Biomedical subjects

Komandoor Srivathsan

Publications and source records attributed to Komandoor Srivathsan.

7 recordsLinked to original sources

PubMed2005

Ventricular tachycardia in the absence of structural heart disease.

In up to 10% of patients who present with ventricular tachycardia (VT), obvious structural heart disease is not identified. In such patients, causes of ventricular arrhythmia include right ventricular outflow tract (RVOT) VT, extrasystoles, idiopathic left ventricular tachycardia (ILVT), idiopathic propranolol-sensitive VT (IPVT), catecholaminergic polymorphic VT (CPVT), Brugada syndrome, and long QT syndrome (LQTS). RVOT VT, ILVT, and IPVT are referred to as idiopathic VT and generally do not have a familial basis. RVOT VT and ILVT are monomorphic, whereas IPVT may be monomorphic or polymorphic. The idiopathic VTs are classified by the ventricle of origin, the response to pharmacologic agents, catecholamine dependence, and the specific morphologic features of the arrhythmia. CPVT, Brugada syndrome, and LQTS are inherited ion channelopathies. CPVT may present as bidirectional VT, polymorphic VT, or catecholaminergic ventricular fibrillation. Syncope and sudden death in Brugada syndrome are usually due to polymorphic VT. The characteristic arrhythmia of LQTS is torsades de pointes. Overall, patients with idiopathic VT have a better prognosis than do patients with ventricular arrhythmias and structural heart disease. Initial treatment approach is pharmacologic and radiofrequency ablation is curative in most patients. However, radiofrequency ablation is not useful in the management of inherited ion channelopathies. Prognosis for patients with VT secondary to ion channelopathies is variable. High-risk patients (recurrent syncope and sudden cardiac death survivors) with inherited ion channelopathies benefit from implantable cardioverter-defibrillator placement. This paper reviews the mechanism, clinical presentation, and management of VT in the absence of structural heart disease.

Journal Article↗

PubMed2005

Safety of wireless capsule endoscopy in patients with implantable cardiac defibrillators.

OBJECTIVES: Wireless video capsule endoscopy (CE) is a new technology that allows visualization of the entire small intestinal mucosa. It is indicated for the evaluation of obscure gastrointestinal bleeding (OGIB) and other disorders of the small intestine. Studies to date suggest that CE is safe and associated with few adverse events. A concern, which has not been studied, is the potential effect of CE on implanted cardiac devices such as implantable cardiac defibrillators (ICD) and other electromedical devices. We previously found CE to be safe in patients with cardiac pacemakers. The primary aim of this study was to evaluate the safety of CE in patients with ICDs who were being evaluated for OGIB. In addition, a secondary aim of the study was to determine whether ICDs had any effect on the images captured by CE. METHODS: Patients referred for the evaluation of OGIB and who also had an ICD were enrolled into the study after informed consent. Five consecutive patients (four females and one male; mean age: 72 yr; range: 60-81 yr) with ICDs were studied. All patients had transvenous endocardial ICDs located in the chest. Prior to CE, patients had a baseline electrocardiogram (ECG) and ICD interrogation. Thereafter, CE was performed in a hospital setting with telemetry monitoring performed simultaneously. A post-procedure ICD interrogation was carried out to evaluate changes in programmed parameters. A cardiologist and ICD nurse specialist together reviewed both the telemetry monitor and the post-procedure ICD interrogation on each patient. When CE studies were reviewed, observations pertaining to technical difficulties and interference with video imaging were documented. RESULTS: No arrhythmia or other adverse cardiac events were noted during capsule transmission. No interference by the ICD on the CE video images was seen. CONCLUSIONS: CE was performed safely in these five patients with ICDs, and was not associated with any adverse cardiac events. ICDs also do not appear to interfere with video capsule imaging.

Aged↗

PubMed2004

Noninvasive assessment of right atrial pressure using Doppler tissue imaging.

Right atrial pressure (RAP) reflects volume and pressure hemodynamics of right cardiac chambers. Previous attempts for noninvasive assessment of RAP include 2-dimensional and Doppler correlates of RAP, which require the presence of optimal subcostal views that may not be always feasible. In this study we utilized Doppler tissue imaging of the tricuspid annulus in the apical 4-chamber view, for noninvasive assessment of RAP. An inverse relationship was demonstrated between mean RAP and the interval between the end of the systolic annular motion to the onset of the early diastolic filling wave (right ventricular regional isovolumic relaxation time).

Aged↗

PubMed2004

Cardiovascular outcome in hospitalized patients with minimal troponin I elevation and normal creatine phosphokinase.

