PubMed Health⌕ Search

Biomedical subjects

Bharat K Kantharia

Publications and source records attributed to Bharat K Kantharia.

15 recordsLinked to original sources
PubMed2006

Case report: Delayed detection of ventricular tachycardia due to intradevice interactions by implantable atrio-ventricular pacer/cardioverter defibrillator.

Current generations of implantable cardioverter defibrillators are capable of providing sophisticated dual chamber atrioventricular and rate-responsive pacing therapies, and even cardiac resynchronization therapy. Appropriate programming of the devices is necessary for them to perform all such sophisticated tasks. In this report, we describe a case where detection of ventricular tachycardia was delayed due to intradevice interactions between the pacemaker and defibrillator components of the device.

Cardiac Pacing, Artificial↗
PubMed2006

Electrical storm of monomorphic ventricular tachycardia after a cardiac-resynchronization-therapy-defibrillator upgrade.

In patients with significant left ventricular dysfunction and congestive heart failure despite optimal medical therapy, implantation of cardiac resynchronization therapy-defibrillation (CRT-D) devices has been shown to improve symptoms and mortality. In this report, we describe a case of a patient with ischaemic cardiomyopathy who developed incessant ventricular tachycardia (VT) after undergoing an upgrade from an implantable cardioverter defibrillator to a CRT-D device. The patient required multiple anti-arrhythmic agents, removal of the coronary sinus lead, and radiofrequency ablation to control VT. Thus, in rare patients, the CRT devices may potentially cause 'proarrhythmia' with serious consequences.

Aged↗
PubMed2006

Decremental ramp atrial extrastimuli pacing protocol for the induction of atrioventricular nodal re-entrant tachycardia and other supraventricular tachycardias.

AIM: The primary aim of this study was to evaluate the utility of decremental ramp atrial extrastimuli pacing protocol (PRTCL) for induction of atrioventricular nodal re-entrant tachycardia (AVNRT), and other supraventricular tachycardias (SVTs), compared to standard (STD) methods. METHODS: The study cohort of 121 patients (age 57.51 +/- 14.02 years) who presented with documented SVTs and/or symptoms of palpitations and dizziness, and underwent invasive electrophysiological evaluation was divided into Group I (AVNRT, n = 42) and Group II (Control, n = 79). The PRTCL involved a train of six atrial extrastimuli, delivered in a decremental ramp fashion. The STD methods included continuous burst and rapid incremental pacing up to atrioventricular (AV) block cycle length, and single and occasionally double atrial extrastimuli. Prolongation in the Atrio-Hisian (Delta-AH) intervals achieved by both methods were compared, as were induction frequencies. RESULTS: In Group I, three categories of responses--(1) induction of AVNRT, (2) induction of echo beats only, and (3) none--were observed in 29 (69%), 11 (26%), and 2 (5%) patients with the PRTCL, when compared with 14 (33%), 16 (38%), and 12 (29%) patients with STD methods in the baseline state without the use of pharmacological agents. The Delta-AH intervals for each of these three categories were larger using PRTCL versus STD methods; 293.3 +/- 95.2 ms versus 192.9 +/- 61.4 ms (P < 0.005), 308.6 +/- 68.5 ms versus 189. 9 +/- 64.9 ms (P < 0.0005), and 203.0 +/- 86.3 ms versus 145.8 +/- 58.9 ms (P = NS), respectively. In Group II, in one patient with dual AV nodal physiology but no clinical tachycardia, the PRTCL induced nonsustained (12 beats) AVNRT. Additionally, in this group, both PRTCL and STD methods induced atrial tachycardia in two patients and orthodromic AV re-entrant tachycardia in one patient. CONCLUSION: Decremental ramp atrial extrastimuli pacing PRTCL demonstrates a superior response for induction of typical AVNRT as compared to STD techniques. Because of easy and reliable induction of AVNRT and echo beats by the PRTCL, we recommend it as a method to increase the likelihood of induction of AVNRT. For induction of other SVTs, the PRTCL and the STD methods are comparable.

Arrhythmias, Cardiac↗
PubMed2005

Electroanatomical mapping and radiofrequency catheter ablation of atrial tachycardia originating from the recipient heart with recipient-to-donor atrio-atrial conduction after orthotopic heart transplantation.

Atrial tachycardias resulting from recipient-to-donor atrio-atrial conduction after orthotopic heart transplantation are difficult to treat. We present two patients in whom atrial tachycardia originating in the recipient heart were successfully treated by radiofrequency ablation guided by electroanatomical CARTO mapping system. These cases illustrate that such atrial tachycardia are curable by radiofrequency ablation. Electroanatomical CARTO mapping is useful in identifying the site of origin of the tachycardia and the atrio-atrial conduction sites.

Aged↗
PubMed2005

Atrial fibrillation: modern concepts and management.

Atrial fibrillation (AF) is a common cardiac arrhythmia responsible for significant morbidity and mortality. In recent years, progress has been made in determining the genetic abnormalities that may lead to AF. New trials have shown that rate control and anticoagulation are acceptable as a primary treatment strategy in many patients who have a high risk of recurrence. Newer and safer antiarrhythmics are now available. Pacemaker and implantable cardiac defibrillator technology is rapidly evolving and may play a significant role in future treatment and prevention of AF. Direct thrombin inhibitors are likely to add a user-friendly option to the current standard therapy for stroke prevention.

Anti-Arrhythmia Agents↗
PubMed2005

Diffuse cerebral air embolism treated with hyperbaric oxygen: a case report.

