BIFURCATIONS IN HEART RHYTHMS

1995 ◽  
Vol 05 (06) ◽  
pp. 1439-1486 ◽  
Author(s):  
TERESA REE CHAY
Keyword(s):  
Current Pulse ◽  
Antiarrhythmic Drugs ◽  
Sinus Node ◽  
Period Doubling ◽  
Rhythmic Activity ◽  
Class Iii ◽  
History Of ◽  
Reentrant Arrhythmia ◽  
The Right ◽  
Doubling Sequence

Heart rhythms exhibit the following interesting phenomena: First, rhythmic cells such as sinus node cells cease their rhythmic activity when a single brief current pulse of the right magnitude is given to the cell at the right time. Second, a premature pulse can initiate a tachycardia (i.e., reentrant arrhythmia) from a quiescent atrial tissue. This tachycardia can be sustained for hours until another brief current pulse is given. Third, ECG recording sometimes shows alternans in electrical activity prior to ventricular tachycardia. Some suggested that this alternans is the first bifurcation in a period doubling sequence. Fourth, a certain class of antiarrhythmic drugs may increase the chance of sudden cardiac death for patients with a history of myocardial infarction. Fifth, when an "adjustable" tricuspid ring is shortened, the conduction velocity of a reentrant wave becomes oscillatory. When the ring size is shortened further, reentry terminates after several oscillatory cycles. Sixth, sustained reentry arises in a tricuspid ring when Class IC drugs (i.e., which exclusively block the sodium channel) are added. On the other hand, Class III (which exclusively blocks the potassium channel) can terminate sustained reentry in the tricuspid ring. In this tutorial review, we explain how one can utilize a bifurcation analysis to explain all these interesting phenomena involved in heart rhythms.

scholarly journals Correction of severe facial asymmetry: A case with fractured condyle

2019 ◽  
Vol 9 ◽  
pp. 59-64
Author(s):  
Ramesh Agrawal ◽  
Dolly P. Patel ◽  
Bhagyashree B. Desai
Keyword(s):  
Facial Asymmetry ◽  
Post Treatment ◽  
Radiographic Examination ◽  
Rigid Fixation ◽  
Class Iii ◽  
Class Iii Malocclusion ◽  
History Of ◽  
Condylar Head ◽  
The Stability ◽  
The Right

The current paper depicts the challenges faced during the treatment of a complicated case of mandibular condylar head fracture, facial asymmetry, and centric relation-centric occlusion (CR-CO) discrepancy along with Class III malocclusion. A 20-year-old female reported with the chief complaint of difficulty in chewing and concern with her appearance due to deviated jaw and had a history of trauma over chin region. The clinical and radiographic examination revealed significant facial asymmetry with long face, right-sided deviation of the mandible, fractured condyle, CR-CO discrepancy, cross- bite with Class III malocclusion, and a missing mandibular single incisor along with non-vital 21 and 22. She was treated with 0.022 MBT appliance along with guiding plane for CR-CO correction followed by asymmetric bilateral sagittal split osteotomy and differential set back on the right and left sides and finally rigid fixation. A good facial profile and functional occlusion were achieved and non-vital 21 and 22 were esthetically rehabilitated with PFM crowns. The stability of surgical as well as orthodontic corrections was excellent and appreciable in the records obtained 2-year post-treatment. When faced with mutilated malocclusion, with multiple problems, sequential correction of functional malocclusion with dental decompensation followed by skeletal correction with surgical approach has yielded a appreciable facial correction with good stability showing 2-year post-treatment follow-up.

