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)     

Palliative treatment of malignant ascites by intraperitoneal bleomycin after dialytic ultrafiltration with haemofilter

Dialytic ultrafiltration with haemofilter was performed in 16 patients with malignant ascites refractory to treatment with sodium restriction, diuretic and systemic chemotherapy. A continuous flow of ascitic fluid at a rate of 300–400 ml/min through a haemofilter was maintained by a blood pump. The protein-rich ascitic fluid was re-infused into the peritoneal cavity with sodium and water removed. An average of 5.2 1 of filtrate was removed over a mean interval of 3.5 h. Bleomycin (60 mg) was administered intraperitoneally following the procedure. Complete response was observed in six patients (37.25%) and partial response occurred in four (25%). The remaining patients showed no response. Complications of the dialytic ultrafiltration procedure and toxicity of intraperitoneal administration of bleomycin were minimal. The technique of dialytic ultrafiltration is simple, safe and cost-effective and could be used as an adjuvant therapy for intraperitoneal chemotherapy.     

Mucosal pharmacokinetics and pilot study of short course of parenteral imipenem in the eradication of Helicobacter pylori

Abstract Eradication of Helicobacter pylori infection is known to reduce the incidence of duodenal ulcer recurrence. The most commonly used regimen for H. pylori infection is triple antimicrobial therapy for 1-2 weeks. This treatment is associated with frequent side effects and hence unsatisfactory compliance. As in vitro data showed that H. pylori is sensitive to imipenem, the pharmacokinetics of this drug in the gastric milieu, and the clinical efficacy of imipenem with omeprazole in eradicating H. pylori infection were studied. Imipenem/cilastatin levels in serum, gastric secretion and gastric mucosa were assayed in four patients after intravenous injection of a bolus dose of 500 mg. The serum and gastric secretion levels of imipenem achieved were more than 10 times the minimum inhibitory concentration of the drug for H. pylori. Gastric mucosal levels of imipenem vary considerably with time, which probably indicates rapid elimination of the drug into the gastric lumen. In the second part of this study, imipenem/cilastatin was given intravenously for the first 2 days after diagnosis of H. pylori infection in patients with endoscopically confirmed duodenal ulcers. The patients were also treated with 4 weeks of omeprazole. Clearance of H. pylori was initially achieved at the end of 2 days in 20 out of 22 (91%) patients. However, when the biopsies were repeated at 8 weeks, recurrence of H. pylori infection was evident in 19 cases (86.3%) indicating a failure of eradication. It was concluded that imipenem/cilastatin in combination with omeprazole failed to eradicate H. pylori infection.     

Understanding the pathogenesis of type 2 diabetes: can we get off the metabolic merry-go-rounds?

The aetiology of non-insulin-dependent diabetes mellitus (NIDDM) is not known. The concordance of NIDDM in identical twins and differences in the prevalence rate of NIDDM between different racial groups suggest a genetic cause. Hyperglycaemia in established diabetes is caused by a combination of hepatic insulin resistance, impaired peripheral (muscle and fat) glucose uptake and a defect in glucose-mediated insulin secretion. However, it is not known if these defects are all inherited or if one can cause the others. This uncertainty is due to the fact that hyperglycaemia per se can cause defects in insulin action and insulin secretion that resemble those found in NIDDM. Furthermore the elevated free fatty acid (FFA) levels found when NIDDM is associated with obesity are known to cause both peripheral and hepatic insulin resistance. Recently we have demonstrated the mechanism by which elevated FFA levels can cause hepatic insulin resistance. However, we also have evidence that the converse holds in that genetically engineered hepatic insulin resistance in a transgenic rat model leads to obesity. Thus an understanding of the pathogenesis of NIDDM is complicated by the fact that hyperglycaemia and obesity can be both causes and consequences of insulin resistance. To overcome these difficulties, studies in young, euglycaemic diabetes-prone subjects have been conducted. Results suggest that there may be different causes for NIDDM in different racial groups.     

