Search

Background: Pace mapping (PM) is used to identify the origin of ventricular arrhythmias (VAs). For intramural VAs, the site of origin often cannot be reached and therefore PM is less accurate.Objective: The purpose of this study was to assess the value of single- and dual-site pace maps to differentiate intramural from nonintramural VAs.Methods: In 18 consecutive patients with idiopathic intramural VAs, pace mapping was performed at 2 breakthrough sites in adjacent anatomic structures. Twelve-lead electrocardiograms of the 2 pace maps were averaged in MATLAB and compared (correlation coefficient [CC]) with the targeted VA. Dual-site pace mapping was performed in a control group of 18 patients with nonintramural VAs at the sites of earliest electrical activation and a breakthrough site in an adjacent anatomic location.Results: Dual-site pace maps had a higher CC than did best single-site pace maps (0.87 ± 0.1 vs 0.81 ± 0.16; P = .02) in patients with intramural VAs. At the site of origin, single-site pace maps had a higher CC than did dual-site pace maps obtained from adjacent anatomic locations (0.93 ± 0.04 vs 0.89 ± 0.05; P = .0004) in patients with nonintramural VAs. Sensitivity, specificity, positive predictive value, and negative predictive value of dual-site pace maps for identifying an intramural VA were 89%, 82%, 84%, 88%, and 86%, respectively. Furthermore, the receiver operating characteristic curve analysis revealed that a CC cutoff value of ≤0.86 for a single-site pace map best differentiated intramural from nonintramural VAs.Conclusion: A higher CC value for a dual-site pace map obtained from the earliest breakthrough site as well as a CC cutoff value of ≤0.86 for a single-site pace map obtained from the site of earliest electrical activation can best differentiate intramural from nonintramural VAs. [ABSTRACT FROM AUTHOR]

Background: Frequent idiopathic premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy.Objective: The purpose of this study was to assess the impact of variability in PVC frequency throughout the day on PVC-induced cardiomyopathy.Methods: The subjects of this study were 107 consecutive patients (58 men [54%]; mean age 49.7 ± 15.0 years; left ventricular ejection fraction 50.4% ± 11.4%) referred for ablation of frequent PVCs. All patients underwent 24-hour Holter monitoring before the ablation procedure. The circadian variation in PVC burden was determined and correlated with the presence or absence of cardiomyopathy.Results: A total of 43 patients (40%) had cardiomyopathy. Patients with cardiomyopathy had an ejection fraction of 38.4% ± 6.9%, a higher PVC burden (28.5% ± 11.5% vs 19.5% ± 10.5%; P = .0001), less variability in circadian PVC distribution (coefficient of variation hourly: 31.5% ± 21% vs 59.8% ± 32.4%; P = .0001), and more frequent interpolated PVCs (20 patients [47%] vs 15 patients [23%]; P = 0.022), and were more frequently asymptomatic than patients without cardiomyopathy (56% vs 19%; P = .0001). In multivariate analysis, consistency in PVC burden throughout the day was an independent predictor of PVC-induced cardiomyopathy (odds ratio 16.3; 95% confidence interval 1.7-155.3; p = 0.015).Conclusion: In patients with frequent PVCs, consistency in hourly PVC frequency throughout the day is an independent predictor of PVC-induced cardiomyopathy. [ABSTRACT FROM AUTHOR]

The clinical diagnosis of right ventricular (RV) cardiomyopathies is often challenging. It is difficult to differentiate the isolated left ventricular (LV) noncompaction cardiomyopathy (NC) from biventricular NC or from coexisting arrhythmogenic ventricular cardiomyopathy (AC). There are currently few established morphologic criteria for the diagnosis other than RV dilation and presence of excessive regional trabeculation. The gross and microscopic changes suggest pathological similarities between, or coexistence of, RV-NC and AC. Therefore, the term arrhythmogenic right ventricular cardiomyopathy is somewhat misleading as isolated LV or biventricular involvement may be present and thus a broader term such as AC should be preferred. We describe an unusual case of AC associated with a NC in a 27-year-old man who had a history of permanent pacemaker 7 years ago due to second-degree atrioventricular block. [ABSTRACT FROM AUTHOR]

Background: Gamma-glutamyltransferase (GGT) enzyme has an increasing importance in the pathophysiology and prognosis of cardiovascular diseases. It is an indirect marker of microvascular endothelial dysfunction, atherosclerosis, and elevated oxidative stress. There are no adequate data on the relationship between GGT and cardiac syndrome X., Aim: To compare serum GGT levels between patients with cardiac syndrome X and asymptomatic healthy individuals., Methods: Fifty consecutive patients (29 female, 21 male, aged 28-81 years) who underwent coronary angiography due to objective ischaemia and were eventually diagnosed with cardiac syndrome X between July 2009 and January 2010, and 50 healthy asymptomatic control individuals (28 female, 22 male, aged 30-78 years) were studied. Venous blood samples were collected for GGT measurements. A metabolic syndrome (MS) subgroup composed of 15 individuals was formed within the cardiac syndrome X group., Results: Serum total cholesterol, LDL-cholesterol, and triglyceride (TG) levels were significantly higher in the cardiac syndrome X patients than in the control group (195.28 ± 33.71 mg/dL and 168.82 ± 31.45 mg/dL, p < 0.01, 121.62 ± 30.53 mg/dL and 98.44 ± 27.28 mg/dL, p < 0.01, 144.30 ± 68.54 mg/dL and 108.94 ± 43.59 mg/dL, p < 0.01, respectively). Serum GGT levels were also significantly higher in the cardiac syndrome X patients than in the control group (30.48 ± 16.36 and 17.88 ± 6. 89 U/L, p < 0.001). The MS patients (n = 15) had significantly higher TG and GGT levels (230.00 ± 41.37 mg/dL and 107.57 ± 37.90 mg/dL, p < 0.01, 38.47 ± 21.27 U/L and 27.06 ± 12.61 U/L, p < 0.001, respectively) and lower HDL levels (35.47 ± 6.91 mg/dL and 48.26 ± 9.97 mg/dL, p < 0.05) compared to patients without MS. The cardiac syndrome X group exhibited a significant positive correlation between GGT and body mass index, and GGT and TG (r = 0.321, p = 0.023, r = 0.293, p = 0.039, respectively)., Conclusions: GGT activity in patients with cardiac syndrome X was higher than in healthy controls. Moreover, GGT activity was further increased in those patients with cardiac syndrome X who had also MS.