Sinus rhythm QRS amplitude and fractionation in patients with nonischemic cardiomyopathy to identify ventricular tachycardia substrate and location

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Reliability of QRS duration and morphology on surface electrocardiogram to identify ventricular dyssynchrony in patients with idiopathic dilated cardiomyopathy

Using Fourier phase analysis of equilibrium radionuclide angiography in both ventricles, inter- and intraventricular delays were correlated with QRS morphology and duration in 103 patients with idiopathic dilated cardiomyopathy. We found that left bundle branch block on the left axis may reflect a high intra-left ventricular dyssynchrony. A precise evaluation of the dyssynchrony appears useful because a high proportion of patients with incomplete bundle branch block, left anterior hemiblock, or "normal" QRS exhibit a marked intra-LV dyssynchrony and may respond to cardiac resynchronization therapy.     

Prognostic role of inducible ventricular tachycardia in patients with dilated cardiomyopathy and asymptomatic nonsustained ventricular tachycardia

We studied the prognostic relevance of inducible ventricular tachycardia in 32 patients with dilated cardiomyopathy and spontaneous nonsustained asymptomatic ventricular tachycardia. Programmed ventricular stimulation included basic drive cycle lengths of 600, 500, 430, 370, 330 and 300 msec at single, double, and triple extrastimuli. Ventricular tachycardia (greater than or equal to 6 beats) was initiated in 7 patients (22%), with sustained monomorphic ventricular tachycardia being seen in 4 of them. During median follow-up of 21 months (13-44), 14 patients died. Sudden cardiac death occurred in two of the seven patients with inducible tachycardia and in only one of the 25 patients in whom it was not possible to induce tachycardia. Although patients with inducible tachycardia did not differ clinically from those in whom tachycardia could not be induced, the projected mean survival time was significantly shorter in those with inducible tachycardia (10 months vs. 32 months, P = 0.04). For late sudden cardiac death, the positive predictive value of inducible tachycardia was 28%. The negative predictive value was 96%. We conclude that induction of ventricular tachycardia by programmed stimulation might indicate poorer prognosis in patients with dilated cardiomyopathy.     

Usefulness of QRS prolongation in predicting risk of inducible monomorphic ventricular tachycardia in patients referred for electrophysiologic studies

QRS prolongation on surface electrocardiography has been identified as a marker for increased cardiac mortality. A potential mechanism for increased mortality is ventricular tachycardia (VT). This study aimed to evaluate the relation between bundle branch block and sustained monomorphic VT inducibility in patients referred for electrophysiologic studies. We analyzed a cohort of 777 patients (age 63 +/- 18 years, 67% men, left ventricular [LV] ejection fraction [EF] 45% +/- 16, prior myocardial infarction 41%) referred for electrophysiologic studies between 1994 and 2001 who underwent programmed stimulation for VT. Forty-five percent of patients were referred for syncope or a history of VT and/or ventricular fibrillation. Thirty-one percent of patients had prolonged QRS duration (> or =120 ms). Patients with prolonged QRS duration were older, had lower LVEFs, and were more likely to have a history of myocardial infarction. Prolonged QRS was a significant predictor of sustained monomorphic VT inducibility (p <0.0001). On multivariate analysis correcting for age, sex, LVEF, history of myocardial infarction, medications, and QRS conduction delay proved to be independently associated with sustained monomorphic VT inducibility (relative risk 3.290, 95% confidence interval 2.185 to 4.953 for prolonged vs normal QRS duration). Thus, a prolonged QRS duration on surface electrocardiography is a strong, independent predictor of inducible sustained monomorphic VT. Conduction delay may be an important risk factor, providing a substrate for the development of reentrant monomorphic VT, and furthermore suggests a potential mechanism for the increased mortality observed in patients with prolonged QRS.     

Differentiating arrhythmogenic right ventricular cardiomyopathy from right ventricular outflow tract ventricular tachycardia using multilead QRS duration and axis.

