Resynchronization: what if the left ventricular lead cannot reach the lateral or posterolateral wall?

BACKGROUND: The recommended left ventricular (LV) lead position for cardiac resynchronization therapy (CRT) is at the lateral or posterolateral wall. However, LV leads cannot always be implanted at this site. The objective of our study was to compare the clinical response to CRT when the LV lead could be implanted or not at the lateral or posterolateral wall. METHODS: In consecutive patients implanted with a CRT device, we documented the final position achieved by the tip of the LV lead in the left anterior oblique projection. Patients were prospectively followed for 6 months after implantation. They were defined as responders if they were alive, had gained 1 New York Heart Association (NYHA) functional class, and had not been hospitalized for heart failure. RESULTS: The study population consisted of 77 patients (56 men, 71 +/- 10 years, 62 NYHA class III, 15 NYHA class IV). The LV lead was implanted at the lateral or posterolateral wall in 54 patients (group A) and at the anterior or anterolateral wall in 23 patients (group B). At 6 months, seven patients (9%) died (all in group A). There were 37 responders (69%) in group A as compared to 22 (96%) in group B. CONCLUSIONS: The responder rate was not inferior when the LV lead was implanted at the anterior or anterolateral wall. Thus, in case of failed implantation at the lateral or posterolateral wall, positioning the LV lead in a more anterior location appears to be a reasonable alternative. Further studies are required to confirm these findings.

Where are the left ventricular leads really implanted? A study of 90 consecutive patients.

BACKGROUND: Cardiac resynchronization therapy (CRT) is a recognized treatment for severe heart failure. The recommended left ventricular (LV) lead position is at the lateral or posterolateral wall. However, LV leads cannot always be implanted at the expected site. The aim of our study was to describe in a large series of patients the anatomical position really achieved by LV leads at implant. METHOD: In consecutive patients referred for CRT, we determined the LV lead implantation success rate, the success rate for the initial target vein, and the final position achieved by the tip of the LV lead in the left and right anterior oblique projections. RESULTS: Ninety patients (66 men, 71 +/- 9 years, 20% New York Heart Association (NYHA) class IV) were referred for an LV lead implantation between September 2003 and March 2006. A LV lead could be implanted in 92% of patients. In 70%, LV leads were implanted in the initial target vein. The final location was lateral or posterolateral in 68% and anterior or anterolateral in 32% of patients. The mean procedural time was 117 +/- 42 minutes. CONCLUSIONS: LV lead implantation was achieved in 92% of patients with mean procedure duration of less than 2 hours. Nevertheless, 30% of LV leads were implanted outside of the initial target vein and 32% at the anterior or anterolateral wall. Further studies are warranted to compare the responder rate to CRT when the LV lead is at the lateral or posterolateral wall or when the LV lead is at an alternative site.

Diagnosis of left ventricular diastolic dysfunction in the setting of acute changes in loading conditions.

INTRODUCTION: Conventional pulsed wave Doppler parameters are known to be preload dependent, whereas newly proposed Doppler indices may be less influenced by variations in loading conditions. The aim of the present study was to evaluate the effects of haemodialysis-induced preload reduction on both conventional and new Doppler parameters for the assessment of left ventricular (LV) diastolic function. METHODS: This prospective observational study was conducted in a medical-surgical intensive care unit (ICU) and nephrology department of a teaching hospital. In total, 37 haemodialysis patients with end-stage renal disease (age [mean +/- standard deviation]: 52 +/- 13 years) and eight ventilated ICU patients with acute renal failure receiving vasopressor therapy (age 57 +/- 16 years; Simplified Acute Physiology Score II 51 +/- 17) were studied. Echocardiography was performed before and after haemodialysis. Conventional pulsed wave Doppler indices of LV diastolic function as well as new Doppler indices, including Doppler tissue imaging early diastolic velocities (E' wave) of the septal and lateral portions of the mitral annulus, and propagation velocity of LV inflow at early diastole (Vp) were measured and compared before and after ultrafiltration. RESULTS: The volume of ultrafiltration was greater in haemodialysis patients than in ICU patients (3.0 +/- 1.1 l versus 1.9 +/- 0.9 l; P = 0.005). All conventional pulsed wave Doppler parameters were altered by haemodialysis. In haemodialysis patients, E' velocity decreased after ultrafiltration when measured at the septal mitral annulus (7.1 +/- 2.5 cm/s versus 5.9 +/- 1.7 cm/s; P = 0.0003), but not at its lateral portion (8.9 +/- 3.1 cm/s versus 8.3 +/- 2.6 cm/s; P = 0.37), whereas no significant variation was observed in ICU patients. Vp decreased uniformly after ultrafiltration, the difference being significant only in haemodialysis patients (45 +/- 11 cm/s versus 41 +/- 13 cm/s; P = 0.04). Although of less magnitude, ultrafiltration-induced variations in Doppler parameters were also observed in haemodialysis patients with altered LV systolic function. CONCLUSION: In contrast to other Doppler parameters, Doppler tissue imaging E' maximal velocity measured at the lateral mitral annulus represents an index of LV diastolic function that is relatively insensitive to abrupt and marked preload reduction.

Hand-held echocardiography with Doppler capability for the assessment of critically-ill patients: is it reliable?

OBJECTIVE: To evaluate the diagnostic capability of a hand-carried ultrasound device (HCU) in critically ill patients when using conventional transthoracic echocardiography (TTE) as a reference. DESIGN: Prospective, descriptive study. SETTING: Medical-surgical intensive care unit of a teaching hospital. PATIENTS: All patients requiring a TTE study were eligible. INTERVENTIONS: Each patient underwent an echocardiographic examination using a full-feature echocardiographic platform (Sonos 5500, Philips Medical Systems, Andover, MA) and a small battery-operated device (SonoHeart Elite, SonoSite, Bothell, WA). The operators (level III training in echocardiography) were randomized (HCU vs. TTE) and they independently interpreted the echocardiograms at the patient bedside. RESULTS: During a 2-month period, 55 consecutive patients (age: 61+/-16 years, simplified acute physiology score 46+/-15, body mass index 26+/-7) were studied, 40 of them being mechanically ventilated (73%). The number of acoustic windows was comparable using HCU and TTE (2.3+/-0.8 vs. 2.4+/-0.8: P=0.24). The overall diagnostic accuracy of HCU was lower compared with conventional TTE (137/171 vs. 158/171 clinical questions solved: P=0.002), reaching 80% and 92%, respectively. Despite its spectral Doppler capability, HCU missed diagnoses that were adequately identified by TTE: elevated left ventricular pressure ( n=2), relevant valvulopathy ( n=2) and moderate ( n=4) or severe ( n=2) pulmonary hypertension. Acute management was altered by HCU and TTE findings in 27 patients (49%) and 28 patients (51%), respectively. CONCLUSIONS: In this study, HCU had a lower diagnostic accuracy compared with conventional TTE, despite its spectral Doppler capability. Further studies are needed to validate these evolving diagnostic tools in critical care settings.