Enrico Baracca

A Feasible Approach for Direct His-Bundle Pacing Using a New Steerable Catheter to Facilitate Precise Lead Placement

Introduction: Much clinical evidence has shown that right ventricular (RV) apical pacing is detrimental to left ventricular function. Preservation of the use of the His‐Purkinje (H‐P) system may be ideal in heart block that is restricted to the AV node, but may be of no benefit when H‐P disease exists.

Determination of the Longest Intrapatient Left Ventricular Electrical Delay May Predict Acute Hemodynamic Improvement in Patients After Cardiac Resynchronization Therapy

Background—One of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site. Methods and Results—Thirty-two consecutive patients (23 men; mean age, 71±11 years; LV ejection fraction, 30±6%; 18 with ischemic cardiomyopathy; QRS, 181±25 ms; all mean±SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV dP/dtmax at baseline and during pacing. Overall, 2.9±0.8 different veins and 6.4±2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV dP/dtmax coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV dP/dtmax in all patients at each site (AR1 &rgr;=0.98; P<0.001). A Q-LV value >95 ms corresponded to a >10% in LV dP/dtmax. An inverse correlation between paced QRS duration and improvement in LV dP/dtmax was seen in 24 patients (75%). Conclusions—Pacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV dP/dtmax. A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV dP/dtmax of ≥10%.

Multipoint pacing by a left ventricular quadripolar lead improves the acute hemodynamic response to CRT compared with conventional biventricular pacing at any site

BACKGROUND Response to cardiac resynchronization therapy (CRT) remains challenging. Pacing from multiple sites of the left ventricle (LV) has shown promising results. OBJECTIVE The purpose of this study was to systematically compare the acute hemodynamic effects of multipoint pacing (MPP) by means of a quadripolar lead with conventional biventricular (BiV) pacing. METHODS Twenty-nine patients (23 men; mean age 72 ± 12 years; LV ejection fraction 29% ± 7%; 15 with ischemic cardiomyopathy, 17 with left bundle branch block; mean QRS 183 ± 23 ms) underwent CRT implantation. Per patient, 3.2 ± 1.2 different veins and 6.3 ± 2.4 pacing sites were tested. LV electrical delay (Q-LV) was measured at each location, along with the increase in LV dP/dtmax (maximum rate of rise of LV pressure) obtained by BiV and MPP. The effect of MPP, by means of simultaneous pacing from distal and proximal dipoles, was investigated at all available sites. RESULTS Overall, 3.2 ± 1.2 different MPP measurements were collected per patient. When all sites were considered, LV dP/dtmax increased from 951 ± 193 mm Hg/s at baseline to 1144 ± 255 and 1178 ± 259 mm Hg/s on BiV and MPP, respectively. When the best site was considered, LV dP/dtmax increased from a baseline value of 942 ± 202 mm Hg/s to 1200 ± 267 mm Hg/s (BiV) and 1231 ± 267 mm Hg/s (MPP). The mean QRS duration at any site during MPP and conventional CRT was 171 ± 18 and 175 ± 16 ms (P = .003), respectively. CONCLUSION Compared with BiV pacing at any LV site, MPP yielded a small but consistent increase in hemodynamic response. A correlation between the increase in hemodynamics and Q-LV on MPP was observed for all measurements, including those taken at the best and worst sites. The MPP-induced improvement in contractility was associated with significantly greater narrowing of the QRS complex than conventional BiV pacing.

Determination of the Longest Intra-Patient Left Ventricular Electrical Delay May Predict Acute Hemodynamic Improvement in Cardiac Resynchronization Therapy Patients

Background—One of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site. Methods and Results—Thirty-two consecutive patients (23 men; mean age, 71±11 years; LV ejection fraction, 30±6%; 18 with ischemic cardiomyopathy; QRS, 181±25 ms; all mean±SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV dP/dtmax at baseline and during pacing. Overall, 2.9±0.8 different veins and 6.4±2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV dP/dtmax coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV dP/dtmax in all patients at each site (AR1 &rgr;=0.98; P<0.001). A Q-LV value >95 ms corresponded to a >10% in LV dP/dtmax. An inverse correlation between paced QRS duration and improvement in LV dP/dtmax was seen in 24 patients (75%). Conclusions—Pacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV dP/dtmax. A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV dP/dtmax of ≥10%.

