Complete heart block and cardiac tamponade secondary to Merkel cell carcinoma cardiac metastases

This is a unique case of Merkel cell carcinoma, a rare neuroendocrine tumor, metastasizing to the heart and inducing a progression of cardiac complications such as new-onset atrial fibrillation, malignant pericardial effusion with tamponade physiology, first-degree heart block, and complete heart block. Metastases to the heart are relatively rare but should be suspected if a patient with a known neoplasm presents with new cardiac manifestations. This is the first case report of cardiac metastases from Merkel cell carcinoma causing cardiac tamponade or complete heart block. This case highlights the clinical decision-making involved in managing cardiac tamponade and complete heart block in the setting of metastatic disease to the heart.     

Atrioventricular Conduction Abnormalities in Patients Undergoing Isolated Aortic or Mitral Valve Replacement

Cardiac conduction defects are common in patients with aortic valve disease. Several studies have suggested that the spontaneous occurrence of complete heart block in these patients is related to the extent of calcium deposits in the aortic valve and adjacent structures. No studies have been done to relate the occurrence of complete heart block at the time of valve replacement to predictive factors. We evaluated 102 consecutive patients undergoing isolated aortic valve replacement and 100 patients undergoing isolated mitral valve replacement. Although transient complete heart block was relatively common in each group (17.6% and 13%, respectively), we were not able to identify any factors predictive of its occurrence. There was a very low incidence of late heart block in a follow-up period of over four years. Thus, the capability for temporary pacing is mandatory in patients undergoing volve replacement. However, transient complete AV block during the perioperative period does not predict late recurrence of AV block and, therefore, prophylactic pacemaker or electrode implantation during or following transient block appears unnecessary.     

Temporary Pacing in Complete Heart Block due to Lyme Disease: A Case Report

The authors present the case of a 44-year-old man who was admitted with complete heart block and signs of severe bradycardia. After steroid administration and temporary pacemaker treatment the complete heart block resolved. During this therapy transient ST segment and T wave abnormalities occurred. The positive Borrelia burgdorferi antibody titer arrived only after therapy had been completed. This is regarded as the first case of Lyme carditis with complete heart block diagnosed in eastern Europe. Carditis resolved without antibiotic treatment and has not recurred.     

Electrocardiographic Clues in Diagnosing Syncope

Intermittent or transient episodes of cerebral dysfunction or syncope may result from complete heart block, which often goes unrecognized for years. Electrocardiographic patterns of conduction disturbances in one or both bundle branches are important clues to subsequent development of complete heart block.     

Acute Reversible Diffuse Conduction System Disease due to Lyme Disease

During the acute phase of Lyme disease, a 56-year-old man without previous heart disease developed complete heart block with alternating left and right bundle branch block pattern QRS complexes. Electrophysiological study performed in the acute phase revealed marked HV prolongation, although the level of heart block was at the atrioventricular node. The heart block was mildly symptomatic and resolved (as did the bundle branch block) with antibiotic therapy. Lyme disease may cause reversible His-Purkinje disease.     

Dobutamine-induced complete heart block

Dobutamine is commonly administered as a pharmacologic stressor in patients with limitations precluding exercise testing. The case report presented is one of transient complete heart block resulting from dobutamine sestamibi stress testing. Shortly after initiating the dobutamine infusion, the patient became pale and presyncopal, with hypotension and a heart rate of 50 beats per minute. Subsequently, third-degree heart block developed which lasted transiently and resolved. Subsequent cardiac evaluation of the patient revealed no cardiac etiology for her symptoms. Though bradycardia is infrequently noted in patients receiving dobutamine during stress electrocardiogram, complete heart block is a possibility during dobutamine-induced stress echocardiography and must be recognized as a potential risk.     

Survival and Follow-up After Pacemaker Implantation: A Comparison of Patients With Sick Sinus Syndrome, Complete Heart Block, and Atrial Fibrillation

The number of patients receiving cardiac pacemakers for sick sinus syndrome (SSS) has increased considerably in recent years. The literature has suggested that patients with sick sinus syndrome have a shorter life expectancy with pacemaker therapy than patients with total heart block or atrial fibrillation. We studied the survival rate of 1,049 patients with complete heart block, 592 with sick sinus syndrome and 447 with atrial fibrillation. After 10 years we found a survival rate of 54.5% for patients paced for SSS, 34.4% for those with complete heart block, and 24.7% for those with atrial fibrillation (statistical significance: SSS--heart block: p less than 0.05; SSS--atrial fibrillation: p less than 0.01; heart block--atrial fibrillation: NS). Considering the calculated survival rates of a comparable normal population (i.e., 56.5%; 41.2%; 47.8%), the differences in survival expectancy are even more pronounced (SSS-normal: NS; heart block-normal p less than 0.05; atrial fibrillation-normal: p less than 0.05). For patients with sick sinus syndrome, the life expectancy parallels that of the general population, while that of patients with complete heart block or atrial fibrillation have a life expectancy that is considerably lower.     

