Electrocardiographic criteria for differentiating aberrancy and ventricular extrasystole in chronic atrial fibrillation: validation by intracardiac recordings

Many electrocardiographic criteria have been proposed for the differentiation of ventricular extrasystole and supraventricular conduction with aberrancy in atrial fibrillation but the validity of these have not been confirmed by intracardiac studies. We recorded His bundle electrograms in nineteen patients (eleven men, eight women) referred for diagnosis of abnormal QRS complexes in the context of chronic atrial fibrillation. Of 1,068 wide QRS complexes analyzed, 91% proved to be of ventricular origin. Electrocardiographic criteria which were specific for ventricular extrasystole included: left bundle branch block morphology, right bundle branch block morphology with a monophasic R in lead V1 or an RS or QS pattern in lead V6, presence of a "compensatory pause", i.e., compensatory cycle (V2-V3) longer than the average cycle length of ten normally conducted beats preceding the abnormal complex (927 +/- 317 vs 780 +/- 199, mean +/- SD in msec. p less than 0.005), frontal QRS axis of the abnormal complex directed superiorly or to the right and the presence of a "short-long" cycle sequence. Right bundle branch morphology with a triphasic R in lead V1 or QRS pattern in V6 and concordant initial vector in lead V1 or in more than one ECG leads were very specific for supraventricular conduction with aberrancy. Analysis of coupling interval and Ashman's phenomenon, i.e., the long-short cycle sequence, were not specific for supraventricular conduction with aberrancy. We conclude that in digitalis-treated patients with chronic atrial fibrillation the majority of abnormal QRS complexes are of ventricular origin. The diagnosis of ventricular extrasystole or aberrancy can be made using a single ECG lead (V1) and applying a combination of easily applied criteria.     

Electrophysiologic substrate associated with pacing-induced heart failure in dogs: potential value of programmed stimulation in predicting sudden death.

To investigate the possible mechanisms of sudden death and the potential role of electrophysiologic testing in congestive heart failure, this study evaluated the electrophysiologic substrate in a model of heart failure induced by rapid pacing. Seventeen mongrel dogs underwent cardiac pacing at 220 to 240 beats/min for 5 weeks (paced group) and 11 other dogs served as a sham-operated control group. Rapid pacing of the right ventricle produced clinical and hemodynamic features of congestive heart failure. Dogs in the paced group had prolonged cardiac conduction time as reflected by longer epicardial activation time (36.1 +/- 2.4 vs. 30.8 +/- 0.8 ms, p less than 0.05). The ventricular effective refractory period was significantly prolonged after the development of heart failure (141 +/- 4 vs. 177 +/- 5 ms, p less than 0.01, at a basic pacing cycle length of 300 ms), whereas no significant change was found in the control group (140 +/- 4 vs. 145 +/- 4 ms, p = NS). The prolongation of the ventricular effective refractory period correlated with an increase in left ventricular end-diastolic pressure (r = 0.55, p less than 0.001) and the ventricular effective refractory period correlated inversely with cardiac index (r = -0.49, p less than 0.025). The rest membrane potential of ventricular muscle was less negative in the paced group compared with the control group (-80.7 +/- 2.2 vs. -85.6 +/- 2.2 mV, p less than 0.05). Intracellularly recorded action potential duration of ventricular muscle was longer in the paced than in the control group (236 +/- 9.8 vs. 198.9 +/- 2.6 ms, p less than 0.01), action potential duration at 90% repolarization).(ABSTRACT TRUNCATED AT 250 WORDS)     

ISPD Cardiovascular and Metabolic Guidelines in Adult Peritoneal Dialysis Patients Part I – Assessment and Management of Various Cardiovascular Risk Factors

