Flecainide challenge test: Predictors of unmasking of type 1 Brugada ECG pattern among those with non-type 1 Brugada ECG pattern

AbstractBackgroundMany subjects in community have non-type 1 Brugada pattern ECG with atypical symptoms, relevance of which is not clear. Provocative tests to unmask type 1 Brugada pattern in these patients would help in diagnosing Brugada Syndrome. However sensitivity and specificity of provocating drugs are variable.MethodsWe studied 29 patients referred to our institute with clinical presentation suggestive but not diagnostic of Brugada or with non-Type 1 Brugada pattern ECG. Flecainide Challenge Test (FCT) was done in these patients (IV Flecainide test in 4 patients and Oral Flecainide in 25 patients). Resting 12-lead ECG with standard precordial leads and ECG with precordial leads placed 1 Intercostal space above were performed after flecainide administration every 5 min for first 30 min and every 30 min thereafter until ECG became normal or upto 6 h. The positivity was defined as inducible Type 1 Brugada pattern in atleast 2 right sided leads.ResultMedian age was 35(range = 5–65) years. In 16 (55%) patients the Type 1 Brugada pattern was unmasked. There were no episodes of major AV block, atrial or ventricular tachyarrhythmia. Three groups were considered for analysis: Group 1(n = 9) – FCT Positive among patients with non-type 1 Brugada ECG pattern, Group 2(n = 4) – FCT Negative among the patients with non-type 1 Brugada ECG pattern, and Group 3(n = 7) – FCT Positive among patients with no spontaneous Brugada ECG pattern. Binary logistic regression analysis found that family h/o SCD was predictive of FCT positivity in Group 1 (Odd’s ratio 21, 95% Confidence interval 1.04 to 698.83, p = 0.004).ConclusionOral flecainide is useful and safe for unmasking of Type I Brugada pattern. In our study, among the many variables studied, family history of sudden cardiac death was the only predictor of flecainide test positivity among those with non-Type 1 Brugada pattern

Study of glancing and blunt fin shock-boundary layer interactions at low supersonic mach numbers

Experiments have been carried out investigating both sharp fin and blunt fin-induced turbulent boundary layer interactions at freestream Mach numbers of-1 .80 and 2 .47. Two sharp fin models of wedge angle 10° and 15° and three blunt fin models of different nose diameter were chosen for this study . Surface pressure distributions were measured and surface flow visualization studies were carried out for all the cases . The results show that the interactions at these relatively lower freestream Mach numbers are broadly similar to those observed at higher Mach numbers (> 3.0). It is suggested that the influence of the blunt nose exists atleast upto 3d in the spanwise or lateral direction

Flecainide toxicity in a preterm neonate with permanent junctional reciprocating tachycardia

We report a case of flecainide toxicity in a premature neonate with permanent junctional reciprocating tachycardia which was managed successfully by reversal of the sodium blockade with intravenous sodium bicarbonate and supportive care. This report highlights the importance of strict supervision and monitoring while administering antiarrhythmic drugs in neonates and prompt institution of appropriate remedial action for treatment when toxicity is suspected

Relaminarization in highly favourable pressure gradients on a convex surface13;

The active stiffening and active compensation analyses are carried out to present the influence of active stiffness on the dynamic behaviour of piezo-hygro-thermo-elastic laminates. A coupled piezoelectric finite element formulation involving a hygrothermal strain field is derived using the virtual work principle and is employed in a nine-noded field consistent Lagrangian element. The closed-loop system is modelled with elastic stiffness, active stiffness introduced by isotropic actuator lamina and geometric stiffness due to stresses developed by hygrothermal strain. Through a parametric study, the influence of active stiffening and active compensation effects or the dynamics of cross-ply and angle-ply laminated plates and shells are highlighted. The active stiffening on thin shells is significantly influenced by boundary effects and the actuator efficiency further decreases with increase in curvature. The reduction in natural frequencies of cross-ply laminates due to hygrothermal strain is actively compensated by active stiffening; however, it is observed that the actuator performance reduces significantly with increase in curvature particularly in angle-ply laminates, which demands the use of directional actuators. The active stiffening and active compensation effects are low in moderately thick piezo-hygro-thermo-elastic plates and shells, which are less influenced by boundary condition

Bundle branch reentry: A rare mechanism of ventricular tachycardia in endomyocardial fibrosis, without ventricular dilation