Optimization of left ventricular pacing site plus multipoint pacing improves remodeling and clinical response to cardiac resynchronization therapy at 1 year

BACKGROUND Approximately one-third of the patients with heart failure (HF) treated with cardiac resynchronization therapy (CRT) fail to respond. Positioning the left ventricular (LV) pacing lead in the area of the latest electrical delay may improve the response to CRT. Multipoint pacing (MPP) of the LV has been shown to improve the acute hemodynamic response. OBJECTIVE The purpose of this study was to test the hypothesis that patients treated with MPP in whom LV pacing location is optimized have better long-term clinical outcomes than do patients treated with conventional CRT. METHODS We evaluated the echocardiographic and clinical response of 110 patients with HF treated for nearly 1 year with either conventional CRT (standard [STD] group, n = 54, 49%), CRT with hemodynamic and electrical optimization of the LV pacing site (optimized [OPT] group, n = 36, 33%), or OPT combined with MPP (OPT + MPP group, n = 20, 18%). Responders were classified in terms of reduction in end-systolic volume index ≥15%, reduction in New York Heart Association (NYHA) class ≥1, and Packer score variation (NYHA response with no HF-related hospitalization events or death). RESULTS In STD, OPT, and OPT + MPP groups, 56%, 72%, and 90% of patients, respectively, were end-systolic volume index responders (P = .004) and 67%, 78%, and 95% were NYHA class responders (P = .012); 59%, 67%, and 90% of patients exhibited a 1-year Packer score of 0 (P = .018). These trends remained significant after adjustment for confounding factors by multivariate logistic analysis. CONCLUSION Combining MPP with optimal positioning of the LV lead on the basis of electrical delay and hemodynamics enhances reverse remodeling and improves clinical outcomes beyond the effect due to conventional CRT.

A new noninvasive method for estimation of pulmonary arterial pressure in mitral stenosis

Abstract The appearance of an increased pulmonary artery (PA) pressure is an important moment in the clinical history of mitral stenosis. A direct measurement of PA pressure levels is possible only with rightsided cardiac catheterization. This technique, being invasive is not risk-free and, consequently, many noninvasive methods for the evaluation of PA pressure have been proposed.1 These procedures usually lack sensitivity and are limited in their ability to detect and quantify mild to moderate modifications of PA pressure. The introduction of Doppler echocardiography allowed the development of new procedures.2–6 Unfortunately this method is not applicable in the absence of Doppler-detectable tricuspid regurgitation.7 Furthermore, the computed systolic PA pressure value is approximate because a clinical estimation of the right atrial pressure is necessary. Moreover, a good acoustic window and satisfactory flow tracings are indispensable. To avoid the aforementioned drawbacks we attempted a different approach to the noninvasive estimation of PA pressure, devising a method based on the modifications induced by an increased PA pressure on the power spectrum of the pulmonary component of the second heart sound. We used fast-Fourier analysis to examine the acoustic characteristics of this heart sound and to define its frequency distribution in patients with normal and increased PA pressure to search for a relation between the PA pressure level and the spectral characteristics of the pulmonary component of the second heart sound.

Implantation of Left Ventricular Leads Using a Telescopic Catheter System

Background: Implantation procedures for cardiac resynchronization therapy (CRT) remain challenging with regard to coronary sinus (CS) cannulation and left ventricular (LV) lead positioning. Technologic advances in catheter design may facilitate CS cannulation and LV lead placement.

Ventricular-arterial coupling in patients with heart failure treated with cardiac resynchronization therapy: may we predict the long-term clinical response?

