Junctional rhythm

Oral Premature atrial, AV junctional and ventricular contractions paroxysmal atrial (supraventricular) tachycardia paroxysmal AV junctional rhythm atrial flutter paroxysmal and chronic atrial fibrillation established atrial fibrillation when therapy is appropriate paroxysmal ventricular tachycardia not associated with complete heart block maintenance therapy after electrical conversion of atrial fibrillation or flutter. Parenteral When oral therapy is not feasible or when rapid therapeutic effect is required. 

Scherlag BJ, Lazzara R, Helfant RH. Differentiation of A-V junctional rhythms . Circulation 1973 48 304-12. 

The most common cardiac manifestations of digitalis toxicity include atrioventricular junctional rhythm, premature ventricular depolarizations, bigeminal rhythm, and second-degree atrioventricular blockade. However, it is claimed that digitalis can cause virtually any arrhythmia. 

Vomiting is common in patients with digitalis overdose. Hyperkalemia may be caused by acute digitalis overdose or severe poisoning, whereas hypokalemia may be present in patients as a result of long-term diuretic treatment. (Digitalis does not cause hypokalemia.) A variety of cardiac rhythm disturbances may occur, including sinus bradycardia, AV block, atrial tachycardia with block, accelerated junctional rhythm, premature ventricular beats, bidirectional ventricular tachycardia, and other ventricular arrhythmias. 

Unifocal or multiform ventricular premature contractions, ventricular tachycardia, atrioventricular dissociation, accelerated junctional rhythm, and atrial tachycardia with block... 

A 66-year-old woman with pre-existing first-degree AV block, developed sinus bradycardia, a junctional rhythm, a prolonged QT interval, and syncopal episodes (serum lithium concentration 1.4 mmol/1 in a 40-hours sample) about 2 weeks after beginning lithium therapy. She was treated successfully with a pacemaker and a lower dose of lithium (133). 

Symptomatic bradycardia, junctional rhythm, non-sustained and/or monomorphic ventricular tachycardia... 

The safety and efficacy of mibefradil in association with beta-blockers was assessed in 205 patients with chronic stable angina, randomized to placebo or mibefradil 25 or 50 mg/day for 2 weeks (6). Besides an improvement in angina with mibefradil, it dose-dependently reduced heart rate and increased the PR interval. One patient taking mibefradil had an escape junctional rhythm 26 hours after the last dose of 50 mg. The nodal rhythm disappeared on withdrawal of mibefradil, but based on the overall results it was concluded that mibefradil was safe and effective when given for a short time with beta-blockers. 

The adverse effects of a single oral dose of propafenone for cardioversion of recent-onset atrial fibrillation have been evaluated in a systematic review (18). The adverse effects were transient dysrhythmias (atrial flutter, bradycardia, pauses, and junctional rhythm), reversible widening of the QRS complex, transient hypotension, and mild non-cardiac effects (nausea, headache, gastrointestinal disturbances, dizziness, and paresthesia). 

Nitrous oxide causes drowsiness and headache. Anesthesia with nitrous oxide as the sole anesthetic in normal humans for periods of 7.-A h has induced tachypnea, tachycardia, increased systemic blood pressure, atrioventricular junctional rhythm, acute cardiovascular failure, mydriasis, diaphoresis, and occasional clonus and opisthotonus. 

Quinidine is used to treat and control atrial fibrillation and atrial flutter. Quinidine is also approved to treat premature ventricular contractions and to treat paroxysmal atrial tachycardia or paroxysmal atrioventricular junctional rhythm. It may also be used to treat malaria, although quinine is preferred. 

Bradycardia may result from sinus bradycardia, second- or third-degree AV block, or sinus arrest with junctional rhythm. 

IV. Diagnosis is based on a history of recent overdose or characteristic arrhythmias (eg, bidirectional tachycardia and accelerated junctional rhythm) in a patient receiving chronic therapy. Hyperkalemia suggests acute ingestion but may also be seen with very severe chronic poisoning. Senim potassium levels higher than 5.5 mEq/L are associated with severe poisoning. 

No changes in the pharmacokinetics of digoxin were seen in a singledose study of intravenous digoxin and moracizine in 9 healthy subjects or in a study in patients receiving maintenance treatment with digoxin over a 13-day period. However, cardiac arrhythmias (AV junctional rhythm and heart block) were seen, which resolved when the moracizine was stopped. ... 

Aconite poisoning has been reported to occur after mistaken use of the unprepared herb, inappropriate preparation, or overdose. Poisoning may affect the nervous system (dizziness, blurred vision, mydriasis, loss of vision, and numbness of mouth, limbs, or whole body), digestive system (severe nausea and vomiting), and circulatory system (palpitations, low blood pressure, cold extremities, chest pain, bradycardia, sinus tachycardia, ventricular ectopics, ventricular arrhythmias, and junctional rhythm) (Bisset 1981 Chan 2009 Fitzpatrick et al. 1994). 

A 56-year-old man with hypertension suffered a 62% total body surface area burn (day 0) and on day 4 developed atrial fibrillation with a rapid ventricular rate, which was treated with amiodarone and digoxin. After pyloroplasty for a bleeding ulcer on day 20, he developed a postoperative ileus and was given metoclopramide 20 mg intravenously every 6 hours. Beginning on day 54, he started to have episodes of bradycardia and asystole. Some episodes required atropine and others resolved spontaneously. Some converted initially to a junctional rhythm, but all ultimately reverted to sinus tachycardia. Digoxin and metoclopramide were withdrawn and several hours later the bradydysrhythmias stopped. 

Similarly, some systems identify an event sensed on the ventricular channel of the pacemaker which is not preceded by an atrial event, either paced or sensed, as a premature ventricular contraction (PVC). PVC s have a very definite implication for the clinician. The pacemaker s definition is far more specific as the pacemaker cannot analyze the morphology of the complex. Hence, nonphysiologic make-break electrical potentials associated with an internal insulation failure or conductor fracture will also be identified as PVCs as will accelerated junctional rhythms or episodes of atrial undersensing but with intact AV nodal conduction. Some systems may also identify runs of ventricu-... 

Drug overdose An 84-year-old man took total of 60 (6.25 mg) tablets and rapidly developed hypotension (systolic blood pressure 70 mmHg), bradycardia (45/ minute), and a junctional rhythm [6" ]. He was given intravenous glucagon and dopamine infusion and recovered after 14 hours. The carvedilol serum concentration was 472 pg/1, compared with a predicted steady-state concentration of 8.5 pg/1 during treatment with 6.25 mg bd. 

Important to differentiate junctional rhythm from idioventricular rhythm (a life-threatening arrhythmia)... 

Junctional rhythm can prevent ventricular standstill should never be suppressed... 

Accelera-ted Junctional rhythm (continued) What causes it What to do... 

Many patients suffer from rhythm disturbances early after transplantation. Commonly they have a junctional rhythm until normal sinus activity reoccurs. Intravenous isoproterenol therapy early after transplantation can maintain the heart rate about 100-120 beats per minute, optimizing the cardiac output and preventing arrhythmias. Epicar-dial (atrio-)ventricular pacing is an alternative to pharmacological therapy. Asymptomatic, transient atrial arrhythmias are common with an incidence of about 20%-25% during hospital stay. Ventricular arrhythmias are more common than atrial arrhythmias (incidence up to 60%) and reflect the ischemic and reperfusion injury (prolonged ischemia time), hypokalemia or hypomagnesemia. 

May be difficult to differentiate atrial fibrillation from multifocal atrial tachycardia and junctional rhythm. 

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