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AORN Journal Jul 2002The maze III procedure is a surgical treatment for atrial fibrillation (A fib), a rhythm problem in which the heart's upper chambers (i.e., atria) beat rapidly and... (Review)
Review
The maze III procedure is a surgical treatment for atrial fibrillation (A fib), a rhythm problem in which the heart's upper chambers (i.e., atria) beat rapidly and irregularly, sometimes beating more than 400 times per minute. Approximately 10% of Americans older than 60 years of age suffer from A fib. The maze procedure was designed to create a maze on the atria with multiple incisions that allow sinus rhythm to be conducted to the atrioventricular node without creating a reentry circuit. Currently, it is not a widely used procedure, but its popularity continues to increase. The maze III procedure generally is reserved as a treatment of last resort for a patient with A-fib that is unresponsive to medication therapy, electrical cardioversion, surgical ablation, or pacemaker implantation. The maze III procedure, performed as open-heart surgery, has a high success rate for sustaining normal heart rhythms, usually without the need for a pacemaker; however, all other medical and nonsurgical treatment options are exhausted before the maze III procedure is performed.
Topics: Atrial Fibrillation; Cryosurgery; Heart; Heart Atria; Humans; Patient Care Planning; Perioperative Nursing
PubMed: 12134399
DOI: 10.1016/s0001-2092(06)61101-0 -
Pacing and Clinical Electrophysiology :... Jun 2024New antithrombotic medications and improved stent designs have reduced branch occlusion, although the sino-atrial nodal artery (SANA) may still be occluded after a... (Review)
Review
BACKGROUND
New antithrombotic medications and improved stent designs have reduced branch occlusion, although the sino-atrial nodal artery (SANA) may still be occluded after a percutaneous coronary intervention (PCI), causing sinus node dysfunction (SND). Ischemic sinus nodes are usually asymptomatic but can cause sinus arrest sometimes requiring pacemaker placement. In rare cases, junctional escape rhythms, a manifestation of sinus exit blocks after PCI, can predict cardiogenic shock.
METHODS
We present a case study of a patient who underwent bifurcation PCI to the LMCA to the LCX but subsequently developed cardiogenic shock as a result of SND, a junctional escape rhythm required substantial inotropic support. This case offers an exemplification of a sparsely documented, yet infrequent manifestation of iatrogenic ischemic SND at an unorthodox site, the confluence of the LMCA-LCX. In addition, we conducted a comprehensive analysis of 22 scholarly works pertaining to the subject of sinus node dysfunction (SND) subsequent to PCI resulting from ischemia caused by stenosis or occlusion of the SANA.
RESULTS
RCA was responsible for 96.1% of SND cases, whereas LCX was responsible for 3.9%. SND was asymptomatic in 49.3% of cases and junctional escape rhythm in 37.6% of symptomatic cases. 28% needed a temporary transvenous pacemaker, while 7.8% needed a permanent one. Interventional management recanalized the SANA in 5.2% of patients, restoring flow.
CONCLUSION
Transient sino-atrial node ischemia after PCI can cause acute SND. Before stent implantation, doctors should consider SND. Complete plaque evaluation around the SANA is needed before choosing the best PCI procedure.
PubMed: 38923028
DOI: 10.1111/pace.15029 -
Computers in Biology and Medicine Feb 2017A phenomenological model for simulating the photoplethysmogram (PPG) during atrial fibrillation (AF) is proposed. The simulated PPG is solely based on RR interval...
A phenomenological model for simulating the photoplethysmogram (PPG) during atrial fibrillation (AF) is proposed. The simulated PPG is solely based on RR interval information, and, therefore, any annotated ECG database can be used to model sinus rhythm, AF, or rhythms with premature beats. A PPG pulse is modeled by a linear combination of a log-normal and two Gaussian waveforms. The model PPG is obtained by placing individual pulses according to the RR intervals so that a connected signal is created. The model is evaluated on synchronously recorded ECG and PPG signals from the MIMIC and the University of Queensland Vital Signs Dataset databases. The results show that the model PPG signals closely resemble real signal for sinus rhythm, premature beats, as well as for AF. The model is used to study the performance of a low-complexity RR interval-based AF detector on simulated PPG signals with five different pulse types generated using the MIT-BIH AF database at signal-to-noise ratios (SNRs) from 0 to 30dB. PPGs composed of pulses with a dicrotic notch tend to increase the rate of false alarms, especially at lower SNRs. The model is capable of generating simulated PPG signals from RR interval series with sinus rhythm, AF, and premature beats. Considering the lack of annotated, public PPG databases with arrhythmias, the simulation of realistic PPG signals based on annotated ECG signals is expected to facilitate the development and testing of PPG-specific AF detectors.
