Larger interventricular conduction time enhances mechanical response to resynchronization therapy.

BACKGROUND: Previous studies have reported that the left ventricular (LV) pacing site is a major determinant of the hemodynamic response to cardiac resynchronization therapy (CRT). However, lead positioning in a lateral or posterolateral cardiac vein may not be optimal for every patient. The objective of this study was to assess the relationship between the right ventricular (RV)-to-LV conduction time and the systolic function during CRT on the basis of changes to LV pressure-volume loops. METHODS: Left ventricular pressure and volume data were determined using a conductance catheter during CRT device implantation in 10 patients. Four endocardial LV sites were systematically assessed at four atrioventricular delays. The RV-to-LV conduction time was measured as the time interval between spontaneous peak R waves, recorded through the RV lead and the LV catheter. RESULTS: The optimal pacing site varied among patients. However, the pacing site associated with the maximum RV-to-LV conduction time resulted in a stroke volume improvement comparable to the pacing site identified through individual hemodynamic optimization (41 ± 17 mL vs 44 ± 18 mL, P = 0.266). Moreover, the RV-to-LV conduction time recorded at each endocardial pacing site correlated positively with the increase in stroke volume (r = 0.537; P < 0.001), stroke work (r = 0.642; P < 0.001), and the pressure-derivative maximum (r = 0.646; P < 0.001) obtained with CRT. CONCLUSIONS: An optimal acute response to CRT can be obtained by positioning the LV lead at the site associated with the maximum RV-to-LV conduction time. A significant correlation appears to exist between RV-to-LV conduction time and the improvement in systolic function with CRT.

Discordant electrical and mechanical atrial delays affect intracavitary electrogram-based cardiac resynchronization therapy optimization.

AIMS: It has been shown that atrioventricular (AV) delay optimization improves cardiac resynchronization therapy (CRT) response. Recently, an automatic algorithm (QuickOpt™, St Jude Medical), able to quickly identify the individual optimal AV interval, has been developed. The algorithm suggests an AV delay based on atrial intracavitary electrogram (IEGM) duration. We hypothesized that the difference between electrical and mechanical atrial delays could affect the effectiveness of QuickOpt method. The aim of this study was to test this hypothesis in 23 CRT patients who were recipients of St. Jude Medical devices. METHODS AND RESULTS: Using echocardiography, aortic flow velocity time integral (VTI) was evaluated at baseline, at QuickOpt suggested AV delay and after reducing it by 25 and 50%. Mechanical inter-atrial delay (MIAD) derived from echo/Doppler and electrical inter-atrial delay (EIAD) derived from IEGM were also analysed. Optimal AV delay was identified by the maximal VTI. In 11 patients (Group 1) the maximal VTI was achieved at the AV delay suggested by the algorithm, in 6 patients (Group 2) after a 25% reduction, and in 6 patients (Group 3) after a 50% reduction. While EIAD was similar among the three groups, MIAD was significantly different (P< 0.001). MIAD was longer than EIAD in Group 1 (P= 0.028) and shorter than EIAD in Groups 2 (P= 0.028) and 3. (P< 0.001). Mechanical inter-atrial delay was the only independent predictor of the AV interval associated with the best VTI (R(2) = 0.77; P< 0.001). CONCLUSION: Our results show that MIAD plays the main role in determining the optimal AV delay, thus caution should be taken when optimizing AV by IEGM-based methods.

Application of the Seattle Heart Failure Model in patients on cardiac resynchronization therapy.

BACKGROUND: The Seattle Heart Failure Model (SHFM) is a multimarker risk assessment tool able to predict outcome in heart failure (HF) patients. AIM: To assess whether the SHFM can be used to risk-stratify HF patients who underwent cardiac resynchronization therapy with (CRT-D) or without (CRT) an implantable defibrillator. METHODS AND RESULTS: The SHFM was applied to 342 New York Heart Association class III-IV patients who received a CRT (23%) or CRT-D (77%) device. Discrimination and calibration of SHFM were evaluated through c-statistics and Hosmer-Lemeshow (H-L) goodness-of-fit test. Primary endpoint was a composite of death from any cause/cardiac transplantation. During a median follow-up of 24 months (25th-75th percentile [pct]: 12-37 months), 78 of 342 (22.8%) patients died; seven patients underwent urgent transplantation. Median SHFM score for patients with endpoint was 5.8 years (25th-75th pct: 4.25-8.7 years) versus 8.9 years (25th-75th pct: 6.6-11.8 years) for those without (P < 0.001). Discrimination of SHFM was adequate for the endpoint (c-statistic always ranged around 0.7). The SHFM was a good fit of death from any cause/cardiac transplantation, without significant differences between observed and SHFM-predicted survival. CONCLUSION: The SHFM successfully stratifies HF patients on CRT/CRT-D and can be reliably applied to help clinicians in predicting survival in this clinical setting.

Rotational mechanics of the left ventricle in AL amyloidosis.

