Vulnerability of the right ventricle to cathodal,anodal, and bipolar stimulation at double diastolic threshold strength

Summary The repetitive ventricular response (RVR) to three stimulation techniques (bipolar, cathodal and anodal) was investigated in 35 patients. 26 patients suffered from coronary heart disease and 9 patients from dilative cardiomyopathy. The stimulation study was performed at a ventricular driving rate of 120/min with one and two premature ventricular extrastimuli. We used rectangular impulses of 1.8 ms duration at duable diastolic threshold strength. RVR was scored as follows: 0: no RVR, 1: one nonstimulated RVR, 2: two nonstimulated RVR, 3: three nonstimulated RVR, 4: four to ten nonstimulated RVR, 5: more than ten nonstimulated RVR lasting less than 2 minutes, 6: sustained ventricular tachycardia or ventricular fibrillation. We found that with unipolar anodal stimulation the diastolic threshold was significantly greater and the effective refractory period of the right ventricle was significantly shorter as compared to the other stimulation techniques. Between the three different electrode configurations there were no significant differences concerning the number of consecutive ventricular depolarizations following premature stimulation. Conclusion: the phenomenon of RVR is not influenced by the stimulation technique (bipolar, cathodal and anodal) at double diastolic threshold.Supported by the Robert-Müller-Stiftung     

Prevalence, predictors, and mortality significance of the causative arrhythmia in patients with electrical storm

INTRODUCTION: Electrical storm (ES) is characterized by either refractory ventricular tachycardia (VT) or ventricular fibrillation (VF). However, little is known about the prevalence, predictors, and mortality implications of the causative arrhythmia in ES. We sought to assess the prevalence, predictors, and survival significance of VT and VF as the causative arrhythmia of ES in implantable cardioverter defibrillator (ICD) patients. METHODS AND RESULTS: Consecutive patients from January 2000 to December 2002 who presented to the ICD clinic with > or = 2 separate ventricular arrhythmic episodes requiring shock within 24 hours were included in the study. ICD interrogation confirmed the number of shocks and provided electrograms for interpretation of the causative arrhythmia. Patients were grouped as VF or VT according to the causative arrhythmia. Their prevalence, predictors, and mortality rates were compared. Of 2,028 patients assessed in the ICD clinic, 208 (10%) presented with ES. VF was the cause of ES in 99 of 208 patients, for an overall prevalence of 48%. Original ICD indication, coronary artery disease, and amiodarone therapy were predictive for the causative arrhythmia. There was no mortality difference between the VT and VF groups; however, both groups had significantly increased mortality compared to a control ICD population without ES. CONCLUSION: VF is the causative arrhythmia for a sizable proportion of patients with ES. The initial ICD indication, coronary artery disease, and amiodarone therapy are predictors of the causative arrhythmias in ES. There does not appear to be any mortality difference between ES patients with VT and VF, but mortality is increased in patients with ES versus control ICD patients without ES.     

Signal-averaged electrocardiography: history, techniques, and clinical applications.

Signal averaging principles have been utilized since around 1875. Their application in medicine to enhance biologic signals was first made in 1947 for improved detection of electroencephalographic signals. The year 1963 marked the first application of this technique to cardiac signals. The more prevalent use in adult cardiology is in the detection of ventricular late potentials (VLPs) which correspond to areas of delayed ventricular activation as slowed conduction velocity. These VLPs have value in predicting the likelihood of malignant ventricular arrhythmias after myocardial infarction (MI). Negative predictive values on the order of 96-99% are convincing as to their ability to predict no arrhythmic event post-MI. Positive predictive values, on the other hand, are poor (10-29%) but improve (35-62%) in combination with other parameters such as depressed left ventricular function and frequent ventricular ectopy. Additional accepted uses for the signal-averaged electrocardiogram (SAECG) include prediction of successful ablative surgery for intractable ventricular tachycardia and facilitating evaluation of patients presenting with syncope of an unclear etiology. Potential future applications of the SAECG are (1) in following patients for rejection after cardiac transplant, (2) as a screening tool for the need for electrophysiologic study, (3) as a predictor of vessel patency after thrombolysis or percutaneous transluminal coronary angiography, and (4) as a tool to assess proarrhythmia. As the technique of signal averaging continues to evolve, its applications may become more diverse and its clinical effectiveness may improve.     

