Prophylactic implantable cardioverter defibrillator therapy in dilated cardiomyopathy: impact of left ventricular function.

BACKGROUND: The value of an implantable cardioverter defibrillator (ICD) for primary prevention in dilated cardiomyopathy (DCM) is unclear, as randomized trials could not show a survival benefit compared to drug therapy. It has not been investigated if patients with a very poor left ventricular function (LVEF) could profit from an ICD. METHODS: Consecutive patients with DCM who received an ICD between December 1996 and November 2003 were included in this analysis. Patients were divided in group A (secondary prevention) and group B (primary prevention). Both groups were stratified in subgroups with left ventricular ejection fraction (LVEF) below and above 20%. RESULTS: Fifty eight patients were included (male 50, age 56.4+/-12.7 years). Follow-up was 34+/-19 months. There was no difference regarding death (18% vs. 11%), but significant differences (p value <0.05) regarding any adverse events (55% vs. 22%), any ICD intervention (48% vs. 17%) and ICD interventions for life-threatening arrhythmias (27% vs. 0%) between group A and B. LVEF was not predictive for events in group A, whereas in group B only patients with a LVEF <20% had events (p value 0.02). Over time there was an increase of the LVEF of more than 15% determined by echocardiography in 36% of patients, significantly more often in group B. CONCLUSIONS: Indication for primary prevention with an ICD in DCM should be made with caution. Larger studies are needed to determine if patients with LVEF of <20% might benefit from an ICD.

Atrial fibrillation: estimated excess rate of stroke due to lacking adherence to guidelines.

QUESTIONS UNDER STUDY: Many patients with atrial fibrillation (AF), risk factors for stroke and no obvious contraindications do not receive oral anticoagulation. Estimations of the increased rate of stroke due to neglected anticoagulation, particularly in an elderly, non-selected population, are unknown. METHODS: Consecutive patients with paroxysmal or permanent atrial fibrillation admitted to the medical or surgical department of our hospital for any reason were studied. Risk factors for stroke and contraindications for anticoagulation were recorded. Estimations of the increased rate of cerebrovascular events due to neglected anticoagulation were based on data of a large meta-analysis. Patients were further stratified into different age and risk groups. RESULTS: 484 patients with a mean age of 75 (12) years were studied, 45% were female. 237 patients had no oral anticoagulation at hospital discharge, despite guideline recommendations. Contraindications for anticoagulation were found in 85 (36%) of these patients, resulting in 152 patients with neglected anticoagulation (31% of all patients with AF). We estimated that, if all those patients would have been treated according to guidelines, 7.4 strokes per year could be prevented in the study population. The estimated rate of preventable events was 4.9%/year (7.4/152). CONCLUSIONS: With better adherence to guidelines for oral anticoagulation in patients with atrial fibrillation and risk factors for stroke, a significant number of strokes could be prevented.

Evidence for left ventricular remodeling after percutaneous coronary intervention: effect of percutaneous coronary intervention on left ventricular ejection fraction and volumes.

BACKGROUND: Post-stress ejection fraction (EF), end-diastolic (EDV) and end-systolic (ESV) volumes by gated myocardial perfusion SPECT (MPS) are well validated, reproducible and of prognostic significance. However, little is known about the impact of percutaneous coronary intervention (PCI) on left ventricular volumes and remodeling. METHODS: Thirty-eight patients who underwent MPS before and 6 months after PCI were evaluated. MPS were interpreted deriving summed stress (SSS), rest (SRS) and difference (SDS = SSS-SRS; extent of ischemia) scores. EF, EDV and ESV were generated by QGS trade mark. Pre-PCI MPS were compared to post-PCI MPS. RESULTS: Single vessel disease was present in 63% of patients. PCI of one vessel was performed in 82% of patients. After 6 months, SSS (10.6 +/- 6.3 vs. 2.8 +/- 4.3, p < 0.001) and SDS (8.2 +/- 5.6 vs. 1.4 +/- 2.3, p < 0.001) had improved; however, EF did not change significantly (55 +/- 10 vs. 57 +/- 13, p = ns). Still, EDV (105 +/- 25 ml vs. 96 +/- 25 ml, p = 0.006) and ESV (49 +/- 19 ml vs. 41 +/- 18 ml, p = 0.001) were significantly reduced. CONCLUSION: Results of MPS documented the beneficial effect of PCI on symptoms and extent of ischemia. In addition, the findings showed a significant decrease in ESV and EDV after PCI as compared to pre-PCI findings which points to a positive effect on left ventricular remodeling even in the absence of significant changes in EF.

Cardiac resynchronization in severe heart failure and left bundle branch block: a single center experience.