AIMS: The aim of this study was to investigate whether alterations in left ventricular (LV) twisting and untwisting motion could be induced by cardiac involvement in patients with immunoglobulin light-chain (AL) systemic amyloidosis. METHODS AND RESULTS: Forty-five patients with AL amyloidosis and 26 control subjects were evaluated. After standard echocardiographic measurement and two-dimensional (2D) speckle tracking echocardiography, LV rotation at both basal and apical planes, twisting, twisting rate, and longitudinal strain were measured. Tissue Doppler imaging (TDI) derived early diastolic peak velocity at septal mitral annulus (E') was also evaluated. Twenty-six of 45 patients with systemic amyloidosis were classified as having cardiac amyloidosis (CA) if the mean value of the LV wall thickness was ≥ 12 mm or not (NCA) if this value was not reached. In NCA patients, both LV twist and untwisting rate were increased while they were decreased in CA patients making them similar to the control group. Longitudinal strain was reduced only in CA patients. Impaired relaxation as indicated by E' values was progressively reduced in the course of the disease. CONCLUSIONS: Both twisting and untwisting motions are increased in patients with AL systemic amyloidosis with no evidence of cardiac involvement while they are reduced in patients with evident amyloidosis cardiac involvement. This finding suggests that impaired LV relaxation induces a compensatory mechanism in the early phase of the disease, which fails in more advanced stage when both twisting and untwisting rates are reduced. The increase in LV rotational mechanics could be a marker of subclinical cardiac involvement.

Effects of smoking in patients treated with cardiac resynchronization therapy.

Smoking is associated with increased morbidity and mortality in cardiac patients. However, data on the prognostic impact of smoking in heart failure (HF) patients on cardiac resynchronization therapy with defibrillator (CRT-D) are absent. We investigated the effects of smoking on all-cause mortality and on a composite endpoint (all-cause death/appropriate device therapy), appropriate and inappropriate device therapy, in 649 patients with HF who underwent CRT-D between January 2003 and October 2011 in 6 Centers (4 in Italy and 2 in USA). 68 patients were current smokers, 396 previous-smokers (patients who had smoked in the past but who had quit before the CRT-D implant), and 185 had never smoked. The risk of each endpoint by smoking status was evaluated with both Kaplan-Meier and Cox proportional-hazard analysis. After adjusting for age, left ventricular ejection fraction, QRS width and ischemic etiology, both current and previous smoking were independent predictors of all-cause death [HR = 5.07 (95 % CI 2.68-9.58), p < 0.001 and HR = 2.43 (95 % CI 1.38-4.29), p = 0.002, respectively) and of composite endpoint [HR = 1.63 (1.04-2.56); p = 0.033 and HR = 1.46 (1.04-2.04) p = 0.027]. In addition, current smokers had a significantly higher rate of inappropriate device therapy compared to never smokers [HR = 21.74 (4.53-104.25), p = 0.005]. Our study indicates that in patients with HF who received a CRT-D device, current and previous smoking increase the event rate per person-time of death and of appropriate and inappropriate ICD therapy more than other known negative prognostic factors such as age, left ventricular dysfunction, prolonged QRS duration and ischemic etiology.

Characteristics of left ventricular rotational mechanics in patients with systemic amyloidosis, systemic hypertension and normal left ventricular mass.

INTRODUCTION: Recently, two-dimensional (2D) speckle-tracking echocardiography has enabled assessment of a particular behaviour of left ventricular (LV) motion defined as twisting/untwisting. The aim of our study is to evaluate whether in early stage of hypertension and systemic amyloidosis, subclinical alteration of LV twist and untwist is already present even if no LV hypertrophy is evidenced. METHODS: Forty-seven patients with light chain immunoglobulin amyloidosis (AL) entered the study and were classified having cardiac amyloidosis (CA) or not (NCA) if the mean value of LV wall thickness was ≥12 mm or not. Twenty-two consecutive patients with history of arterial essential hypertension (Hyp Group) and no sign of LV hypertrophy were enrolled. A total of 26 asymptomatic healthy subjects, age-matched, were analysed as control group. All three groups of patients and healthy subjects underwent traditional and 2D speckle-tracking echocardiography evaluation. LV diameters, volumes, wall thickness, mass, ejection fraction, E/A and E/E' ratio were evaluated. RESULTS: Twisting and untwisting rates were significantly increased in NCA and Hyp group when compared with CA and control group. Moreover, despite similar LV mass and diastolic dysfunction degree, untwisting rate peak was significantly delayed in NCA when compared with Hyp group. In patients with CA, untwisting rate delay was similar to patients with NCA. CONCLUSION: Our results show that amyloidosis and systemic hypertension produce both LV twist and untwist rate enhancement before LV hypertrophy is developed. In patients with amyloidosis irrespectively of LV infiltration degree, a significant LV untwisting rate peak delay occurs suggesting that different aetiology of cardiac involvement could differently affect LV untwisting rate.

Tricuspid annular plane systolic excursion evaluation improves selection of cardiac resynchronization therapy patients.

