Dual Morphology of Idiopathic Ventricular Tachycardia

INTRODUCTION: Idiopathic ventricular tachycardia (VT) typically has a single morphology originating either in the right ventricular outflow tract (RVOT) or near the posterior fascicle of the left ventricle (LV) in most instances. We present our observations in six patients with idiopathic VT in whom two morphologies were present. METHODS AND RESULTS: Of 55 patients with idiopathic VT who underwent radiofrequency (RF) ablation, 44 had LV "fascicular" tachycardia, whereas 11 had RVOT tachycardia. During RF energy delivery, there was a change in VT morphology in two patients with idiopathic LV tachycardia. This second morphology was not ablated initially, recurred at follow-up, and was reablated successfully. In two additional patients with idiopathic LV tachycardia, a second VT was inducible after ablation of the "clinical" VT. This second morphology recurred at follow-up and was ablated successfully in one patient. The site where the second VT was ablated in all the three patients was remote from that of the first VT. In two patients with RVOT tachycardia, a second VT, originating from a different area of the RVOT, was induced after RF ablation of the "clinical" VT. This second VT recurred at follow-up and was reablated successfully in one patient. CONCLUSION: Idiopathic VT is a more heterogenous entity than hitherto believed. A second VT was seen in 11% of patients during or after RF ablation of the "clinical" VT. The appearance of a second VT suggests either a different exit site of the same circuit or another site of origin.     

Emergence of Bidirectional Accessory Pathway Conduction in Adulthood

Emergence of AP Conduction in Adulthood. A 30-year-old woman presented with tachycardiomyopathy due to atrial flutter-fibrillation and underwent radiofrequency ablation of the AV node and VVIR pacemaker implantation. There was no evidence of any accessory pathway (AP) conduction during the AV nodal ablation or during chronic ventricular pacing. One year later, she had a transient preexcited tachycardia. A year after this, her ECG showed 1:1 AV conduction with preexcitation. Electrophysiologic study revealed a left lateral AP with anterograde and retrograde refractory periods of 280 and 240 msec, respectively. Successful radiofrequency ablation of the AP was performed. This case highlights a unique emergence of an AP in adult life.     

Anatomy of the Coronary Sinus and Epicardial Coronary Venous System in 620 Hearts: An Electrophysiology Perspective

Anatomy of the Coronary Venous System . Introduction: Cannulation of the coronary sinus (CS) is a prerequisite for left ventricular (LV) pacing and certain ablation procedures. The detailed regional anatomy for the coronary veins and potential anatomic causes for difficulty with these procedures has not been established. Methods and Results: Therefore, we performed macroscopic measurements in 620 autopsied hearts (mean age 60 ± 23 years, 44% female). The CS was preserved for analysis in 96%. Sixty‐three percent had a Thebesian valve that covered the posterior aspect of the CS ostium with extension to the superior (50%) and inferior aspects (18%) and was obstructive with fenestrations in 3 specimens. Partial or near occlusive valves were present occasionally at the ostium of the great cardiac vein (Vieussens; 8%) and middle cardiac vein (5%). Ninety‐three percent had left atrial branches, and 41% had at least one branch with lumen > 3 French. For CRT lead placement, the mid‐lateral LV was accessible from the middle cardiac vein (20%), the left posterior vein (92%) or the anterior interventricular vein (86%). Among specimens where the left phrenic nerve was preserved it crossed the LV mid‐lateral wall in 45%. Conclusions: Epicardial coronary vein anatomy is variable, and the mid‐lateral LV wall can potentially be accessed through various tributaries of the epicardial veins. The orientation of the Thebesian valve favors cannulation of the CS from an anterior (ventricular) and inferior approach. Anterobasal, mid‐lateral, and inferior apical LV coronary veins lie in proximity to the course of the phrenic nerve. (J Cardiovasc Electrophysiol, Vol. 24, pp. 1‐6, January 2013)     

LOW BIRTH WEIGHT BABIES : INCIDENCE AND RISK FACTORS

In a prospective hospital based study, during the period from Jan 95 to Dec 96, 3100 consecutively delivered live newborns were studied for the incidence of low birth weight neonates and to evaluate the associated risk factors. One thousand fourteen newborns were classified as low birth weight babies. The incidence expressed per 1000 live births was 327 (32.7%). Of these, 815 (80.4%) were small for gestational age neonates and 199 (19.6%) were preterm neonates. Five hundred seventy small for gestational age neonates (70%) were weighing between 2001 to 2500 gms. Mothers belonging to the age group of 19-25 years delivered the maximum number of low birth weight babies (618/1014) and of these 82.8% were small for gestational age neonates. There were 48 neonates with low birth weight born to mothers below the age of 18 years. Primiparous mothers were found to contribute higher number of low birth weight neonates (414/1014). Spacing as a factor did not show any major difference. Two hundred sixty two low birth weight neonates were born to mothers with significant obstetrical problems such as pregnancy induced hypertension, bad obstetrical history and premature rupture of membranes. The incidence of 32.7% of low birth weight babies is high enough to ring alarm bells.     

Factors Influencing the Benefit of Adjunctive Devices during Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction: Meta-Analysis and Meta-Regression

Background: Routine use of adjunctive devices to percutaneous coronary intervention (PCI) for the treatment of patients of ST-segment elevation myocardial infarction (STEMI) is questionable. Also, the clinical characteristics of STEMI patients that can modulate the treatment benefits of adjunctive devices are not fully understood.
Objective: To synthesize the existing literature to summarize the therapeutic benefit of the adjunctive devices and to identify the patient characteristics which relate to this therapeutic benefit.
Methods: We conducted (i) meta-analyses of the randomized controlled trials (RCT) comparing the performance of the adjunctive devices with PCI for three reperfusion-related outcomes: myocardial blush grade (MBG) < 3, failed ST-segment resolution (STR), and Thrombolysis In Myocardial Infarction (TIMI) flow grade < 3; (ii) stepwise meta-regressions of the effect of trial characteristics on between-trial heterogeneity; and (iii) analyses to examine whether the reperfusion-related end-points explained the between-trial difference in cardiac death and major adverse cardiac events (MACE).
Results: Our meta-analyses represent data from 23 RCT and 5,728 subjects. The overall therapeutic benefit attributable ranged from 32 to 35% for the reperfusion-related outcomes, and thrombectomy devices were more beneficial than the distal protection devices. Meta-regression identified gender, receipt of glycoprotein (GP) IIb/IIIa inhibitor, and baseline TIMI flow grade as significant predictors of improved reperfusion across trials. The available clinical trials were individually underpowered and not designed to detect the influence of adjunctive devices on death or MACE.
Conclusions: Routine use of adjunctive devices cannot be recommended. Thrombus burden, treatment with GP IIb/IIIa inhibitors, and gender may modify the reperfusion benefit of adjunctive devices.