BACKGROUND: Ventricular tachycardia (VT) resulting from arrhythmogenic right ventricular cardiomyopathy (ARVC) may be difficult to differentiate from idiopathic right ventricular outflow tract (RVOT) VT. OBJECTIVES: The purpose of this study was to investigate the hypothesis that QRS characteristics would be different in ARVC because of altered conduction through abnormal myocardium. METHODS: In 24 RVOT VT patients (18 women and 6 men; age 42 +/- 10 years) and 20 ARVC patients (12 women and 8 men; age 38 +/- 14 years), mean QRS duration, frontal plane axis, and precordial R-wave transition were measured in 12-lead ECGs recorded during VT. RESULTS: Mean QRS duration was longer in all 12 leads in ARVC patients. A significant difference was noted in leads I, III, aVL, aVF, V(1), V(2), and V(3) (P <.05). Leads I and aVL had the largest mean difference between ARVC and RVOT VT patients of 17.6 +/- 4.7 ms and 15.8 +/- 7.5 ms, respectively (P <.0001). Lead I QRS duration > or =120 ms had a sensitivity of 100%, specificity 46%, positive predictive value 61%, and negative predictive value 100% for ARVC. The area under the receiver operating characteristic (ROC) curve was 0.89. The addition of mean QRS axis <30 degrees (R相似文献   

Correlation between inducibility of sustained ventricular tachycardia and QRS duration

Some studies provide a link between the width of QRS complexesand late potentials occurring at the end of the QRS complexin signal-averaged recordings. The purpose of this study wasto compare three methods of QRS duration measurement: the conventional12 lead ECG. the Frank vectorcardiogram (VCG) and the signal-averagedelectrocardiogram. The recordings were made at a similar timein 121 consecutive patients with the Cardionics PC-based system(ECG and VCG) and the ardionics high resolution ECG, based onmethods described by Simson. Patients with bundle branch blockwere excluded. All patients had presented a myocardial infarctionand were studied either for spontaneous ventricular arrhythmiasor systematically 3 to 6 weeks after an acute myocardial infarction. The signal-averaged ECG and VCG QRS durations were similar in41 patients without inducible ventricular arrhythmias and withnormal signal-averaged ECG but were longer (P<0·001)than the conventional ECG QRS duration. In 36 patients withspontaneous and inducible ventricular tachyarrhythmias, theQRS duration was significantly longer on signal-averaged ECGthan on VCG (P<0·05) and longer on VCG than on conventionalECG (P<0·05). The QRS duration was also significantly(P<0·001) longer with the three techniques in patientswith spontaneous ventricular tachycardia (VT) than in patientswithout spontaneous and inducible VT. A QRS duration on VCG 110 ms and on conventional ECG 100 ms had a sensitivity of93% and 77% and a specificity of 83% and 85% respectively forpredicting an abnormal signal-averaged ECG. In conclusion, the measurement of QRS duration with the conventionalECG, VCG or the signal-averaged ECG could be a simple methodto detect the patients with myocardial infarction prone to VT.     

晚期扩张型心肌病患者QRS波时限与心脏机械同步性的相关性研究

目的评价晚期扩张型心肌病患者QRS波时限是否与心脏机械同步性相关。方法非连续入选晚期扩张型心肌病患者30例,按QRS波时限分为窄QRS组(QRS波时限<120 ms)及宽QRS组(QRS波时限≥120 ms),采用GE Vivid7彩色超声诊断仪应用组织多普勒显像技术测量:①室间机械延迟(IVMD);②室内同步性指数(TSI)并观察③收缩最延迟的部位,比较两组差异。结果窄QRS组的IVMD较宽QRS组窄(为11.5±8.2ms vs40.6±16.7ms,P=0.006),TSI两组无差异(88.6±35.9 ms vs 117.2±40.8 ms,P=0.09)。宽QRS组半数存在室间不同步,而窄QRS组则无室间不同步。宽、窄QRS组室内不同步的比例分别为71.4%、87.5%,两者无差别。收缩最延迟的部位可见于后间隔、侧壁、后壁及下壁,各自占38.6%、23%、23%及15.4%。结论晚期扩张型心肌病患者QRS波时限与室内同步性不直接相关,但宽QRS波患者较常存在左右室间收缩的不同步。收缩最延迟部位因人而异。     

Implantable defibrillator event rates in patients with unexplained syncope and inducible sustained ventricular tachyarrhythmias: a comparison with patients known to have sustained ventricular tachycardia

OBJECTIVES

To assess the clinical significance of inducible ventricular tachyarrhythmias among patients with unexplained syncope.

