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Implantable cardioverter-defibrillator (ICD) therapy decreases arrhythmic and all-cause mortality in patients at high risk of sudden death. However, its clinical benefit in elderly patients is uncertain. The aim of this study was to assess the long-term efficacy of ICD treatment in elderly patients and to identify markers of successful ICD therapy and risk factors of mortality. We performed multivariate analysis of a prospective long-term database from 2 tertiary care centers including 936 consecutive patients with an ICD. Predictors of ICD therapy and risk factors for mortality were assessed in patients ≥75 years old at ICD implantation compared to younger patients. Mean follow-up time was 43 ± 40 months. Rates of ICD therapy were similar in the 2 age groups. No significant predictors of ICD therapy could be identified in older patients. Median estimated survival was 132 months in patients

Abnormal baseline electrocardiograms (ECGs) are common in patients with isolated left ventricular noncompaction (IVNC). Whether certain electrocardiographic parameters are associated with a poor clinical outcome, however, remains elusive. The present study was therefore designed to comprehensively assess the predictive value of baseline ECG findings in patients newly diagnosed with IVNC.74 patients diagnosed with IVNC were included in the analysis. During follow-up, 8 patients (11%) died of a cardiovascular cause or underwent heart transplantation (primary outcome measure). On univariate analysis, several variables, including repolarization abnormalities (ST segment elevation/depression, T-wave inversion) in the inferior leads (5-year estimator: 67.1 ± 10.7% vs. 98 ± 2.2%; P = 0.001), an increase in PQ- (hazard ratio (HR) 1.032, P=0.004) and QTc-duration (HR 1.037, P=0.001), were predictive of cardiovascular death or heart transplantation. On multivariate analysis, only PQ- and QTc-duration and the presence of repolarization abnormalities in the inferior leads remained significantly predictive of a poor outcome.PQ duration, QTc duration, and repolarization abnormalities in the inferior leads are independently predictive of a poor prognosis in IVNC. Further prospective studies are required to conclusively investigate the usefulness of baseline ECG parameters for risk stratification in patients with IVNC.

BACKGROUND Fabry disease (FD) is an inherited X chromosomal lysosomal storage disease resulting in intracellular storage of globotriaosylceramide. Cardiac involvement is most frequently manifested as left ventricular hypertrophy (LVH). However patients with FD may also have various conduction abnormalities before LVH develops. The present study was designed to analyse early conduction abnormalities on baseline ECG of patients with FD and to investigate their diagnostic value. METHODS AND RESULTS Baseline electrocardiographic (ECG) and echocardiographic measurements of patients with FD (n = 30) were compared with those of heart rate and age matched healthy individuals (n = 50). The PQ interval (131 ± 18 vs 155 ± 20 ms p < 0.000001) and the QRS width (83 ± 11 vs 90 ± 9 ms p < 0.05) were significantly shorter and repolarisation dispersion was more pronounced in patients with FD (QTc dispersion: 66 ± 32 vs 40 ± 24 ms p < 0.001 T(peak) T(end) dispersion: 56 ± 20 vs 37 ± 16 ms p < 0.0005). Moreover P wave duration was significantly shorter (74 ± 16 vs 105 ± 14 ms p < 0.000001) in FD and accounted predominantly for the shortening of the PQ interval. P wave duration showed a 92 sensitivity and 80 specificity for the diagnosis of FD. CONCLUSIONS P wave duration PQ interval and QRS width are shorter and repolarisation dispersion more pronounced in patients with FD compared with heart rate and age matched controls. The significant shortening of the PQ interval in FD occurs because of a marked shortening of the P wave duration which in itself demonstrated a high sensitivity and specificity for early detection and treatment of this disease.

