| 1. |
- Corino, Valentina D A, et al.
(författare)
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Circadian variation of variability and irregularity of heart rate in patients with permanent atrial fibrillation: Relation to symptoms and rate-control drugs.
- 2015
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Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 309:12, s. 2152-2157
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to evaluate the diurnal variation of the variability and irregularity of the heart rate (HR) in patients with permanent atrial fibrillation (AF), with and without rate-control drugs. Thirty-eight patients with permanent AF were part of an investigator-blind cross-over study, comparing diltiazem, verapamil, metoprolol, and carvedilol. We analyzed five Holter recordings per patient: at baseline (no rate-control drug) and with each of the four drug regimens. HR, variability (standard deviation, pNN20, pNN50, pNN80, and rMSSD) and irregularity (approximate (APEn) and sample entropy) parameters were computed in 20-minute long non-overlapping segments. Circadian rhythmicity was evaluated using the cosinor analysis to each parameter series, that is characterized by the 24-h mean (MESOR) and the excursion over the mean (the amplitude). Arrhythmia-related symptoms were assessed by a questionnaire measuring symptoms severity (SS) and frequency (SF). HR and variability parameters showed a significant circadian variation in most patients, whereas only a small minority of the patients had circadian variation of irregularity parameters. The patients with circadian ApEn at baseline had more severe symptoms (SS = 9±4 vs. 6±5, p<0.05; circadian vs. non-circadian variation). All drugs decreased the MESOR of HR and increased the MESOR of variability parameters. Only carvedilol and metoprolol decreased the normalized amplitude over the 24-h of all parameters and HR. In conclusion, HR and RR variability parameters present a circadian variation in patients with permanent AF, whereas few patients demonstrated circadian fluctuations in irregularity parameters, suggesting different physiological mechanisms.
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| 2. |
- Corino, Valentina D.A., et al.
(författare)
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Non-invasive evaluation of the effect of metoprolol on the atrioventricular node during permanent atrial fibrillation
- 2014. - January
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Ingår i: Computing in Cardiology 2014. - : Oxford University Press (OUP). - 2325-8861. - 9781479943463 - 9781479943470 ; 41, s. 889-892
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Konferensbidrag (refereegranskat)abstract
- The aim of this study was to evaluate changes in AV nodal properties during administration of metoprolol, using a novel ECG-based method for parameter estimation. The AV nodal parameters account for the probability of an impulse not passing through the fast pathway, the absolute refractory periods of the slow and fast pathways (aRPs and aRPf), representing the functional refractory period, and related prolongation in the respective refractory periods. Twenty patients (age 71±8 years, 14 men) with permanent AF from the RATe control in Atrial Fibrillation (RATAF) database were included in this study. Recordings during baseline and metoprolol administration were analyzed. Furthermore, simulated RR series were generated mimicking metoprolol administration. During metoprolol administration, aRP was significantly prolonged in both pathways (aRPs: 342±39 vs. 408±81 ms, p<0.001; aRPf: 432±74 vs. 527±83 ms, p<0.001). Similar results were found for the simulated RR series: both aRPs and aRPf were significantly prolonged with metoprolol. The AV nodal parameters reflect expected changes after metoprolol administration, i.e., a prolongation in functional refractory period. The simulations suggest that aRP may serve as an estimate of the functional refractory period.
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| 3. |
- Corino, Valentina D. A., et al.
(författare)
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Rate-Control Drugs Affect Variability and Irregularity Measures of RR Intervals in Patients with Permanent Atrial Fibrillation
- 2015
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 26:2, s. 137-141
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Tidskriftsartikel (refereegranskat)abstract
- Heart Rate Variability and Irregularity During AF IntroductionIrregularity measures have been suggested as risk indicators in patients with atrial fibrillation (AF); however, it is not known to what extent they are affected by commonly used rate-control drugs. We aimed at evaluating the effect of metoprolol, carvedilol, diltiazem, and verapamil on the variability and irregularity of the ventricular response in patients with permanent AF. Methods and ResultsSixty patients with permanent AF were part of an investigator-blind cross-over study, comparing 4 rate-control drugs (diltiazem, verapamil, metoprolol, and carvedilol). We analyzed five 20-minute segments per patient: baseline and the 4 drug regimens. On every segment, heart rate (HR) variability and irregularity of RR series were computed. The variability was assessed as standard deviation, pNN20, pNN50, pNN80, and rMSSD. The irregularity was assessed by regularity index, approximate (ApEn), and sample entropy. A significantly lower HR was obtained with all drugs, the HR was lowest using the calcium channel blockers. All drugs increased the variability of ventricular response in respect to baseline (as an example, rMSSD: baseline 171 47 milliseconds, carvedilol 229 +/- 58 milliseconds; P < 0.05 vs. baseline, metoprolol 226 +/- 66 milliseconds; P < 0.05 vs. baseline, verapamil 228 +/- 84; P < 0.05 vs. baseline, diltiazem 256 +/- 87 milliseconds; P < 0.05 vs. baseline and all other drugs). Only -blockers significantly increased the irregularity of the RR series (as an example, ApEn: baseline 1.86 +/- 0.13, carvedilol 1.92 +/- 0.09; P < 0.05 vs. baseline, metoprolol 1.93 +/- 0.08; P < 0.05 vs. baseline, verapamil 1.86 +/- 0.22 ns, diltiazem 1.88 +/- 0.16 ns). ConclusionModification of AV node conduction by rate-control drugs increase RR variability, while only -blockers affect irregularity.