Introduction: Bundle branch reentry as a mechanism of ventricular tachycardia (VT) in endomyocardial fibrosis (EMF) is not described. Case report: A 52-year-old woman with left ventricular (LV) EMF had VT needing cardioversion. She had mitral regurgitation and left bundle branch block, but no LV dilation or heart failure. During electrophysiological study, clinical VT could be easily induced, and it was confirmed to be bundle branch reentrant VT (BBRVT). She was treated with ablation of the right bundle branch. Conclusion: BBRVT can occur in EMF even without cardiac dilatation. Its recognition is important, as radiofrequency ablation can be curative

Relaminarization in highly favourable pressure gradients on a convex surface

We report here the results of experiments on two flows – one on a convex surface and the other on a flat surface – designed to bring out explicitly the influence of streamwise curvature on relaminarization in highly favourable pressure gradients. In both flows, the initial conditions and the streamwise distribution of the Launder pressure-gradient parameter $K$ are virtually identical. The maximum value of $K$ is $6.2 x 10^{-6}$, well above the critical value of about $3.5 x 10^{-6}$ usually advocated for relaminarization. The spatial extent of the acceleration zone is of order 10 initial boundary-layer thicknesses, appreciably shorter than in earlier work in order better to simulate conditions at the leading edge of a typical aircraft wing. The fall in skin friction coefficient is steeper and the rise in shape factor sharper on the convex surface than on the flat surface, indicating that relaminarization on the convex surface is both more rapid and more nearly complete. In the crucial relaminarizing zone, two-layer quasi-laminar theory is found to predict the convex-surface mean-flow parameters more accurately than the flat-surface flow, without any explicit modelling of curvature effects. Thus, experimental results and supporting calculations both indicate that the dominant effect of streamwise convex curvature on the mean flow is to promote more rapid and complete relaminarization in an accelerated turbulent boundary layer, thus enhancing the probability of its occurrence on the leading edge of swept wings where both factors are significantly in operation

Relaminarization in highly favourable pressure gradients on a convex surface

We report here the results of experiments on two flows - one on a convex surface and the other on a flat surface - designed to bring out explicitly the influence of streamwise curvature on relaminarization in highly favourable pressure gradients. In both flows, the initial conditions and the streamwise distribution of the Launder pressure-gradient parameter K are virtually identical. The maximum value of K is 6.2 × 10, well above the critical value of about 3.5 × 10 usually advocated for relaminarization. The spatial extent of the acceleration zone is of order 10 initial boundary-layer thicknesses, appreciably shorter than in earlier work in order better to simulate conditions at the leading edge of a typical aircraft wing. The fall in skin friction coefficient is steeper and the rise in shape factor sharper on the convex surface than on the flat surface, indicating that relaminarization on the convex surface is both more rapid and more nearly complete. In the crucial relaminarizing zone, two-layer quasi-laminar theory is found to predict the convex-surface mean-flow parameters more accurately than the flat-surface flow, without any explicit modelling of curvature effects. Thus, experimental results and supporting calculations both indicate that the dominant effect of streamwise convex curvature on the mean flow is to promote more rapid and complete relaminarization in an accelerated turbulent boundary layer, thus enhancing the probability of its occurrence on the leading edge of swept wings where both factors are significantly in operation

Utility of late gadolinium enhancement on magnetic resonance imaging in hypertrophic cardiomyopathy patients in an Indian cohort

This prospective observational study sought to correlate segmental late gadolinium enhancement (LGE) seen in cardiac magnetic resonance imaging with occurrence of ventricular arrhythmias (VAs) in patients with hypertrophic cardiomyopathy. LGE was assessed in a 17-segmental model of heart. Of 57 patients, VAs were present in 26.3% of patients and 10.5% had sustained ventricular tachycardia. LGE was present in 43.9% of patients. Presence of LGE in 4 or more segments was associated with VAs with a sensitivity of 73% and specificity of 76% with area under curve of 0.733 in C-statistics

Familial atrioventricular nodal re-entrant tachycardia: A case seriers and a systematic review

Multiple reports of familial clustering suggest that genetic factors may contribute in the pathogenesis of atrioventricular nodal re-entrant tachycardia (AVNRT). We report three cases of AVNRT in a father and his two sons along with a review of literature of other similar cases. Electrophysiological studies induced typical AVNRT, which was successfully eliminated by radiofrequency ablation in all of them. Of the 22 reported cases, 96% had typical (slow-fast) variant of AVNRT. The predominant pattern of inheritance appears to be autosomal dominant, though other patterns may exist. Further research is needed to understand the genetic influence of AVNRT and its pathophysiology. Keywords: Familial, AVNRT, Tachycardi