Management of patients with palpitations: a position paper from the ...

Managing patients with palpitations 929asymptomatic (i.e. not associated with palpitations) may suggest aprobable diagnosis and/or guide the decision to undertake furtherinvestigations. 15,59 The specificity of ambulatory ECG monitoring, atleast in formulating a diagnosis of arrhythmic palpitations or nonarrhythmicpalpitations, is optimal, whereas the sensitivity is extremelyvariable and depends on the following factors: the monitoringtechniques used, the duration of monitoring, patient compliance,and, most importantly, the frequency of the attacks.In patients with palpitations of unknown origin, Holter monitoringhas displayed a rather low sensitivity value (33–35%). 81 In ameta-analysis of seven studies conducted on patients withsyncope and/or palpitations of unknown origin, Holter monitoringhas been seen to have a sensitivity value of only 22%. 82 By contrast,in patients in whom the symptoms are quite frequent (i.e. daily orweekly), external loop recorders and event recorders have shownboth a higher diagnostic value (66–83%) and a better cost/effectivenessratio than Holter devices. 71,83 Finally, in patients withsymptoms of possible arrhythmic origin, mobile cardiac outpatienttelemetry has been seen to exhibit a higher diagnostic value thanthe other external devices. 71,84,85ILRs have been successfully used to study syncope, in which theyhave shown a better cost/effectiveness ratio than the conventionaltests, 86,87 and they can be useful in the study of palpitations ofunknown origin. 69,88,89 Indeed, the RUP study (recurrent unexplainedpalpitations study) recently demonstrated the superiorityof ILR over the conventional diagnostic strategy of Holter andevent recorder monitoring and EPS in the evaluation of a relativelysmall cohort of patients with infrequent palpitations (i.e. monthlyfrequency) reporting both a higher diagnostic value (73% vs. 21%)and a better cost/effectiveness ratio. 52 In patients implanted withpacemakers or ICDs, useful information on the origin of palpitationscan be obtained by interrogating the memory of the device. 90Although many patients with palpitations of unknown originwho undergo ambulatory ECG monitoring prove to have rhythmdisorders that are generally benign, such as atrial or ventricularpremature beats, or episodes of sinus rhythm and sinus tachycardia,a substantial percentage (6–35%) of the arrhythmias diagnosedprove to be clinically significant, such as supraventricular tachycardiasand atrial fibrillation. 5 Ventricular tachycardia is much lesscommon and is typical of patients with structural or arrhythmogenicheart diseases. Finally, a small percentage of patients with palpitationsof unknown origin have major bradyarrhythmic disorders,such as severe sinus bradycardia and paroxysmal advanced atrioventricularblock. 52,71LimitationsAmbulatory ECG monitoring has some important limitations.Indeed, it is not always possible to formulate a precise diagnosisof the type of arrhythmia recorded, especially when single-leadECG devices are used. For example, it may be difficult to make acorrect differential diagnosis between a supraventricular tachycardiawith aberrant conduction and a ventricular tachycardia. Moreover,ambulatory ECG monitoring is unable to distinguish withcertainty between bradyarrhythmias due to a reflex mechanismand those caused by a disorder of the cardiac conductionsystem, a distinction that has prognostic and therapeutic implications.Finally, ambulatory ECG monitoring requires the patientto experience a recurrence of symptoms. This delays the diagnosisand, should the palpitations be due to malignant arrhythmias,exposes the patient to the potential risk of adverse events. Themain advantages and limitations of the different ambulatory ECGmonitoring systems are summarized in Table 9.IndicationsAccording to the ACC/AHA guidelines for the use of ambulatoryECG monitoring, 69,70 recurrent palpitations of unknown originconstitute a class-I indication for long-term ECG monitoring. Therecommendations regarding the choice of the ambulatory ECGmonitoring device most suited to the individual patient arereported in Table 9. ILRs are used in selected patients withsevere and infrequent palpitations (inter-symptom interval .4weeks) and when all other investigations, including external ambulatoryECG monitoring, prove to be negative. 66Electrophysiological studyElectrophysiological study, as an invasive procedure, is usually consideredat the end of the diagnostic work-up. However, EPS hassome important advantages over ambulatory ECG monitoring.First of all, it is able to correctly identify the type of arrhythmiaresponsible for the palpitations. Moreover, it enables ablativetherapy of the induced tachyarrhythmias to be performed duringthe same session in which the diagnosis is made. Finally, whileEPS enables a diagnosis to be made and specific therapy to beinitiated immediately, ambulatory ECG monitoring requires thepatient to experience a recurrence of symptoms. This delays thediagnosis and, should the palpitations be due to malignant arrhythmias,exposes the patient to the potential risk of adverse events.For this reason, in patients with significant heart disease and inthose with palpitations that precede syncope, in whom the riskof adverse events is higher, electrophysiological evaluation generallyprecedes the use of ambulatory ECG monitoring. In all othercases, it normally follows ambulatory ECG monitoring when thelatter proves non-diagnostic. For the recommendations of EPS inpatients with palpitations of unknown origin we refer thereaders to the ACC/AHA/ESC 2003 Guidelines on supraventriculararrhythmias 16 and the ACC/AHA/ESC 2006 Guidelines formanagement of patients with ventricular arrhythmias and the preventionof sudden cardiac death. 17Specific needs in patients at riskof strokeIt is well known that atrial fibrillation is associated with anincreased risk of thromboembolism, especially in patients withcertain risk factors as those considered in the CHA 2 DS 2 VAScrisk score. 14 It is therefore important to exclude atrial fibrillation asthe underlying cause of the symptoms in patients with palpitationsof unknown origin and a high thromboembolic risk.However, it must be underlined that once atrial fibrillation hasbeen diagnosed as a cause of palpitations, there is up to nowonly limited data on the importance of assessing atrial fibrillationDownloaded from http://europace.oxfordjournals.org/ at :: on December 6, 2011