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| 4. |
- Holmqvist, Fredrik, et al.
(författare)
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Abnormal atrial activation in young patients with lone atrial fibrillation.
- 2011
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092 .- 1099-5129. ; Okt, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- Aims Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal hearts. Methods and results Thirty-six patients with lone AF were included before the age of 40 years (34 ± 4 years, 34 men) and compared with age- and gender-matched control subjects. Standard 12-lead electrocardiogram (ECG) was recorded for at least 10 s. P-wave morphology and duration were estimated using signal-averaged P-wave analysis. Echocardiography was performed in association with the ECG recording. Heart rate (67 ± 13 vs. 65 ± 7 b.p.m., P = 0.800) and PQ-interval (163 ± 16 vs. 164 ± 23 ms, P = 0.629) were similar in AF cases and controls, as was P-wave duration (136 ± 13 vs. 129 ± 13 ms, P = 0.107). The distribution of P-wave morphology differed between the AF cases and controls [33/58/0/8 vs. 75/25/0/0% (Type 1/Type 2/Type 3/atypical), P = 0.001], with a larger proportion of patients with AF exhibiting signs of impaired interatrial conduction. Conclusion A significant difference in P-wave morphology distribution was seen between patients with early-onset, lone paroxysmal AF and age- and gender-matched healthy control subjects. This finding indicates that alterations in atrial electrophysiology are common in the early stage of the arrhythmia, and since it occurs in young patients without co-morbidity may well be the cause rather than the consequence of AF.
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| 5. |
- Sandberg, Frida, et al.
(författare)
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Drug effect evaluation during permanent atrial fibrillation using an AV-node model
- 2013
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Ingår i: Computing in Cardiology 2013, CinC 2013. - 9781479908844 ; 40, s. 1243-1246
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Konferensbidrag (refereegranskat)abstract
- The purpose of the present study is to evaluate the effect of rate control drugs on the AV node characteristics during atrial fibrillation (AF) using a model-based approach. A statistical model of the AV nodal function is employed, defined by parameters which characterize the arrival rate of atrial impulses, the refractoriness of the fast and the slow AV-nodal pathway and the probability of atrial impulse to pass through either of the two pathways. The RATAF (RATe control in Atrial Fibrillation) study database consists of recordings from 60 patients with permanent AF at baseline and on treatment with metoprolol, verapamil, diltiazem and carvedilol, respectively. The resulting model parameter estimates indicate that the refractory period of the slow pathway as well as that of the fast pathway increased significantly during treatment with all four drugs. The results suggest that the proposed AV-node model can be used for non-invasive evaluation of the effect of rate control drugs.
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| 6. |
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| 7. |
- Ulimoen, Sara R., et al.
(författare)
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Comparison of Four Single-Drug Regimens on Ventricular Rate and Arrhythmia-Related Symptoms in Patients With Permanent Atrial Fibrillation
- 2013
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Ingår i: American Journal of Cardiology. - : Elsevier BV. - 1879-1913 .- 0002-9149. ; 111:2, s. 225-230
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Tidskriftsartikel (refereegranskat)abstract
- Rate control of atrial fibrillation (AF) is a main treatment modality. However, data are scarce on the relative efficacy of calcium channel blockers and 13 blockers or between drugs within each class. The purpose of the present study was to compare the effect of 4 rate-reducing, once-daily drug regimens on the ventricular heart rate and arrhythmia-related symptoms in patients with permanent AF. We included 60 patients (mean age 71 +/- 9 years, 18 women) with permanent AF in an investigator-blind cross-over study. Diltiazem 360 mg/day, verapamil 240 mg/day, metoprolol 100 mg/day, and carvedilol 25 mg/day were administered for 3 weeks in a randomized sequence. The 24-hour heart rate was measured using Holter monitoring, and arrhythmia-related symptoms were assessed using the Symptom Checklist questionnaire before randomization and on the last day of each treatment period. The 24-hour mean heart rate was 96 +/- 12 beats/min at baseline (no treatment), 75 +/- 10 beats/min with diltiazem, 81 +/- 11 beats/min with verapamil, 82 +/- 11 beats/min with metoprolol, and 84 +/- 11 beats/min with carvedilol. All drugs reduced the heart rate compared to baseline (p <0.001 for all). The 24-hour heart rate was significantly lower with diltiazem than with any other drug tested (p <0.001 for all). Compared to baseline, diltiazem significantly reduced both the frequency (p <0.001) and the severity (p = 0.005) of symptoms. In contrast, verapamil reduced symptom frequency only (p = 0.012). In conclusion, diltiazem 360 mg/day was the most effective drug regimen for reducing the heart rate in patients with permanent AF. Arrhythmia-related symptoms were reduced by treatment with the calcium channel blockers diltiazem and verapamil, but not by the 13 blockers. (C) 2013 Elsevier Inc. All rights reserved. (Am J Cardiol 2013;111:225-230)
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