Heart rate variability in patients hospitalized for decompensated diastolic heart failure at admission and after clinical stabilization.

AIMS: We investigated heart rate variability (HRV) in patients hospitalized for decompensated diastolic heart failure and the effect of compensation course on HRV parameters. We also examined the association between the degree of diastolic dysfunction and HRV indices. PATIENTS & METHODS: A total of 42 patients hospitalized for decompensated heart failure, who had a measured ejection fraction ≥ 50%, and ten age- and sex-matched healthy volunteers were enrolled. RESULTS: All HRV indices were lower compared with the control group both at admission (p < 0.001) and after compensation, although a significant increase was observed in each index measured after clinical stabilization (p < 0.001). Improvement in HRV indices was lowest in patients with a restrictive pattern among groups of different degrees of diastolic dysfunction. CONCLUSION: Impairment in HRV in decompensated diastolic heart failure is more pronounced with increasing grade of diastolic dysfunction. It remains to be investigated whether decompensation may be predicted by marked depression in these indexes or if severely impaired HRV is a consequence of decompensation.

Impact of preprocedural imaging on outcomes of catheter ablation in patients with atrial fibrillation.

PURPOSE: This study aims to determine the impact of preprocedural imaging using computerized tomography (CT) or magnetic resonance imaging (MRI) with 3-D reconstruction on procedural efficiency, efficacy, complications and clinical outcome in patients who undergo radiofrequency catheter ablation (RFA) to eliminate atrial fibrillation (AF). METHODS: In this registry, a CT (n = 161) or MRI (n = 37) was obtained prior to RFA in 198 of 333 consecutive patients (age 61 ± 10 years) with paroxysmal (172) or persistent (161) AF. Antral pulmonary vein isolation was performed in all patients using an open-irrigation-tip catheter with a 3-D electroanatomical navigation system. Procedural and clinical outcomes were compared among patients who underwent RFA with and without preprocedural imaging. RESULTS: The mean duration of the procedure (246 ± 47 vs. 242 ± 40 min, P = 0.55), fluoroscopy (47 ± 13 vs. 50 ± 10 min, P = 0.16), and total RF application (83 ± 27 vs. 78 ± 23 min, P = 0.17) were similar among patients who did and did not have preprocedural imaging. The likelihood of a complication also was similar (5/198 [3%] vs. 4/135 [3%], P = 1.0). A repeat ablation was performed in 95/198 (48%) and 61/135 (45%) of the patients who did and did not have imaging study, respectively (P = 0.62). At 22 ± 9 months, after a mean of 2 ± 1 procedures, 140/198 (71%) and 101/135 (75%) of the patients who did and did not have preprocedural imaging were in sinus rhythm (P = 0.4). CONCLUSIONS: Preprocedural awareness of pulmonary venous and left atrial anatomy does not appear to have an effect on procedural efficiency or clinical outcomes in patients who undergo catheter ablation for AF.

The role of interpolation in PVC-induced cardiomyopathy.

BACKGROUND: Frequent premature ventricular complexes (PVCs) can cause cardiomyopathy. The mechanism is not known and may be multifactorial. OBJECTIVE: This study assessed the role of PVC interpolation in PVC-induced cardiomyopathy. METHODS: In 51 consecutive patients (14 women, age 49 ± 15 years, ejection fraction (EF) 0.49 ± 0.14) with frequent PVCs, 24-hour Holter recordings were performed. The amount of interpolation was determined and correlated with the presence of PVC-induced cardiomyopathy. In addition, parameters measured during an electrophysiology study were correlated with the Holter findings. RESULTS: Fourteen of the 21 patients (67%) with cardiomyopathy had interpolated PVCs, compared with only 6 of 30 patients (20%) without PVC-induced cardiomyopathy (P <.001). Patients with interpolated PVCs had a higher PVC burden than patients without interpolation (28% ± 12% vs. 15% ± 15%; P = .002). The burden of interpolated PVCs correlated with the presence of PVC cardiomyopathy (21% ± 30% vs. 4% ± 13%; P = .008). Both PVC burden and interpolation independently predicted PVC-induced cardiomyopathy (odds ratio 1.07, 95% confidence interval 1.01 to 1.13, P = .02; and odds ratio 4.43, 95% confidence interval 1.06 to 18.48, P = .04, respectively). The presence of ventriculoatrial block at a ventricular pacing cycle length of 600 ms correlated with the presence of interpolation (P = .004). Patients with interpolation had a longer mean ventriculoatrial block cycle length than patients without interpolated PVCs (520 ± 110 ms vs. 394 ± 92 ms; P = .01). CONCLUSION: The presence of interpolated PVCs was predictive of the presence of PVC cardiomyopathy. Interpolation may play an important role in the generation of PVC-induced cardiomyopathy.

