Prevalence of asymptomatic upper extremity venous obstruction in 302 patients undergoing first implantation of cardioverter defibrillator.

BACKGROUND: Little is known about the prevalence of upper extremity vein obstruction or anomalies in patients before first implantation of implantable cardioverter defibrillator (ICD). It remains unclear in which patients contrast venography is warranted before implantation procedure. METHODS: Results of clinical data and contrast venography of 302 consecutive patients scheduled for first ICD implantation were analyzed. RESULTS: Prevalence of upper vein obstruction was 6.6% (20/302 patients) in a typical patient population undergoing first ICD implantation. Age, left ventricular ejection fraction, underlying heart disease, prior open-heart surgery, or cardiopulmonary resuscitation were not predictors of obstruction. Patients with previous cardiac pacemaker implantation had a higher rate of obstruction, though this was not statistically significant (20% vs 15.7%, P = 0.54). Persistent left vena cava was found in 0.7%. CONCLUSION: There is no clinical parameter sufficient enough to predict upper extremity venous obstruction. Contrast venography may be considered in patients with previous pacemaker placement but should not be a routine diagnostic tool in unselected patients prior to first ICD-implantation procedure.

An impaired renal function and advanced heart failure represent independent predictors of the incidence of malignant ventricular arrhythmias in patients with an implantable cardioverter/defibrillator for primary prevention.

AIMS: Malignant ventricular arrhythmias and inappropriate therapies represent unsolved problems in patients with implantable cardioverter/defibrillator (ICD) for primary prevention. This study focuses on the incidence of such therapies and thereby seeks to identify new predictors of adverse events to enhance risk stratification. METHODS AND RESULTS: Ninety-four consecutive patients with mild-to-moderate heart failure (NYHA II-III) and depressed left ventricular function (≤35%) were followed for 34 ± 20 months. Two hundred and ninety-one malignant ventricular arrhythmias were documented in 51 patients (54%). Eighteen patients (19%) received inappropriate ICD therapies (e.g. atrial fibrillation, sinus tachycardia, etc.). Patients with malignant arrhythmia (1.34 ± 0.44 vs. 1.16 ± 0.4 mg/dL, P = 0.017) and patients suffering from inappropriate ICD therapies (1.54 ± 0.48 vs. 1.2 ± 0.38 mg/dL; P = 0.007) revealed a significantly worse renal function before ICD implantation than participants without any therapy. An increased serum creatinine at baseline (2 vs. 1 mg/dL; odds ratio (OR) 3.96; P = 0.02; 95% CI: 1.2-13.04) and NHYA class III compared with II (OR: 2.96; P = 0.02; 95% CI: 1.16-7.48) represent strong and independent predictors for the occurrence of ventricular arrhythmias. Moreover, an impaired renal function is identified as an independent risk factor for inappropriate therapies (OR: 5.6; P = 0.004; 95% CI: 1.72-18.22). CONCLUSION: An impaired renal function and advanced heart failure before ICD implantation for primary prevention are identified as independent predictors for the incidence of appropriate ICD interventions. With regard to current guidelines and economical aspects, patients suffering from an impaired renal function or advanced heart failure seem to benefit most from ICD therapy.

T-wave variability detects abnormalities in ventricular repolarization: a prospective study comparing healthy persons and Olympic athletes.

BACKGROUND: Sudden cardiac death in athletes is more common than in the general population. Routine screening procedures are performed to identify competitors at risk. A new Holter-based parameter analyzes variation of the ventricular repolarization (TVar). The aim of this study was to evaluate differences in electrocardiogram (ECG), Echo, and Holter (H) in competitive athletes compared to a healthy control group consisting of medical students (MS). METHODS: A total of 40 athletes (19 females, Olympic team, Luxembourg) and 40 MS (22 females) were examined by means of a resting ECG, treadmill exercise (TE), echocardiogram (Echo), as well as H recordings during a routine screening visit. To analyze TVar, a 20-minute H recording at rest (sampling rate 1000 per second) was performed. Moreover, heart rate variability (HRV) as well as HR turbulence (HRT) was computed. RESULTS: No differences in demographic variables were detected. Quantification of HRV detected a significant increase in the vagal component of autonomic cardiac modulation. In contrast, no differences for HRT were found. Echo parameter demonstrated a thicker septal wall without differences of the posterior wall. TVar values were normal in range, but did differ significantly between the two groups. No correlation between TVar and echo as well as Holter parameters was detected. CONCLUSIONS: TVar was able to demonstrate significant differences in terms of alterations of ventricular activation. This might indicate an early change of myocardial repolarization representing a substrate for life-threatening arrhythmia. Larger studies on the predictive value of TVar including follow-up are necessary to confirm this preliminary finding.