BACKGROUND: Among patients with acute coronary syndrome, elevated cardiac troponin and creatine phosphokinase MB fraction levels have both prognostic and diagnostic values. However, in hospitalized patients, cardiac biomarkers are measured in a variety of clinical situations including but not limited to acute coronary syndrome. Moreover, these patients may have elevated troponin levels with no increase in creatine phosphokinase MB fraction levels. OBJECTIVE: To evaluate the cardiovascular outcome of acutely ill, hospitalized patients with minimal troponin I increase with normal creatine phosphokinase MB fraction. METHODS: We identified 64 patients retrospectively from our database with minimal troponin I increase and normal creatine phosphokinase MB fraction hospitalized between November 1998 and April 2000. Discharged patients were questioned about re-hospitalization for myocardial infarction, unstable coronary syndrome, congestive heart failure and percutaneous coronary intervention by means of a structured questionnaire. For those patients who died during hospitalization, data were collected from hospital records. For patients who died at home or at a different institution, a surviving relative completed the questionnaire. Primary outcomes were death, myocardial infarction and the need for revascularization or re-hospitalization. RESULTS: Composite endpoint of death, myocardial infarction, percutaneous coronary intervention or coronary artery bypass grafting and re-hospitalization for cardiac cause occurred in 35.95% of patients within 1 year. CONCLUSIONS: There is a significant composite event rate of death, myocardial infarction or re-hospitalization for cardiac causes in acutely ill, hospitalized patients with normal creatine phosphokinase MB fraction and minimally elevated troponin I, regardless of the cause for hospitalization.

Aged↗

PubMed2004

Safety of capsule endoscopy in patients with pacemakers.

BACKGROUND: Capsule endoscopy, a new technology, allows visualization of the entire small intestinal mucosa. The main indication for capsule endoscopy at present is the evaluation of GI bleeding of obscure origin. Studies to date suggest that capsule endoscopy is safe and is associated with few adverse events. One concern, which has not been studied, is the potential effect of the capsule on cardiac pacemakers and other electromedical devices. The primary aims of this study were to evaluate the safety of capsule endoscopy in patients with cardiac pacemakers who are being evaluated for GI bleeding of obscure origin and to determine whether pacemakers have any effect on the images captured by the capsule endoscope. METHODS: Patients with cardiac pacemakers referred for evaluation of GI bleeding of obscure origin were entered into the study. Before the procedure, an electrocardiogram was obtained, and pacemaker functions were checked. Capsule endoscopy was performed in a hospital setting to allow closer monitoring, instead of the outpatient clinic, which is our routine. Cardiac rhythm was assessed simultaneously during capsule endoscopy with a Holter monitor. Post-procedure pacemaker function was again checked for any disturbance. When the capsule endoscopy studies were reviewed, observations were made with particular reference to technical difficulty or interference with imaging. OBSERVATIONS: Five consecutive patients (4 men, 1 woman; mean age, 73 years, range 56-92 years) with cardiac pacemakers were studied. In all patients, the indication for capsule endoscopy was GI bleeding of obscure origin. A cardiologist and pacemaker nurse specialist reviewed the Holter monitor recordings and evaluated pacemaker function after the procedure for each patient. No arrhythmia or other adverse cardiac event was noted during capsule transmission. No pacemaker-induced interference on the capsule endoscopy images was observed. CONCLUSIONS: Capsule endoscopy appears to be safe in patients with cardiac pacemakers and does not appear to be associated with any significant adverse cardiac event. Pacemakers do not interfere with capsule imaging.

Aged↗

PubMed2003

Biventricular implantable cardioverter defibrillator and inappropriate shocks.

A 53-year-old man with nonischemic cardiomyopathy underwent implantation of a biventricular implantable cardioverter defibrillator (ICD) for symptomatic ventricular tachycardia. He received five shocks while attempting to exercise, 48 hours after implantation. Interrogation of the device revealed double counting of ventricular sensed events by the left and right ventricular leads. Shortening the AV delay and AV nodal blockade (beta-blocker) to promote ventricular pacing failed to prevent additional inappropriate ICD discharges. After detailed consideration of all options including AV nodal ablation, we chose to disconnect the left ventricular lead pending availability of newer devices with sensing functions limited to the right ventricular lead. Since then, the patient has not experienced any additional inappropriate discharges.

Atrioventricular Node↗

PubMed2003

Swallow syncope.

Swallow syncope is a rare disorder caused by hypersensitive vagotonic reflex in response to deglutition. A 26-year-old man complained of recurrent light-headedness and near syncope on swallowing was hospitalized for monitoring and evaluation. Continuous electrocardiographic and invasive arterial pressure monitoring showed ingestion of a solid meal evoked light-headedness and complete AV block without an escape rhythm that lasted for 5.6 seconds. This patient received a Medtronic Kappa (401B) DDDR pacemaker with the rate drop feature. The patient has remained asymptomatic on follow-up for the past 2 years.

Adult↗