P1096Cardioneuroablation changes the type of vaso-vagal response in patients with asystolic reflex syncope

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
R Piotrowski ◽  
A Zuk ◽  
J Baran ◽  
A Sikorska ◽  
T Krynski ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Postgraduate Medical Education ◽  
Sinus Node ◽  
Pacemaker Implantation ◽  
Heart Rate Variability Parameter ◽  
History Of ◽  
The Right ◽  
The Impact

Abstract Funding Acknowledgements Centre of Postgraduate Medical Education No. 501-1-10-14-19 Background. Cardioneuroablation (CNA) - ablation of ganglionated plexi (GP) to eliminate or reduce parasympathetic overactivity, has been recently proposed as a new therapeutic method in patients with vaso-vagal syncope (VVS) due to cardioinhibitory or mixed mechanism. Purpose. To assess the impact of CNA on the type of VV response during tilt testing (TT). Methods. The study group consisted of the first 20 patients (7 males, mean age 38 ± 9 – year – old) enrolled in the ongoing prospective Roman study (NCT 03903744). All patients had a history of ECG documented syncope due to asystole and confirmed asystolic form of VVS at baseline TT. CNA was performed using electroanatomical system Carto 3 and radiofrequency applications delivered in the right and left atrium at the right anterior GP and right inferior GP sites. The second TT was performed three months later. Resting heart rate (HR) and heart rate variability parameter (SDDN) were also assessed. Results. At baseline TT, nineteen patients had cardioinhibitory syncope (asystole ranging from 3 to 60 s)  (sinus node arrest – 17 patients, A-V block – 2 patients) and 1 had mixed form of VVS (asystole lasting 3 s preceded by hypotension). During three-month follow-up no syncopal episodes were noted. At the 3-month TT, 6 (30 %) patients had no syncope whereas the remaining 13 (65 %)  had syncope – twelve (60 %) due to vasodepressor mechanism and only one (5 %) due to asystole - as before CNA. One patient did not have TT because of pregnancy. Mean resting HR after CNA was significantly faster and SDNN significantly lower than before the procedure (82 ± 9 vs 69 ± 11 beats/min, p = 0.0004 and 74 ± 22 vs 143 ± 40 ms, p = 0.00003, respectively) and these changes were was similar in those who fainted during second TT and those who did not (82 ± 11 vs 81 ± 4 beats/min, p = NS and (75 ± 2 vs 77 ± 18 ms, p = NS, respectively). Conclusions. CNA profoundly affects the type of VV reaction causing normalization of the response to tilting or changing cardiodepression to vasodepression. These effects are also depicted by changes in HR and heart rate variability. Elimination of TT-induced reflex asystole may prevent clinical recurrences of syncope during short-term follow-up. These findings encourage to conduct further studies involving CNA since this method appears to be effective and obviates the need for pacemaker implantation in young people with reflex asystolic syncope.

scholarly journals Functional Treatment of an Asymmetry Case Having Left Side Paralysis: A Case Report

2010 ◽  
Vol 04 (03) ◽  
pp. 341-347
Author(s):  
Meliha Rubenduz ◽  
Ozge Uslu
Keyword(s):  
Case Report ◽  
Facial Asymmetry ◽  
Class Iii ◽  
Herpes Encephalitis ◽  
Acrylic Plate ◽  
Total Treatment ◽  
History Of ◽  
Smile Esthetics ◽  
The Right ◽  
Removable Appliance

This case report presents the results of functional and myofunctional treatment of a 9-year, 5-month-old male patient with laterognathy, facial asymmetry and dentofacial deformity. The patient had a history of herpes encephalitis at age 8.5 months and palsy on the left side in early childhood, and his left side remained paralyzed as a sequela. The patient had dentoalveolar asymmetry with a Class I right and Class III left canine relation, a 1.5 mm midline deviation, anterior cross-bite, an overjet of -3 mm and an overbite of 3 mm. The dentoalveolar and facial asymmetries were corrected using a modified removable appliance, with an acrylic vestibular shield inserted on the right side to guide the mandible in the upper arch and an acrylic plate with artificial teeth in the lower arch. The patient was instructed to practice myofunctional exercises regularly. In total, treatment, including observation, was completed in a period of 2 years and 10 months, at which time, a marked correction in facial asymmetry and profile and improvement in smile esthetics could be observed. (Eur J Dent 2010;4:341-347)

scholarly journals Class III malocclusion with maxillary deficiency, mandibular prognathism and facial asymmetry