Congenital left ventricular aneurysms and diverticula (LVA/Ds) are rare cardiac malformations that can be detected using echocardiography or other imaging techniques. Some of these patients present with ventricular arrhythmias. This study investigated clinical characteristics of patients with congenital LVA/D presenting with arrhythmic manifestations. Over the previous 20 years 250 patients were diagnosed to have congenital LVA/D at our institution. Diagnosis was made using echocardiography after exclusion of coronary artery disease, local cardiac inflammatory processes, traumatic causes, or cardiomyopathies. At initial presentation 32 of the 250 patients (13%, average age 45 years, range 25 to 65, 21 men and 11 women) exhibited arrhythmias. At least 2 LVA/Ds were present in 6 of these patients. LVA/Ds were localized at the posterobasal, apical, anteroseptal, and anterolateral walls in 12, 11, 4, and 5 patients, respectively. The most common complaints at presentation were syncope or presyncope in 18 patients and palpitations in 11 patients. One patient had survived sudden cardiac death. Long-term electrocardiographic recordings showed ventricular tachycardia (VT) or ventricular fibrillation in 17 patients (53%). Twelve patients underwent electrophysiologic testing. Nine patients had inducible ventricular tachyarrhythmia, whereas induced tachycardia was similar to that during spontaneous arrhythmia in 7 patients. In conclusion, patients with congenital LVA/Ds who present with arrhythmic manifestations commonly have VT. Electrophysiologic testing can reproduce clinical VT in most of these patients.

BACKGROUND: For successful cardiac resynchronisation therapy (CRT) a spatial and electrical separation of right and left ventricular electrodes is essential. The spatial distribution of electrical delays within the coronary sinus (CS) tributaries has not yet been identified. OBJECTIVE: Electrical delays within the CS are described during sinus rhythm (SR) and right ventricular pacing (RVP). A coordinate system grading the mitral ring from 0° to 360° and three vertical segments is proposed to define the lead positions irrespective of individual CS branch orientation. METHODS: In 13 patients undergoing implantation of a CRT device 6±2.5, (median 5) lead positions within the CS were mapped during SR and RVP. The delay to the onset and the peak of the local signal was measured from the earliest QRS activation or the pacing spike. Fluoroscopic positions were compared to localizations on a nonfluoroscopic electrode imaging system. RESULTS: During SR, electrical delays in the CS were inhomogenous in patients with or without left bundle branch block (LBBB). During RVP, the delays increased by 44±32 ms (signal onset from 36±33 ms to 95±30 ms; p

A 66-year-old man with Kartagener's syndrome, situs inversus totalis, and recurrent supraventricular tachycardia and a 49-year-old man with atrial fibrillation and drug-refractory rapid ventricular rate response were referred for catheter ablation. In the first case, the mirrored anatomy of the right atrium was reconstructed using three-dimensional electroanatomical mapping, which guided successful ablation of a typical atrioventricular nodal reentrant tachycardia. In the second case, computerized tomography showed the presence of left atrial isomerism with interruption of the inferior vena cava and azygous continuation into the superior vena cava, guiding advancement of the ablation catheter for access into the positionally right atrial ablation site. These cases illustrate the role of imaging in patients with unusual anatomy of the cardiac chambers and major blood vessels guiding optimal catheter access for catheter ablation.

Catheter ablation is an effective and safe treatment for various arrhythmic disorders. Patients are frequently admitted for an overnight stay after the ablation procedure to monitor for possible postprocedural complications or recurrence of the arrhythmia. The aim of this study was to assess patient satisfaction in patients with supraventricular tachycardia following catheter ablation on an outpatient basis.243 consecutive patients (129 male, 53%; mean age 49 +/- 17 years) underwent electrophysiological study and radiofrequency catheter ablation either on an outpatient basis or a hospitalisation that included at least an overnight hospital stay (inpatient) at a university hospital. All patients were asked to complete a specially designed questionnaire that addressed patient satisfaction as well as the clinical outcome after ablation at six months.The ablation procedure was performed on an outpatient basis in 119 patients (49%). The long-term procedural success rate was 99%. The overall patient satisfaction with the ablation procedure and with the clinical outcome at six months was 90%. There were no significant differences between outpatient and inpatient groups with respect to ablation results and patient satisfaction. Patients in the outpatient group returned to work after 2.8 +/- 1.9 days as compared to 3.9 +/- 2.2 days in the in hospital group (p = 0.001).Overall patient satisfaction and self-reported clinical outcome are comparable for outpatient and inpatient catheter ablations. Patients undergoing outpatient procedures may return to work earlier. Therefore, outpatient ablation procedures may be considered for selected patients without significant comorbidities.

