The evaluation of wide QRS complex tachycardias (WCT)remains a common dilemma for clinicians.Numerous algorithms exist to aid in arriving at the correct diagnosis.Unfortunately,these algorithms are difficult to rememb...The evaluation of wide QRS complex tachycardias (WCT)remains a common dilemma for clinicians.Numerous algorithms exist to aid in arriving at the correct diagnosis.Unfortunately,these algorithms are difficult to remember,and overreliance on them may prevent cardiologists from understanding the mechanisms underlying these arrhythmias.One distinct subcategory of WCTs are those that present with a"typical"or"classic" left bundle branch block pattern.These tachycardias may be supraventricular or ventricular in origin and arise from functional or fixed aberrancy,bystander or participating atriofascicular pre-excitation,and bundle branch reentry.This review will describe these arrhythmias,illustrate their mechanisms,and discuss their clinical features and treatment strategies.展开更多
The prevalence of obesity in both developed and developing countries has increased dramatically in recent years.1Many people who are obese develop metabolic changes that increase the risk of diabetes mellitus and ... The prevalence of obesity in both developed and developing countries has increased dramatically in recent years.1Many people who are obese develop metabolic changes that increase the risk of diabetes mellitus and adverse cardiovascular outcomes. Obesity leads to the development of insulin resistance, lipid abnormalities and increased blood pressure.……展开更多
Coronary heart disease (CHD) remains the number one killer of men and women in the United States of America despite major advances in interventional technologies for the treatment of coronary artery disease. CHD is ra...Coronary heart disease (CHD) remains the number one killer of men and women in the United States of America despite major advances in interventional technologies for the treatment of coronary artery disease. CHD is rapidly becoming a major cause of morbidity and mortality in developing nations as well and is now recognized as the leading cause of death worldwide.展开更多
Purpose. To evaluate and compare the effects of heart rate on conduction velocity in the cavotricus-pid isthmus (CTI) and septum in patients with and without typical atrial flutter (AF) using electro-anatomic mapping ...Purpose. To evaluate and compare the effects of heart rate on conduction velocity in the cavotricus-pid isthmus (CTI) and septum in patients with and without typical atrial flutter (AF) using electro-anatomic mapping (EAM) of the right atrium (RA).Methods. Ten patients(age 53+10 yrs,7M/3F)with AF and 13 patients (age 51+11 yrs, 5M/8F) with atrio-ventricular nodal reentrant tachycardia (AVNRT) underwent conventional electrophysionogical study, electro -anatomic mapping and radiofrequency ablation. Using EAMs obtained during coronary sinus pacing at pacing cycle length (PCL) 600 ms, 400 ms, and 300 ms, we evaluated conduction velocities in the CTI and septum of RA in 10 patients with AF and compared EAMs to 13 patients with AVNRT to determine whether the conduction slowing required to maintain AFL was related to changes in volume alone or altered RA electrophysiology.Results. Conduction velocities in CTI and septum were significantly slower at all PCL when AF was compared to AVNRT(P<0.05). Additionally, in the AF group, septal conduction velocities were slower at PCL 600 ms and 400 ms, but not at 300 ms compared to CTI (P<0.05). In AF, during PCL 300. conduction in CTI slowed significantly compared to PCL 600 and 400 ms such that there was no difference between CTI and septum at PCL 300.Conclusions. There is slower conduction in the septum compared to the CTI in all patients. However, in patients with AF, there is significant slowing of conduction in the CTI and septum as well as decremen-tal rate-dependent slowing of conduction in the CTI. These findings indicate that in addition to RA enlargement, changes in atrial electrophysiology distinguish AF patients from patients with AVNRT.展开更多
文摘The evaluation of wide QRS complex tachycardias (WCT)remains a common dilemma for clinicians.Numerous algorithms exist to aid in arriving at the correct diagnosis.Unfortunately,these algorithms are difficult to remember,and overreliance on them may prevent cardiologists from understanding the mechanisms underlying these arrhythmias.One distinct subcategory of WCTs are those that present with a"typical"or"classic" left bundle branch block pattern.These tachycardias may be supraventricular or ventricular in origin and arise from functional or fixed aberrancy,bystander or participating atriofascicular pre-excitation,and bundle branch reentry.This review will describe these arrhythmias,illustrate their mechanisms,and discuss their clinical features and treatment strategies.
文摘 The prevalence of obesity in both developed and developing countries has increased dramatically in recent years.1Many people who are obese develop metabolic changes that increase the risk of diabetes mellitus and adverse cardiovascular outcomes. Obesity leads to the development of insulin resistance, lipid abnormalities and increased blood pressure.……
文摘Coronary heart disease (CHD) remains the number one killer of men and women in the United States of America despite major advances in interventional technologies for the treatment of coronary artery disease. CHD is rapidly becoming a major cause of morbidity and mortality in developing nations as well and is now recognized as the leading cause of death worldwide.
文摘Purpose. To evaluate and compare the effects of heart rate on conduction velocity in the cavotricus-pid isthmus (CTI) and septum in patients with and without typical atrial flutter (AF) using electro-anatomic mapping (EAM) of the right atrium (RA).Methods. Ten patients(age 53+10 yrs,7M/3F)with AF and 13 patients (age 51+11 yrs, 5M/8F) with atrio-ventricular nodal reentrant tachycardia (AVNRT) underwent conventional electrophysionogical study, electro -anatomic mapping and radiofrequency ablation. Using EAMs obtained during coronary sinus pacing at pacing cycle length (PCL) 600 ms, 400 ms, and 300 ms, we evaluated conduction velocities in the CTI and septum of RA in 10 patients with AF and compared EAMs to 13 patients with AVNRT to determine whether the conduction slowing required to maintain AFL was related to changes in volume alone or altered RA electrophysiology.Results. Conduction velocities in CTI and septum were significantly slower at all PCL when AF was compared to AVNRT(P<0.05). Additionally, in the AF group, septal conduction velocities were slower at PCL 600 ms and 400 ms, but not at 300 ms compared to CTI (P<0.05). In AF, during PCL 300. conduction in CTI slowed significantly compared to PCL 600 and 400 ms such that there was no difference between CTI and septum at PCL 300.Conclusions. There is slower conduction in the septum compared to the CTI in all patients. However, in patients with AF, there is significant slowing of conduction in the CTI and septum as well as decremen-tal rate-dependent slowing of conduction in the CTI. These findings indicate that in addition to RA enlargement, changes in atrial electrophysiology distinguish AF patients from patients with AVNRT.