Evaluation of fractal-coated temporary pacing leads in the early postoperative course.

BACKGROUND: The performance of temporary pacing wires is still limited by capture and sensing problems. Fractal coating can enhance electrical properties and reliability. We therefore investigated fractal-laminated wires in comparison with conventional wires. METHODS: In 21 patients two unipolar, fractal-coated pacing wires (fe) and one conventional bipolar electrode (se) were implanted in ventricular position. Afterward pacing threshold (V), R-wave sensing (mV), lead impedance (ohm), and slew-rate (mV/s) were measured. Loss of capture or sensing and dislocation was documented. fe wires were examined with energy dispersive x-ray diffraction (EDX)-analysis and scanning electrode microscopy (SEM). RESULTS: Failure in pacing was less frequent in fe wires. Also fe leads had lower pacing thresholds at implantation (0.76 +/- 0.15 V vs 1.51 +/- 0.95 V, P< 0.0001) and afterward. Furthermore fe wires showed lower increase of pacing threshold/time (0.25 V/day vs 0.42 V/day). R-wave sensing and slew-rate values in the fe group on day of operation (5.81 +/- 4.80 mV; 0.63 +/- 0.71 V/s) were lower than in the se group (10.37 +/- 6.89 mV; 1.85 +/- 1.71 V/s P< 0.0001) and afterward. Nevertheless, decrease of amplitude/time was lower in fe wires (0.17mV/day vs 0.46 mV/day). fe wires always had lower impedance values. CONCLUSIONS: Lower pacing threshold and increase of threshold/time in fe wires indicate more reliable function. Initial lower sensitivity values are still not understandable and must be investigated. However, fe wires, constancy of sensing and impedance values was more stable, so fe epicardial wires can be recommended for safe and feasible use.

ST segment depression in hypertensive patients: a comparison of exercise test versus Holter ECG.

INTRODUCTION: This study compared ST segment depression (ST depression) during cycle ergometry (ergometry) versus simultaneous 24-hour ambulatory blood pressure measurement and electrocardiogram recording (24-h ABPM/ECG) during everyday life. METHODS: In a German multicenter study, ergometry and 24-h ABPM/ECG records of 239 hypertensive patients were retrospectively analyzed. ST depression was defined as an ST segment depression (1 mm limb or chest recordings V1 to V6) in an incremental cycle ergometry, or 1 mm in the 24-h ABPM/ECG recording under everyday conditions. Blood pressure parameters at the onset of ST depression in the context of the respective method were compared. RESULTS: 18 patients had ST depression only in ergometry (group B), 23 had ST depression only during 24-h ABPM/ECG monitoring (group C) and 28 patients had ST depression with both methods (group D). Group A had no ST depression with any method. In group D, at the onset of ST depression with 24-h ABPM/ECG investigation, all parameters except diastolic blood pressure were significantly lower compared with the corresponding parameters at the onset of ST depression with ergometry (systolic blood pressure: 148 +/- 19 vers 188 +/- 35 mmHg, p < 0.001; heart rate: 93 +/- 12 vs 120 +/- 21 beat/min, p < 0.0001; double product: 13,714 +/- 2315 vs 22,992 +/- 3,985 mmHg/min), p < 0.0001). CONCLUSION: ST depressions during everyday life detected by 24-h ABPM/ECG are characterized by a substantially lower triggering threshold for blood pressure level parameters compared with ergometry. The two methods detecting ischemia do not replace but complement each other.

Acute effects of cardiac resynchronization therapy on left ventricular Doppler indices in patients with congestive heart failure.