Introduction. For pulmonary vein isolation in patients with atrial fibrillation (AF), some centers use the double transseptal puncture technique for catheter access in order to facilitate catheter manipulation within the left atrium. However, no safety data has so far been published using this approach.Method. 269 ablation procedures were performed in 243 patients (mean age years, 75% men) using the double transseptal puncture for catheter access in all cases. Patients were considered for ablation of paroxysmal (80%), persistent (19%), and permanent (1%) AF. 230 procedures were performed on an outpatient basis (85.5%), and 26 were repeat procedures (9.7%).Results. The double transseptal puncture catheter access was successfully achieved in all patients. The procedural success with the endpoint of pulmonary vein isolation was reached in 255 procedures (95%). A total of 1048 out of 1062 pulmonary veins (99%) were successfully isolated. Major complications occurred in eight patients (3.0%). Of these, seven patients (2.6%) had pericardial effusion requiring percutaneous drainage, and one patient (0.4%) suffered a minor reversible stroke. One patient (0.4%) had a minor air embolism with transient symptoms.Conclusion. The double transseptal puncture catheterization technique allows easy catheter manipulation within the left atrium to reach the goal of acute procedural success in AF ablation. Procedure-related complications are rare, and the technique can be used safely for AF ablation in the outpatient setting.

Randomized trials have demonstrated that implantable cardioverter defibrillator (ICD) therapy may reduce the risk of death in patients with non-ischaemic cardiomyopathy (CMP). In this study, we aimed at determining the long-term benefit of ICD therapy among patients with dilated CMP (DCM) and among those with other non-ischaemic cardiac diseases (NICDs).We performed a single-centre longitudinal study to assess the outcomes of 176 patients with NICDs who were implanted with an ICD for primary or secondary prevention of cardiac death. The cumulative survival rate after 1, 2, 5, and 10 years was 91, 87, 78, and 65%, respectively. Mortality risk did not differ significantly between patients with DCM and those with other NICDs. Atrial fibrillation, recurrent ventricular arrhythmias requiring ICD therapy, and right ventricular pacing, but not delayed intrinsic ventricular conduction, were associated with higher risk. New York Heart Association (NYHA) functional classor =III was an independent predictor of adverse outcome among patients with DCM [hazard ratio (HR) 5.27, P = 0.01], whereas reduced left ventricular function with ejection fraction35% (HR 12.1, P0.001) and anti-arrhythmic drug use (HR 4.82, P = 0.03) were independent predictors among those with other NICDs. Renal insufficiency with estimated glomerular filtration rate60 mL/min/1.73 m(2) (HR 5.9, P0.001) was a strong independent predictor of mortality among all patients with NICD, irrespective of underlying cardiac condition.In ICD patients with DCM, higher NYHA functional class is associated with adverse outcomes. Impaired left ventricular function and anti-arrhythmic drug use predict higher mortality among patients with non-dilated, NICDs. Impaired renal function is a strong predictor of mortality in all patients with NICD.

Purpose: Optimal atrioventricular delay (AVD) setting for cardiac resynchronisation therapy, i.e. biventricular pacing in patients with heart failure, remains a formidable challenge. Thus, the purpose of this study was to evaluate the effects of different AVD on inter- and intra-ventricular resynchronisation using phase histograms of radionuclide ventriculography (RNV). Methods: In 17 consecutive patients (mean age 64 ± 6years), RNV was performed 236 ± 350days after pacemaker implantation for cardiac resynchronisation therapy. Images were acquired during atrial pacing at 80bpm and during biventricular pacing with AVD ranging from 80 to 160ms. Inter-ventricular dyssynchrony was measured by the delay between the mean phase angles of the left and right ventricles. Intra-ventricular dyssynchrony was measured by the standard deviation (SD) of left ventricular phase histograms. Results: Left ventricular (LV) ejection fraction (EF) was inversely correlated to LV dyssynchrony (SD of LV phase histogram, R = −0.82, p