OBJECTIVE To evaluate the effects of cardiac resynchronization therapy (CRT) on ventricular-arterial coupling (VAC) in patients with refractory congestive heart failure (HF), left bundle brunch block, and sinus rhythm. BACKGROUND The ratio between arterial elastance (Ea) and left ventricular end-systolic elastance (Ees), the so-called VAC, defines the efficiency of the myocardium in pumping blood. METHODS Seventy-eight patients were studied with echocardiography before CRT, and 1 year later. End-systolic elastance was calculated according to the method of Chen. Arterial elastance (ratio of the systolic pressure to the stroke volume), end-systolic volume (ESV), and quality of life (QoL) (Minnesota Living with Heart Failure Questionnaire) were assessed at the baseline and after 1 year. Patients with a reduction>15% of ESV or a decrease>33% in QoL score were considered responders to CRT. RESULTS QRS duration and interventricular delay were significantly reduced with CRT compared with baseline (156+/-2 vs. 195+/-3 ms, P<0.001; and 25+/-2 vs. 55+/-3 ms, P<0.001, respectively). Arterial elastance/Ees decreased significantly on CRT (2.47+/-1.48 vs. 1.41+/-0.87, P<0.0001). The lowering of Ea/Ees was congruent to a decrease in intraventricular delay (83.1+/-55.7 vs. 28.4+/-49.5 ms, P<0.0001) and an increase in ejection fraction (26+/-6.3 vs. 36.9+/-8.0%, P<0.0001). Responders to CRT were 74 and 71% of the overall patient population, considering as endpoint QoL or ESV, respectively. The analysis of VAC showed a baseline cut-off value of 2, above which 88% and 69% of patients responded to CRT, considering as endpoint QoL or ESV, respectively. CONCLUSIONS The non-invasive assessment of VAC may be proposed as an immediate, easy, and optimal tool for quantifying the effect of CRT in patients with HF.

The effect of captopril on peripheral hemodynamics in patients with esential hypertension: Comparison between oral and sublingual administration

SummaryA comparative study of the effects of oral and sublingual captopril on the hemodynamics of the peripheral musculocutaneous vasculature was carried out on ten patients with essential hypertension. Both routes of administration of captopril lead to lower blood pressure and decreased regional resistance, and to an increased arterial blood flow at rest. The first measurable effect and the peak effect on blood pressure and peripheral hemodynamics appear slightly earlier with sublingual administration. The data provided in this study support the usefulness of the sublingual route in clinical situations in which oral administration of captopril is not feasible.

Prevalence of conduction delay of the right atrium in patients with SSS: Implications for pacing site selection

Objectives To evaluate the prevalence of severe right atrial conduction delay in patients with sinus node dysfunction (SND) and atrial fibrillation (AF) and the effects of pacing in the right atrial appendage (RAA) and in the inter-atrial septum (IAS). Methods Forty-two patients (15 male, 72 ± 7 years) underwent electrophysiologic study to measure the difference between the conduction time from RAA to coronary sinus ostium during stimulation at 600 ms and after extrastimulus (ΔCTos). Patients were classified as group A if ΔCTos > 60 ms and group B if < 60 ms. Each Group was randomized to RAA/IAS pacing and algorithms ON/OFF. Results Fifteen patients (36%, group A) had ΔCTos = 76 ± 11 ms and 27 patients (64%, group B) had ΔCTos = 36 ± 20 ms. Twenty-two patients were paced at the RAA and 20 at the IAS. During the study, no AF recurrences were reported in 11 of 42 (26%) patients, independently of RAA or IAS pacing. Patients from group A and RAA pacing had 0.79 ± 0.81 episodes of AF/day during DDD, which increased to 1.52 ± 1.41 episodes of AF/day during DDDR + Alg (P = 0.046). Those with IAS pacing had 0.5 ± 0.24 episodes of AF/day during DDD, which decreased to 0.06 ± 0.08 episodes of AF/day during DDDR + Alg (P = 0.06). In group B, no differences were reported between pacing sites and pacing modes. Conclusions Severe right atrial conduction delay is present in one-third of patients with SND and AF: continuous pacing at the IAS is superior to RAA for AF recurrences. In patients without severe conduction delay, no differences between pacing site or mode were observed.