BACKGROUND: Patients with heart failure frequently exhibit intraventricular conduction delays, which contribute to asynchronous contraction patterns and impaired hemodynamic performance. Cardiac resynchronization therapy (CRT) with biventricular (BV) and left ventricular (LV) pacing has been shown to improve both hemodynamic and clinical performance. This study investigated the effects of CRT on LV Doppler indices in these patients. METHODS AND RESULTS: Thirty-two patients with advanced heart failure (New York Heart Association class > or =III, QRS >120 milliseconds, PR interval >150 milliseconds) were studied 4 weeks after implantation of a CRT system. Doppler echocardiography was conducted in 3 separate CRT modes, right ventricular, LV, and BV stimulation at 3 different atrioventricular delays. CRT resulted in significant improvement of Doppler parameters such as filling time (FT, 313 +/- 111 milliseconds at baseline --> 363 +/- 154 milliseconds [BV], P <.05), aortic velocity time integral (AO(VTI) 23.2 +/- 7.4 cm at baseline --> 26.8 +/- 8.8 cm [LV], P <.05), and the myocardial performance index (MPI, 1.21 +/- 0.51 at baseline --> 0.85 +/- 0.34 [BV], P <.05). The most improvement was observed with LV and BV stimulation at short and intermediate atrioventricular delays (80-120 milliseconds), independent of ischemic or idiopathic origin. CONCLUSIONS: CRT improves hemodynamic performance in patients with heart failure with intraventricular conduction delays. Doppler echocardiography allows noninvasive evaluation of acute CRT effects in patients with heart failure. In particular, FT, AO(VTI), and MPI are useful parameters for noninvasive follow-up and optimization of pacing parameters.

Treatment of persistent atrial fibrillation using phased radiofrequency ablation technology.

A novel ablation system consisting of a duty-cycled phased radiofrequency generator and multielectrode mapping and ablation catheters has been introduced to provide ablation therapy in patients with symptomatic atrial fibrillation (AF). Contiguous lesions may be created using anatomically designed ablation catheters maneuvered under fluoroscopic guidance without the use of a 3D electroanatomic mapping system. In addition to pulmonary vein isolation using a circular, decapolar ablation catheter, an ablation strategy targeting complex fractionated atrial electrograms can be performed using two supplemental multiarray catheters specifically designed for ablation at the left atrial septum and within the left atrial body. Procedural times for treating persistent AF using phased radiofrequency are reported as being between 2 and 2.5 h. Freedom from AF ranges between 33 and 75% after a single procedure, which is comparable to other conventional ablation approaches (utilizing electroanatomic mapping). Additional studies in larger patient numbers are needed to understand the long-term maintenance of results and potential adverse effects of the technology.

Catheter ablation of electrical storm.

Electrical storm (ES) is defined as the occurrence of ≥ three distinct episodes of ventricular arrhythmia (VA) in patients with implanted defibrillators within 24 h. Whereas conventional strategies for acute rhythm stabilization may be effective in some patients the occurrence of ES impairs survival and predicts recurrent VA. Catheter ablation in the setting of ES is complex and involves decisive strategies for individualized ablation approaches adapted to the patient's cardiac abnormalities. Success rates have been documented to be between 79 and 94% in larger studies and effective ablation improves survival and freedom from any VA. Ablation should be considered early in the treatment plan and availability may be improved by interhospital collaboration with highly experienced VA intervention centers.

Postablation asymptomatic cerebral lesions: long-term follow-up using magnetic resonance imaging.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) is complicated by cerebral emboli resulting in acute ischemia. Recently, cerebral ischemic microlesions have been identified with diffusion-weighted magnet resonance imaging (MRI). OBJECTIVE: The clinical course and longer-term characteristics of these lesions are not known and were investigated in this study. METHODS: Of 86 patients, 33 (38%) had new asymptomatic cerebral lesions documented on MRI after catheter ablation for AF; 14 of these 33 (42%) underwent repeat MRI at different time intervals (2 weeks to 1 year) during follow-up, and clinical symptoms as well as size and number of residual lesions were documented. RESULTS: In postablation cerebral MRI, 50 new lesions were identified (3.6 lesions/patient) in 14 patients. No patient presented any neurological symptoms. Distribution of the lesions was predominantly in the left hemisphere (60%) and the cerebellum (26%); 52% of the lesions were small (≤3 mm maximum diameter), 42% were medium (4 to 10 mm) and 3 lesions (6%) had a maximum diameter >10 mm. Follow-up MRI after a median of 3 months revealed 3 residual lesions in 3 of 14 patients corresponding to the large acute postablation lesions (>10 mm). The remaining 47 of 50 (94%) of the small or medium-sized lesions were not detectable at follow-up evaluation. CONCLUSIONS: Most asymptomatic cerebral lesions observed acutely after AF ablation procedures were ≤10 mm in diameter. 94% of all lesions healed without scarring at follow-up >2 weeks after ablation. The larger acute lesions produced chronic glial scars. Neither chronic nor acute lesions were associated with neurological symptoms.