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in young adults. On the basis of histopathological findings its pathogenesis may involve both a genetic origin and an inflammatory process. Bartonella henselae may cause endomyocarditis and was detected in myocardium from a young male who succumbed to sudden cardiac death. HYPOTHESIS: We hypothesized that chronic infection with Bartonella henselae could contribute to the pathogenesis of ARVC. METHODS: We investigated sera from 49 patients with ARVC for IgG antibodies to Bartonella henselae. In this study, 58 Swiss blood donors tested by the same method served as controls. RESULTS: Six patients with ARVC (12%) had positive (>1:256) IgG titres in the immunofluorescence test with Bartonella henselae. In contrast, only 1 elevated titre was found in 58 controls (p ≤ 0.05). Interestingly, all patients with increased titres had no familial occurrence of ARVC. CONCLUSIONS: Further studies in larger patient cohorts seem justified to investigate a possible causal link between chronic Bartonella henselae and ARVC, in particular its sporadic (nonfamilial) form. Copyright © 2008 Wiley Periodicals, Inc.

This overview gives an update on the molecular mechanisms, clinical manifestations, diagnosis and therapy of arrhythmogenic cardiomyopathy (ACM). ACM is mostly hereditary and associated with mutations in genes encoding proteins of the intercalated disc. Three subtypes have been proposed: the classical right-dominant subtype generally referred to as ARVC/D, biventricular forms with early biventricular involvement and left-dominant subtypes with predominant LV involvement. Typical symptoms include palpitations, arrhythmic (pre)syncope and sudden cardiac arrest due to ventricular arrhythmias, which typically occur in athletes. At later stages, heart failure may occur. Diagnosis is established with the 2010 Task Force Criteria (TFC). Modern imaging tools are crucial for ACM diagnosis, including both echocardiography and cardiac magnetic resonance imaging for detecting functional and structural alternations. Of note, structural findings often become visible after electrical alterations, such as premature ventricular beats, ventricular fibrillation (VF) and ventricular tachycardia (VT). 12-lead ECG is important to assess for depolarisation and repolarisation abnormalities, including T-wave inversions as the most common ECG abnormality. Family history and the detection of causative mutations, mostly affecting the desmosome, have been incorporated in the TFC, and stress the importance of cascade family screening. Differential diagnoses include idiopathic right ventricular outflow tract (RVOT) VT, sarcoidosis, congenital heart disease, myocarditis, dilated cardiomyopathy, athlete’s heart, Brugada syndrome and RV infarction. Therapeutic strategies include restriction from endurance and competitive sports, β-blockers, antiarrhythmic drugs, heart failure medication, implantable cardioverter-defibrillators and endocardial/epicardial catheter ablation.

BACKGROUND Magnetic fields may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets, which are small in size but produce strong magnetic fields, have become widely available in recent years. Therefore, NdFeB magnets may be associated with an emerging risk of device interference. OBJECTIVE We conducted a clinical study to evaluate the potential of small NdFeB magnets to interfere with cardiac pacemakers and ICDs. METHODS The effect of four NdFeB magnets (two spherical magnets 8 and 10 mm in diameter, a necklace made of 45 spherical magnets, and a magnetic name tag) was tested in forty-one ambulatory patients with a pacemaker and 29 patients with an ICD. The maximum distance at which the magnetic switch of a device was influenced was observed. RESULTS Magnetic interference was observed in all patients. The maximum distance resulting in device interference was 3 cm. No significant differences were found with respect to device manufacturer and device types. CONCLUSION Small NdFeB magnets may cause interference with cardiac pacemakers and ICDs. Patients should be cautioned about the interference risk associated with NdFeB magnets during daily life.

