tachycardia (VT), in patients following myocardial infarction (MI) is unknown.

Methods: Consecutive ST-elevation MI patients with left ventricular ejection fraction ≤ 40% following revascularization underwent early EPS. An implantable cardioverter defibrillator (ICD) was implanted for a positive (inducible monomorphic VT) but not a negative (no arrhythmia or inducible ventricular fibrillation [VF]/flutter) EPS.

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Aims: The optimal left ventricular ejection fraction (LVEF) to select patients early post myocardial infarction (MI) for risk stratification for prevention of sudden cardiac death (SCD) in the era of primary percutaneous coronary intervention (PPCI) is unknown.

Methods And Results: Consecutive patients (n = 1722) treated with PPCI for ST-elevation MI underwent early (median 4 days) LVEF assessment. An electrophysiological study (EPS) was performed if LVEF ≤40% and a prophylactic implantable-cardioverter defibrillator (ICD) implanted for a positive [inducible monomorphic ventricular tachycardia (VT)], but not a negative, result.

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Background: A negative electrophysiology study (EPS) may delineate a subgroup of patients with severely impaired left ventricular ejection fraction (LVEF) whose care can be safely managed long-term without an implantable cardioverter-defibrillator.

Methods And Results: Consecutive patients treated with primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction underwent early (median 4 days) LVEF assessment. Patients with LVEF ≤40% underwent EPS.

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Aims: Ventricular tachycardia (VT) induction at electrophysiological (EP) study early after ST elevation myocardial infarction (STEMI) has been a predictor of spontaneous ventricular arrhythmia. Reperfusion therapy for STEMI may have resulted in altered VT character. We attempted to determine differences in VT cycle length (CL) and VT recurrence rates, in patients who received early and late reperfusion treatment for STEMI.

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Background: Electrophysiological study (EPS) after myocardial infarction may have a role in identifying patients at risk of sudden cardiac death. It has been shown previously that inducible very fast ventricular tachycardia (VT; cycle length [CL], 200-230 ms) is predictive of arrhythmia recurrence; however, its significance early after reperfusion in ST-segment-elevation myocardial infarction is unknown.

Methods And Results: Consecutive patients with ST-segment-elevation myocardial infarction treated with primary percutaneous coronary intervention with a left ventricular ejection fraction ≤40% underwent early EPS with an implantable-cardioverter defibrillator implanted for inducible VT, but not for a negative EPS.

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A 43-year-old male living in Bengaluru sought emergency services due to high-grade fever, headache, myalgia, abdominal pain and distension. Platelet count (except the first-96,000/mm(3)) and coagulation profile was in normal limits. The dengue serology was positive for IgM and Ig G (immunoglobulin M and G) antibodies.

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Purpose: Several antiplaque agents are being available in the market in spite of vast development of modern medical science, satisfactory treatment of 'oral diseases' by newer drugs is not fully achieved, rather the chemical compounds has exposed the patients to it is different ill effects, therefore, there is interest to find out effective remedy of any disease by harmless herbal drugs thus the aim of this study was to compare plaque formation at 24 hours after the use of Triphala, Hi ora, Chlorhexidine and Colgate Plax mouth washes.

Methods: A controlled, randomized, double-blind, crossover clinical trial was designed. Thirty subjects underwent four consecutive experimental phases with four treatments: Triphala, Hi Ora, Chlorhexidine and Colgate Plax.

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Aims: The prognostic significance of ventricular tachycardia (VT) induced by three extrastimuli (ES) is similar to that of VT induced by one or two ES in patients with coronary disease and abnormal left ventricular (LV) function. The significance of VT inducible with four ES is unclear. To examine the prognostic significance of VT inducible with the fourth ES in patients with post-myocardial infarct (MI) LV dysfunction.

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We sought the correlation between duration of myocardial ischemia and severe left ventricular (LV) diastolic dysfunction (restrictive filling pattern [RFP]) in patients with acute ST-elevation myocardial infarction (STEMI). Duration of ischemia determines infarct size and survival after STEMI. However, the impact of duration of ischemia on LV diastolic function has not been previously studied.

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Background: Prompt thrombolytic reperfusion reduces postinfarct ventricular electrical instability after ST elevation myocardial infarction (STEMI).

Objective: The purpose of this study was to examine the relationship between reperfusion time and inducible ventricular tachycardia (VT) early and spontaneous ventricular arrhythmias (VAs) late after primary percutaneous coronary intervention (PCI) for STEMI.

Methods: Consecutive patients were recruited if they (1) had no prior coronary disease, (2) had been reperfused with primary PCI, (3) had postinfarct ejection fraction ≤40%, and (4) had undergone cardiac electrophysiologic study (n = 128).

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Background: Sudden death risk is highest early after myocardial infarction (MI). Inducible ventricular tachycardia (VT) confers increased risk of spontaneous ventricular arrhythmias.

Objective: The purpose of this study was to evaluate outcomes of electrophysiology (EP)-guided defibrillator implantation early after ST-elevation MI in patients with ejection fraction ≤40%.

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ST segment resolution (STR) predicts epicardial and microvascular reperfusion after primary percutaneous coronary intervention (PPCI) or thrombolysis for ST-elevation myocardial infarction. Immediate restoration of epicardial coronary flow, with improved microvascular perfusion, is much more likely with PPCI. However, the predictive value of immediate STR compared to 90 minutes after PPCI remains unknown.

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Q waves can develop early in infarction and indicate infarct progression better than symptom duration. ST resolution (STR) is a predictor of reperfusion success. Our aim was to assess the prognostic impact of Q waves on presentation and STR after primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction.

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Background: Methods to identify high-risk patients and timing of implantable cardioverter-defibrillator (ICD) therapy after ST-elevation myocardial infarction need further optimization.

Methods And Results: We evaluated outcomes of early ICD implantation in patients with inducible ventricular tachycardia. Consecutive patients treated with primary percutaneous coronary intervention for acute ST-elevation myocardial infarction underwent early left ventricular ejection fraction (LVEF) assessment.

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