BACKGROUND

Induction of sustained ventricular arrhythmias at electrophysiology study in patients with unexplained syncope and structural heart disease is usually assigned diagnostic significance. However, the true frequency of subsequent spontaneous ventricular tachyarrhythmias in the absence of antiarrhythmic medications is unknown.

METHODS

In a retrospective case-control study, the incidence of implantable cardiac defibrillator (ICD) therapies for sustained ventricular arrhythmias among patients with unexplained syncope or near syncope (syncope group, n = 22) was compared with that of a control group of patients (n = 32) with clinically documented sustained ventricular tachycardia (VT). Sustained ventricular arrhythmias were inducible in both groups and neither group received antiarrhythmic medications. All ICDs had stored electrograms or RR intervals. Clinical variables were similar between groups except that congestive cardiac failure was more common in the syncope group.

RESULTS

Kaplan-Meier analysis of the time to first appropriate ICD therapy for syncope and control groups produced overlapping curves (p = 0.9), with 57 ± 11% and 50 ± 9%, respectively, receiving ICD therapy by one year. In both groups, the induced arrhythmia was significantly faster than spontaneous arrhythmias, but the cycle lengths of induced and spontaneous arrhythmias were positively correlated (R = 0.6, p < 0.0001). During follow-up, three cardiac transplantations and seven deaths occurred in the syncope group, and two transplantations and five deaths occurred in the control group (36-month survival without transplant 52 ± 11% and 83 ± 7%, respectively, p = 0.03).

CONCLUSIONS

In patients with unexplained syncope, structural heart disease and inducible sustained ventricular arrhythmias, spontaneous sustained ventricular arrhythmias occur commonly and at a similar rate to patients with documented sustained VT. Thus, electrophysiologic testing in unexplained syncope can identify those at risk of potentially life-threatening tachyarrhythmias, and aggressive treatment of these patients is warranted.     

Mapping of ventricular tachycardia in patients with ischemic cardiomyopathy: Current approaches and future perspectives

Despite the technical improvements made in recent years, the overall long‐term success rate of ventricular tachycardia (VT) ablation in patients with ischemic cardiomyopathy remains disappointing. This unsatisfactory situation has persisted even though several approaches to VT substrate ablation allow mapping and ablation of noninducible/nontolerated arrhythmias. The current substrate mapping methods present some shortcomings regarding the accurate definition of the true scar, the modality of detection in sinus rhythm of abnormal electrograms that identify sites of critical channels during VT and the possibility to determine the boundaries of functional re‐entrant circuits during sinus or paced rhythms. In this review, we focus on current and proposed ablation strategies for VT to provide an overview of the potential/real application (and results) of several ablation approaches and future perspectives.     

Substrate-modification using electroanatomical mapping in sinus rhythm to treat ventricular tachycardia in patients with ischemic cardiomyopathy