A 54-year-old woman presented for cardiac evaluation of atypical chest pain. Workup included coronary angiography and a left ventriculogram, during which air was inadvertently injected, resulting in the development of an acute right hemisphere syndrome. Right carotid angiography was immediately performed, yielding only a delayed diffuse venous phase without focal vessel cutoffs. Within 60 minutes, the patient underwent hyperbaric oxygen therapy for the suspected cerebral air emboli. After removal from the chamber for technical reasons, she had a generalized tonic-clonic seizure, and further hyperbaric oxygen therapy was withheld. Initial computed tomography imaging obtained approximately 8 hours after symptom onset showed signs of early right hemispheric edema. Subsequent magnetic resonance imaging studies were markedly abnormal and suggestive of diffuse bilateral but predominantly right-sided parietal lobe edema with mildly positive diffusion-weighted imaging. Follow-up magnetic resonance imaging at 6 months was normal, and the patient's neurological examination returned to normal.

Embolism, Air↗
PubMed2005

Marked QT prolongation and torsades de pointes secondary to acute ischemia in an elderly man taking dofetilide for atrial fibrillation: a cautionary tale.

Dofetilide has been shown to be effective and safe in maintaining sinus rhythm in patients with persistent atrial fibrillation and congestive heart failure. Because of serious side effects of an increase in the QT interval causing torsades de pointes, dofetilide must be initiated with close monitoring of the QT interval in an inpatient setting. However, little has been reported about conditions surrounding the change in QT interval after the steady state is achieved that may have implications in the safety and efficacy of the drug. We report marked QT prolongation and torsades de pointes in a setting of flash pulmonary edema resulting from acute myocardial ischemia in a patient who was being treated with dofetilide for atrial fibrillation. Our case reminds the clinicians that the adverse and proarrhythmic effects of dofetilide can occur due to changes in the arrhythmic substrate during acute severe ischemia.

Aged↗
PubMed2004

Usefulness of pindolol for treatment of neurocardiogenic syncope.

This study evaluated the efficacy of pindolol, a noncardioselective beta blocker with intrinsic sympathetic activity, on neurocardiogenic syncope using a head-up tilt-table test in 66 patients. Pindolol was equally effective in men and women and the 2 age groups (>60 and <60 years) of the study cohort. The earliest benefit was seen </=3 days after initiating treatment. Side effects were better tolerated in younger patients (age <60 years).

Adolescent↗
PubMed2003

Pathophysiology and management of neurocardiogenic syncope.

OBJECTIVE: To discuss the physiologic mechanisms underlying neurocardiogenic syncope in the context of several different management strategies. PATHOPHYSIOLOGY: Neurocardiogenic syncope or the "common faint" is variously called neurally mediated hypotension, vasovagal syncope, or vasodepressor syncope. It is the most common type of syncope. The pathophysiology of neurocardiogenic syncope is complex and not completely elucidated. Individuals susceptible to neurocardiogenic syncope are unable to maintain the adaptive neurocardiovascular responses to upright posture for prolonged periods. These patients tend to have a modest reduction in central blood volume, which is aggravated by upright posture. It is often noted in individuals receiving sympathetic blocking agents and vasodilator drugs for hypertension, elderly patients receiving tranquilizers, patients with anemia, and individuals with tran- sient reductions in blood volume such as those that occur after a brisk diuresis or blood donation. The classic syncopal episode often is preceded by a constellation of prodromal symptoms several seconds before the event that may include nausea, headache, diaphoresis, dizziness, chest pain, palpitations, dyspnea, and paresthesia. MANAGEMENT: Head-up tilt testing has become the diagnostic study of choice for the identification of patients with neurocardiogenic syncope. Therapeutic options include general measures such as volume expansion; pharmacologic approaches such as beta-adrenergic receptor blockade, anticholinergic agents, selective serotonin reuptake inhibitors, methylxanthines, and alpha agonists; and invasive methods such as placement of a dual-chamber cardiac pacemaker.

Adrenergic alpha-Agonists↗
PubMed2002

Prolonged sustained ventricular fibrillation without loss of consciousness in patients supported by a left ventricular assist device.

Patients with cardiomyopathy of either ischemic or nonischemic origin are at increased risk for malignant ventricular arrhythmias. Normally sustained ventricular fibrillation (VF) leads to death very rapidly. We report two patients who remained in sustained VF, supported by a left ventricular assist device, for a prolonged period of time. Perfusion pressure through the device was sufficient to allow the patients to remain awake and responsive for several hours while in VF. The cases represent two of the longest reported episodes of sustained VF recorded in awake patients implanted with such devices.

Aged↗
PubMedDate not supplied

Effect of cardiac resynchronization therapy on diastolic dysfunction as assessed by transthoracic two-dimensional Doppler echocardiography.

Cardiac resynchronization therapy (CRT) in patients with left ventricular systolic dysfunction and electrical dyssynchrony has been shown to improve morbidity and mortality. Improvement in diastolic dysfunction may contribute to these results. In this retrospective study, the authors assessed the effect of CRT on the E/A ratio and mitral valve deceleration time, which are commonly utilized parameters of left ventricular diastolic function. In 13 patients (aged 62 +/- 11.3 years), the E/A ratio increased from 1.17 +/- 0.58 to 1.49 +/- 0.66 (p = nonsignificant) and the mitral valve deceleration time increased from 178.48+/-57.71 milliseconds to 227.70 +/- 76.18 milliseconds (p = 0.054) post-CRT. In patients without mitral regurgitation, there was a significant increase in E/A ratio, from 1.22 +/- 0.4 to 1.86 +/- 0.47 (p = 0.025), but no significant change in the mitral valve deceleration time post-CRT was observed. These data suggest improvement in diastolic dysfunction as assessed by routine two-dimensional echocardiography in patients who receive CRT devices.

Adult↗