Effects of haemodialysis on maximum P wave duration and P wave dispersion.
ABSTRACT Analysing a 12-lead surface electrocardiogram (ECG), the inter-lead variability of the P wave interval, i.e. P wave dispersion, is defined as the difference between the maximum and the minimum P wave duration. Our aim was to assess the effect of haemodialysis on P wave duration and dispersion in non-diabetic patients with end-stage renal failure on chronic haemodialysis.
Twenty-eight patients (14 men and 14 women, mean age 58+/-16 years, average duration of dialysis 4.5+/-2.8 years) were examined. Prior to haemodialysis, echocardiography (M-mode and two-dimensional) was performed. Haemodialysis sessions were carried out with polysulfone dialysers and bicarbonate dialysate fluids. Twelve-lead ECGs were recorded at the beginning, 15 and 30 min after starting dialysis, at the end, and 2 h after completion of each session. Ionic parameters were checked during the study. P wave durations were measured with calipers in three consecutive complexes of each lead by one observer.
P maximum was 58+/-16 ms at the beginning, and showed an increase by the end of dialysis to 98+/-8.9 ms (P<0.0001). Pre-dialysis P dispersion was 23+/-10 ms and increased to 41+/-16 ms by the end of the sessions (P<0.0001). In patients with a left atrial diameter larger than 45 mm, P dispersion increased from 23+/-11 to 53+/-10 ms (P<0.0003) by the end of the sessions.
According to our results, ionic imbalance and dialysis itself may cause changes in P duration and dispersion simultaneously.
Article: Alterations of atrial electrophysiology induced by electrolyte variations: combined computational and P-wave analysis.[show abstract] [hide abstract]
ABSTRACT: Haemodialysis (HD) therapy represents a unique model to test in vivo, in humans, the effects of changes in plasma ionic concentrations. Episodes of paroxysmal atrial fibrillation (AF) often occur during the treatment. We investigated the effects of HD-induced electrolyte variations on atrial electrophysiology by analysing ECG P-wave duration (PWd), which reflects atrial conduction velocity (CV), and simulated atrial action potential (AP). In 20 end-stage renal disease patients PWd (signal-averaged ECG), heart rate (HR), blood pressure, Na(+), K(+), Ca(2+), and Mg(2+) plasma concentrations were measured before and after HD session. The Courtemanche computational model of human atrial myocyte was used to simulate the atrial AP. AP upstroke duration (AP(ud)), AP duration and atrial cell effective refractory period (ERP) were computed. Extracellular electrolyte concentrations and HR were imposed to the average values measured in vivo. HD decreased K(+) (from 4.9 +/- 0.5 to 3.9 +/- 0.4 mmol/L, P < 0.001) and Mg(2+) (0.92 +/- 0.08 to 0.86 +/- 0.05 mmol/L, P < 0.05), and increased Na(+) (139.8 +/- 3.4 to 141.6 +/- 3.1 mmol/L, P < 0.05) and Ca(2+) (1.18 +/- 0.09 to 1.30 +/- 0.07 mmol/L, P < 0.001) plasma concentrations. PWd systematically increased in all the patients after HD (131 +/- 11 to 140 +/- 12 ms, P < 0.001), indicating an intra-atrial conduction slowing. PWd increments were inversely correlated with K(+) variations (R = 0.73, P < 0.01). Model-based analysis indicated an AP(ud) increase (from 2.58 to 2.94 ms) after HD, coherent with experimental observations on PWd, and a reduction of ERP by 12 ms. Changes of plasma ionic concentrations may lead to modifications of atrial electrophysiology that can favour AF onset, namely a decrease of atrial CV and a decrease of atrial ERP.Europace 02/2010; 12(6):842-9. · 1.98 Impact Factor
Article: Comparison of P-wave dispersion in healthy dogs, dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction.[show abstract] [hide abstract]
ABSTRACT: P-wave dispersion (Pd) is a new ECG index used in human cardiology and veterinary medicine. It is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different ECG leads. So far no studies were performed assessing the importance of P-wave dispersion in dogs. The current study was aimed at determining proper value of Pd in healthy dogs (group I), dogs with chronic valvular disease (group II) and dogs with disturbances of supraventricular conduction (group III). The tests were carried out in 53 healthy dogs, 23 dogs with chronic valvular disease and 12 dogs with disturbances of supraventricular conduction of various breeds, sexes and body weight from 1,5 to 80 kg, aged between 0,5 and 17 years, submitted to the ECG examination. ECG was acquired in dogs in a standing position with BTL SD-8 electrocardiographic device and analyzed once the recording was enlarged. P-wave duration was calculated in 9 ECG leads (I, II, III, aVR, aVL, aVF, V1, V2, V4) from 5 cardiac cycles. The proper P-wave dispersion in healthy dogs was determined at up to 24 ms. P-wave dispersion was statistically significant increased (p<0.01) in dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction. In dogs with the atrial enlargement the P-wave dispersion is also higher than in healthy dogs, although no significant correlation between the size of left atria and Pd was noticed (p=0.1, r=0,17). The P-wave dispersion is a constant index in healthy dogs, that is why it can be used for evaluating P wave change in dogs with chronic valvular disease and in dogs with disturbances of supraventricular conduction.Acta Veterinaria Scandinavica 03/2011; 53:18. · 1.00 Impact Factor
Article: Electrocardiographic P-wave characteristics in patients with end-stage renal disease: P-index and interatrial block.[show abstract] [hide abstract]
ABSTRACT: PURPOSE: P-wave parameters including P-wave dispersion (P (d)) have been examined in general population to predict development of atrial fibrillation (AF). But data on end-stage renal disease (ESRD) population are limited. P index (Pi) and interatrial block (IAB) as novel parameters may more accurately predict AF and have not been previously investigated in ESRD patients. We aimed to evaluate these novel ECG parameters in ESRD patients. METHODS: Eighty-six HD, 47 CAPD, and 43 age- and gender-matched control subjects were enrolled in the study. P-wave duration was measured in all 12-leads of the surface ECG. The standard deviation of the P-wave duration across the 12 ECG leads was accepted as a Pi. P-wave duration above and equal to 110 ms was defined as IAB. All P-wave parameters were evaluated digitally by two observers. RESULTS: Pi was found to be significantly different among the groups in ANOVA. In post hoc analysis, P (i) was increased in HD group compared with the control group (p = 0.01). Also, P (i) tended to increase in CAPD group compared with controls (p = 0.06). The effect of ESRD on P (i) was independent of age, gender, and systolic blood pressure in univariate covariant analysis. The prevalence of IAB was 61, 55, and 32 % in patients with HD, CAPD, and controls, respectively (p = 0.001). P (d) was significantly higher in HD group compared with healthy controls. However, Pd values of CAPD patients did not show significant difference compared with controls. CONCLUSION: The present study demonstrated that IAB frequency and Pi were increased in patients with ESRD.International Urology and Nephrology 05/2012; · 1.47 Impact Factor