Background Patients with congenital left ventricular aneurysms and diverticula may present with arrhythmia. The incidence of ventricular arrhythmias and the clinical outcome of these patients have not been reported to date. Methods Among 250 consecutive patients with congenital left ventricular aneurysms and diverticula detected by echocardiography, the clinical outcome of patients who presented with ventricular arrhythmias or associated symptoms was investigated. Results Of 250 patients with congenital left ventricular aneurysms and diverticula, 30 had ventricular arrhythmias or syncope at initial presentation. During a follow-up of 85 months, spontaneous ventricular tachycardia occurred in 17 of these patients (57%). Ventricular tachycardia was sustained in 13, with a monomorphic pattern in 9 patients. In 82% (11 patients), ventricular tachycardia was inducible during electrophysiologic testing. In 7 patients a sustained monomorphic ventricular tachycardia with a right bundle branch block pattern similar to the clinical tachycardia was induced. Twenty patients were treated with antiarrhythmic agents. Eleven patients received an implantable cardioverter defibrillator. Appropriate device discharges were observed in 73% during a follow-up of 61 months. One patient underwent surgical resection of a congenital left ventricular aneurysm. Three patients underwent successful catheter ablation for incessant ventricular tachycardia. Of these, 2 were free of any clinically relevant arrhythmia during follow-up. Three patients died (10, 41, and 89 months after initial presentation). In 2 of them, the cause of death was attributed to ventricular arrhythmia. Conclusion The clinical outcome of patients with congenital left ventricular aneurysms and diverticula and arrhythmia is variable. Clinical ventricular tachycardia in these patients is often monomorphic and usually inducible during electrophysiologic study, indicating a role for this test in risk stratification. Appropriate discharges are frequent in implantable cardioverter defibrillator recipients with congenital left ventricular aneurysms and diverticula.

Background: The mortality of cardiogenic shock (CGS) remains high despite currently available pharmacological and mechanical treatment options. The standard of care in medically refractory situations has been the insertion of an intra-aortic balloon pump. The purpose of this study was to investigate the feasibility, safety, and hemodynamic impact of the TandemHeart® percutaneous left ventricular assist device (pVAD) in CGS. Methods: Thirteen patients from five centers in the US with the diagnosis of CGS were enrolled in the study. Hemodynamic measurements, including cardiac index (CI), mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), and central venous pressure (CVP) were performed presupport, during support and after device removal. Patients were monitored for 6 months. Results: The pVAD was successfully implanted in all 13 patients, with duration of support averaging 60 ± 44 hr. During support, CI increased from 2.09 ± 0.64 at baseline to 2.53 ± 0.65 (P = 0.02), MAP increased from 70.6 ± 11.1 to 81.7 ± 14.6 (P = 0.01), PCWP decreased from 27.2 ± 12.2 to 16.5 ± 4.8 (P = 0.01), and CVP from 12.9 ± 3.7 to 12.6 ± 3.6 (P = NS). Ten patients survived to device explant, 6 of whom were bridged to another therapy. Seven patients survived to hospital discharge and were all alive at 6 months. The two most common adverse events were distal leg ischemia (n = 3) and bleeding from the cannulation site (n = 4). Conclusion: The TandemHeart® PTVA System may be a useful complementary treatment for patients with CGS, especially as a bridge to another treatment. Further study is needed to definitively establish safety and efficacy. © 2006 Wiley-Liss, Inc.

Ein 45-jahriger, bisher vermeintlich gesunder Patient, brach beim Rauchen auf dem Balkon in Anwesenheit seines Bruders bewusstlos zusammen. Dieser verstandigte sofort die Sanitat, die bei Eintreffen Kammerflimmern feststellte. Es erfolgte eine sofortige Defibrillation sowie eine mechanische Reanimation mit Erreichen eines Spontankreislaufes nach 20 min. Der Patient wurde intubiert und mit der REGA ins Universitatsspital gebracht. Dort wurden mittels Computertomographie eine intrazerebrale Blutung sowie eine Lungenembolie ausgeschlossen. Als kardiovaskulare Risikofaktoren lagen eine Adipositas ( BMI 37 kg/m), ein Nikotinabusus (40 py), eine positive Familienanamnese fur eine koronare Herzerkrankung, sowie eine mittelschwere Niereninsuffizienz vor. Folgendes RuheEKG wurde angefertigt

