Implantable cardioverter-defibrillator programming and electrical storm: Results of the OBSERVational registry On long-term outcome of ICD patients (OBSERVO-ICD).

BACKGROUND: Electrical storm (ES) is defined as 3 or more episodes of ventricular fibrillation (VF) or ventricular tachycardia (VT) within 24 hours and is associated with increased cardiac and all-cause mortality. OBJECTIVE: The purpose of this study was to test whether aggressive implantable cardioverter-defibrillator (ICD) programming can be associated with ES. METHODS: The OBSERVational registry On long-term outcome of ICD patients (OBSERVO-ICD) is a multicenter, retrospective registry enrolling all consecutive patients undergoing ICD implantation from 2010 to 2012 in 5 Italian high-volume arrhythmia centers. Clinical history and risk factors were collected for all patients, as were ICD therapy-related variables such as detection zones and delays. The total number of arrhythmic episodes and therapies delivered by the ICD were collected through out-of-hospital visits and remote monitoring. RESULTS: The registry enrolled 1319 consecutive patients, of whom 62 (4.7%) experienced at least 1 ES during follow-up (median 39 months). Patients who experienced ES had a significantly lower VF detection zone (P = .002), more frequently had antitachycardia pacing therapies programmed off during capacitor charge (P = .001), and less frequently had an ICD set with delayed therapies for VT zones (P = .042) and VF zone (P = .036). Patients who experienced ES had a significantly higher incidence of death and heart failure-related death compared to patients with no ventricular arrhythmias and patients with unclustered VTs/VFs (P = .025 and P <.001, respectively). CONCLUSION: Patients with ES had a more aggressive ICD programming setup, including lower VF detection rates, shorter detection times, and no antitachycardia pacing therapies during capacitor charge. This kind of ICD programming potentially could increase the likelihood of ES and the related risk of death.

Effect of cardiac resynchronization therapy on cardiotrophin-1 circulating levels in patients with heart failure.

Cardiotrophin-1 (CT-1) is a member of the interleukin (IL-6) family of cytokines. Plasma CT-1 levels correlate with the left ventricle mass index in patients with dilatated cardiomyopathy and congestive heart failure (CHF). The aim of this paper was to evaluate CT-1 plasma levels, before and after cardiac resynchronization therapy CRT, and to characterizeits prognostic role in patients with CHF. Fifty-two consecutive patients (M/F = 39/13; 56 ± 11 years old) underwent clinical and echocardiographic evaluation, and blood sample collection at baseline. The same evaluation was repeated 6.4 ± 0.79 months after CRT. Patients with a decreased LV end-systolic volume by at least 15% (reverse remodeling) were considered echo responders to CRT. Twenty-nine patients (56%) were responders to CRT. After CRT, only 15 patients (29%) showed increased CT-1 after CRT. They were all non responders to CRT. A multivariate, logistic model showed CT-1 as an independent predictor of CRT echo response (p = 0.005; OR 0.97). During follow-up (18 ± 7 months), 21 cardiac events in 18 patients occurred. A Cox multivariable model showed plasma BNP pre-CRT (p = 0.02; CI 1.2-5.6; OR 3.1) and CT1 post-CRT (p = 0.01; CI 1.4-4.3; OR 2.7) as independent predictors of cardiac events. Analysis of CT-1 plasma levels deserves future consideration for larger, longitudinal studies in patients with CHF.

Cardiac resynchronization therapy in cardiomyopathies.

Cardiomyopathies are a heterogeneous group of diseases of the myocardium that represent a major cause of morbidity and mortality due to progressive heart failure or sudden death. Cardiac resynchronization therapy has become an essential therapeutic tool in the treatment of heart failure patients today. It is an optimal choice in patients with dilated cardiomyopathy; however, its role in the management of patients with other forms of cardiomyopathies is still under investigation. This article discusses the most recent evidence for the use of cardiac resynchronization therapy in cardiomyopathies.

Natriuretic peptides: molecular biology, pathophysiology and clinical implications for the cardiologist.

