Lesson Sixty-five EHRA/HRS/APHRS expert consensus on p remature ventricular comp lexes and non-sustained ventricular tachycard ia

●心電學(xué)英語(yǔ)

Lesson Sixty-five EHRA/HRS/APHRS expert consensus on p remature ventricular comp lexes and non-sustained ventricular tachycard ia

Premature ventricular com plexes

Premature ventricular complexes(PVCs)are common both in patients with and without structural heart disease(SHD)and may be asymptomatic even for patientswith high frequency of these beats.Other patients may be highly symptomatic with relatively few ectopic beats.

Several studies have demonstrated an association between frequent PVCsand a potentially reversible cardiomyopathy,which in selected patients resolves after catheter ablation.The number of PVCs/24 h that is associated with impaired LV function has generally been reported atburdens above 15-25%of the total cardiac beats,though thismay be as low as 10%.However, since PVCs may be the result of an underlying cardiomyopathy,itmay be difficult to prospectively determine which of these sequences is operative in a given patient.Importantly,the vastmajority of patients with frequentPVCswillnotgo on to develop cardiomyopathy but currently available data do not allow for accurate risk prediction.

Diagnostic evaluation

Electrocardiogram and ambulatorymonitoring

The vastmajority ofpatientswithoutSHDwhohave PVCs have a benign prognosis.An exceptionmay be a very small subsetofpatientswith PVCs thathavea short coupling interval(＜300ms)between the prematureand the preceding beats,a finding which suggests the short QT syndrome and increases the risk ofmalignant VAs. Aswith other VAs,the first step in the evaluation of a patientwith PVCs is to determine the presence or absenceof SHD.For patientswith arrhythmic orother cardiac symptoms,a resting 12-lead ECG is very helpful to evaluate the presence ofmyocardial scar(Q-waves or fractionated QRScomplexes),the QT interval,ventricular hypertrophy,and other evidence of SHD.An echocardiogram provides assessment of right ventricular (RV)and LV structureand function,valvularabnormalities,and pulmonary artery systolic pressure and is recommended for patients with symptomatic PVCs,a high frequency of PVCs(＞10%burden),orwhen the presenceofSHD issuspected.

Exercise testing

For selected patients,especially when there is a suggestion of symptoms associated with exercise,exercise stress testing should be considered to determine whether PVCsare potentiated or suppressed by exercise, to assesswhether longer duration VAs are provoked.A negative exercise test can decrease the probability that catecholaminergic polymorphic ventricular tachycardia (CPVT)is the underlying cause.Premature ventricular complexes thatworsen with exercise should prompt further investigation as these patientsaremore likely to require treatment.

Imaging investigations

Although themajority ofpatientswith PVCs can beaccurately assessed with a 12-lead ECG and echocardiography,contrast-enhanced MRImay provide additional diagnostic and prognostic datawhen the presence or absence of SHD remains in doubt.While thereare no large-scale studies investigating which patients should undergo MRI,themanagementof several forms of SHD associated with PVCsmay be guided by MRI,including dilated cardiomyopathy,hypertrophic cardiomyopathy (HCM),sarcoidosis,amyloidosis,and arrhythmogenic rightventricular cardiomyopathy(ARVC).In these conditions,the presence of ventricular wallmotion abnormalities or myocardial scar detected by delayed gadolinium enhancementmay provide useful prognostic information.In selected patients for whom the diagnosis of ARVC is suspected,the signal-averaged ECG may provide useful information and forms aminor diagnostic criterion for thisdisorder.

Treatment

Indications for treatment in patients without structural heartdisease

In the absence of SHD,themost common indication for treating PVCs remains the presenceofsymptoms thatarenot improved by explanation of theirbenign nature and reassurance from the physician.Some patients may require treatment for frequentasymptomatic PVCs if longitudinal imaging surveillance reveals an interval decline in LV systolic function or an increase in chamber volume.For patientswith＞10 000 PVCs/24 h,follow-up with repeatechocardiography and Holtermonitoring should be considered.It should also be recognized thatPVCburden often fluctuatesover time.