Tachycardia-induced cardiomyopathy in patients with idiopathic ventricular arrhythmias: the incidence, clinical and electrophysiologic characteristics, and the predictors

Idiopathic Ventricular Arrhythmias and Cardiomyopathy. Introduction: Idiopathic ventricular arrhythmias in the form of monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia (VT) can cause tachycardia‐induced cardiomyopathy (TICMP). The aim of this study was to determine the incidence, clinical and electrophysiologic characteristics, and the predictors of TICMP in patients with idiopathic ventricular arrhythmias. Methods: Study population consisted of 249 consecutive patients (148 F/101 M, 45 ± 20 y/o) with frequent PVCs and/or VT. All patients underwent transthoracic echocardiography and 24‐hour Holter monitoring. TICMP was defined as left ventricular ejection fraction (LVEF) of ≤50% in the absence of any detectable underlying heart disease and improvement of LVEF ≥15% following effective treatment of index ventricular arrhythmia. Results: Seventeen (6.8%) patients had TICMP. Patients with TICMP compared to patients with preserved LVEF were more likely to be male (65% vs 39%, P = 0.043) and asymptomatic (29% vs 9%, P = 0.018), and were more likely to have higher PVC burden (29.4 ± 9.2 vs 8.1 ± 7.4, P < 0.001), persistence of PVCs throughout the day (65% vs 22%, P = 0.001), and repetitive monomorphic VT (24% vs 0.9%, P < 0.001). PVC burden of 16% by ROC curve analysis best separated the patients with TICMP compared to patients with preserved LVEF (sensitivity 100%, specificity 87%, area under curve 0.96). Conclusions: TICMP was relatively common (～1 in every 15 patients) in our study population. The predictors of TICMP were male gender, absence of symptoms, PVC burden of ≥16%, persistence of PVCs throughout the day, and the presence of repetitive monomorphic VT . (J Cardiovasc Electrophysiol, Vol. 22, pp. 663‐668, June 2011)     

Retrograde aortic access during ventricular tachycardia ablation: Indications,techniques, and challenges

The retrograde aortic (RA) route is a widely used access route for mapping and ablation of ventricular tachycardias (VT) arising from the left ventricular endocardium. With the expanding role of VT ablation in patients with significant comorbidity, the choice between the RA and transseptal access routes is an increasingly important consideration. An individualized decision based on the location of the arrhythmogenic substrate, vascular anatomy, aortic valve morphology, and operator experience is necessary when deciding on the optimal access route. Among patients with challenging vascular anatomy, growing experience from structural interventions such as transcatheter aortic valve replacements and peripheral vascular interventions has provided valuable insights into techniques for safe retrograde access. The present review focuses on patient selection for RA access, potential complications associated with the technique, and optimal approaches for access in patients with challenging vascular or aortic valve anatomy.     

特发性右心室流出道室性心动过速/室性早搏的性别、年龄和临床特点

Objective The aim of this study was to clarify gender,age and clinical feature of idiopathic right ventricular outflow tract ventricular tachycardia/premature ventricular complexes(ROVT/PVC). Methods We studied 478 patients[mean age(39. 8 ± 13. 8)years]with idiopathic ROVT/PVC who were admitted to our center consecutively in past 15 years. All of them underwent catheter mapping and radiofrequency catheter ablation (RFCA), and the original sites of ventricular tachycardia/premature ventricular complexes were confirmed by catheter mapping and radiofrequency catheter ablation. Results Of 478 patients, 288 patients (60. 3% )were female, 190 patients(39. 7% )were male, female/male ratio was 1.52. The early onset of symptom was at (41.2 ± 12. 7 ) years for female, and ( 37.6 ± 15. 0) years for male ( P ＜ 0. 05 ). Almost all patients had palpitation in varying degrees. Sixty-seven of 478 patients( 14.2% ) had history of near-syncope,and 13 of 478 patients(2. 7% )had history of syncope. Two hundred and sixty-three patients( 55% )underwent unsuccessful treatment with antiarrhythmic drugs before the radiofrequency ablation. Of them, 110 patients (23%)had received one kind of antiarrhythmic drug, 104 patients (21.8%)had received two types of antiarrhythmic drugs,49 patients( 10. 3% )had received three types of antiarrhythmic drugs. Conclusion ROVT/VPC occur more in female than in male,the early onset of symptom is older for female than for male. Almost all patients have symptom in varying degrees, some of them have near-syncope or syncope.     