Natriuretic peptides (NPs) counter the effects of volume overload or adrenergic activation of the cardiovascular system. They are able to induce arterial vasodilatations, natriuresis and diuresis, and they reduce the activities of the renin-angiotensin-aldosterone system and the sympathetic nervous system. However, in addition to wall stress, other factors have been associated with elevated natriuretic peptide levels. Since 2000, because of their characteristics, NPs have become quantitative plasma biomarkers of heart failure. Nowadays, NPs play an important role not only in the diagnosis of heart failure, but also for a prognostic purpose and a guide to medical therapy. Finally, a new drug that modulates the NP system or recombinant analogs of NPs are now available in patients with heart failure.

Superselective cannulation of coronary sinus branch with telescopic system during left ventricular lead placement.

We present a case of a 55-year-old man with idiopathic dilated cardiomyopathy, ejection fraction (EF) of 27%, left bundle branch block with QRS duration of 160 ms, NYHA class III, and optimal medical therapy for at least 6 months who was referred to our division for cardiac resynchronization therapy (CRT) using a biventricular pacing device. During the operation, the coronary sinus branch cannulation failed using classical angioplasty guide wire techniques. The pacing lead was successfully implanted into the posterior target vein using a telescopic dual-catheter system.

Effects of global longitudinal strain and total scar burden on response to cardiac resynchronization therapy in patients with ischaemic dilated cardiomyopathy.

AIMS: To evaluate whether quantification of the extent of scarred left ventricular (LV) tissue by speckle-tracking strain echo (2DSE) can predict response to cardiac resynchronization therapy (CRT) in patients with ischaemic dilated cardiomyopathy (DCM). METHODS AND RESULTS: Forty-five patients (58.3 +/- 8.3 years; 24 males) with ischaemic DCM scheduled for CRT, and 25 controls were studied. A week before implantation all the patients underwent standard Doppler echo, 2DSE, and contrast-enhanced magnetic resonance (MR). Clinical and echocardiographic evaluation was repeated 6 months after CRT. The patients were considered as responders to CRT if LV end-systolic volume decreased by 15%. In DCM patients, LV ejection fraction was 29.2 +/- 5.1%. By evaluating the 765 segments with MR, subendocardial infarct was identified in 17.0% and transmural infarct in 18.3%. With 2DSE, the average global longitudinal strain (GLS) was -23.1 +/- 3.6% in controls and -15.1 +/- 5.1% in DCM (P = 0.001). GLS showed a close correlation with total scar burden using MR (r = 0.64, P < 0.001). At follow-up, patients were subdivided into responders (n = 30; 66.7%) and non-responders (n = 15; 33.3%) to CRT. GLS was significantly different in non-responders than in responders (GLS: -10.4 +/- 5.1 in non-responders vs. -18.4 +/- 14% in responders, P < 0.001). In a multivariable analysis, GLS (P < 0.0001) and radial intraventricular dyssynchrony (P < 0.001) were powerful independent determinants of response to CRT. CONCLUSION: GLS is strongly associated with total scar burden assessed by MR, and is an excellent independent predictor of response to CRT.

Severe obesity and P-wave dispersion: the effect of surgically induced weight loss.

BACKGROUND: Recent data have shown that obesity is an important potential risk factor for atrial fibrillation (AF). The mechanism of development of AF in obesity patients is still unclear and may be related to atrial refractoriness heterogeneity. The aim of our study was to determine the influence of bariatric surgery with a consequent substantial weight loss on P-wave dispersion in morbidly obese population. METHODS: We enrolled in this study 40 severe obese patients, and 40 age-matched non-obese healthy subjects were also recruited as controls. All subjects underwent conventional 12-lead electrocardiography for the analysis of P-wave dispersion. All subjects underwent bariatric surgery and were resubmitted to electrocardiography, biochemical, and anthropometric examination within 12 months after intervention. RESULTS: Severe obese patients had greater values in P-wave duration and dispersion than the normal weight controls. Bariatric surgery reduced significantly P-wave dispersion. There was a significant correlation between decrease of atrial refractoriness heterogeneity and bariatric-surgery-induced weight loss. CONCLUSIONS: In severe obese patients, surgically induced weight loss reduction is associated with significant decreased in P-wave dispersion. The reduction of the atrial refractoriness heterogeneity may be of clinical significance by reducing the risk of atrial fibrillation in morbidly obese subjects.