Topics: Algorithms; Atrial Fibrillation; Computer Simulation; Electrocardiography; Heart Rate; Heart Rate Determination; Humans; Models, Cardiovascular; Models, Statistical; Photoplethysmography; Reproducibility of Results; Sensitivity and Specificity
PubMed: 28061368
DOI: 10.1016/j.compbiomed.2016.12.016 -
Heart Rhythm Dec 2020The 3-dimensional (3D) nature of sinoatrial node (SAN) function has not been characterized in the intact human heart.
BACKGROUND
The 3-dimensional (3D) nature of sinoatrial node (SAN) function has not been characterized in the intact human heart.
OBJECTIVE
The purpose of this study was to characterize the 3D nature of SAN function in patients with structural heart disease (SHD) using simultaneous endocardial-epicardial (endo-epi) phase mapping.
METHODS
Simultaneous intraoperative endo-epi SAN mapping was performed during sinus rhythm at baseline (SR) and postoverdrive suppression at 600 ms (SR) and 400 ms (SR) using 2 Abbott Advisor HD Grid Mapping Catheters. Unipolar and bipolar electrograms (EGMs) were exported for phase analysis to determine (1) activation exits; (2) wavefront propagation sequence; (3) endo-epi dissociation; and (4) fractionation. Comparison of these variables was made among the 3 rhythms from an endo-epi perspective.
RESULTS
Sixteen patients with SHD were included. SR activations were unicentric and predominantly exited cranially (87.5%) with endo-epi synchrony. However, with overdrive suppression, a tendency for caudal exit shift and endo-epi asynchrony was observed: SR vs SR: cranial endo 75% vs 87.5% (P = .046); cranial epi 68.8% vs 87.5% (P = 0.002); caudal endo 12.5% vs 6.2% (P = 0.215); caudal epi 25% vs 6.2% (P = .0003); and SR vs SR: cranial endo 81.3% vs 87.5% (P = 0.335); cranial epi 68.7% vs 87.5% (P = 0.0034; caudal endo 12.5% vs 6.2% (P = .148); caudal epi 31.2% vs 6.2% (P = 0.0017), consistent with multicentricity. EGM fractionation was more prevalent with overdrive suppression.
CONCLUSION
During mapping of the intact human heart, SAN demonstrated redundancy of sinoatrial exits with postoverdrive shift in sites of earliest activation and epi-endo dissociation of sinoatrial exits.
Topics: Epicardial Mapping; Female; Follow-Up Studies; Heart Diseases; Heart Rate; Humans; Male; Middle Aged; Sinoatrial Node
PubMed: 32622994
DOI: 10.1016/j.hrthm.2020.06.034 -
Effect of presenting rhythm on image integration to direct catheter ablation of atrial fibrillation.Journal of Interventional Cardiac... Sep 2008Magnetic resonance (MR) imaging of the left atrium (LA) can be integrated with electroanatomic mapping systems to guide catheter ablation of atrial fibrillation (AF).... (Clinical Trial)
Clinical Trial
INTRODUCTION
Magnetic resonance (MR) imaging of the left atrium (LA) can be integrated with electroanatomic mapping systems to guide catheter ablation of atrial fibrillation (AF). The usefulness of this technique is dependent on the accuracy of image integration.
OBJECTIVE
The aim of this study is to determine the effect of heart rhythm at the time of pre-procedure MR imaging and heart rhythm at the time of ablation on integration error.
METHODS
Fifty-two consecutive patients who underwent catheter ablation for AF were included. All patients underwent MR imaging of LA and pulmonary veins and image integration with real-time electroanatomic mapping. The rhythm at the time of MR imaging and on the day of ablation was recorded. CARTO-Merge software (Biosense-Webster) was used to calculate the average accuracy of integration of electroanatomic points with MR-derived reconstructions.
RESULTS
There was no significant difference in integration error between patients who were in AF at the time of their MR vs. those who were in sinus rhythm at the time of their MR (1.76 +/- 0.26 vs. 1.88 +/- 0.31 mm, p = 0.15). There was also no significant difference in integration error between patients who were in concordant vs. discordant rhythms at the time of MR vs. day of ablation (1.81 +/- 0.23 vs. 1.89 +/- 0.32 mm, p = 0.40). There was a trend toward less integration error between patients who were in AF on the day of ablation vs. those in sinus rhythm (1.74 +/- 0.26 vs. 1.89 +/- 0.31 mm, p = 0.07).
CONCLUSIONS
Image integration can be performed to direct catheter ablation of AF regardless of the rhythm at the time of imaging and ablation.