Indications for treatment in patientswith structuralheart disease

In patientswith SHD,symptoms form the primary grounds for considering whether treatment is indicated. Elimination of high burden PVCs(＞10%)in patients with impaired LV function can be associated with significant improvementof LV function,evenwhen significant scarring is present.Catheter ablation may also be helpful when frequent PVCs interfere with cardiac resynchronization therapy.

Medical therapy

For patients whose symptoms are not effectively managed by explanation of their benign nature and reassurance from the physician,a trialofbeta-blockers or non-dihydropyridine calcium antagonistsmay be considered though the efficacy of these agents is quite limited with only 10-15%of patients achieving＞90% PVC suppression.Whilemembrane-active antiarrhythmic drugs(AADs)aremore effective to suppress PVCs, the risk-benefit ratiohasnotbeen carefully evaluated in patients without SHD.Nevertheless,these agents are highly effectiveandmay significantly improve symptoms inmarkedly symptomatic patients.Because these agents may increase the risk ofmortality in patientswith significant SHD,perhapswith theexception ofamiodarone, caution is advised before using them for PVC suppression.

Catheterablation

Catheter ablation of PVCs is recommended for highly selected patients who remain very symptomatic despite conservative treatment or for those with very high PVC burdens associated with a decline in LV systolic function.Multiple studies indicate high efficacy of ablation with PVC elimination in 74-100%of patients. However,procedural successmay be dependent on site oforiginwith lowerefficacy reported for coronary venous and epicardial foci than for other sites.The efficacy of catheter ablationmay be reduced for patientswithmultiplemorphologiesof PVCs or those forwhom the clinical PVCmorphology cannot be induced at the time of the procedure.Although complete PVC elimination is the goal of ablation,it should be noted that partial successmay still be associated with significant improvement in LV systolic function.The published complication rates of catheter ablation for PVC suppression are generally low(～1%).

Non-sustained ventricular tachycardia

Non-sustained ventricular tachycardia(NSVT)is defined as runs ofbeats arising from the ventricleswith duration between 3 beatsand 30 sand with cycle length of＜600ms(＞100 b.p.m.).Similar to PVCs,NSVT is a relatively common finding in patients with either structurally normal or abnormal hearts.NSVT is foundin nearly 6%of patients evaluated for palpitations.In general,therapy for the underlying cardiac disease is indicated rather than for the arrhythmia itself.However, the findingof NSVTshould always trigger furtherevaluation of the patient.

Non-susta ined ventricular tachycardia in the structurally normalheart

Exercise-related NSVT is relatively common and appears to be associated with aworse prognosiswhen it occursduring recovery.Polymorphic NSVT requiresextensive evaluation in both symptomatic and asymptomatic patientswith carefulassessment for the presence of coronary ischaemia.An important inherited arrhythmia which may present as exercise-induced NSVT is CPVT.This condition is typicallymanifested by polymorphic or bidirectional VT which are triggered by sympathetic stimulation and exercise(commonly occurringatan exercise levelof120-130 b.p.m.)and isassociated with an increased risk of sudden death.The underlyingmechanism of CPVT is calcium overload leading to delayed afterdepolarizations as a result ofmutations in the genes coding for ryanodine receptor or calsequestrin proteins.Non-sustained ventricular tachycardia is a relatively common finding among athletes.Other causes of NSVT in the absence of SHD include QT interval prolongation caused bymutations in proteins regulating repolarizing currents or electrolyte abnormalities.Athleteswith NSVT should be evaluated for the presence of HCM,a diagnosiswhichmay overlap with some degree of LVH as an adaptation to exercise. Becauseof this challenging distinction,expertconsultation should be obtained if this diagnosis is suspected. Although only limited data are available regarding the significance of NSVT in athletes without a structural cardiac disease,discontinuation of training isnotgenerally recommended.