Different effects of cardiac resynchronization therapy on left atrial function in patients with either idiopathic or ischaemic dilated cardiomyopathy: a two-dimensional speckle strain study.

AIMS: In dilated cardiomyopathy (DCM), attenuation of left atrial (LA) booster pump function has been observed, and attributed both to altered LA loading conditions owing to left ventricular (LV) diastolic dysfunction and to LA involvement in the myopathic process. The aim of the present study was to detect LA systolic dysfunction in DCM using speckle-tracking two-dimensional strain echocardiography (2DSE), and to assess the effects of cardiac resynchronization therapy (CRT) on LA myocardial strain during 6 month follow-up. METHODS AND RESULTS: A total of 90 patients (aged, 52.4 +/- 10.2 years) with either idiopathic (n = 47) or ischaemic (n = 43) DCM underwent standard Doppler echo and 2DSE analysis of atrial longitudinal strain in the basal segments of LA septum and LA lateral wall, and in LA roof. The two groups were comparable for clinical variables (NYHA class: III in 72.2%; IV in 27.8%). LV volumes, ejection fraction, stroke volume, and mitral valve effective regurgitant orifice were similar between the two groups. No significant differences were evidenced in Doppler transmitral inflow measurements. LA diameter and maximal volume were also similar between the two groups. Conversely, LA active emptying volume and fraction were both lower in patients with idiopathic DCM. Peak systolic myocardial atrial strain was significantly compromised in patients with idiopathic DCM compared with ischaemic DCM in all the analysed atrial segments (P < 0.001). At follow-up, 64 patients (71.1%) (37 idiopathic and 27 ischaemic) were responders, and 26 (28.9%) (10 idiopathic; 16 ischaemic) were non-responders to CRT (responder: decrease of LV end-systolic volume >15%). A significant improvement in LA systolic function was obtained only in patients with ischaemic DCM responders to CRT (P < 0.001). By multivariable analysis, in the overall population, it was found that ischaemic aetiology of DCM (beta-coefficient = 0.62; P < 0.0001) and positive response to CRT (beta-coefficient = 0.42; P < 0.01) were the only independent determinants of LA lateral wall systolic strain. CONCLUSIONS: Two-dimensional strain represents a promising non-invasive technique to assess LA atrial myocardial function in patients with DCM. LA pump and reservoir function at baseline and after CRT are more depressed in idiopathic compared with ischaemic DCM patients. Future longitudinal studies are warranted to understand further the natural history of LA myocardial function, the extent of reversibility of LA dysfunction with CRT, and the possible prognostic impact of such indexes in patients with congestive heart failure.

Sympathovagal balance analysis in idiopathic postural orthostatic tachycardia syndrome.

The idiopathic postural tachycardia syndrome (POTS) is a complex disorder characterized by chronic orthostatic symptoms and an increase in heart rate within 10 minutes of standing on upright posture, without significant orthostatic hypotension. We describe a case of a 36 year-old patient with POTS, diagnosed by head-up tilt testing. Power spectral analysis of heart rate variability (HRV), performed during the tilt test, revealed the ratio of low and high frequency powers (LF/HF) that increased with the onset of orthostatic intolerance. The increase in LF/HF power ratio may represent sympathetic beta-receptors hyperactivity. Atenolol alleviated his clinical symptoms.

Effect of weight loss following bariatric surgery on myocardial dispersion of repolarization in morbidly obese patients.

