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Biomedical subjects

Deepak Bhakta

Publications and source records attributed to Deepak Bhakta.

11 recordsLinked to original sources
PubMed2006

Prognostic importance of wall motion abnormalities in patients with ischemic cardiomyopathy and an implantable cardioverter-defibrillator.

Patients with extensive regional wall motion abnormalities are predisposed to development of ventricular tachyarrhythmia. The prognostic effect of this in patients with an implantable cardioverter-defibrillator (ICD) and coronary artery disease (CAD) is not known. Echocardiographic left ventricular systolic indexes, wall motion score index (WMSI), and extent of regional akinesia in 140 patients (65 +/- 10 years old; 92% men) with an ICD and CAD were studied. Arrhythmic events requiring ICD therapy and causing death (n = 41, 29%) were recorded over a mean follow-up of 1.4 +/- 0.8 years. Left ventricular basal fractional shortening, ejection fraction, global WMSI, and extent of akinesia, especially in the inferoposterior regions of a right coronary artery territory, were univariate predictors (all p values <0.05). Global WMSI (hazard ratio 2.18, 95% confidence interval 1.03 to 4.65, p = 0.04) and fractional shortening (hazard ratio 0.93, 95% confidence interval 0.88 to 1.00, p = 0.04) were multivariate predictors. Global WMSI (p = 0.04) and > or =2 right coronary region akinetic segments (p = 0.05) provided incremental risk prediction to left ventricular ejection fraction in a global risk-assessment model (chi-square p = 0.001). Presence of right coronary region akinesia better identified those at increased risk of events (p = 0.02) compared with the presence of left anterior descending region akinesia (p = 0.2), independent of systolic function. In conclusion, global WMSI and left ventricular basal fractional shortening were important additional risk predictors of ICD events in CAD. Global WMSI and right coronary region inferoposterior akinesia provided independent and incremental risk assessment to left ventricular ejection fraction and improved identification of those at increased risk of ICD-related events in patients with ischemic cardiomyopathy.

Aged↗
PubMed2006

Value of the 12-lead ECG in wide QRS tachycardia.

A wealth of useful diagnostic criteria is available to assist the health care worker in arriving at the correct diagnosis in cases of a wide QRS tachycardia (WQRST). Despite the abundance of good criteria for determining the diagnosis in cases of WQRST, they are of no use if they cannot be readily applied in an urgent clinical situation because they cannot be easily recalled or are too complex and cumbersome to use. It may be that refresher courses in the differential diagnosis of WQRST, especially for emergency physicians who are often the "first responders" to patients with WQRST, can improve physicians' diagnostic accuracy in this important disorder.

Bundle-Branch Block↗
PubMed2005

Thoracic spinal cord stimulation reduces the risk of ischemic ventricular arrhythmias in a postinfarction heart failure canine model.

BACKGROUND: Thoracic spinal cord stimulation (SCS) is a promising therapy in treating refractory angina. This study was designed to investigate SCS with regard to the risk of arrhythmias during myocardial ischemia and its cardiac electrophysiological effects. METHODS AND RESULTS: We studied 22 dogs with healed anterior myocardial infarction (MI) and superimposed heart failure (HF) induced by rapid ventricular pacing. SCS was applied at the dorsal T1-T2 segments of the spinal cord (at 50 Hz, 0.2 ms) for 15 minutes. Transient (2-minute) myocardial ischemia was induced on 2 separate occasions (no SCS and SCS) to provoke ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation; VT/VF). Ischemic episodes were separated by 90 minutes, and dogs were randomly assigned to receive SCS or no SCS before the first or second ischemic episode. SCS reduced the occurrence of VT/VF from 59% to 23% when SCS was applied during transient myocardial ischemia (odds ratio, 0.36; 95% confidence interval, 0.1626 to 0.5646; P=0.0009). SCS also decreased sinus rate by 7.5+/-14 bpm (P=0.048), increased the PR interval by 11.1+/-14.7 ms (P=0.009), and reduced systolic blood pressure by 9.8+/-13.6 mm Hg (P=0.02). CONCLUSIONS: Thoracic SCS appears to protect against ischemic VT/VF in a canine model of healed MI and HF. SCS reduced sinus rate and systolic blood pressure, changes consistent with the previously known antisympathetic effect of SCS, which may have contributed to the antiarrhythmic benefits.

Animals↗
PubMed2005

Familial clustering of muscular and cardiac involvement in myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is associated with both skeletal and cardiac muscle involvement. The aim of the present study was to determine whether familial clustering is observed in the severity of muscle involvement in DM1. We evaluated 51 sibling groups constituting 112 patients with genetically-verified DM1. The siblings were similar to each other in age, cytosine-thymine-guanine (CTG) repeat length, age at disease onset, muscular impairment rating score, and electrocardiographic markers of cardiac conduction disease. After adjusting for the similarities between siblings in age and CTG repeat length, the siblings remained similar to each other in measures of both skeletal and cardiac muscle involvement. These results suggest that factors other than CTG repeat length play a role in the severity and progression of the degenerative skeletal and cardiac muscle disease in DM1.