OBJECTIVE: To assess the feasibility and longterm outcome of cardiac resynchronization therapy (CRT) in patients with impaired left ventricular function (LVEF <35%), left bundle branch block (QRS >120 ms) and dyspnoea NYHA 0 III at a single centre. METHODS AND RESULTS: Forty-seven patients were referred for implantation of a CRT device. In only 4 patients (9%) the device could not be implanted due to technical problems during the procedure. In the remaining 43 patients (65 +/- 10 years; 7 female) a CRT device was implanted. Follow-up time was 12 +/- 10 months. Twenty-one patients had dilated cardiomyopathy (DCM) and 22 patients had coronary artery disease (CAD). NYHA functional class improved from 3.0 +/- 1.4 to 2.5 +/- 0.7 (p <0.0001), accompanied by an improvement of LVEF [median 20% (range 15-25) vs 32% (range 20-40); p <0.0001]. A significant reduction of hospitalisation time for heart failure was found when the year before and the year after device implantation [18 days (range 5-27) vs 1 day (range 0-3); p <0.0001] were compared. Twelve (28%) patients, 9 with CAD, and 3 with DCM died. Two CAD patients and all patients with DCM who died had a combined CRT device with implantable cardioverter/defibrillator. CONCLUSION: In patients with severely impaired LVEF and wide QRS due to LBBB, CRT is feasible and safe. It improved dyspnoea and LVEF and reduced hospitalisation stays for heart failure during long-term follow-up.

Relation of N-terminal pro-B-type natriuretic peptide to symptoms, severity, and left ventricular remodeling in patients with organic mitral regurgitation.

Natriuretic peptides reflect cardiac stress and may therefore be useful in the management of patients with valvular heart disease. Data regarding these biomarkers in organic mitral regurgitation (MR) are sparse. In this study, 144 patients with moderate or severe organic MR were prospectively enrolled in an observational, multicenter study to analyze the relation of N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) to symptoms, severity of MR, and echocardiographic parameters. NT-pro-BNP levels (median 373 pg/ml, interquartile range 150 to 997) were associated with age, gender, creatinine, New York Heart Association (NYHA) functional class, atrial fibrillation, left ventricular (LV) end-systolic dimension, and the LV ejection fraction. Independent predictors of increased NT-pro-BNP levels were NYHA functional class (p = 0.003), atrial fibrillation (p = 0.005) and LV end-systolic dimension (p = 0.029). MR severity and left atrial dimension were not independently associated with NT-pro-BNP levels. NT-pro-BNP levels increased significantly with NYHA class (p <0.001) but not with MR severity (p = 0.144). NT-pro-BNP levels were significantly higher in symptomatic patients than in asymptomatic patients (582 pg/ml [interquartile range 246-1,360] vs 157 pg/ml [interquartile range 64 to 256], p <0.0001). The area under the receiver-operating characteristic curve to predict symptoms for NT-pro-BNP was 0.80 (95% confidence interval 0.71 to 0.88), which was significantly higher than for all echocardiographic variables (p <0.001 for all). In conclusion, NYHA functional class, atrial fibrillation, and LV end-systolic dimension are independent predictors of increased NT-pro-BNP levels in patients with moderate or severe organic MR. Therefore, NT-pro-BNP may be helpful in the clinical evaluation and management of patients with MR, especially when it is doubtful whether symptoms are related to MR or not.

Value of repeated cardiac magnetic resonance imaging in patients with suspected arrhythmogenic right ventricular cardiomyopathy.

AIM: Diagnosis of early stages of arrhythmogenic right ventricular cardiomyopathy (ARVC) with minimal structural abnormalities is challenging. The purpose of this study was to assess the value of repeated cardiac magnetic resonance imaging (CMR) in patients referred for right ventricular arrhythmias and clinical suspicion of ARVC. METHODS AND RESULTS: Prospective follow-up study of 18 patients (8 females) studied with CMR for suspected ARVC. Patients with implanted defibrillators (ICD) were excluded. Mean follow-up was 37 +/- 16 (12-59) months. Patients were assigned to 2 categories (ARVC likely or ARVC unlikely) according to a CMR-score based on right ventricular abnormalities. Clinical follow-up revealed no disease progression in 17 patients (94%). In 1 patient, an ICD was implanted because of disease progression. Of 9 patients with initial findings suggestive of ARVC, follow-up CMR remained positive in 3 and was diagnosed as normal in 6, mainly due to the inability to confirm the presence of fatty infiltrates at follow-up (5 of 6 patients). Initially, 9 patients had a normal CMR and 8 of those remained normal during follow-up. CONCLUSION: Repeated CMR after an average follow-up of 3 years was normal in 6 of 9 patients with clinical findings consistent with early stages of ARVC at the time of baseline CMR. Thus, CMR diagnosis of early stage ARVC is difficult and should be made with caution.

Implantable cardioverter defibrillator proarrhythmia due to an interaction with "noncompetitive atrial pacing": an algorithm to prevent atrial arrhythmias.

An episode of device related proarrhythmia observed with a dual chamber ICD is reported. Ventricular tachycardia was induced due to an inappropriate interaction of programmed device settings with automatic algorithms, including noncompetitive atrial pacing (NCAP), an algorithm used to prevent atrial tachyarrhythmias.

