A smooth pseudo Wigner-Ville distribution was employed to investigate both time and frequency characteristics in a very low-frequency component (less than 0.04 Hz) of 24-hour heart rate fluctuation. In some cases of heart failure the authors could see remarkable and very low-frequency oscillations of the Wigner-Ville distribution, which are related to Cheyne-Stokes respiration. However the Wigner-Ville distribution of normal subjects did not have such oscillations, but more random spectral characteristics instead. Furthermore, the authors calculated 1/f/sup /spl alpha// regression slopes of average spectrum to be a crude estimate of fractal dimensions. The slopes are more negative in heart failure patients than normals (-1.866/spl plusmn/0.888 vs. -0.957/spl plusmn/0.180 p<0.005), which associates a loss of dimensionality of heart rate fluctuation in heart failure.
Patients with severe kidney function impairment often have autonomic dysfunction, which could be evaluated noninvasively by heart rate variability (HRV) analysis. Nonlinear HRV parameters such as detrended fluctuation analysis (DFA) has been demonstrated to be an important outcome predictor in patients with cardiovascular diseases. Whether cardiac autonomic dysfunction measured by DFA is also a useful prognostic factor in patients with end-stage renal disease (ESRD) receiving peritoneal dialysis (PD) remains unclear. The purpose of the present study was designed to test the hypothesis.Patients with ESRD receiving PD were included for the study. Twenty-four hour Holter monitor was obtained from each patient together with other important traditional prognostic makers such as underlying diseases, left ventricular ejection fraction (LVEF) and serum biochemistry profiles. Short-term (DFAα1) and long-term (DFAα2) DFA as well as other linear HRV parameters were calculated.A total of 132 patients (62 men, 72 women) with a mean age of 53.7±12.5 years were recruited from July 2007 to March 2009. During a median follow-up period of around 34 months, eight cardiac and six non-cardiac deaths were observed. Competing risk analysis demonstrated that decreased DFAα1 was a strong prognostic predictor for increased cardiac and total mortality. ROC analysis showed that the AUC of DFAα1 (<0.95) to predict mortality was 0.761 (95% confidence interval (CI). = 0.617-0.905). DFAα1≧ 0.95 was associated with lower cardiac mortality (Hazard ratio (HR) 0.062, 95% CI = 0.007-0.571, P = 0.014) and total mortality (HR = 0.109, 95% CI = 0.033-0.362, P = 0.0003).Cardiac autonomic dysfunction evaluated by DFAα1 is an independent predictor for cardiac and total mortality in patients with ESRD receiving PD.
The role of radiofrequency catheter ablation (RFCA) of supraventricular tachycardia (SVT) in infants and toddlers is still unclear.From 1993 to 2006, 27 (17 males, 10 females) of 210 patients underwent RFCA at an age less than 6 years. Indications included drug-refractory SVT or tachycardia-induced cardiomyopathy. The medical records were reviewed and the patients were interviewed regarding their current status. The 27 patients underwent RFCA at a median age of 4.4 years (8 months to 5.9 years) and a median body weight of 15 kg (6.6-30 kg). The SVT was mainly atrioventricular reentry tachycardia (15/27) and multiple mechanisms in 3. One-third of them had associated congenital heart disease, and 5 underwent RFCA using only 2-3 catheters. Immediate success rate was 92.6%, with low early (3.7%) and late recurrence (7.4%) after 5.4 +/-3.7 years follow-up. Tachycardia-induced cardiomyopathy was noted in 4 and resolved in all after RFCA. Procedure-related complications included complete atrioventricular block in 1 and Bezold-Jarisch reflex in another. No other risk factors for outcomes were noted, even with low body weight.The outcome of RFCA for medically refractory SVT, even associated with tachycardia-induced cardiomyopathy, in infants and toddlers is favorable.