Adolescent↗
PubMed2004

Prevalence of structural cardiac abnormalities in patients with myotonic dystrophy type I.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is a neurological disorder with known cardiac involvement, including conduction disturbances, arrhythmias, and ventricular dysfunction. We studied which clinical and electrocardiographic features are associated with structural cardiac abnormalities. METHODS: History, physical examination, electrocardiography, and genetic testing were performed on 382 patients with DM1, and cardiac imaging was performed on 100 of these patients. RESULTS: Clinical congestive heart failure was found in 7 of the 382 patients (1.8%). Structural cardiac abnormalities determined with cardiac imaging included left ventricular hypertrophy (19.8%), left ventricular dilatation (18.6%), left ventricular systolic dysfunction (14.0%), mitral valve prolapse (13.7%), regional wall motion abnormality (11.2%), and left atrial dilatation (6.3%). Left ventricular systolic dysfunction was associated with increasing age (relative risk [RR], 1.9 per decade; 95% CI, 1.1-3.2; P =.02), cytosine-thymine-guanine (CTG) repeat length (RR, 2.8 per 500 repeats; 95% CI, 1.3-6.3; P =.01), P-R >200 ms (RR, 14.7; 95% CI, 3.0-73.1; P =.001), and QRS >120 ms (RR, 5.7; 95% CI, 1.5-21.8; P =.01). P-R >200 ms was predictive of regional wall motion abnormalities. QRS >120 ms correlated with regional wall motion abnormalities and left atrial dilatation. CONCLUSIONS: Several clinical and electrocardiographic findings in patients with DM1 are significantly associated with structural heart abnormalities. These results suggest an underlying genetic and pathophysiologic correlate that may lead to cardiac disease in these patients.

Adolescent↗
PubMed2004

Cardiac function tests in neuromuscular diseases.

Myocardial involvement is a known complication of neuromuscular diseases and is a leading cause of morbidity and mortality in these disorders. Identifying patients early using cardiac function tests helps understand the mechanisms underlying cardiac involvement and may help limit the progression of cardiac disease before the onset of significant symptoms and limitation. This article outlines the tests available to assess cardiac involvement associated with neuromuscular diseases and offers guidelines for management once they are discovered.

Arrhythmias, Cardiac↗
PubMed2004

Multivessel coronary thrombosis secondary to cocaine use successfully treated with multivessel primary angioplasty.

Cocaine use has been associated with a significant risk of myocardial ischemia and myocardial infarction (MI). The previous approach to the treatment of cocaine-induced MI focused on medical treatment with verapamil, nitroglycerine and thrombolytics. Percutaneous revascularization for the cocaine-associated MI has been reported and is the preferred treatment modality. Identification of culprit vessel in the patients presenting with acute myocardial infarction associated with cocaine use is problematic owing to the frequent presence of baseline electrocardiogram (ECG) changes. Chronic cocaine use predisposes to diffuse coronary vasculopathy and may cause systemic alteration of coagulation parameters. Multivessel coronary thrombosis presenting as myocardial infarction associated with cocaine use has not been previously reported. This study describes a case of multivessel coronary thrombosis caused by cocaine ingestion successfully treated with multivessel primary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed2003

Heart rate variability declines with increasing age and CTG repeat length in patients with myotonic dystrophy type 1.

BACKGROUND: Cardiac myopathy manifesting as arrhythmias is common in the neurological disease, myotonic dystrophy type 1 (DM1). The purpose of the present study was to evaluate heart rate variability (HRV) in patients with DM1. METHODS: In a multicenter study, history, ECG, and genetic testing were performed in DM1 patients. RESULTS: In 289 patients in whom the diagnosis of DM1 was confirmed by a prolonged cytosine-thymine-guanine (CTG) repeat length the most common ambulatory ECG abnormality was frequent ventricular ectopy (16.3%). The 24-hour time domain parameters of SDNN (SD of the NN interval) and SDANN (SD of the mean NN, 5-minute interval) declined as age and CTG repeat length increased (SDNN: -8.5 ms per decade, 95% confidence intervals [CI]-12.9, -4.2, -8.7 ms per 500 CTG repeats, CI -15.7, -1.8, r=0.24, P<0.001; SDANN: -8.1 ms per decade, CI -12.4, -3.8, -8.8 ms per 500 CTG repeats, CI -15.7, -1.9, r=0.23, P<0.001). Short-term frequency domain parameters declined with age only (total power: -658 ms2 per decade, CI: -984, -331, r=0.23, P<0.001; low frequency (LF) power -287 ms2 per decade, CI: -397, -178, r=0.30, P<0.001; high frequency (HF) power: -267 ms2 per decade, CI: -386, -144, r=0.25, P<0.001). The LF/HF ratio increased as the patient aged (0.5 per decade, CI: 0.1, 0.9, r=0.13, P=0.03). CONCLUSIONS: In DM1 patients a decline in HRV is observed as the patient ages and CTG repeat length increases.

Adolescent↗
PubMed2003

Complete situs inversus and bicuspid aortic valve stenosis.

Patients with congenital heart disease are increasingly surviving to adulthood and present interesting challenges during cardiac catheterization. Situs inversus with dextrocardia is a type of cardiac malposition most likely to exist with a structurally normal heart. We present the case of a patient with complete situs inversus and bicuspid aortic valve stenosis, a hitherto unreported association. Prototypical findings in this cardiac malposition are illustrated for proper recognition with emphasis on technical tips for left and right heart catheterization.

Aortic Valve Stenosis↗