Mukund A. Prabhu

The Utility of Exercise Testing in Risk Stratification of Asymptomatic Patients With Type 1 Brugada Pattern

Risk stratification of asymptomatic patients with a Brugada type 1 ECG pattern remains an unresolved clinical conundrum. In contrast to provocative pharmacological testing in Brugada syndrome, there is limited data on the role of exercise stress testing as a risk stratification modality. The objective of this study was to evaluate the utility of exercise testing in asymptomatic patients with type 1 Brugada pattern to prognosticate major arrhythmic events (MAE) during follow‐up.

Evaluation of baseline ECG in patients undergoing Oral Flecainide Challenge test for suspected Brugada Syndrome: An analysis of lead II

Background and Objectives We analyzed Lead II in patients undergoing an Oral Flecainide Challenge test (FCT), to identify any pointers that could predict a positive FCT and thereby help in recognition of latent BS. Methods The following parameters in lead II were retrospectively analyzed from the pre-test ECG in 62 patients undergoing FCT for suspected BS: The presence or absence of S waves, S wave amplitude, duration and upslope duration; J point parameters- Early repolarization, QRS notch, and QRS Slur; ST segment parameters-lack of isoelectric ST segment, ST duration and QT interval. Results 48 had positive FCT (Group-1) while 14 were negative for FCT(Group-2). Lack of an isoelectric ST segment (50% vs 14.29%, p = 0.018) and slurring of QRS (33.33% vs 0%, p = 0.014) was more common in Group-1 than Group-2. Group-1 had shorter ST segment duration (median 81.5 (IQR 64–103.5) vs 110 (IQR 90–132), p = 0.002) and shorter ST: QT ratio (median 0.28 (IQR 0.22–0.35) vs 0.23 (0.18–0.27), p = 0.007). QRS notch/depressed J point (87.5%), QRS slur (100%), and lack of isoelectric ST segment (92.31%) had high sensitivity for predicting an inducible Type 1 Brugada pattern. Combining two parameters- ST: QT ratio<0.24 and lack of isoelectric ST segment-considerably improved the specificity (73.3%), and the positive predictive value of the test to 76%. The results remained accurate when validated in a small prospective cohort. Conclusion Shortened ST segment in Lead II, lack of isoelectric ST segment, slurred QRS and ST/QT ratio <0.24 are predictive of underlying Brugada pattern in baseline ECG.

‘Optimized’ LV only pacing using a dual chamber pacemaker as a cost effective alternative to CRT

Background Cardiac Resynchronization therapy (CRT) remains largely under-used in developing countries owing to the high cost of therapy. In this pilot study, we explore ‘optimized’ Left Ventricle Only Pacing (LVOP) as a cost effective alternative to cardiac resynchronization therapy in selected patients with heart failure. Hypothesis In economically poorer patients with heart failure, left bundle branch block (LBBB) and intact AV node conduction, synchronization can be obtained using a dual chamber pacemaker (leads in right atrium and Left ventricle) with the help of 2D strain imaging. Methods and results 4 patients underwent LVOP for symptomatic heart failure. Post procedure ‘optimization’ was done using 12 lead electrocardiography and 2D- Strain imaging. Difference between Time to Peak longitudinal strain and Aortic valve Closure (Diff TPL-AC) was calculated for each segment at different AV delays and the AV delay with the smallest Diff TPL-AC was programmed. The mean AV delay that resulted in electrical and mechanical synchrony was 150 ms. After a mean follow up of 6 months, all patients had improved by at least 1 NYHA class. The mean reduction in QRS duration post procedure was −54.5 ± 22.82 ms and the mean improvement in EF was 7 ± 2.75%. Conclusion Optimized LVOP using 2D strain and ECG can be a cost-effective alternative to CRT in patients with LBBB, heart failure and normal AV node conduction.

Bio-width index: a novel biomarker for prognostication of long term outcomes in patients with anaemia and heart failure

Abstract Background: The utility of biomarkers for prognostication of long term outcomes in patients with anaemia and heart failure(HF) is not well defined. The objective of this study was to assess the ability of a novel biomarker, bio-width index (BWI),to improve risk stratification in patients with anaemia and acutely decompensated heart failure(ADHF), in comparison to conventional markers, B-type natriuretic peptide(BNP) and red- cell distribution width(RDW). Methods: Data from 1569 consecutive patients with ADHF treated at a multidisciplinary HF unit was analysed in this study. The bio-width index (BWI) was calculated by multiplying BNP to RDW and dividing the product by 10 (BWI = BNP x RDW/10). The primary outcome was one year all-cause mortality. Results: During follow up (median 422 days), subjects with anaemia had significantly higher one year mortality (49.6 vs. 30.5%, p < .001). Cox regression analysis revealed that, BWI(HR 2.13, 95%CI 2.02–2.24, p = .018) as well as BNP(HR 1.86, 95%CI 1.78–1.94, p = .024), and RDW (HR 1.98, 95%CI 1.91–2.05, p = .033) were all independent predictors of one year mortality after adjusting for conventional risk factors. BWI had a higher discriminative ability compared to BNP(AUC 0.90 vs. 0.75, p < .001) and RDW(AUC 0.90 vs. 0.81, p = .012). The patients with higher BWI ( >1024.9) had a higher one year mortality(85.1 vs. 29.2%, p < .001). In addition, BWI significantly improved the net reclassification compared to both BNP(p = .002) and RDW(p = .018). Conclusions: In patients with anaemia and ADHF, bio-width index is superior to the established biomarkers such as BNP and RDW in prognostication of long term mortality.

Supra-Hisian Conduction Block As An Unusual Presenting Feature of Takotsubo Cardiomyopathy.

Atrioventricular (AV) block is rare in Takotsubo cardiomyopathy (TC).

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.

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.

An unusual type of accessory pathway in tricuspid atresia

The occurrence of pre-excitation in tricuspid atresia (TA) is slightly more common than that in normal children. The accessory pathway (AP), when it occurs in the setting of congenital atrioventricular valvar disease, is usually ipsilateral to the side of the abnormal valve. This report describes a patient with TA who had pre-excitation due to a left-sided AP that masked and modified the typical electrocardiographic features. The electrophysiological study confirmed an epicardial left posterior AP that was successfully ablated with radiofrequency energy, through the coronary sinus. Left-sided APs including epicardial ones may rarely be seen in TA and can potentially cause difficulties due to lack of vascular access to the heart after the Fontan surgery if arrhythmias occur. They are amenable to successful radiofrequency ablation and need to be dressed prior to Fontan surgery. <Learning objective: Pre-excitation may become manifest during follow-up even if minimal at initial presentation. Accessory pathways may occur in the left side of the heart in tricuspid atresia, in contrast to the usual notion that APs occur ipsilateral to the side of the abnormal valve. Electrophysiological study may be useful prior to Fontan-type procedures as this helps in identifying and to prognosticate pre-excitation so that ablation of the pathway can be performed prior to the Fontan procedure.>.

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.