BACKGROUND: Weight-stable obese subjects have an increased risk of arrhythmias and sudden death, even in the absence of cardiac dysfunction, and the risk of sudden cardiac death (SCD) with increasing weight is seen in both genders. The mechanism of unexplained deaths in obese patients is still unclear and may be related to ventricular repolarization abnormalities. The aim of this study is to determine the effect of severe obesity on spatial and transmural ventricular repolarization and to clarify the influence of bariatric surgery with a consequent substantial weight loss on arrhythmogenic substrate in the morbidly obese population. METHODS: For the study, we enrolled 100 severely obese patients; 50 age-matched non-obese healthy subjects were also recruited as controls. All subjects underwent conventional 12-lead electrocardiography for analysis of spatial and transmural ventricular repolarization assessed by corrected QT dispersion (QTc-d), corrected JT dispersion (JTc-d) and transmural dispersion of repolarization, (TDR). All subjects underwent bariatric surgery and were resubmitted to electrocardiographic, biochemical and anthropometric examination 12 months postoperatively. RESULTS: Severely obese patients had greater values in QTc-d, JTc-d and TDR than the normal-weight controls. Bariatric surgery reduced significantly the QTc-d value, JTc-d value and TDR value. There was a significant correlation between decrease of heterogeneity of repolarization indexes (QTd, JTd and TDR) and bariatric surgery-induced weight loss. CONCLUSIONS: In severely obese patients, surgically-induced weight loss is associated with significant decrease in the heterogeneity of ventricular repolarization. The reduction of spatial (QTc-d, JTc-d) and transmural dispersion of repolarization (TDR) may be of clinical significance, by reducing the risk of potentially fatal arrhythmias in morbidly obese subjects.

Recurrent unexplained palpitations (RUP) study comparison of implantable loop recorder versus conventional diagnostic strategy.

OBJECTIVES: The aim of the study was to compare the diagnostic yield and the costs of implantable loop recorder (ILR) with those of the conventional strategy in patients with unexplained palpitations. BACKGROUND: In patients with unexplained palpitations, especially in those with infrequent symptoms, the conventional strategy, including short-term ambulatory electrocardiogram (ECG) monitoring and electrophysiological study, sometimes fails to establish a diagnosis. METHODS: We studied 50 patients with infrequent (< or =1 episode/month), sustained (>1 min) palpitations. Before enrollment, patients had a negative initial evaluation, including history, physical examination, and ECG. Patients were randomized either to conventional strategy (24-h Holter recording, a 4-week period of ambulatory ECG monitoring with an external recorder, and electrophysiological study) (n = 24) or to ILR implantation with 1-year monitoring (n = 26). Hospital costs of the 2 strategies were calculated. RESULTS: A diagnosis was obtained in 5 patients in the conventional strategy group, and in 19 subjects in the ILR group (21% vs. 73%, p < 0.001). Despite the higher initial cost, the cost per diagnosis in the ILR group was lower than in the conventional strategy group (euro 3,056 +/- euro 363 vs. euro 6,768 +/- euro 6,672, p = 0.012). CONCLUSIONS: In subjects without severe heart disease and with infrequent palpitations, ILR is a safe and more cost-effective diagnostic approach than conventional strategy.

Coronary sinus spasm during left ventricular lead implantation for biventricular pacing.

The authors present a case of coronary sinus spasm during left ventricular lead implantation for biventricular pacing relieved by direct infusion of nitroglycerin.

Effect of dynamic myocardial dyssynchrony on mitral regurgitation during supine bicycle exercise stress echocardiography in patients with idiopathic dilated cardiomyopathy and 'narrow' QRS.