Recent advances in implantable cardioverter defibrillator (ICD) technology have enabled implementation of an automatic monitoring feature in ICDs that provides daily measurements of several technical parameters such as battery status, pacing, and high-voltage impedance. The system alerts the patient with an audible alarm to contact the physician in case the measured parameters are not within normal limits. Early detection of intermittent and potentially serious complications justifies routine use of this feature. This report describes a patient with an ICD who died suddenly due to ventricular fibrillation, which was not appropriately treated by the device. The cause of device malfunction was most likely an intermittent lead fracture that was not detected by the automatic impedance monitoring and alert feature of this device. Based on these data, potential benefits and theoretical pitfalls of automatic impedance monitoring and alert features are discussed.

INTRODUCTION: Ventricular tachycardia (VT) late after myocardial infarction is usually due to reentry in the border zone of the infarct area. Identification of critical parts of the VT reentry circuit by catheter mapping without needing to induce VT is a desirable goal for VT ablation. The aim of this study was to develop a model to predict reentry circuit locations based on characteristics of sinus or paced electrograms and pace mapping (PM) recorded from the infarct region. METHODS: Left ventricular electroanatomic mapping with the CARTO mapping system was performed in 16 male patients with recurrent VT late after myocardial infarction. A total of 1072 left ventricular sites were recorded during atrial pacing (AP) and right ventricular pacing (RVP), and the corresponding electrograms were analyzed for their local activation time (LAT), onset (ONS), end (END), duration (DUR), and amplitude (AMP) in each pacing sequence. At 1041 of these sites, PM was performed; the resulting stimulus to QRS intervals (S-QRS) was determined at 931 sites, the remaining 110 sites did not capture. All the obtained parameters were compared with the location of 18 ablation target areas with a radius of 2 cm defined by success of radiofrequency (RF) ablation or entrainment during VT, or both. RESULTS: Of 1072 sites, 227 (21%) were in the target and 845 (79%) were outside the target. All parameters were significantly different (p < 0.05) in AP and in RVP between inside and outside the target in a univariate analysis. In a multivariate analysis LAT, END, DUR, and AMP in AP, END and AMP in RVP, and S-QRS were independent predictors for the target (p < 0.05). A combination of selected parameters of these predictors (DUR in AP, AMP in RVP, and S-QRS) had a specificity of 64% with a sensitivity of 80% for the target. CONCLUSION: The observations suggest that ablation guided by a combination of abnormal electrograms in different rhythms can be useful to ablate VT and reduce the necessity of VT induction. Anatomically fixed regions of block may be important for reentry and be identifiable during sinus rhythm.

Background— Minute ventilation sensors of cardiac pacemakers measure ventilation by means of transthoracic impedance changes between the pacemaker case and the electrode tip. We investigated whether this technique might detect sleep-related breathing disorders. Methods and Results— In 22 patients, analog waveforms of the transthoracic impedance signal measured by the pacemaker minute ventilation sensor over the course of a night were visualized, scored for apnea/hypopnea events, and compared with simultaneous polysomnography. Analysis of transthoracic impedance signals correctly identified the presence or absence of moderate to severe sleep apnea (apnea/hypopnea index, AHI >20 h −1 ) in all patients (receiver operating characteristics, ROC=1.0). The ROC for AHI scores of ≥5 h −1 and ≥10 h −1 showed an area under the curve of 0.95, P P P Conclusions— Detection of apnea/hypopnea events by pacemaker minute ventilation sensors is feasible and accurate compared with laboratory polysomnography. This technique might be useful to screen and monitor sleep-related breathing disorders in pacemaker patients.