Late potential analysis: is a mathematically-derived X,Y,Z lead system comparable to a true orthogonal X,Y,Z lead system?

BACKGROUND: Analysis of ventricular late potentials (LP) with signal-averaged ECG (SAECG) using three bipolar, orthogonal X,Y, Z leads is a validated method of risk-stratification in patients prone to ventricular tachycardia. The aim of this study was to validate a ECG system, which allows LP analysis using X,Y, Z leads mathematically derived from the standard 12-lead ECG. METHODS AND RESULTS: In 36 patients (age 56 +/- 12 years, coronary artery disease 71%, LVEF 46 +/- 14%) with known or suspected ventricular tachyarrhythmia, two consecutive SAECGs were recorded, one with mathematically derived and another one with true X,Y, Z leads. Time domain measurements with these different lead systems were compared using linear regression analysis and "Bland-Altman" plots. Correlation was good (r = 0.92) for the filtered QRS complex duration, but poor for the terminal QRS amplitude (RMS) and duration (LAS) criteria (r = 0.66 and 0.61, respectively; P < 0.0001). Defining LPS as present if at least two of the three time domain criteria were abnormal, the result matched in 28 (78%), but differed in 8 (22%) patients. CONCLUSION: SAECG using X,Y, Z leads mathematically derived from the standard 12-lead ECG compared to true bipolar X,Y, Z leads show a close correlation in filtered QRS duration, but can differ considerably in the other time domain measurements, resulting in different interpretation of LP analysis in 22%. Therefore, SAECG registration should currently be performed with true X,Y, Z leads, until the accuracy of other approaches is validated.

Arrhythmogenic right ventricular cardiomyopathy: diagnostic and prognostic value of the cardiac MRI in relation to arrhythmia-free survival.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a potentially fatal disease, which is often difficult to diagnose. As a non-invasive test cardiac magnetic resonance imaging (CMR) has become an important tool in establishing the diagnosis. The aim of this study was to evaluate the diagnostic and prognostic value of CMR in patients with suspected ARVC and to assess the long-term outcome of patients with CMR-diagnosed ARVC. Thirty-six patients with suspected ARVC (26 male, 10 female, median age 41 years) underwent non-invasive and invasive clinical tests as gold standard for ARVC diagnosis. ARVC was clinically diagnosed in 19 patients and excluded in 17 patients. Both groups underwent CMR, and diagnosis was confirmed by CMR in 16/18 patients with clinically diagnosed ARVC (sensitivity 89%), and correctly excluded in 14/17 of patients with clinically excluded ARVC (specificity 82%). This result indicates a positive predictive value of the CMR of 84%, and a negative predictive value of 88%, respectively (p < 0.0001). Using a scoring system, multiple CMR parameters were compared in the two groups in regard of the clinical diagnosis. By univariate analysis, right ventricular fatty tissue infiltration (p = 0.0003) was predictive for diagnosis. Compared by outcome, 37% of patients with clinically and by CMR-diagnosed ARVC had an arrhythmic event during a mean follow-up of 16 +/- 11 months. These data suggest that CMR is a highly sensitive and specific method to diagnose or exclude ARVC, and thus, has an important prognostic impact on predicting arrhythmia free survival.

Rate response of a closed-loop stimulation pacing system to changing preload and afterload conditions.

Closed-loop stimulation (CLS) is a new sensor concept for rate adaptive pacing measuring changes in the unipolar right ventricular impedance, which correlates to changes of the right ventricular contractility and reflects the autonomic nervous innervation of the heart. Some patients do not tolerate the CLS mode because of inappropriate tachycardia, mainly related to postural changes. This study tested if the rate response of the CLS sensor is influenced not only by myocardial contractility but also by rapid changes in right ventricular filling. In 12 patients (10 men, median age 77 years) with a Biotronik Inos(2)-CLS DDDR pacemaker and 14 controls (13 men, median age 59 years) head-up tilt and handgrip testing was performed to provoke rapid changes in pre- and afterload. Tilting the pacemaker patients resulted in a nonphysiological steep increase of the sensor rate (increase >20 beats/min, peak after 1 minute, return to baseline within 2-3 minutes), which was significantly different from the control group, showing only a slight rise in intrinsic heart rate immediately after tilting. Simultaneously to the rapid increase in sensor rate, the pacemaker patients showed a marked orthostatic decline of systolic blood pressure. During handgripping, heart rate and blood pressure curves were similar in both groups. In patients with this CLS pacemaker, rapid preload reduction during head-up tilting caused an overshooting sensor rate increase, reproducing the authors' clinical observation of postural pacemaker tachycardia in some patients. Consequently, they concluded that the rate response of the CLS pacing system can be inappropriately influenced by rapid shifts of blood volume, affecting right ventricular filling.