The P wave in the surface ECG represents atrial electrical activation and may be altered in certain pathological conditions. Atrial compartment operation has been used to convert chronic AF to sinus rhythm. However, this procedure may result in changes of impulse conduction in various atrial compartments and alters the P wave morphology. This study sought to elucidate the P wave changes after the atrial compartment operation for AF. Fifteen patients undergoing the atrial compartment operation for chronic AF were studied. In the operation, the atrium was divided into three compartments, namely the left atrium, the atrial septum including sinus and AV nodes, and the right atrial compartment. The anatomic connection between adjacent compartments were preserved at the posterior lower margin of incisions. The surface lead P waves were correlated with intracardiac recording and stimulation in various atrial compartments. Fifteen age‐ and sex‐matched control patients without structural heart diseases were compared. The results showed that patients undergoing the atrial compartment operation had a prolonged P wave duration ( 190 ± 27 vs 95 ± 14 ms, P < 0.001 ), a prolonged PR interval ( 207 ± 23 vs 155 ± 20 ms, P < 0.001 ), and a shortened PR segment ( 17 ± 19 vs 60 ± 17 ms, P < 0.001 ). The increase in P wave duration was primarily due to a conduction delay from the sinus node to the other atrial compartments as the conduction time from the high right atrium to the right atrial appendage was 132 ± 57 ms (vs 21 ± 6 ms for control, P < 0.001 ), and the conduction time from the high right atrium to the distal coronary sinus was 140 ± 55 ms (vs 70 ± 15 ms, P < 0.001 ). However, the conduction from the high right atrium to the low septal right atrium, which were located in the same compartment, was not impaired. Also, the conduction in the AV node and His‐Purkinje system were not impaired. The mean axis of P waves varied greatly, but was not statistically different from that of the control group ( 60 ± 48° vs 52 ± 18° , P > 0.05 ). Although the patients undergoing atrial compartment operation had a larger left atrial size, their P wave amplitude was smaller ( 1.0 ± 0.3 vs 1.3 ± 0.3 mm, P < 0.01 ), and an increased negative terminal force in V 1 was not seen ( 0.02 ± 0.02 vs 0.02 ± 0.01 mm/s, P > 0.05 ). Alteration in P wave morphology was seen in 14 patients. All the P waves showed a biphasic configuration with an initial positive and a terminal slurred negative deflection in leads II, III, and aVF. The terminal components represented the activation of right atrial appendage in 5 patients, the left atrium in 1, and the combined activation of right atrial appendage and the left atrium in 8 patients. The P wave morphology suggested that activation of both the right atrial appendage and the left atrial compartments proceeded in a caudocranial direction as a result of the atrial incisions. In conclusion, atrial compartment operation altered the conduction time and direction in the atria and resulted in characteristic P wave changes. (PACE 2003; 26:1864–1872)
Heart rate recovery (HRR) is a marker for survival. Little is known about the association between HRR and metabolic risks in healthy children or adolescents.We examined 993 healthy children and adolescents aged 12-19 years with reliable measures of cardiovascular fitness from the National Health and Nutrition Examination Survey 1999-2002. HRR parameters 1-3 min after exercise were calculated from exercise test results. Anthropometric and metabolic risk factors as well as metabolic Z score were obtained.The HRR parameters were inversely correlated with most of the metabolic risks, including waist circumference, systolic blood pressure (SBP), serum triglycerides, and serum C-reactive protein (CRP) levels, and were positively correlated with serum HDL levels. In multiple linear regression analysis, among the metabolic risks, waist circumference was the only parameter associated with HRR parameters (P = 0.038, 0.001, and 0.001 for 1-, 2-, and 3-min HRR, respectively) in boys. In girls, waist circumference (P = 0.001 and <0.001 for 2- and 3-min HRR, respectively), SBP (P = 0.029 for 1-min HRR), serum glucose (P = 0.021 for 2-min HRR), and serum CRP (P = 0.007 for 2-min HRR) levels were the most important determinants of HRR parameters. The adjusted 1-min HRR did not change across four quartiles of metabolic Z score, while the adjusted 3-min HRR decreased significantly with four quartiles of metabolic Z score.Metabolic risks are inversely associated with HRR in healthy children and adolescents. Our finding suggests that there is a link between metabolic risks and autonomic nervous system functions in healthy young ages.
Abstract Approximately 70% of survivals of out-of-hospital cardiac arrest (OHCA) have coronary artery disease, with acute vessel occlusion observed in 50%. Predictors of mortality in acute myocardial infarction (AMI) patients successfully resuscitated for OHCA were not well-determined. Between May, 2016 and July, 2018, 1428 consecutive patients with OHCA visited the emergency department of Far Eastern Memorial Hospital, New Taipei City, Taiwan. A total number of 117 patients with return-of-spontaneous-circulation (ROSC) were diagnosed of AMI, mostly confirmed by coronary angiography. The mean age was 60.0±13.6 (mean SD) with male gender 105/117. Endpoint was survival to discharge. The survival rate was 55.6%. Shockable rhythm (Ventricular tachycardia or fibrillation) during CPR (correlation coefficient, CC: 0.635; p<0.001), ST elevation myocardial infarction (CC: 0.550; p=0.003), sinus rhythm on first ECG (CC: 0.474; p=0.012) and higher HDL (CC: 0.471; p=0.0027) were associated better outcome (survival and neurological recovery). However, older age (CC: −0.564; p=0.002), ST depression on first ECG post resuscitation (CC: −0.481; p=0.011), hyperglycemia (CC: −0.419; p=0.030), higher HbA1C level (CC: −0.569; p=0.007), and hyperkalemia (CC: −0.612; p=0.001) were associated with worse outcome (Mortality). In conclusion, in the AMI patients presenting with OHCA after ROSC, unshockable rhythm during CPR, older age, non-sinus rhythm and ST segment depression on first ECG post resuscitation, hyperglycemia, higher HbA1C level, lower HDL level, and hyperkalemia were associated with higher hospital mortality.
'/%3e%3cuse xlink:href='%23a' transform='rotate(60)'/%3e%3ccircle r='17' fill='%23000095'/%3e%3ccircle r='15' fill='%23fff'/%3e%3c/svg%3e)
