Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Weakness, orthopnea, dizziness, breathlessness, presyncope, syncope, pulmonary congestion, and altered mental status Atrial rhythm and rate are dyssynchronous with the ventricular rhythm and rate Appropriately timed atrial contraction does not precede the paced ventricular event +++ GENERAL CONSIDERATIONS ++ Prevalence is 10–50% and more common in the elderly Common with VVI pacing and reduced with dual-chamber pacing Diagnosis established by the objective findings of ventricular-atrial conduction, cannon waves, and transient mitral regurgitation Atrial contraction and resultant atrial stretch activate the baroreceptors to produce vagally mediated vasodilatation and decrease in heart rate May occur in any pacing mode when atrioventricular (AV) synchrony is uncoupled Incidence has a wide range depending on whether patients were switched from an AV synchronous mode to VVI mode or were studied in VVI mode In VVI mode, incidence is 7–10% When switched from DDD to VVI mode, symptoms are experienced by 80% of patients +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Pulsations in the neck Palpitations Fatigue, weakness, apprehension Chest pain Dyspnea Dizziness Presyncope, syncope +++ PHYSICAL EXAM FINDINGS ++ Arterial blood pressure in supine and standing position with ventricular pacing and sinus rhythm (drop of 20 mm Hg suggests pacemaker syndrome) Cannon a waves Pulsatile liver S3 gallop, pulmonary rales +++ DIFFERENTIAL DIAGNOSIS ++ Newer forms of pacemaker syndromes such as prolonged AV conduction (intrinsic AV node problem or drug induced) in AAI or AAIR mode AV dyssynchrony caused by mode switching +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ CBC, basic metabolic panel +++ ELECTROCARDIOGRAPHY ++ ECG may be used to document ventriculoatrial conduction during symptoms Ambulatory ECG monitoring may be useful in confirming the diagnosis +++ IMAGING STUDIES ++ Doppler echocardiogram may be used to document hemodynamic changes secondary to VVI pacemaker +++ DIAGNOSTIC PROCEDURES ++ Hemodynamic measurements with and without pacemaker rhythm (20 mm Hg drop) Relief of patient’s symptoms with SR (sinus rhythm) or AV synchrony +++ TREATMENT +++ CARDIOLOGY REFERRAL ++ Patients should be evaluated by an electrophysiologist +++ HOSPITALIZATION CRITERIA ++ Usually can be managed as outpatient If syncope or serious symptoms occur, patient should be hospitalized +++ MEDICATIONS ++ Trial of antiarrhythmic drugs to eliminate retrograde ventriculoatrial conduction +++ THERAPEUTIC PROCEDURES ++ Atrial pacing and sensing unless contraindicated In VVI pacing, upgrading to DDD mode with physiologic AV pace intervals Reducing the lower rate of VVI pacing to reduce the number of paced events ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.