Differential Effect of Adenosine on Anterograde and Retrograde Fast Pathway Conduction in Patients with Atrioventricular Nodal Reentrant Tachycardia

Adenosine and Retrograde Fast Pathway Conduction . Introduction : Several studies have shown that the fast pathway is more responsive to adenosine than the slow pathway in patients with AV nodal reentrant tachycardia. Little information is available regarding the effect of adenosine on anterograde and retrograde fast pathway conduction.
Methods and Results : The effects of adenosine on anterograde and retrograde fast pathway conduction were evaluated in 116 patients (mean age 47 ± 16 years) with typical AV nodal reentrant tachycardia. Each patient received 12 mg of adenosine during ventricular pacing at a cycle length 20 msec longer than the fast pathway VA block cycle length and during sinus rhythm or atrial pacing at 20 msec longer than the fast pathway AV block cycle length. Anterograde block occurred in 98% of patients compared with retrograde fast pathway block in 62% of patients ( P < 0.001). Unresponsiveness of the retrograde fast pathway to adenosine was associated with a shorter AV block cycle length (374 ± 78 vs 333 ± 74 msec, P < 0.01), a shorter VA block cycle length (383 ± 121 vs 307 ± 49 msec, P < 0.001), and a shorter VA interval during tachycardia (53 ± 23 vs 41 ± 17 msec, P < 0.01).
Conclusion : Although anterograde fast pathway conduction is almost always blocked by 12 mg of adenosine, retrograde fast pathway conduction is not blocked by adenosine in 38% of patients with typical AV nodal reentrant tachycardia. This indicates that the anterograde and retrograde fast pathways may be anatomically and/or functionally distinct. Unresponsiveness of VA conduction to adenosine is not a reliable indicator of an accessory pathway.     

Long-Term Evaluation of the Ventricular Defibrillation Energy Requirement

Defibrillation Energy Requirements. Introduction : Defibrillation energy requirements in patients with nonthoracotomy defibrillators may increase within several months after implantation. However, the stability of the defibrillation energy requirement beyond 1 year has not been reported. The purpose of this study was to characterize the defibrillation energy requirement during 2 years of clinical follow-up.
Methods and Results : Thirty-one consecutive patients with a biphasic nonthoracotomy defibrillation system underwent defibrillation energy requirement testing using a step-down technique (20, 15, 12, 10, 8, 6, 5, 4, 3, 2, and 1 J) during defibrillator implantation, and then 24 hours, 2 months, 1 year, and 2 years after implantation. The mean defibrillation energy requirement during these evaluations was 10.9 ± 5.5 J, 12.3 ± 7.3 J, 11.7 ± 5.6 J, 10.2 ± 4.0 J, and 11.7 ± 7.4 J, respectively ( P = 0.4). The defibrillation energy requirement was noted to have increased by 10 J or more after 2 years of follow-up in five patients. In one of these patients, the defibrillation energy requirement was no longer associated with an adequate safety margin, necessitating revision of the defibrillation system. There were no identifiable clinical characteristics that distinguished patients who did and did not develop a 10-J or more increase in the defibrillation energy requirement.
Conclusion : The mean defibrillation energy requirement does not change significantly after 2 years of biphasic nonthoracotomy defibrillator system implantation. However, approximately 15% of patients develop a 10-J or greater elevation in the defibrillation energy requirement, and 3% may require a defibrillation system revision. Therefore, a yearly evaluation of the defibrillation energy requirement may he appropriate.     

Treatment Strategies for Long and Calcified Lesions

This study discusses the treatment strategies used to approach long lesions, lesions in small vessels, and calcified lesions. Traditional treatment strategies for these lesion subtypes have yielded high acute complication rates and poor long-term outcome. A prospective analysis of 160 lesions was performed using intravascular ultrasound (IVUS) guided PTCA for the treatment of long lesions and lesions in small vessels, while a retrospective analysis of 106 calcified lesions was performed that were treated with the combination of rotablation and stenting. Acute and short-term results of TVUS guided PTCA with spot stenting show a 30-day major adverse cardiac event rate (MACE) of 5% with a high procedural success rate (96%), while the long-term outcome resulted in an agiographic restenosis rate of 17.4% and a target lesion revascularization rate of 13%. The combination of rotablation and stenting also rendered results in calcified lesions of a 93% angiographic success rate and a long-term outcome of restenosis of 22.5%. Optimal coronary stenting after rotational atherectomy in calcified lesions can be performed with a high success rate, an acceptable rate of procedural complications, and a low rate of stent thrombosis. This approach was associated with a low incidence of angiographic restenosis compared with results obtained with other interventional approaches. IVUS guided PTCA with spot stenting allows safe treatment of long lesions and lesions in small vessels. Short-term and long-term outcomes including 6-month MACE and angiographic restenosis appear to be better than results achieved in historical controls that utilize balloon angioplasty alone or stents in a manner where the lesion is covered from the proximal normal segment to the distal normal segment.     