AIMS: Cardiac resynchronization therapy (CRT) has become an attractive therapeutic option for patients with end-stage heart failure (HF). Currently, patients are selected for CRT on ECG and on echocardiographic criteria analysed at rest. Whether the physical effort may further increase myocardial dyssynchrony is not fully established. The aim of the study was to test by the use of Doppler myocardial imaging (DMI) if dynamic left ventricular (LV) dyssynchrony during physical effort may be a determinant of dynamic mitral regurgitation in patients with dilated cardiomyopathy and 'narrow' QRS. METHODS AND RESULTS: Sixty patients (62.3 +/- 8.3 years) with idiopathic dilated cardiomyopathy and narrow QRS duration ( < 120 ms) were selected. All the patients underwent standard Doppler echo, colour DMI, supine bicycle exercise stress echocardiography, and cardiopulmonary exercise testing. Cardiac synchronicity was assessed, at rest and at peak exercise, from measurements of time intervals (Ts) between the onset of the QRS complex and the peak myocardial systolic velocity, in a six-basal-six-mid-segmental model. Standard deviation of Ts of the 12 LV segments (Ts-SD-12) was also calculated. In baseline conditions, HF patients showed an LV ejection fraction of 30.1 +/- 4%, and a significant electromechanical delay (Ts-SD-12 > or = 34.4 ms) in 20 patients (33.3%). At peak of physical exercise, a significant electromechanical delay was detected in 35 patients (58.3%), whereas in 47 patients (78.3%) exercise-induced increase in mitral valve effective regurgitant orifice (ERO) was observed. By multivariable analysis, an independent positive association between changes in Ts-SD-12 and in mitral valve ERO (P < 0.0001), as well as an independent inverse correlation of the same changes in Ts-SD-12 with LV stroke volume (P < 0.0001) were detected. In addition, changes in Ts-SD-12 were also independent determinants of peak VO(2) (P < 0.0001) during cardiopulmonary exercise testing. CONCLUSION: Colour DMI is an effective technique for assessing the severity of regional delay in activation of LV walls in HF patients with narrow QRS both at rest and during stress test. The increase in LV dyssynchrony during exercise strongly correlates with the increase in mitral regurgitation severity and with the impairment of LV stroke volume.

Influence of biventricular pacing on myocardial dispersion of repolarization in dilated cardiomyopathy patients.

AIMS: The aim of our study was to evaluate the effect of cardiac resyncronization therapy on QT dispersion (QTd), JT dispersion (JTd), and transmural dispersion of repolarization (TDR), markers of heterogeneity of ventricular repolarization in a study population with severe heart failure. METHODS AND RESULTS: Fifty patients (43 male, 7 female, age 60.2+/-3.1 years) suffering from congestive heart failure (n=39 NYHA class III; n=11 NYHA class IV) as a result of coronary artery disease (n=19) or of dilated cardiomyopathy (n=31), with sinus rhythm (SR), QRS duration >120 ms (mean QRS duration=156+/-21 ms), an ejection fraction <35%, left ventricular end-diastolic diameter >55 mm, presence of atrioventricular asynchrony, intra- and inter-ventricular asynchrony, underwent permanent biventricular pacemaker implantation. A 12-lead standard electrocardiogram was performed at baseline, during right-, left-, and biventricular pacing (BiVP) and QTd, JTd, and TDR were assessed. BiVP significantly reduced QTd (73.93+/-19.4 ms during BiVP vs. 91+/-6.7 ms in SR, P=0.004), JTd (73.18+/-17.16 ms during BiVP vs. 100.72+/-39.04 at baseline, P=0.003), TDR (93.16+/-15.60 vs. 101.55+/-19.08 at baseline, P<0.004), compared with SR. Right ventricular endocardial pacing and left ventricular epicardial pacing both increased QTd (RVendoP 94+/-51 ms, P<0.03; LVepiP 116+/-71 ms, P<0.02), and TDR (RVendoP 108.13+/-19.94 ms, P<0.002; LVepiP 114.71+/-26.1, P<0.05). There was no effect on JTd during right and left ventricular stimulation. CONCLUSIONS: BiVP causes a statistically significant reduction of ventricular heterogeneity of repolarization and has an electrophysiological anti-arrhythmic influence on the arrhythmogenic substrate of dilated cardiomyopathy.

Biventricular pacing and heterogeneity of ventricular repolarization in heart failure patients.