Topics: Adult; Aged; Atrial Fibrillation; Body Surface Potential Mapping; Catheter Ablation; Female; Humans; Magnetic Resonance Spectroscopy; Male; Middle Aged; Subtraction Technique; Surgery, Computer-Assisted; Treatment Outcome; Young Adult
PubMed: 18506606
DOI: 10.1007/s10840-008-9265-7 -
Journal of Electrocardiology 2007More than 100 million computer-interpreted electrocardiograms (ECG-C) are obtained annually. However, there are few contemporary published data on the accuracy of...
BACKGROUND
More than 100 million computer-interpreted electrocardiograms (ECG-C) are obtained annually. However, there are few contemporary published data on the accuracy of cardiac rhythm interpretation by this method.
PURPOSE
The purpose of this study is to determine the accuracy of ECG-C rhythm interpretation in a typical patient population.
METHODS
We compared the ECG-C rhythm interpretation to that of 2 expert overreaders in 2112 randomly selected standard 12-lead ECGs.
RESULTS
The ECG-C correctly interpreted the rhythm in 1858 and incorrectly identified the rhythm in 254 (overall accuracy, 88.0%). Sinus rhythm was correctly interpreted in 95.0% of the ECGs (1666/1753) with this rhythm, whereas nonsinus rhythms were correctly interpreted with an accuracy of only 53.5% (192/359) (P < .0001). The ECG-C interpreted sinus rhythm with a sensitivity of 95% (confidence interval, 93.8-96.7), specificity of 66.3%, and positive predictive value of 93.2%. The ECG-C interpreted nonsinus rhythms with a sensitivity of 72%, (confidence interval, 68.7-73.7), a specificity of 93%, and a positive predictive value of 59.3%. Of the 254 ECGs that had incorrect rhythm interpretation, additional major errors were noted in 137 (54%).
CONCLUSIONS
The ECG-C demonstrates frequent errors in the interpretation of nonsinus rhythms. In addition, incorrect rhythm interpretation by the ECG-C was frequently further compounded by additional major inaccuracies. Expert overreading of the ECG remains important in clinical settings with a high percentage of nonsinus rhythms.
Topics: Arrhythmias, Cardiac; Artifacts; California; Diagnosis, Computer-Assisted; Electrocardiography; Humans; Observer Variation; Quality Assurance, Health Care; Reproducibility of Results; Retrospective Studies; Sensitivity and Specificity
PubMed: 17531257
DOI: 10.1016/j.jelectrocard.2007.03.008 -
Frontiers in Bioscience (Landmark... Jun 2010Circadian rhythms are known for locomotory and reproductive behaviours, and the functioning of sensory organs, nervous structures, metabolism and developmental... (Review)
Review
Circadian rhythms are known for locomotory and reproductive behaviours, and the functioning of sensory organs, nervous structures, metabolism and developmental processes. The mechanisms and cellular bases of control are mainly inferred from circadian phenomenologies, ablation experiments and pharmacological approaches. Cellular systems for regulation summarised here comprise the retina, the eyestalk neuroendocrine X-organ-sinus gland system, several neuropeptides such as red pigment concentrating, hyperglycaemic and pigment-dispersing hormones, and factors such as serotonin and melatonin. No master clock has been identified, but a model of distributed clockwork involves oscillators such as the retinular cells, neurosecretory systems in the optic lobes, putative brain pacemakers, and the caudal photoreceptor. Extraretinal brain photoreceptors mediate entrainment. Comparative analyses of clock neurons and proteins known from insects may allow the identification of candidate clock neurons in crustaceans as putative homologues in the two taxa. Evidence for the existence of "insect-like" intracellular clock proteins and (light sensitive) transcription factors is scarce, but clock-, period-, and cryptochrome-gene products have been localised in the CNS and other organs rendering further investigations into crustacean clockwork very promising.
Topics: Animals; Biological Clocks; Brain; Circadian Rhythm; Circadian Rhythm Signaling Peptides and Proteins; Crustacea; Models, Biological; Neurons; Photoreceptor Cells, Invertebrate
PubMed: 20515741
DOI: 10.2741/3661 -
European Journal of Radiology Sep 2012To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG...
PURPOSE
To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT).
MATERIALS AND METHODS
An ECG simulator (EKG Phantom 320, Müller & Sebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mAs; 0.4s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined.
RESULT
Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p<0.05) were bifocal pacemaker (61%), pacemaker dysfunction (22%), SVES (20%), ventricular salvo (20%), and atrial fibrillation (14%). Significantly (p<0.05) prolonged scan time (>8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s).