特发性右心室流出道室性心动过速/室性早搏的性别、年龄和临床特点

Objective The aim of this study was to clarify gender,age and clinical feature of idiopathic right ventricular outflow tract ventricular tachycardia/premature ventricular complexes(ROVT/PVC). Methods We studied 478 patients[mean age(39. 8 ± 13. 8)years]with idiopathic ROVT/PVC who were admitted to our center consecutively in past 15 years. All of them underwent catheter mapping and radiofrequency catheter ablation (RFCA), and the original sites of ventricular tachycardia/premature ventricular complexes were confirmed by catheter mapping and radiofrequency catheter ablation. Results Of 478 patients, 288 patients (60. 3% )were female, 190 patients(39. 7% )were male, female/male ratio was 1.52. The early onset of symptom was at (41.2 ± 12. 7 ) years for female, and ( 37.6 ± 15. 0) years for male ( P ＜ 0. 05 ). Almost all patients had palpitation in varying degrees. Sixty-seven of 478 patients( 14.2% ) had history of near-syncope,and 13 of 478 patients(2. 7% )had history of syncope. Two hundred and sixty-three patients( 55% )underwent unsuccessful treatment with antiarrhythmic drugs before the radiofrequency ablation. Of them, 110 patients (23%)had received one kind of antiarrhythmic drug, 104 patients (21.8%)had received two types of antiarrhythmic drugs,49 patients( 10. 3% )had received three types of antiarrhythmic drugs. Conclusion ROVT/VPC occur more in female than in male,the early onset of symptom is older for female than for male. Almost all patients have symptom in varying degrees, some of them have near-syncope or syncope.     

Right ventricular dysfunction in patients undergoing left ventricular assist device implantation: predictors, management, and device utilization

Nonreversible failure of the right ventricle is seen in 0.04% to 0.1% of postcardiotomy cases. The incidence of right ventricular dysfunction after left ventricular assist device (LVAD) implantation that fails to resolve in the operating room is reported to be as frequent as 20% to 50% and imposes a considerable burden in terms of postoperative morbidity and mortality. Should this syndrome supervene, the mortality of an LVAD operation increases from 19% to 43%. Although most patients can be maintained with prolonged inotropic support, 10% to 15% may require implantation of a separate right ventricular support device.     

Comparison of the results of programmed ventricular stimulation from the right ventricular apex and outflow tract: a randomized, prospective study

Objective: The aim of this prospective study was to analysethe yield of programmed ventricular stimulation at the rightventricular apex compared with the outflow tract. Methods: A stepwise randomized cross-over protocol of programmedventricular stimulation with alternating stimulation at bothsites was used in 66 patients who were studied because of sustainedventricular tachycardia (n = 30), ventricular fibrillation (n= 7), or non-sustained ventricular tachycardia and/or syncope(n = 29). Results: There were no significant differences between the resultsof stimulation from either right ventricular site with regardto the presence or absence of structural heart disease, spontaneousarrhythmia, ejection fraction or effective refractory periods.Overall, monomorphic ventricular tachycardia was inducible in33 patients (50%); in 25 patients (75.8%), this arrhythmia wasinduced from both sites. However, in only 17 of these 25 patients(68%) did the induced monomorphic ventricular tachycardias havethe same morphologies and similar (± 50 ms) cycle lengths.Ventricular fibrillation was inducible in 11 patients (17%),mostly by three extrastimuli (n=8; 73%). Conclusions: (1) stimulation from at least two right ventricularsites is desirable because of their independent contributionto the induction of ventricular tachyarrythmias, (2) the non-inducibilityor inducibility at one ventricular site does not predict theeffect at another stimulation site, (3) the effective refractoryperiod at the right ventricular apex and outflow tract do notdiffer, (4) the inducibility of multiple ventricular tachycardiamorphologies emphasizes the importance of documenting the causeof spontaneous arrhythmias with multiple electrocardiographicleads to ensure the correct interpretation of arrhythmias inducedby programmed stimulation, (5) clinical or haemodynamic featurescannot predict whether one or more stimulation sites will berequired for induction of ventricular tachycardia. These resultsare important for the diagnostic evaluation and assessment ofpharmacological or non-pharmacological interventions.     

