Sarcomeric gene mutations in phenotypic positive hypertrophic cardiomyopathic patients in Indian population.

HCM is a monogenic cardiac disorder with a high risk of sudden cardiac death, heterogeneous phenotypic expression and genetic profile. HCM is expressed as autosomal dominant in fashion with the prevalence of 1:500 in the general population. The main objective of the current study was to unravel the mutation status in sarcomeric genes in urbanizing Pune population. HCM patients were recruited from Bharti hospital and Poona hospital and research centre, Pune after being screened by 2-D echocardiography. DNA was extracted from whole blood samples and PCR amplification was performed for selected exons from pre-selected genes, amplimers of >300 b.p were restriction digested and the SSCP technique was optimized for maximum result output. HCM patients shows the maximum prevalence of mitral regurgitation (23.3%) while the minimum prevalence was left auricular diameter (10%). Maximum variation spectrum was present in MYBPC3 genes as most of them were "benign" type as per Polyphen-2 tool status. Mutations in the MYH7 gene produce a prominent impact on splicing by the creation of a new SRP40 binding site (Exon Splicing Enhancer) as predicted by Human Splicing Finder 3.1. I736T mutation in the MYH7 gene results in replacement of ß-strand by α-helix upstream from mutation site which may have a profound impact on protein tertiary structure as predicted by Polyphen-2 tool (probably damaging-1.00). Also, two 'novel' mutations and one 'novel' variation were reported in the present study. Thus, the MYBPC3 gene shows maximum mutation load among other sarcomeric genes. Double gene mutations do not represent much severe pathophysiology as compared to single gene mutated and genotypic negative HCM patients.

Reversible left ventricular dysfunction due to endless loop tachycardia in patient with dual chamber pacemaker- A case report.

A 60 years male patient underwent permanent pacemaker [DDDR -with dual chamber pacing (D) with dual chamber sensing (D) with dual mode of response (D) with rate responsive pacing(R) -St Jude's medical (Abbott- Endurity 2160)] implantation for complete heart block (CHB). After 4 months patient was admitted for congestive heart failure. 12 Lead electrocardiograms (ECG) was suggestive of tachycardia at 130 beats per minute (regular rhythm), with ventricular complexes preceded by pacing spikes and maintenance of 1:1 atrio-ventricular relationship. Echocardiography showed global hypokinesia of left ventricular (LV) myocardium with reduced LV ejection fraction. LV dysfunction and heart failure were attributed to tachy-cardiomyopathy. Pacemaker telemetry data demonstrated that the tachycardia was likely to be pacemaker-mediated endless loop tachycardia (ELT). ELT in this case was perpetuated secondary to shortening of post ventricular atrial refractory period (PVARP), intact retrograde ventriculo-atrial (VA) conduction and addition of antiarrhythmic drugs prolonging retrograde VA conduction. Rate response (Dynamic) PVARP was reprogrammed allowing PVARP extension. Following this ELT was terminated. LV ejection fraction was normalized on subsequent follow up visit after seven days.

Evaluation of bachmann bundle pacing versus right atrial pacing in prevention of atrial fibrillation after coronary artery bypass surgery.

BACKGROUND: In patients undergoing coronary artery bypass surgery (CABGS), occurrence of atrial fibrillation (AF) is common in the postoperative period and is associated with increased morbidity with longer intensive unit care (ICU) and hospital stay. Prevention with antiarrhythmic drugs is of limited success and associated with significant side effects. Therefore alternative approaches, such as Bachmann Bundle pacing, are required. METHODS AND RESULTS: 154 consecutive patients, mean age 58±8.8 years, including 134 males and 20 females, were randomized to three groups; Group I : No pacing n= 54, Group II : RA pacing n= 52, Group III : Bachmann Bundle pacing n= 48. All the groups were well matched with regard to age, left atrial size, ejection fraction and use of beta blockers. Patients in Groups II and III were continually paced at a rate of 100 beats per minute (bpm) or at 10 bpm more than patients' intrinsic heart rate. All the patients were monitored for 72 hours by telemetry and occurrence of AF was noted. Incidence of AF was 0% (none of 48 patients) in Group III as compared to 16.6% in Group I (9 of 54 patients) (p 0.003) and 12.5% in Group II (5 of 52 patients) (p 0.03). There was a trend towards shorter ICU stay in Group III (3.9 days) as compared to Group II (4.5 days) and Group I (4.1 days). Among the three groups, the reduction in mean P wave duration also was greater in Bachmann bundle paced group. CONCLUSION: In patients undergoing CABGS, Bachmann bundle pacing is superior to right atrial / no pacing in the post operative period for preventing occurrence of AF and reducing ICU stay, commensurate with a reduction in mean P wave duration on surface ECG.

Ablation of incessant orthodromic reciprocating tachycardia in a child with congenitally corrected transposition of great arteries and ebsteinoid malformation of left atrioventricular valve.

We report about a patient with congenitally corrected transposition of the great arteries and ebsteinoid malformation of left atrioventricular (AV) valve who presented with incessant orthodromic atrioventricular reciprocating tachycardia due to a left posteroseptal accessory pathway. Radiofrequency catheter ablation using trans-septal approach successfully eliminated the posteroseptal pathway across the morphologic tricuspid valve. This report highlights the importance of delineating the anatomy of the interatrial septum in complex congenital heart diseases for performing safe trans-septal puncture during ablation of accessory pathways.