Non-sustain ed ventricular tachycardia in structuralheartdisease

Non-sustained ventricular tachycardia is common in ischaemic heart disease and can be recorded in 30-80%of patients during long-term ECGmonitoring where it is usually asymptomatic.No studies have demonstrated amortality benefit of suppressing NSVT with either AADs or catheter ablation and treatment is usually not indicated in asymptomatic patients.A range of studies have demonstrated thatNSVT occurring during the first few days after an acute coronary eventhas noadverse long-term prognostic significance1.However, when NSVT occurs 48 h ormore after MI,there is an increased mortality and morbidity even when asymptomatic.For a patientwith non-ischaemic dilated cardiomyopathy,the prognostic significance of NSVT is uncertain and no studies have provided precise guidance for treatmentin thisgroup ofpatients.

The occurrence of NSVT in patientswith an implanted ICD isassociatedwith an increased frequency of shocks and all-causemortality.For these patients,programming the ICD to a long VT detection time and a high ventricular fibrillation(VF)detection ratemay be especially important.

Diagnostic evaluation

For patientswith an apparently normal heart,the 12-lead ECG should be scrutinized forevidenceof typicaloutflow tractVT,polymorphic VT(PMVT),including torsadesde pointes(TdP),oran inherited arrhythmia syndrome,such as the long QT,short QT,Brugada,or early repolarization syndromes.Outflow tract VAs typically have an inferior axiswith either RV or LV origin. When the precordial transition is＜V3and the ratio of the R-and S-waves in lead V2during PVCs or VT divided by this ratio during sinus rhythm exceeds 0.6,a LV outflow tractorigin isstrongly suggested.In addition to the ECG,an echocardiogram to assess the presence or absence of SHD should also be considered for all patientswith NSVT.For caseswhereSHD issuspected but cannotbe definitively diagnosed with echocardiography, cardiac MRImay be especially useful to confirm the presence or absence ofmyocardial scar or wallmotion abnormalities.

Treatment

Non-sustained ventricular tachycardia in the absence of structuralheartdisease

Most short-lastingmonomorphic NSVTs originate from the RV or LV outflow tracts.These arrhythmiasonly require treatment if they are symptomatic,incessant,or produce LV dysfunction.Sudden death is very rare in patientswith outflow tract VT.The treatmentof these arrhythmias iseithermedicalwith abeta-blocker, anon-hydropyridine calcium blocker,class IC drugs,or with catheter ablation.Non-sustained ventricular tachycardiawith a focalmechanismmay also occur from the papillarymuscles and respond to beta-blockers or catheterablation.In addition,reentrant LV VT utilizing false tendons can be treated with verapamil,though with a relatively high recurrence risk on oral therapy. Catheter ablation is effective for idiopathic reentrant LV VT and should be considered even when this sustained arrhythmia is terminated by intravenous verapamil. Catheter ablation can be recommended for patientswith idiopathic NSVT that is highly symptomatic and drug refractory,especially if itisexercise-induced.

Non-sustained ventricular tachycardia in patients with structuralheartdisease

The recordingofpolymorphic NSVT should prompt a thorough evaluation for the presence of coronary ischaemia as the primary therapy for this arrhythmia should be directed to improving coronary perfusion.If non-sustained PMVT can be classified as a CPVT,the risk of life-threatening arrhythmia is high and beta-blockade therapywith potentialplacementofan ICD is recommended.In cases of TdPVT,anymedication or electrolyte disturbance that prolongs repolarization should beaddressed.