Catheter ablation of electrical storm in a collaborative hospital network.

An electrical storm (ES) is defined as multiple ventricular arrhythmia episodes leading to implantable cardioverter defibrillator interventions. Although conventional rhythm stabilization might be of help acutely, ES involves high mortality and morbidity. We evaluated the effect of catheter ablation strategies in the setting of an interhospital collaborative network on the recurrence of ventricular arrhythmia episodes and mortality in patients with ES. Consecutive patients presenting for invasive treatment of ES from December 2007 to December 2009 were included. All patients underwent catheter ablation of ventricular arrhythmia. The strategies were adapted to the individual cardiac pathologic features. The follow-up examination constituted periodic implantable cardioverter defibrillator interrogation. A total of 32 patients were included. Of the 32 patients, 29 (91%) had monomorphic ventricular tachycardia and 3 ventricular fibrillation. The mean number of implantable cardioverter defibrillator-treated episodes within 7 days before ablation was 16 ± 11. Of the 32 patients, 27 underwent ablation within 24 hours after admission, and 5 underwent acute ablation within 8 hours. In 3 patients, epicardial ablation was performed. In all but 2 patients (6%), the clinical arrhythmia was successfully ablated. During a median follow-up of 15 months, 10 patients (31%) had recurrences of sustained ventricular arrhythmia, including 2 patients (6%) with recurrent ES. Three patients (9%) died during the follow-up period. In conclusion, catheter ablation effectively suppressed ventricular arrhythmia midterm recurrences in patients presenting with ES. Catheter ablation is complex in these severely sick patients. The recurrence rate of ventricular arrhythmia appears to be 31% and the mortality rate to be 9%. Collaborative hospital networks to increase the prompt availability of ES ablation might help to optimize the ES outcome.

Detailed electrical analysis of lead failures in a small-scaled right ventricular defibrillator lead: reality of Sprint Fidelis medical device recalls.

INTRODUCTION: This paper illustrates our experience with the Sprint Fidelis lead (SF, single coil model 6931). We investigated lead failure incidence, analysed for possible predictive factors and examined the efficacy of integrated early ICD warning systems. METHODS: We analysed 181 consecutive patients with SF (follow up: 406 +/- 250 days). Left ventricular ejection fraction, age, gender, follow up, ICD indication, type of device, duration of implantation, and target vein used for implantation were evaluated as potential predictive factors of lead failure. Additionally, the predictive value of recommended impedance alert adaptations, the potential effects of the sensing integrity counter (SIC), and of the new lead integrity alert (LIA)(R) were studied. RESULTS: Nine lead failures were identified. Lead failure occurred significantly more often in patients with single- and dual-chamber devices. None of the patients under cardiac resynchronisation therapy (CRT) had a lead failure (p=0.04). Seven failures (78%) became apparent through inappropriate shock interventions. Impedance alert adaptations did not prevent any inappropriate shock intervention, but the SIC and the activation of the LIA might have prevented inappropriate interventions. A fractured pace/sense ring conductor was identified as the most vulnerable part of the SF lead (in 7 failures, 78%). CONCLUSION: We verified an increased failure rate in patients with the SF lead. Only patients with CRT devices were free from lead failure, suggesting a correlation with increased physical activity. The impedance alert reprogramming did not predict any inadequate shock interventions but LIA may become a new valuable tool for the early detection of lead failure signs.

Incidence and characteristics of appropriate and inappropriate therapies in recipients of ICD implanted for primary prevention of sudden cardiac death.

BACKGROUND: We evaluated the number of appropriate and inappropriate therapies for ventricular tachyarrhythmias and trigger mechanisms in 55 MADIT II (MII)-like (group 1) and 86 SCD-HeFT-like (group 2) patients. METHODS AND RESULTS: We analyzed 399 appropriate episodes in 31 patients with implantable cardioverter defibrillators (ICD) implanted according to the MII trial indications, and 502 appropriate episodes in 47 patients matching the SCD-HeFT trial criteria (mean follow-up in both groups = 33 +/- 19 months). In group 1, 39 treated episodes were inappropriate (9% of all episodes), while in group 2, 76 episodes were treated inappropriately (15% of all episodes). At least one episode of inappropriate ICD therapy was recorded in 18% of patients in group 1 (n = 10) and in 22% of patients in group 2 (n = 19). CONCLUSIONS: Our study supports the implantation of ICD as primary prevention in patients who are at risk of sudden cardiac death, although the proportion of inappropriate ICD interventions remains high.