BACKGROUND: The beneficial effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) remodeling have been extensively described. Few data are available about the effects of CRT on right ventricular (RV) function and remodeling. HYPOTHESIS: We hypothesized that CRT could also induce reverse remodeling in the right ventricle and that RV baseline functional status expressed as tricuspidal annular plane systolic excursion (TAPSE) could affect CRT response. METHODS: Echocardiographic investigation was performed before and 6 months after CRT. In 192 patients, TAPSE, LV, and RV dimensions with functional parameters and LV dyssynchrony index were evaluated. RESULTS: At 6 months' follow-up, 86 patients (45%) were responders to CRT according to at least 15% LV end-systolic volume reduction. Among baseline echocardiographic parameters, responders had significantly lower TAPSE, larger LV volumes, and higher LV dyssynchrony index. In responders, LV volume reduction, ejection fraction increase, and mitral regurgitation improvement were associated with RV dimensions reduction, increased TAPSE, and improved LV dyssynchrony. Receiver operating characteristic curve analysis showed that TAPSE, at 17 mm optimal cutoff, yielded 64% sensitivity and 60% specificity in predicting CRT response; similarly, LV dyssynchrony index, at 41.25 ms optimal cutoff, predicted CRT response with 60% sensitivity and 62% specificity. A subgroup analysis demonstrated that the coexistence of high TAPSE and high dyssynchrony index values increased probability of CRT response. CONCLUSIONS: Our results show that CRT induces RV and LV reverse remodeling and that CRT patient selection can be improved by simply measuring TAPSE value.

Thrombus aspiration with export catheter in ST elevation myocardial infarction.

BACKGROUND: Many thrombectomy devices have failed to confirm initial promising results during primary angioplasty. This may be due to device complexity and operator experience. The objective of this study was to assess the safety and efficacy of the EXPORT catheter for thrombus aspiration in patients with ST elevation myocardial infarction (STEMI). METHODS: EXPORT catheter was used in patients with STEMI and angiographic evidence of thrombus in vessels with a reference diameter > or =1.5 mm. Direct stenting and glycoprotein IIb/IIIa inhibitors were liberally employed to optimize angiographic and clinical results. Epicardial and myocardial angiographic parameters, in-hospital major adverse cardiac events (MACE, i.e., cardiac death, myocardial infarction, target vessel revascularization) were assessed. RESULTS: EXPORT catheter was used in 129 patients without any device-related complications. Angiographic analysis following thrombus aspiration revealed a significant improvement in TIMI frame count (P = 0.0001), myocardial perfusion (P = 0.0001), TIMI thrombus grade (P = 0.0001), and TIMI flow (P = 0.0001). Stent implantation did not significantly improve myocardial perfusion, TIMI thrombus grade, or TIMI flow, but improved TIMI frame count, minimal lumen, and reference vessel diameter. When compared to a historical STEMI control group not undergoing thrombus aspiration, our EXPORT population showed significant improvements in reperfusion parameters. In-hospital MACE were uncommon (4.5%) despite high-risk patient characteristics. CONCLUSIONS: Our study demonstrates that routine use of EXPORT catheter in patients with STEMI and coronary thrombosis is feasible, safe, and associated with significant improvements in flow-related angiographic parameters. The relative simplicity of this approach makes it an attractive option in this challenging situation.

Safety and efficacy of the AngioJet in patients with acute myocardial infarction: results from the Florence Appraisal Study of Rheolytic Thrombectomy (FAST).

OBJECTIVES: To assess the safety and efficacy of the AngioJet coronary device, given the uncertain risk-benefit balance of rheolytic thrombectomy in patients with acute myocardial infarction (AMI). BACKGROUND: Current risk of inadequate myocardial perfusion for thrombus embolization in primary coronary interventions is not negligible. The AngioJet thrombectomy device showed promising results in terms of safety and efficacy, but failed to confirm them in a large, multicenter, randomized trial, and the risk-benefit balance is still uncertain. METHODS: The AngioJet device was employed in 116 consecutive patients with AMI and angiographic evidence of extensive thrombosis in a vessel with a reference diameter > 2.5 mm. Stents and glycoprotein IIb/IIIa inhibitors were liberally used. Epicardial and myocardial reperfusion angiographic parameters, and in-hospital major adverse cardiac events (MACE, i.e., cardiac death, myocardial infarction, target vessel revascularization) were assessed. RESULTS: The AngioJet was successfully used in all patients. Angiographic analysis showed that the AngioJet significantly improved epicardial coronary flow (p < 0.01), frame count (p < 0.01) and myocardial blush (p < 0.01), while stenting yielded significant improvements only in diameter stenosis, minimum lesion diameter and correlated vessel parameters (p < 0.01). In-hospital MACE were uncommon [9 (8%)], despite the patientsO characteristics. When compared to an AMI population with similar thrombus burden but not undergoing thrombectomy, our AngioJet population showed significant improvement of reperfusion parameters. Moreover, there was greater AngioJet benefit in the high versus moderate thrombus burden subset; laboratory and operator experience also correlated significantly with final angiographic results. CONCLUSIONS: Our study supports the favorable risk-benefit profile of AngioJet device use in selected patients with AMI when used in experienced laboratories and by trained operators.