Risk of right bundle-branch block and complete heart block during pulmonary artery catheterization

The need for the prophylactic insertion of a pacemaker before pulmonary artery catheterization in patients with pre-existing left bundle-branch block (LBBB) is controversial. To determine the incidence of new right bundle-branch block (RBBB) and complete heart block during bedside pulmonary artery catheterization, 293 patients undergoing 307 pulmonary artery catheterizations were prospectively studied. Nine patients had pacemaker rhythms and 19 patients had an RBBB on their precatheterization ECGs and therefore were excluded from analysis. In the remaining 279 pulmonary artery catheterizations, eight (3%) were associated with the development of a new RBBB. None of the 14 patients with a pre-existing LBBB developed complete heart block. The incidence of complete heart block during pulmonary artery catheterization of patients with previous LBBB was not higher than the incidence of RBBB in patients without underlying conduction defects. Because of the rare but grave consequences of RBBB in patients with pre-existing LBBB, we recommend the use of standby external pacemakers and equipment for transvenous pacemaker insertion in these patients during pulmonary artery catheterization. We do not recommend prophylactic pacemaker insertion.     

Pacemaker Inhibition and Asystole in a Pacemaker Dependent Patient

A 17-year-old female with Kearns Sayre syndrome, complete heart block, and an implanted single chamber (VVIR) pacemaker, underwent testing with a GSM cellular phone that was placed directly over the pacemaker site. The pacemaker was immediately inhibited when the phone began to operate. A 6.5-second period of complete heart block with asystole occurred until the phone was switched off.     

Immediate and Persistent Complete Heart Block Following a Horse Kick

Nonpenetrating chest trauma has been reported to cause acute and transient disorders of impulse formation and propagation, including intraventricular conduction delay and heart block. We report a case of immediate and sustained complete heart block following blunt chest injury.     

Heart block after induction of anesthesia in a child.

A case of complete heart block occurred after induction of halothane anesthesia in a previously healthy child. The patient underwent repair of an umbilical hernia under general anesthesia. After a standard halothane, nitrous oxide, and oxygen mask induction, complete heart block was noted on the electrocardiographic monitor. Atropine and 100% oxygen were administered, and sinus tachycardia resulted. With the immediate stabilization of the patient's condition, the surgical team agreed to proceed with the case. After deepening of the level of anesthesia, first with halothane and then with desflurane and easy intubation of the trachea, complete heart block again was noted. Oxygen was administered at 100%, sinus tachycardia resumed, the case was canceled, and the patient emerged from anesthesia without further incident. The patient had an uneventful recovery and was discharged to home.     

Clinical implications of fetal magnetocardiography.

OBJECTIVES: To test the usefulness and reliability of fetal magnetocardiography as a diagnostic or screening tool, both for fetuses with arrhythmias as well as for fetuses with a congenital heart defect. METHODS: We describe 21 women with either a fetal arrhythmia or a congenital heart defect discovered during prenatal evaluation by sonography. Four fetuses showed a complete atrioventricular block, two an atrial flutter, nine ventricular extrasystole, and one a complete irregular heart rate. Five fetuses were suspected to have a congenital heart defect. In all cases magnetocardiograms were recorded. RESULTS: Nine fetuses with extrasystole showed a range of premature atrial contractions, premature junctional beats or premature ventricular contractions. Two fetuses with atrial flutter showed typical flutter waves and four fetuses with complete atrioventricular block showed an uncoupling of P-wave and QRS complex. One fetus showed a pattern suggestive of a bundle branch block. In three of four fetuses with confirmed congenital heart defects the magnetocardiogram showed abnormalities. CONCLUSION: Fetal magnetocardiography allows an insight into the electrophysiological aspects of the fetal heart, is accurate in the classification of fetal arrhythmias, and shows potential as a tool in defining a population at risk for congenital heart defects.     

Termination of "ventricular" arrhythmias from digoxin by selective production of complete atrioventricular block with physostigmine in the dog

In previous studies we have come to doubt that ventricular rhythms of an automatic nature will arise spontaneously from the peripheral Purkinje system. In 20 anesthetized dogs, digoxin was administered i.v. (0.1-1.0 mg/kg) and in 12 dogs by selectively perfusing the atrioventricular (AV) node artery (2 ml; 40 microgram/ml). We obtained the following results. First, selective pharmacological production of complete AV block (acetylcholine or physostigmine) interrupts the "ventricular" arrhythmias considered characteristic of digitalis intoxication.Second, digitalis arrhythmias are difficult to produce when this type of complete heart block had been previously established. Third, abolition of ventricular arrhythmias by selective pharmacological production of heart block can be reversed (i.e., the arrhythmia restored) with atropine. Fourth, rapid pacing of the ventricles during complete heart block in dogs poisoned with digitalis can eventually induce ventricular arrhythmias, but not quickly. We interpret that these digitalis arrhythmias originated within the acetylcholine-sensitive portion of the AV node-His bundle region.     