CONCLUSION
In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols.
Topics: Arrhythmias, Cardiac; Body Burden; Cardiac-Gated Imaging Techniques; Computer Simulation; Heart Rate; Humans; Models, Cardiovascular; Phantoms, Imaging; Radiation Dosage; Radiometry; Tomography, X-Ray Computed
PubMed: 22019599
DOI: 10.1016/j.ejrad.2011.09.019 -
European Heart Journal Feb 1987To determine the type and frequency of supraventricular arrhythmias in patients with mitral stenosis and sinus rhythm we studied 63 such patients, mean (sd) age 48.8...
To determine the type and frequency of supraventricular arrhythmias in patients with mitral stenosis and sinus rhythm we studied 63 such patients, mean (sd) age 48.8 (8.2) years, by 24 hour ambulatory ECG monitoring. Thirty-five patients (55.6%) had supraventricular tachyarrhythmias. Twenty-five (39.7%) had paroxysmal atrial tachycardia, 14 (22.2%) atrial fibrillation, 8 (12.7%) multifocal atrial tachycardia and 5 atrial flutter. Ninety-five per cent (101) of episodes were asymptomatic and 96% non-sustained. Supraventricular premature beats occurred in 59 patients with couplets and triplets in 40 (63.5%) and 28 (44.4%), respectively. Frequent supraventricular premature beats, couplets, triplets and episodes of paroxysmal arrhythmias were commoner in patients greater than 50 years. Ectopic atrial rhythms with varying P wave morphology occurred in 12 patients (19%). Nine patients (14.3%) had suffered systemic embolic episodes. We conclude that supraventricular ectopic and tachyarrhythmias occur frequently in patients with mitral stenosis and sinus rhythm and that most paroxysms are non-sustained and asymptomatic.
Topics: Adult; Ambulatory Care; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Flutter; Cardiac Complexes, Premature; Electrocardiography; Female; Humans; Male; Middle Aged; Mitral Valve Stenosis; Monitoring, Physiologic; Tachycardia; Tachycardia, Ectopic Atrial; Tachycardia, Supraventricular
PubMed: 2436916
DOI: 10.1093/oxfordjournals.eurheartj.a062244 -
Journal of Electrocardiology 1998A new microprocessor-assisted cardiac rhythm algorithm (MAC-RHYTHM), based on median QRST subtraction from 10-second electrocardiographic (ECG) data, was prospectively...
A new microprocessor-assisted cardiac rhythm algorithm (MAC-RHYTHM), based on median QRST subtraction from 10-second electrocardiographic (ECG) data, was prospectively tested on 10,761 ECGs acquired at one of three clinical centers. Atrial waves (P waves, atrial fibrillatory waves, and flutter waves) were detected from the median QRST-subtracted residual signals. Rhythm criteria were applied to the detected atrial waves and their temporal relation to QRS complexes for generating rhythm interpretations. Rhythm statements generated by MAC-RHYTHM were compared against the true rhythm of the ECGs as read by an experienced cardiologist. The results of prospective testing were compared with the results of an earlier retrospective testing using MAC-RHYTHM and a released commercial ECG analysis program on stored ECGs. The prospective results were very similar to the results of MAC-RHYTHM on retrospective data for all the rhythms examined (sinus rhythms, atrial fibrillation, atrial flutter, junctional rhythms, second degree atrioventricular blocks). For three of the abnormal rhythms, namely, atrial fibrillation, junctional rhythms, and second degree atrioventricular blocks, MAC-RHYTHM gave significantly higher sensitivity in both prospective (87.5%, 92.2%, and 80.8%, respectively) and retrospective (82.0%, 81.2%, and 79.6% respectively) testing than the released commercial ECG analysis program (65.0%, 39.6%, and 12.0% respectively). Similarly, for sinus rhythms, MAC-RHYTHM had significantly higher specificity (prospective, 91.0% and retrospective, 91.7%) than the released commercial program (86.5%). The specificity for the abnormal rhythms remained very high with MAC-RHYTHM (prospective, 99.4% to 99.7% and retrospective, 99.1% to 99.7%) compared to the released commercial program (99.0% to 99.9%). This prospective study also indicated that further work is needed to improve the detection of pacemaker spikes and the interpretation of paced rhythms in 10-second resting ECGs.
Topics: Arrhythmias, Cardiac; Diagnosis, Computer-Assisted; Electrocardiography; Heart Atria; Humans; Predictive Value of Tests; Prospective Studies; Retrospective Studies; Sensitivity and Specificity; Signal Processing, Computer-Assisted
PubMed: 9535477
DOI: 10.1016/s0022-0736(98)80016-2