OBJECTIVE: The aim of our study was to evaluate the effect of cardiac resyncronization therapy (CRT) on QT dispersion (QTd), JT dispersion (JTd) and transmural dispersion of re-polarization (TDR), markers of heterogeneity of ventricular repolarization in a study population with severe heart failure. METHODS AND RESULTS: Fifty patients (43 male, 7 female, aged 60.2 ± 3.1 years) suffering from congestive heart failure (N = 39 NYHA class III; N = 11 NYHA class IV) as a result of coronary artery disease (N = 19) or of dilated cardiomyopathy (N = 31), sinus rhythm, QRS duration >130 ms (mean QRS duration >156 ± 21 ms), an ejection fraction < 35%, left ventricular end-diastolic diameter >55 mm, underwent permanent biventricular DDDR pacemaker implantation. A 12-lead standard electrocardiogram was performed at baseline, during right-, left-, and biventricular pacing and QTd, JTd and TDR were assessed. Biventricular pacing significantly reduced QTd (73.93 ± 19.4 ms during BiVP vs 91 ± 6.7 ms at sinus rhythm, p = 0.004), JTd (73.18 ± 17.16 ms during BiVP vs 100.72 ± 39.04 at baseline p = 0.003), TDR (93.16 ± 15.60 vs 101.55 ± 19.08 at baseline; p<0.004), as compared to sinus rhythm. Right ventricular endocardial pacing and left ventricular epicardial pacing both enhanced QTd (RVendoP 94 ± 51 ms, p<0.03; LVepiP 116 ±71 ms, p<0.02) and TDR (RVendoP 108.13 ± 19.94 ms; p<0.002; LVepiP 114.71 ± 26.1; p<0.05).There was no effect on JTd during right and left ventricular stimulation. CONCLUSIONS: Biventricular pacing causes a statistically significant reduction of ventricular heterogeneity of ripolarization and has an electrophysiological antiarrhythmic influence on arrhythmogenic substrate of dilatative cardiomiopathy.

QT dispersion on ECG Holter monitoring and risk of ventricular arrhythmias in patients with dilated cardiomyopathy.

BACKGROUND: QT dispersion (QTd) is increased in patients with dilated cardiomyopathy. Increased QTd has been associated with the risk of sudden death. We studied: a) the relation between QTd on 12-lead ECG and QTd-ECG Holter; b) the relation between QTd apex (QTda) and QTd end (QTde) on ECG Holter and the risk of ventricular arrhythmias in patients with dilated cardiomyopathy. METHODS AND RESULTS: 65 patients with dilated cardiomyopathy (33 idiopathic and 32 post-ischemic etiology; NYHA II-III) were studied. We divided the patients into: Group A -patients with not-sustained ventricular arrhythmias-; and Group B -patients without arrhythmias-. A significant direct correlation between QTd calculated from 12-lead ECG and from ECG Holter was found in all patients. QTda/24h was not significantly different in the two groups (Gr.A 59.9±7.8 msec vs Gr.B 53.6±8.4 msec p=ns) while QTde/24h was significantly higher in Group A (Gr.A 81.9±5.9 msec vs Gr.B 44.5±6.8 msec; p<0.005). In post-ischemic etiology (32 pts; 17 with arrhythmias) the correlation between QTde/24h and ventricular arrhythmias was confirmed (Gr.A 81.4±7.8 msec vs Gr.B 42.6±6.2 msec p<0.002). CONCLUSIONS: ECG Holter recordings can evaluate QTd as well as the QTd on 12-lead ECG. An increased QTde/24h seems to be correlated with the occurence of ventricular arrhythmias in patients with dilated cardiomyopathy and can then be a useful tool to select patients at high risk for sudden death.

Heart rate variability analysis in postural orthostatic tachycardia syndrome: a case report.

The authors present a case of 36 year old male patient with idiopathic postural orthostatic tachycardia syndrome (POTS) diagnosed during head-up tilt testing. Power spectral analysis of heart rate variability (HRV) during the tilt test revealed that the ratio of low and high frequency powers (LF/HF) increased with the onset of orthostatic intolerance. This analysis confirmed in our patient a strong activation in sympathetic tone.