Cardiovascular disease contributes significantly to the adverse clinical outcomes of peritoneal dialysis (PD) patients. Numerous cardiovascular risk factors play important roles in the development of various cardiovascular complications. Of these, loss of residual renal function is regarded as one of the key cardiovascular risk factors and is associated with an increased mortality and cardiovascular death. It is also recognized that PD solutions may incur significant adverse metabolic effects in PD patients. The International Society for Peritoneal Dialysis (ISPD) commissioned a global workgroup in 2012 to formulate a series of recommendations regarding lifestyle modification, assessment and management of various cardiovascular risk factors, as well as management of the various cardiovascular complications including coronary artery disease, heart failure, arrhythmia (specifically atrial fibrillation), cerebrovascular disease, peripheral arterial disease and sudden cardiac death, to be published in 2 guideline documents. This publication forms the first part of the guideline documents and includes recommendations on assessment and management of various cardiovascular risk factors. The documents are intended to serve as a global clinical practice guideline for clinicians who look after PD patients. The ISPD workgroup also identifies areas where evidence is lacking and further research is needed.     

Impact of a Low-Glucose Peritoneal Dialysis Regimen on Fibrosis and Inflammation Biomarkers

♦ Background: The impact of a low-glucose peritoneal dialysis (PD) regimen on biomarkers of peritoneal inflammation, fibrosis and membrane integrity remains to be investigated.♦ Methods: In a randomized, prospective study, 80 incident PD patients received either a low-glucose regimen comprising Physioneal (P), Extraneal (E) and Nutrineal (N) (Baxter Healthcare Corporation, Deerfield, IL, USA) (PEN group), or Dianeal (control group) for 12 months, after which both groups continued with Dianeal dialysis for 6 months. Serum and dialysate levels of vascular endothelial growth factor (VEGF), decorin, hepatocyte growth factor (HGF), interleukin-6 (IL-6), macrophage migration inhibitory factor (MIF), hyaluronan (HA), adiponectin, soluble-intracellular adhesion molecule (s-ICAM), vascular cell adhesion molecule-1 (VCAM-1) and P-selectin, and dialysate cancer antigen 125 (CA125), were measured after 12 and 18 months. This paper focuses on results after 12 months, when patients in the PEN group changed to glucose-based PD fluid (PDF).♦ Results: At the end of 12 months, effluent dialysate levels of CA125, decorin, HGF, IL-6, adiponectin and adhesion molecules were significantly higher in the PEN group compared to controls, but all decreased after patients switched to glucose-based PDF. Macrophage migration inhibitory factor level was lower in the PEN group but increased after changing to glucose-based PDF and was similar to controls at 18 months. Serum adiponectin level was higher in the PEN group at 12 months, but was similar in the 2 groups at 18 months. Body weight, residual renal function, ultrafiltration volume and total Kt/V did not differ between both groups. Dialysate-to-plasma creatinine ratio at 4 h was higher in the PEN group at 12 months and remained so after switching to glucose-based PDF.♦ Conclusion: Changes in the biomarkers suggest that the PEN PD regimen may be associated with better preservation of peritoneal membrane integrity and reduced systemic vascular endothelial injury.     

Low Compliance with National Guidelines for Preventing Transmission of Group 1 Nationally Notifiable Infectious Diseases in Korea

Purpose

This study was performed to evaluate the compliance with, and adequacy of, the Korean national guidelines which had been recommended until 2011 for isolation of patients with group 1 nationally notifiable infectious diseases (NNIDs), namely cholera, typhoid fever, paratyphoid fever, shigellosis, and enterohemorrhagic Escherichia coli (EHEC) infection.

Materials and Methods

We evaluated the clinical and microbiological characteristics of confirmed cases of group 1 NNIDs and compliance with the guidelines in 20 Korean hospitals nationwide in 2000-2010. We also compared the Korean guidelines with international guidelines.

Results

Among 528 confirmed cases (8 cases of cholera, 232 of typhoid fever, 81 of paratyphoid fever, 175 of shigellosis, and 32 EHEC infections), strict compliance with the Korean guideline was achieved in only 2.6% to 50.0%, depending on the disease. While the Korean guidelines recommend isolation of all patients with group 1 NNIDs, international guidelines recommend selective patient isolation and screening for fecal shedding, depending on the type of disease and patient status.

Conclusion

Compliance with the previous national guidelines for group 1 NNIDs in Korea was generally very low. Further studies are needed to evaluate whether compliance was improved after implementation of the new guideline in 2012.