Ventricular Arrhythmias in the North American Multidisciplinary Study of ARVC : Predictors,Characteristics, and Treatment

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with sudden cardiac death. However, the selection of patients for implanted cardioverter-defibrillators (ICDs), as well as programming of the ICD, is unclear.

Objectives

The objective of this study was to identify predictors, characteristics, and treatment of ventricular arrhythmias in patients with ARVC.

Methods

The Multidisciplinary Study of Right Ventricular Cardiomyopathy established the North American ARVC Registry and enrolled patients with a diagnosis of ARVC. Patients were followed prospectively.

Results

Of 137 patients enrolled, 108 received ICDs. Forty-eight patients had 502 sustained episodes of ventricular arrhythmias, including 489 that were monomorphic and 13 that were polymorphic. In the patients with ICDs, independent predictors of ventricular arrhythmias in follow-up included spontaneous sustained ventricular arrhythmias before ICD implantation and T-wave inversions inferiorly. The only independent predictor for life-threatening arrhythmias, defined as sustained ventricular tachycardia (VT) ≥240 beats/min or ventricular fibrillation, was a younger age at enrollment. Anti-tachycardia pacing (ATP), independent of the cycle length of the VT, was successful in terminating 92% of VT episodes.

Conclusions

In the North American ARVC Registry, the majority of ventricular arrhythmias in follow-up are monomorphic. Risk factors for ventricular arrhythmias were spontaneous ventricular arrhythmias before enrollment and a younger age at ICD implantation. ATP is highly successful in terminating VT, and all ICDs should be programmed for ATP, even for rapid VT.     

Right ventricular scar‐related ventricular tachycardia in nonischemic cardiomyopathy: Electrophysiological characteristics,mapping, and ablation of underlying heart disease

1 Background

Right ventricular (RV)‐scar related ventricular tachycardia (VT) is often due to arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) or cardiac sarcoidosis (CS), but some patients whose clinical course has not been described do not fulfill diagnostic criteria for these diseases. We sought to characterize the electrophysiologic substrate and catheter ablation outcomes of such patients, termed RV cardiomyopathy of unknown source (RCUS).

2 Methods and results

Data of 100 consecutive patients who presented with RV cardiomyopathy and/or RV‐related VT for ablation were reviewed (51 ARVC/D, 22 CS; 27 RCUS). Compared to ARVC/D, RCUS patients were older (P = 0.001), less commonly had RV dilatation (P = 0.001) or dysfunction (P = 0.01) and fragmented QRS, parietal block, and T‐wave inversion. Compared to CS, R‐CUS patients had less severe LV dysfunction. Extent and distribution of endocardial/epicardial scar and inducible VTs in RCUS patients were comparable with ARVC/D and CS patients. At a median follow‐up of 23 months, RCUS patients had more favorable VT‐free survival (RCUS 71%, ARVC/D 60%, CS 41%, P = 0.03) and survival free of death or cardiac transplant (RCUS 92%, ARVC/D 92%, CS 62%, P = 0.01). No RCUS patients developed new criteria for ARVC/D or CS in follow‐up.

3 Conclusions

Up to one‐third of patients with RV scar‐related VT are not classifiable as ARVC/D or CS. These patients had a somewhat better prognosis than ARVC/D or sarcoid and did not develop evidence of these diseases during the initial 2 years of follow‐up. The extent to which this population comprises mild ARVC/D, CS, or other diseases is not clear.     

Prognostic implications of ventricular ectopy one week,one month,and sixteen months after an acute myocardial infarction