Although an ICD should be considered for all patientswith a significantly reduced LVEF(＜0.35),there may be a role for programmed electrical stimulation in selected patients with NSVT and ischaemic heart disease who have less severe LV dysfunction(LVEF＜0.40).Implantable cardioverter-defibrillator implantation is recommended in this group of patients if VF or sustained VT is inducible with programmed electrical stimulation.Similarly,if NSVT is observed in a patient with a priorMI,a history ofsyncope,and LVEF＞40%, EPS is generally recommended to guide treatment,usuallywith ICD implantation,should sustained VT be inducible2.Non-sustained ventricular tachycardia in an asymptomatic patient with a LVEF＞40%does not usually require specific antiarrhythmic therapy,and the goal is optimized treatmentof the underlying heart disease.In the setting of HCM,ICD therapy is an appropriate consideration if NSVT is presentwith or without othermajor risk factors.In general,AAD therapy may be considered for patients with SHD who experience symptomatic,recurrent NSVT not resolved by revascularization,optimization ofmedical therapy,or treatment of reversible factors.

詞匯

potentiate v.起加強(qiáng)作用,使...強(qiáng)有力

provoke v.對(duì)...挑釁,激起,誘導(dǎo)

sarcoidosis n.肉樣瘤病

amyloidosis n.淀粉樣變性

gadolinium n.釓

reassurance n.再保證,勸慰,再保險(xiǎn)

surveillance n.監(jiān)視,監(jiān)督

conservative adj.&n.保守,保守的,保守黨,穩(wěn)當(dāng)?shù)?保守者,防腐劑

trigger n.&v.扳機(jī),導(dǎo)火索;觸發(fā),發(fā)動(dòng),使...觸發(fā)

scrutinize v.詳細(xì)檢查

incessant adj.不停的,沒完沒了

注釋

1.A range of指“一系列，一套”，如A lthough still debated,a range of potentialmechanisms through which cocoam ightexert its benefitson cardiovascular health have been proposed.雖然仍存爭(zhēng)議，已提出可有益于心血管健康的一系列潛在機(jī)制。

2.句子“...usually with ICD implantation,should sustained VT be inducible.”中，“should sustained VT be inducible”是虛擬語(yǔ)氣的一種倒裝結(jié)構(gòu)，完整的句子應(yīng)是“if sustained VT should be inducibe”。當(dāng)虛擬從句中包含有助動(dòng)詞、情態(tài)動(dòng)詞、動(dòng)詞be或have時(shí)，可省略if，并把上述動(dòng)詞提到主語(yǔ)之前。

參考譯文

第65課室性期前搏動(dòng)和陣發(fā)性室性心動(dòng)過速EHRA/HRS/APHRS專家共識(shí)

室性期前搏動(dòng)

室性期前搏動(dòng)（PVC）常見于伴或不伴結(jié)構(gòu)性心臟疾病（SHD）患者，有患者PVC頻發(fā)而無(wú)癥狀，另有患者癥狀明顯而異位搏動(dòng)較少。

多個(gè)研究證實(shí)頻發(fā)PVC與潛在可逆性的心肌病之間存在關(guān)聯(lián)，所選患者心肌病在導(dǎo)管消融后消失。已報(bào)道與左心室功能障礙相關(guān)的24h PCV數(shù)即負(fù)荷值通常達(dá)到總心搏數(shù)的15%～25%以上，盡管可低達(dá)10%。然而，鑒于PVC可為心肌病的結(jié)果，因此，對(duì)于特定的患者難以前瞻性地確定這種因果關(guān)系。重要的是大多數(shù)頻發(fā)PVC患者不會(huì)發(fā)展為心肌病，但現(xiàn)有的可用資料并不能做出正確的危險(xiǎn)預(yù)測(cè)。

診斷性評(píng)估

大多數(shù)無(wú)SHD的PVC患者預(yù)后良好。極少數(shù)PVC患者例外，期前搏動(dòng)與其前的心搏之間的偶聯(lián)間期短（＜300ms），提示短QT綜合征，增加惡性室性心律失常的危險(xiǎn)。如同其它室性心律失常，PVC患者評(píng)估的第1步是確定是否存在SHD。對(duì)于心律失常或其他心臟癥狀的患者，靜息12導(dǎo)聯(lián)心電圖非常有助于評(píng)估心臟瘢痕的存在（Q波或碎裂QRS波群）、Q-T間期、心室肥大和SHD的其他跡象。……