Exercise electrocardiographic responses and serum cystatin C levels among metabolic syndrome patients without overt diabetes mellitus.

OBJECTIVES: An impaired heart rate response during exercise (chronotropic incompetence) and an impaired heart rate recovery (HRR) after exercise are predictors of cardiovascular risk and mortality. Cystatin C is a novel marker for cardiovascular disease. We aimed to investigate exercise electrocardiographic responses in patients with metabolic syndrome who were without overt diabetes mellitus, in addition to the association of serum cystatin C levels with the exercise electrocardiographic test results. METHOD: Forty-three consecutive patients admitted to a cardiology outpatient clinic without angina pectoris were recruited if they met criteria for metabolic syndrome but did not have overt diabetes mellitus. Serum cystatin C levels were measured, and all participants underwent exercise electrocardiographic testing. Patients who were found to have ischemia had a coronary angiography procedure. RESULTS: The mean cystatin C level of patients was higher in metabolic syndrome group than healthy controls (610.1 ± 334.02 vs 337.3 ± 111.01 µg/L; P < 0.001). The percentage of patients with ischemia confirmed by coronary angiography was 13.9% in the metabolic syndrome group. Cystatin C levels in the ischemic patients of the metabolic syndrome group were higher than that in nonischemic patients (957.00 ± 375.6 vs 553.8 ± 295.3 µg/L; P = 0.005). Chronotropic incompetence was observed in 30.2% of the patients with metabolic syndrome compared with 16.7% in the control group (P = 0.186). Chronotropic response indices were 0.8 ± 0.18 versus 0.9 ± 0.10 for the two groups, respectively (P = 0.259). HRR was significantly lower in the metabolic syndrome patients compared with the controls (20.1 ± 8.01 vs 25.2 ± 4.5 per min; P < 0.001), and the ST-segment adjustment relative to heart rate(ST/HR index ratio) was 1.4 ± 1.34 versus 0.4 ± 0.31 µV/beat (P < 0.001), respectively. Cystatin C was negatively correlated with the chronotropic response index (CRI) and HRR and was positively correlated with ST/HR index in the entire study population (R = -0.658, -0.346, 0.388, respectively; P < 0.05). CONCLUSIONS: A substantial proportion of metabolic syndrome patients without overt diabetes mellitus had silent coronary ischemia in addition to impairment of objective exercise electrocardiographic parameters. In the metabolic syndrome patients without overt diabetes mellitus, cystatin C levels were found to be elevated and the elevation was more pronounced in the subgroup with silent ischemia. Cystatin C was also correlated with HRR and CRI.

The reliability of fractional flow reserve measurement in patients with diabetes mellitus.

BACKGROUND: Fractional flow reserve (FFR) is an invasive method to assess the functional significance of coronary stenoses. The value of FFR in diabetic patients is controversial because of microvascular dysfunction. The aim of this study is to investigate the effect of diabetes mellitus (DM) on FFR measurements. METHODS: One hundred and twenty-one patients with an intermediate lesion who had undergone FFR measurement were included in the study. Lesion severity was determined by quantitative coronary angiography. The patients were divided into groups according to the presence (group 1) or absence (group 2) of DM. The patients were further categorized according to the degree of luminal narrowing caused by the lesion (40-50, 51-60, and >60%) and reference vessel diameter (> or = 2.8 and <2.8 mm). FFR measurements were compared in each category. RESULTS: There was no difference between the FFR values of diabetic and nondiabetic patients who had coronary lesions with similar degree of luminal narrowing (0.87+/-0.08 vs. 0. 0.85+/-0.07; 0.81+/-0.08 vs. 0.82+/-0.10; 0.81+/-0.10 vs. 0.83+/-0.09, P = 0.957). In the analysis comparing FFR measurements in the categories set according to reference vessel diameter, we did not find a difference either (0.82+/-0.09 vs. 0.83+/-0.09; 0.84+/-0.09 vs. 0.82+/-0.09, P = 0.878). The DeltaFFR value, which is the difference between FFR values before and after adenosine administration, was also similar in diabetic and nondiabetic patients (8.4+/-6.0 vs. 8.4+/-5.5, P = 0.997). CONCLUSION: The presence of DM does not have a significant impact on FFR values in coronary stenoses of intermediate severity.