2016 ◽  
Vol 21 (5) ◽  
pp. 103-113 ◽  
Author(s):  
Guilherme de Araújo Almeida ◽  
Keyword(s):  
Facial Asymmetry ◽  
Class Iii ◽  
Class Iii Malocclusion ◽  
Mandibular Ramus ◽  
Surgical Interventions ◽  
History Of ◽  
Maxillary Constriction ◽  
The Right ◽  
Dentofacial Orthopedics ◽  
Maxillary Deficiency

ABSTRACT This article reports the clinical case of a female patient with history of unsuccessful orthodontic treatment. She presented with Class III malocclusion, mandibular and maxillary constriction, anterior crossbite and facial asymmetry resulting from laterognathism triggered by hyperactivity of the condyle revealed by vertical elongation of the right mandibular ramus. Patient's treatment consisted of orthodontic mechanics and two orthognathic surgical interventions with satisfactory and stable outcomes. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO), as part of the requirements for obtaining the BBO Diplomate title.

SIMULATION OF SINUS NODE ACTIVITY BY AN ELECTRONIC RELAXATION OSCILLATOR

1966 ◽  
Vol 44 (2) ◽  
pp. 301-315 ◽  
Author(s):  
F. A. Roberge ◽  
R. A. Nadeau
Keyword(s):  
Sinus Node ◽  
Relaxation Oscillator ◽  
Rhythmic Activity ◽  
Electronic Relaxation ◽  
Node Activity ◽  
Relaxation Oscillators ◽  
Ventricular Response ◽  
Sinus Node Activity ◽  
The Right ◽  
Intact Heart

After the sinus node was destroyed, its rhythmic activity was simulated by an electronic relaxation oscillator coupled to the beating heart. The output of the oscillator was used to stimulate the right atrium, and the ventricular response was returned to the input of the relaxation oscillator. By manually varying the frequency of this artificial pacemaker it was possible to produce changes in the rate of the atrio–ventricular (A–V) node similar to those obtained by perfusion of the intact sinus node with chronotropic agents. Particular attention was paid to the transitions from "oscillator" rhythm to A–V nodal rhythm, and vice versa. The results provide support for the following hypotheses relative to the intact heart: (i) some form of sinus node activity persists during A–V nodal rhythm, and (ii) the principal pacemakers of the heart, the sinus and A–V nodes, behave as a system of coupled relaxation oscillators.

Z-line degradation and phagocytosis of sarcomeric fragments in myonecrosis

1983 ◽  
Vol 41 ◽  
pp. 790-791
Author(s):  
Melinda L. Estes ◽  
Samuel M. Chou
Keyword(s):  
Vastus Lateralis ◽  
Inflammatory Myopathy ◽  
Muscle Disease ◽  
White Female ◽  
Inflammatory Cell Infiltrate ◽  
Limb Weakness ◽  
Muscle Diseases ◽  
History Of ◽  
The Right ◽  
Mononuclear Inflammatory Cell

Many muscle diseases show common pathological features although their etiology is different. In primary muscle diseases a characteristic finding is myofiber necrosis. The mechanism of myonecrosis is unknown. Polymyositis is a primary muscle disease characterized by acute and subacute degeneration as well as regeneration of muscle fibers coupled with an inflammatory infiltrate. We present a case of polymyositis with unusual ultrastructural features indicative of the basic pathogenetic process involved in myonecrosis.The patient is a 63-year-old white female with a one history of proximal limb weakness, weight loss and fatigue. Examination revealed mild proximal weakness and diminished deep tendon reflexes. Her creatine kinase was 1800 mU/ml (normal < 140 mU/ml) and electromyography was consistent with an inflammatory myopathy which was verified by light microscopy on biopsy muscle. Ultrastructural study of necrotizing myofiber, from the right vastus lateralis, showed: (1) degradation of the Z-lines with preservation of the adjacent Abands including M-lines and H-bands, (Fig. 1), (2) fracture of the sarcomeres at the I-bands with disappearance of the Z-lines, (Fig. 2), (3) fragmented sarcomeres without I-bands, engulfed by invading phagocytes, (Fig. 3, a & b ), and (4) mononuclear inflammatory cell infiltrate in the endomysium.