Background: Ventricular ectopy early after an acute myocardial infarction (AMI) has previously been demonstrated to predict mortality. Less information is available about the prognostic implications of ventricular ectopy occurring late after an AMI, and no information is available about the prognostic implication of the development of ventricular ectopy during the first year after an AMI. Hypothesis: The purpose of the present prospectively conducted trial, a part of the Danish Verapamil Infarction Trial II (DAVIT II), was to evaluate the prognostic implication of (1) ventricular premature complexes (VPCs) recorded by 24-h Holter monitoring 1 week, 1 month, and 16 months after an AMI; and (2) development of > 10 VPCs/h or of any complex ventricular ectopy, that is, pairs, more than two types of VPCs, ventricular tachycardia, or > 10 VPCs/h during follow-up after an AMI. Methods: Patients were monitored 1 week (n = 250), 1 month (n = 210), and 16 months (n = 201) after AMI. Results: Multivariate analyses based on history, clinical findings, and ventricular ectopy showed the following results: After 1 week, > 10 VPC_s/h (p = 0.0006) and heart failure (p< 0.007); after 1 month, >10 VPC_s/h (p = 0.003) and resting heart rate (p < 0.02); and after 16 months, ventricular tachycardia (p = 0.002) independently predicted long-term mortality. Mortality was significantly predicted by the development of > 10 VPC_s/h from 1 week to 1 month (p = 0.003) and 16 months (p = 0.03), and from 1 to 16 months (p = 0.007) after AMI, as well as by the development of any complex ventricular ectopy from 1 week to 1 month (p = 0.02) and 16 months (p = 0.01), and from 1 to 16 months (p = 0.04) after AMI. Conclusion: The present study demonstrated that 1 week and 1 month after an AMI the quantity of VPCs, that is, >10 VPCs/h, predicted mortality, whereas 16 months after an AMI the quality of VPCs, that is, ventricular tachycardia, predicted mortality.     

Cardiac tamponade complicating ventricular arrhythmia ablation: Real life data on incidence,management, and outcome

Background and Objective

Cardiac tamponade during ablation procedures is a life-threatening complication. While the incidence and management of tamponade in atrial fibrillation ablation have been extensively described, the data on tamponade during ventricular ablations are very limited. The purpose of this study is to shed light on the incidence, typical perforation sites, and optimal management as observed through real-life data in a tertiary referral center for ventricular ablation.

Methods and Results

Consecutive patients with structural heart disease undergoing ventricular tachycardia ablation from 2008–2020 were analyzed. Of the 1078 patients undergoing 1287 ventricular ablation procedures, 20 procedures (1.5%) were complicated by cardiac tamponade. In all but one patient, the tamponade was treated with emergent pericardial drainage, while nine patients eventually underwent surgical repair. The perforation occurred during transseptal or subxiphoid puncture in six patients, during ventricle mapping in two patients, and during ablation in five patients (predominantly basal left ventricle). Steam pop as definite perforation cause could only be established in two patients. Regardless of the management of the complication, all patients survived to discharge.

Conclusion

Cardiac tamponade during ventricular ablation occurred in 1.5% of the procedures. In nine patients cardiac repair was necessary. Perforation was mostly associated with subxiphoid puncture or ablation of the basal left ventricle.     

Determination of left ventricular volume, ejection fraction, and myocardial mass by real-time three-dimensional echocardiography

Reconstructed three-dimensional (3-D) echocardiography is an accurate and reproducible method of assessing left ventricular (LV) functions. However, it has limitations for clinical study due to the requirement of complex computer and echocardiographic analysis systems, electrocardiographic/respiratory gating, and prolonged imaging times. Real-time 3-D echocardiography has a major advantage of conveniently visualizing the entire cardiac anatomy in three dimensions and of potentially accurately quantifying LV volumes, ejection fractions, and myocardial mass in patients even in the presence of an LV aneurysm. Although the image quality of the current real-time 3-D echocardiographic methods is not optimal, its widespread clinical application is possible because of the convenient and fast image acquisition. We review real-time 3-D echocardiographic image acquisition and quantitative analysis for the evaluation of LV function and LV mass.     

超声心动图与左室辅助装置：现状、问题及未来

作为终末期心脏病的一种目的性治疗或心脏移植的过渡,左室辅助装置的临床应用在逐渐增多,其治疗终点的评价及并发症的诊断正在成为心血管医学界关注的重要问题。超声心动图在左室辅助装置评价中具有重要价值,可用于术前除外禁忌证、术中监测管道的位置并评价左室充盈和减负荷状态、术后监测低血容量、心包填塞及右心衰竭,并用以评价心肌恢复情况。     

Positional localization: three-dimensional transthoracic echocardiographic techniques for the measurement of cardiac mass, volume, and function

An accurate and reproducible determination of cardiac volume and mass is important for the selection and timing of therapeutic interventions. Quantitative three-dimensional echocardiography has evolved to provide these measurements with the use of a noninvasive, readily available, and inexpensive technique. We introduce and review the principle of positional localization as well as the clinical application of this technique for the measurement of cardiac volume and mass.