Cerebral diffusion-weighted magnetic resonance imaging: a tool to monitor the thrombogenicity of left atrial catheter ablation.

INTRODUCTION: Cerebral embolism and stroke are feared complications of left atrial catheter ablation such as pulmonary vein (PV) ablation. In order to assess the thrombogenicity of left atrial catheter ablation, knowledge of both clinically evident as well as silent cerebral embolism is important. The aim of the current study was to examine the use of diffusion-weighted magnetic resonance imaging (DW-MRI) for detection of cerebral embolism, apparent as well as silent, caused by PV catheter ablation. METHODS AND RESULTS: Twenty consecutive patients without structural heart disease undergoing lasso catheter-guided ostial PV ablation using an irrigated-tip ablation catheter were studied. Cerebral MRI including DW single-shot spin echo echoplanar, turbo fluid attenuated inversion recovery, and T2-weighted turbo spin echo sequences were performed the day after the ablation procedure. Ten patients also underwent preprocedure cerebral MRI. All ablation procedures were performed without acute complications. A mean of 3.2 +/- 0.6 PVs were ablated per patient. No patient had neurological symptoms following the procedure. In 2 of 20 patients (10%), DW-MRI revealed new embolic lesions, which were located in the right periventricular white matter in one and in the left temporal lobe in the other patient. There was no statistically significant difference in age, history of hypertension, left atrial volume, and procedure duration between the 2 patients with and the 18 patients without cerebral embolism following AF ablation. CONCLUSION: This is the first study using highly sensitive DW-MRI of the brain to detect asymptomatic cerebral embolism after left atrial catheter ablation. Even small, clinically silent, embolic lesions can be demonstrated with this technique. DW-MRI can be used to monitor and compare the thrombogenicity of different AF ablation approaches.

Determinants of heart rate turbulence after ventricular premature beats in healthy volunteers.

INTRODUCTION: A decline in the acceleration of the heart rate (HR, heart rate turbulence, HRT) after a ventricular premature capture is associated with increased mortality in patients suffering from coronary artery disease. The physiological properties of HRT have not been evaluated in a large human cohort. METHODS: In 95 healthy individuals, HRT parameters onset (TO) and slope (TS) as well as the turbulence timing (TT) were calculated from 24-hour Holter ECGs. With the help of a simple, linear, weighted regression model, gender specific differences of TO and TS were compared. A multiple linear regression model served to evaluate the influence of age and the basic HR preceding the ventricular premature contraction (VPC) on HRT. RESULTS: The median of TT is present in regression line #5. We discovered that, in men and women, TO is reduced as basic HR rises (p<0.01). In contrast, analysis of TS showed a divergence: in men, TS declines as basic HR increases. However, basic HR modifies TS in women to some extent (p<0.01). A multiple, linear regression model revealed a decrease of HRT with increasing age in men. CONCLUSIONS: The acceleration of HR after a ventricular premature beat occurred within the first 11 beats in more than 75% of our healthy individuals. An increased HR prior to VPC affects HRT in men. Increasing age leads to an attenuation of HRT in men and to a reduction of TO in women. These results emphasise the significance of the physiological properties of HRT when using HRT for risk stratification, especially in elderly patients.

Impact of age and basic heart rate on heart rate turbulence in healthy persons.

Postextrasystolic acceleration of heart rate (HR), known as HR turbulence (HRT) is attenuated in patients with coronary artery disease at increased risk of adverse events. The influence of age and basic HR on HRT have not been evaluated in a large cohort of persons. In 95 healthy individuals, HRT onset (TO) and slope (TS) were calculated from 24-hour ambulatory electrocardiograms, as well as the turbulence timing (TT). Gender specific differences in TO and TS were compared in simple, linear, weighted regression model. The influence of age and the basic HR preceding ventricular premature contractions on HRT were examined. We found that, in men and women, TO decreases as basic HR increases (P < 0.01). In contrast, in men, TS decreased as basic HR increases, whereas in women, basic HR influenced TS only slightly (P < 0.01). A multiple, linear regression model revealed a decrease in HRT with increasing age in men. In conclusion, physiological acceleration of the HR within the first 11 beats after premature ventricular complex (VPC) was observed in >75% of healthy individuals. An accelerating HR preceding the VPC influenced HRT in men. An increasing age was associated with a decrease in HRT in men and a decrease in TO in women. These results illustrate the importance of physiological modulations of HRT when used for risk stratification, especially in older populations.