Popliteal artery thrombosis secondary to a tibial osteochondroma

VASA ◽  
2011 ◽  
Vol 40 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Gruber-Szydlo ◽  
Poreba ◽  
Belowska-Bien ◽  
Derkacz ◽  
Badowski ◽  
...  
Keyword(s):  
Case Report ◽  
Magnetic Resonance Angiography ◽  
Popliteal Artery ◽  
Doppler Ultrasonography ◽  
Histopathological Examination ◽  
Previous History ◽  
Plain Radiography ◽  
Artery Thrombosis ◽  
History Of ◽  
The Right

Popliteal artery thrombosis may present as a complication of an osteochondroma located in the vicinity of the knee joint. This is a case report of a 26-year-old man with symptoms of the right lower extremity ischaemia without a previous history of vascular disease or trauma. Plain radiography, magnetic resonance angiography and Doppler ultrasonography documented the presence of an osteochondrous structure of the proximal tibial metaphysis, which displaced and compressed the popliteal artery, causing its occlusion due to intraluminal thrombosis..The patient was operated and histopathological examination confirmed the diagnosis of osteochondroma.

COMMONWEALTH Forum: The Politics of Science or the Science of Politics

Commonwealth ◽  
2017 ◽  
Vol 19 (1) ◽  
Author(s):  
John Arway
Keyword(s):  
Public Policy ◽  
Natural Resource ◽  
Factual Information ◽  
The Past ◽  
Difference Of Opinion ◽  
History Of ◽  
The Right ◽  
Scientific Facts ◽  
Environmental Agency ◽  
Laws And Regulations

The challenges of including factual information in public policy and political discussions are many. The difficulties of including scientific facts in these debates can often be frustrating for scientists, politicians and policymakers alike. At times it seems that discussions involve different languages or dialects such that it becomes a challenge to even understand one another’s position. Oftentimes difference of opinion leads to laws and regulations that are tilted to the left or the right. The collaborative balancing to insure public and natural resource interests are protected ends up being accomplished through extensive litigation in the courts. In this article, the author discusses the history of environmental balancing during the past three decades from the perspective of a field biologist who has used the strength of our policies, laws and regulations to fight for the protection of our Commonwealth’s aquatic resources. For the past 7 years, the author has taken over the reins of “the most powerful environmental agency in Pennsylvania” and charted a course using science to properly represent natural resource interests in public policy and political deliberations.

Multiple subluxations and comminuted fracture of the cervical spine in a sheep

2015 ◽  
Vol 43 (01) ◽  
pp. 44-38
Author(s):  
C.-C. Lin ◽  
K.-S. Chen ◽  
Y.-L. Lin ◽  
J. P.-W. Chan
Keyword(s):  
Cervical Spine ◽  
Pain Perception ◽  
Cervical Vertebrae ◽  
Traumatic Injury ◽  
Spinal Reflexes ◽  
Spine Trauma ◽  
Blunt Force Trauma ◽  
Comminuted Fracture ◽  
History Of ◽  
The Right

SummaryA 5-month-old, 13.5 kg, female Corriedale sheep was referred to the Veterinary Medicine Teaching Hospital, with a history of traumatic injury of the cervical spine followed by non-ambulatoric tetraparesis that occurred 2 weeks before being admitted to the hospital. At admission, malalignment of the cervical spine with the cranial part of the neck deviating to the right was noted. Neurological examinations identified the absence of postural reactions in both forelimbs, mildly decreased spinal reflexes, and normal reaction to pain perception tests. Radiography revealed malalignment of the cervical vertebrae with subluxations at C1–C2 and C2–C3, and a comminuted fracture of the caudal aspect of C2. The sheep was euthanized due to a presumed poor prognosis. Necropsy and histopathological findings confirmed injuries of the cervical spine from C1 to C3, which were consistent with the clinical finding of tetraparesis in this case. This paper presents a rare case of multiple subluxations of the cervical spine caused by blunt force trauma in a young sheep. These results highlight the importance of an astute clinical diagnosis for such an acute cervical spine trauma and the need for prompt surgical correction for similar cases in the future.

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