scholarly journals Atrial and Ventricular Rate Response and Patterns of Heart Rate Acceleration during Maternal–Fetal Terbutaline Treatment of Fetal Complete Heart Block

2007 ◽  
Vol 100 (4) ◽  
pp. 661-665 ◽  
Author(s):  
Bettina F. Cuneo ◽  
Hui Zhao ◽  
Janette F. Strasburger ◽  
Marc Ovadia ◽  
James C. Huhta ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Block ◽  
Complete Heart Block ◽  
Ventricular Rate ◽  
Heart Rate Acceleration ◽  
Rate Acceleration

IKr and IKs remodeling differentially affects QT interval prolongation and dynamic adaptation to heart rate acceleration in bradycardic rabbits

2007 ◽  
Vol 292 (4) ◽  
pp. H1782-H1788 ◽  
Author(s):  
Fumiaki Suto ◽  
Wei Zhu ◽  
Alice Chan ◽  
Gil J. Gross
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Qt Interval ◽  
Heart Block ◽  
Complete Heart Block ◽  
Electrical Remodeling ◽  
Interval Prolongation ◽  
Heart Rate Acceleration ◽  
Qt Interval Prolongation ◽  
Rate Acceleration

Bradycardic ventricular electrical remodeling predisposes to lethal tachyarrhythmias. We investigated the early temporal sequence and reversibility of electrical remodeling in a rabbit complete heart block model subjected to bradycardic ventricular pacing for either 2 or 8 days, with a third group of animals undergoing 8 days of bradycardic pacing followed by 8 days of physiological-rate pacing. At specified time points after complete heart block induction and pacing initiation, steady-state QT interval measurements and variability as well as dynamic QT interval adaptation to abrupt heart rate acceleration were assessed in the absence and presence of isoproterenol. Rapidly ( IKr) and slowly ( IKs) activating delayed rectifier repolarizing K+ tail current densities were evaluated using whole cell patch clamp in isolated right ventricular myocytes. Steady-state QT interval prolongation at both 2 and 8 days was associated with moderate IKr reduction. IKs downregulation was apparent by day 2 but more profound at day 8. Dynamic QT interval adaptation was impaired under baseline conditions at day 8 but only during isoproterenol administration at day 2. Both in vivo and cellular manifestations of remodeling reverted toward control values after 8 days of physiological-rate pacing. In conclusion, in this bradycardic model, IKs downregulation 1) proceeds more gradually but more extensively than that of IKr and 2) is most prominently associated with impaired dynamic QT interval adaptation to heart rate acceleration. Isoproterenol blunts the dynamic QT interval response in animals with partially downregulated IKs, consistent with stress-related phenomena in known IKs-impaired states. Relative early sparing of IKs could explain the delay in the onset of lethal tachyarrhythmia predisposition in bradycardic electrical remodeling. Reversibility of remodeling supports the potential utility of preventive pacing intervention soon after bradycardia onset.

Drugs and pacemakers for complete heart block

1967 ◽  
Vol 5 (5) ◽  
pp. 19-20
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Heart Rate ◽  
Heart Disease ◽  
Ischaemic Heart Disease ◽  
Heart Block ◽  
Complete Heart Block ◽  
Bundle Of His

Complete heart block can occur in ischaemic heart disease, and can acutely complicate myocardial infarction. Most other cases are associated with fibrosis of the bundle of His of unknown cause, or are congenital. In some patients with chronic heart block, especially the congenital type, adequate output is maintained. In other patients chronic or intermittent heart block may cause Stokes-Adams attacks, or heart failure may not respond to digitalis and diuretics until the heart rate is increased. These require treatment by drugs or, when this fails, by use of anartifical pacemaker.

scholarly journals Fetal heart rate tracing interpretation in cases of fetal heart block: A case series

2021 ◽  
Author(s):  
Fuanglada Tongprasert ◽  
Kasemsri Srisupundit ◽  
Suchaya Leuwan ◽  
Kuntharee Traisrisilp ◽  
Phudit Jatavan ◽  
...  
Keyword(s):  
Heart Rate ◽  
Vaginal Delivery ◽  
Fetal Heart Rate ◽  
Heart Block ◽  
Fetal Heart ◽  
Complete Heart Block ◽  
Case Series ◽  
Fetal Surveillance ◽  
Degree Heart Block ◽  
Second Degree

Simple assessment of FHR baseline variability can differentiate second degree heart block (SHB) from complete heart block (CHB). In cases of SHB, antepartum NST can be reliably used for fetal surveillance. Intrapartum assessment of FHR variability as well as accelerations is useful to select cases for safe vaginal delivery

Creating permanent complete heart block by indirect cauterization without atriotomy

1977 ◽  
Vol 233 (6) ◽  
pp. H723-H726
Author(s):  
H. H. Shiang ◽  
J. Kupersmith ◽  
G. F. Wiemann ◽  
C. Y. Rhee ◽  
R. S. Litwak
Keyword(s):  
Heart Block ◽  
Complete Heart Block ◽  
Ventricular Rate ◽  
Atrial Wall

We created permanent complete heart block (CHB) in 11 dogs without atriotomy by means of indirect cauterization of the atrioventricular (A-V) bundle with a partially insulated wire placed through a small puncture in the atrial wall and guided by palpation. In six acute studies and five chronic studies, all dogs exhibited permanent CHB. To test the block, isoproterenol increased both atrial and ventricular rates 200%–400% without affecting the block. Atropine had no effect on ventricular rate or block.

scholarly journals Systemic sarcoidosis presenting as complete heart block in a patient with normal chest radiography

2019 ◽  
Vol 12 (3) ◽  
pp. e227143
Author(s):  
Muhammad Hamza Saad Shaukat ◽  
Fadi Fahad ◽  
David Weinreb ◽  
Mikhail Torosoff
Keyword(s):  
Lymph Node ◽  
Chest Radiography ◽  
Heart Block ◽  
Complete Heart Block ◽  
Left Ventricular Systolic Dysfunction ◽  
Systolic Dysfunction ◽  
Interventricular Septum ◽  
Left Ventricular ◽  
Ventricular Rate ◽  
Excision Biopsy

A previously healthy 44-year-old Caucasian man presented with recurrent syncope and was found to have a complete heart block with a ventricular rate of 24 bpm. No biochemical abnormalities were identified. Tick borne illnesses were ruled out. Paced echocardiogram revealed left ventricular systolic dysfunction with septal hypokinesis. Chest radiography and subsequent CT scan did not reveal adenopathy. However, a positron emission tomography scan demonstrated increased fluorodeoxyglucose uptake in the spleen, a right retro-clavicular lymph node, right ventricle and the interventricular septum of the heart. Excision biopsy of the retro-clavicular lymph node revealed non-caseating granulomas consistent with sarcoidosis. Complete heart block persisted despite steroid treatment. A pacemaker/biventricular implantable cardioverter defibrillator was placed for complete heart block and primary prevention of ventricular tachycardia and sudden cardiac death.

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