Evaluation of recombinant protein r140, a polypeptide segment of tegumental glycoprotein Sm25, as a defined antigen vaccine against Schistosoma mansoni

To investigate the role of tegumental glycoprotein Sm25 in protective immunity against schistosomiasis, codons 43-182 of its gene (GP22) were amplified by PCR and cloned in the pET 15b bacterial expression system. Recombinant protein r140 was inducibly expressed in the presence of rifampicin and purified by Ni-affinity chromatography. In different vaccination trials, Balb/c mice and Fischer rats repeatedly immunized with r140 in combination with one of several adjuvants (alum, cholera toxin or complexed into proteosomes) produced high titre anti-r140 responses. These antibodies detected an N-glycanase sensitive, 25 kDa antigen in a detergent solubilized worm fraction using Western immunoblotting. The choice of adjuvant affected the isotype distribution of the specific anti-r140 antibodies. Despite the presence of high antibody titres and isotypes which have been shown to correlate with protective immunity, protection against subsequent cercarial challenge was not observed. In addition, no appreciable effects on worm sex ratios or liver egg yields were detected in mice. Studies involving biotin labelling of membrane proteins in live worms showed that the majority of anti-r140 reactive molecules present in adult schistosomes are biotinylated after permeabilization of the parasite surface. Several possibilities to account for the lack of protective immunity are analysed .     

Reproducible Induction of "Atypical" Torsades de Pointes by Programmed Electrical Stimulation:

Sotalol-Induced Polymorphic VT. We present a patient with sotalol-induced polymorphic ventricular tachycardia that was seen only with programmed ventricular stimulation. Electrophysiologic studies performed prior to initiation of sotalol therapy revealed inducible monomorphic ventricular tachycardia. Possible underlying electrophysiologic mechanisms are discussed.     

Outcomes in Patients Requiring Cardioversion Following Catheter Ablation of Atrial Fibrillation

Outcomes of Cardioversion Post AF Ablation.   Introduction: Early recurrence of atrial tachyarrhythmias is commonly noted after catheter ablation of atrial fibrillation (AF). The long-term outcomes of patients who require cardioversion for persistent AF after AF ablation is not known. This study reports the outcomes of patients who underwent cardioversion for persistent AF or atrial flutter following an AF ablation procedure.
Methods: The patient population comprised 55 patients (mean age 58 ± 10 years, 35% paroxysmal) who underwent catheter ablation of AF and subsequently required electrical cardioversion for persistent AF (45 patients) or atrial flutter (10 patients). Cardioversion was defined as early (within 90 days of the ablation procedure) or late (between 90 and 180 days following ablation).
Results: The mean follow-up duration was 15 ± 8 months. Forty-six of the 55 patients (84%) patients experienced recurrence during follow-up. The average time to recurrence after cardioversion was 37 days. Of the 55 patients, 8 (15%) patients had a complete success, 11 (20%) patients had a partial success and 36 patients (65%) had a failed outcome. Seven of the 43 patients (16%) who underwent early cardioversion had a complete success as opposed to one of 12 patients (8%) who underwent late cardioversion (P = 0.49).
Conclusions: This study shows that >80% of patients who undergo cardioversion for persistent AF or atrial flutter after AF ablation have recurrence. The timing of cardioversion did not affect the outcome. These findings allow clinicians to provide realistic expectations to patients regarding the long-term outcome and/or requirement for a second ablation procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 27–32, January 2010)