Objectives This study sought to characterize the relationship of conduction delays detected by pace-mapping, evident as a stimulus to QRS interval (S-QRS) delay ≥40 ms, to ventricular tachycardia (VT) re-entry circuit isthmuses defined by entrainment and ablation. Background Areas of slow conduction and block in old infarcts cause re-entrant VT. Methods In 12 patients with VT after infarction, pace-mapping was performed at 890 sites. Stimulus to QRS intervals were measured and plotted in three-dimensional reconstructions of the left ventricle. Conduction delay was defined as ≥40 ms and marked delay as >80 ms. The locations of conduction delays were compared to the locations of 14 target areas, defined as the region within a radius of 2 cm of a re-entry circuit isthmus. Results Pacing captured at 829 sites; 465 (56%) had no S-QRS delay, 364 (44%) had a delay ≥40 ms, and 127 (15%) had a delay >80 ms. Sites with delays were clustered in 14 discrete regions, 13 of which overlapped target regions. Only 1 of the 14 target regions was not related to an area of S-QRS delay. Sites with marked delays >80 ms were more often in the target (52%) than sites with delays 40 to 80 ms (29%) (p Conclusions Identification of abnormal conduction during pace-mapping can be used to focus mapping during induced VT to a discrete region of the infarct. Further study is warranted to determine if targeting regions of conduction delay may allow ablation of VT during stable sinus rhythm without mapping during VT.

A 34-year-old man presented for evaluation of palpitations. Eight years earlier, he had undergone orthotopic heart transplantation for nonischemic cardiomyopathy. During the electrophysiology study, atrial tachycardia (cycle length, 220 ms) originating in the recipient atrium was present at baseline. Atrioatrial conduction from the recipient atrium to donor atrium was present with 2:1 conduction block (Figure), resulting in a donor atrial cycle length of …

Background — Extensive lines of radiofrequency (RF) lesions through infarct (MI) can ablate multiple and unstable ventricular tachycardias (VTs). Methods for guiding ablation that minimize unnecessary RF applications are needed. This study assesses the feasibility of guiding RF line placement by mapping to identify a reentry circuit isthmus. Methods and Results — Catheter mapping and ablation were performed in 40 patients (MI location: inferior, 28; anterior, 7; and both, 5) with an electroanatomic mapping system to measure the infarct region and ablation lines. The initial line was placed in the MI region either through a circuit isthmus identified from entrainment mapping or a target identified from pace mapping. A total of 143 VTs (42 stable, 101 unstable) were induced. An isthmus was identified in 25 patients (63%; 5 with only stable VTs, 5 with only unstable VTs, and 15 with both VTs). Inducible VTs were abolished or modified in 100% of patients when the RF line included an isthmus compared with 53% when RF had to be guided by pace mapping ( P =0.0002); those with an isthmus identified received shorter ablation lines (4.9±2.4 versus 7.4±4.3 cm total length, P =0.02). During follow-up, spontaneous VT decreased markedly regardless of whether an isthmus was identified. VT stability and number of morphologies did not influence outcome. Conclusions — A 4- to 5-cm line of RF lesions abolishes all inducible VTs in more than 50% of patients. Less ablation is required if a reentry circuit isthmus is identified even when multiple and unstable VTs are present.

Background and Aim Despite major advances in the treatment of heart failure, cardiogenic shock (CGS) remains associated with substantial mortality. Recent data suggest that the TandemHeart percutaneous ventricular assist device (pVAD) may be useful in the management of CGS. The aim of this prospective randomized study was to test the hypothesis that the TandemHeart (pVAD) provides superior hemodynamic support compared with intraaortic balloon pumping (IABP). Methods Forty-two patients from 12 centers presenting within 24 hours of developing CGS were included in the study and treated in an initial roll-in phase (n = 9) or randomized to treatment with IABP (n = 14) or TandemHeart pVAD (n = 19). Thirty patients (71%) had persistent CGS despite having an IABP in place at the time of study enrollment. Results Cardiogenic shock was due to myocardial infarction in 70% of the patients and decompensated heart failure in most of the remaining patients. The mean duration of support was 2.5 days. Compared with IABP, the TandemHeart pVAD achieved significantly greater increases in cardiac index and mean arterial blood pressure and significantly greater decreases in pulmonary capillary wedge pressure. Overall 30-day survival and severe adverse events were not significantly different between the 2 groups. Conclusion In patients presenting within 24 hours of the development of CGS, TandemHeart significantly improves hemodynamic parameters, even in patients failing IABP. Larger-scale studies are required to assess the influence of improved hemodynamics on survival.