Summary The treatment especially of frequent ischemic VT remains a challenge for medical and catheter ablation procedures. We evaluated the efficacy of a substrate-based procedure to eliminate clinical VTs in this patient collective.Methods In 25 consecutive patients (ejection fraction 37±12%) with frequent symptomatic medically refractory ischemic VT (with recurrent ICD-shocks), left ventricular anatomic scar mapping (Biosense Webster CARTO™) was performed in order to modify the underlying myocardial substrate. Scar tissue was identified as having bipolar voltages <0.5 mV. Prior to the procedure an electrophysiological study (EPS) to determine number and morphology of inducible VTs was performed. Linear ablation procedures (8 mm tip, 70 Watts, 70 °C) were based on the findings of scar areas and proximity to anatomic obstacles. Correct location of ablation was documented by similarity of the morphology during pace-mapping. Follow-up included clinical evaluation, ICD holter interrogation plus holter ECG recording.Results The clinical VT was eliminated by linear catheter ablation in 23/25 patients (92%) (failure due to unstable catheter position during transaortic approach in 1 and epicardial origin of VT in 1). In 16/23 patients (70%) complete success could be produced with no VT inducible after substrate modification (1.7±1.0 lines per patient). In 7 patients (30%) only partial success was documented with further VTs inducible after ablation. No procedure-related complications occurred. During follow- up (10±4 months) 4 patients (16%) had occurrences of new VTs documented on ICD holter (3 patients with initially partial success and 1 with initial complete success) differing in cycle length and morphology from the clinical VT. Comparing patients with complete to those with partial success, there was a statistically significant difference of 93 vs. 48% freedom of arrhythmia (p=0.03). No difference in regard to baseline characteristics existed in these two patient subgroups.Conclusions Ablation of frequent VTs in patients with ischemic cardiomyopathy can be safely performed using electro-anatomic scar mapping with a high procedural success of 90%. Based on the morphological findings, linear ablation can suppress inducibility of all VTs in 70% of patients with high mid-term efficacy. In patients with only partial ablation success, non-clinical VTs often occur early during follow-up (50%).     

Substrate-modification using electroanatomical mapping in sinus rhythm to treat ventricular tachycardia in patients with ischemic cardiomyopathy

The treatment especially of frequent ischemic VT remains a challenge for medical and catheter ablation procedures. We evaluated the efficacy of a substrate-based procedure to eliminate clinical VTs in this patient collective.

Methods  

In 25 consecutive patients (ejection fraction 37±12%) with frequent symptomatic medically refractory ischemic VT (with recurrent ICD-shocks), left ventricular anatomic scar mapping (Biosense Webster CARTO™) was performed in order to modify the underlying myocardial substrate. Scar tissue was identified as having bipolar voltages <0.5 mv.=" prior=" to=" the=" procedure=" an=" electrophysiological=" study=" (eps)=" to=" determine=" number=" and=" morphology=" of=" inducible=" vts=" was=" performed.=" linear=" ablation=" procedures=" (8=" mm=" tip,=" 70=" watts,=" 70=" °c)=" were=" based=" on=" the=" findings=" of=" scar=" areas=" and=" proximity=" to=" anatomic=" obstacles.=" correct=" location=" of=" ablation=" was=" documented=" by=" similarity=" of=" the=" morphology=" during=" pace-mapping.=" follow-up=" included=" clinical=" evaluation,=" icd=" holter=" interrogation=" plus=" holter=" ecg=">     

右室心尖部起搏QRS波时限对心功能的影响

目的通过观察起搏QRS波时限来预测长期右室心尖部起搏对心脏功能的影响及与心力衰竭的关系。方法对87例因病态窦房结综合征或三度房室阻滞而安装起搏器的病人进行起搏QRS波时限测量、血浆脑钠肽(BNP)的测定、心脏多普勒超声检查并进行长期动态随访,以术后即刻起搏QRS波190ms作为一个分割值把病人分为两组,观察右室心尖部起搏QRS波时限的延长与心力衰竭之间的关系。结果平均随访43±14月,15例(17.2%)出现明显心衰(NYHAⅢ～Ⅳ级)。术后6个月,心衰组的起搏QRS波时限明显延长,血清BNP值增高(p<0.01)。术后6个月,相比与起搏QRS<190ms组,起搏QRS≥190ms组的BNP明显增高(p<0.01)。整个随访期间,起搏QRS≥190ms组心衰发生率要明显增高(p<0.01)。结论右室心尖部起搏QRS波时限的延长与心脏功能的受损和心力衰竭发生密切相关,可以作为心脏功能损害的预测指标。