Single Pass VDD Pacing in Children and Adolescents

Use of a single pass lead for VDD pacing in complete heart block is well described in adults, but there are only brief reports of its use in children. We have used standard adult size single pass leads in 13 children and adolescents aged 3.7–17.2 years (mean 10.1 years) and weighing 13.5–76 kg (mean 34.8 kg). Congenital complete heart block was present in 7 patients, surgical complete heart block in 5 patients and 2:1 AV block of unknown cause in 1 patient. In four patients, the VDD system was their first pacing system. In nine of the patients, 1–6 previous systems had been used and simultaneous extraction of ventricular leads and/or atrial leads was performed. Leads of four different types were used: Brilliant IMPl5Q, Brilliant + IMR15Q, CapSure 5032, and Unipass 425–13 with 4 different generators: Saphir 600, SaphirII620, Thera VDD 8948, and Unity 292–07. At implantation, via a subclavian vein puncture, excess lead was advanced into the right atrium to allow both atrial sensing and slack for further growth. Ventricular thresholds ranged from 0.2–0.7 V. The minimal atrial amplitude was 0.7–4 mV and the maximum amplitude was 2.5–8 mV. There were no complications. Ail patients have maintained adequate atrial signals for reliable pacing with follow up of 3–36 months (mean 17.6 months) during which time some have undergone considerable growth. Beliable atrial synchronous ventricular pacing is possible in growing children with complete heart block using a standard adult single pass lead.     

Third-degree heart block developing in an HLA-B27-positive individual with a family history of ankylosing spondylitis

A case of complete heart block is presented in a patient whose brothers were known to have ankylosing spondylitis. Uveitis and sacro-iliitis are well recognised among HLA-B27-positive siblings of ankylosing spondylitis. However, heart block is a rare occurrence as a sole presentation in siblings of patients with ankylosing spondylitis.     

Total AV-block in pediatric cardiology]

This study presents the clinical aspects as well as the therapy and prognosis of complete atrioventricular block in childhood. Our own experience is based on the case histories of 12 children with congenital complete AV block, six of them having additional heart disease and of 14 children with acquired AV block, which appeared in 10 of these children already during operation or up to 5 5/12 years after surgery.     

Familial Atrioventricular Heart Block of Adult Onset: Electrocardiogram and HLA Typing Analysis

EBISAWA, K., et.al .: Familial Atrioventricular Heart Block of Adult Onset: Electrocardiogram and HLA Typing Analysis . A family was investigated because of heart block and sinus arrhythmia. The electrical characteristics were: (1) adult onset in all members; (2) complete heart block with atrial fibrillation in 2, and first- or second-degree heart block in 7 members; and (3) sinus arrhythmia in 3 members. Human leukocyte antigen (HLA) typing was performed. HLA A2, B39, Cw7, and DR12 were positive in 4 of 5 members in the heart block group. In the sinus arrhythmia group, HLA DR12 was positive in all members. In the normal group, none of these HLA typings was positive except one. These findings indicate a tighter relationship between heart block and the HLA locus than previously thought.     

Frequent Recurrent Polymorphic Ventricular Tachycardia during Sleep Due to Managed Ventricular Pacing

We report a case of a patient with an implantable cardioverter defibrillator and no prior history of heart block with managed ventricular pacing (MVP) programmed who had frequent recurrent episodes of polymorphic ventricular tachycardia. All of the episodes were initiated by transient atrioventricular block which resulted in short‐long‐short sequences permitted by MVP. This case illustrates that MVP should be used with caution not only in patients with complete heart block, but also in patients at risk for brief heart block due to such states as hypervagatonia due to sleep apnea. (PACE 2010; 641–644)     

Complete Atrioventricular Block after Arsenic Trioxide Treatment in an Acute Promyelocytic Leukemic Patient

A V block after arsenic trioxide (As₂O₃) treatment for refractory acute promyelocytic leukemia is very rare. In this patient, the block was at A-H level and manifested with complete AV block and Wenckebach second-degree type 3:2 block. The junctional recovery time during complete AV block did not significantly prolong after administration of more arsenic trioxide. The effect of heart block of arsenic trioxide seemed reversible after the discontinuation of arsenic trioxide and was not correlated to the leukemic status as observed in this patient.     

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

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 and accelerations is useful to select cases for safe vaginal delivery.