Resynchronization Treatment Research Articles

Cardiac resynchronization treatment in a patient with hypertrophic cardiomyopathy after heart transplantation

Hypertrophic cardiomyopathy (HCM) is characterized by heterogeneous clinical expression. Cardiac transplantation continues to be the gold standard for the treatment of end-stage cardiac diseases refractory to medical therapy. We presented a 27-year-old female patient with HCM who underwent successful cardiac resynchronization therapy after cardiac transplantation. Our patient had an indication for standard pacing. However, previous reports have shown that right ventricular apical pacing might lead to adverse clinical outcomes in patients with heart failure. We have discussed cardiac resynchronization therapy after heart transplantation in patients with standard pacing indications.

Application of echocardiography in resynchronization treatment of heart failure patients.

To review the updated research progress about the application of echocardiography in resynchronization treatment of chronic heart failure patients. The data used in this review were from PubMed, published in English and using the key terms "heart failure", "echocardiography" and "cardiac resynchronization therapy". Relevant articles were reviewed and selected to address the stated purpose. Increasing numbers of studies have suggested the importance of echocardiography in resynchronization treatment of chronic heart failure patients. Echocardiography can evaluate atrioventricular, inter- and intra-ventricular mechanical dyssynchrony before cardiac resynchronization therapy (CRT), as a guidance to assess the optimal left ventricular (LV) pacing location, optimize the atrioventricular and interventricular delays and predict response to CRT. Echocardiography is both non invasive and easily repeatable, and plays a crucial role in appraisal of heart synchronism, instruction of actuator placement, optimization of the device procedure, and prediction of the response to CRT.

It’s a small world after all

It’s a small world after all

A revised approach to patient selection for cardiac resynchronization treatment using multiple asynchrony parameters in Narrow- and Wide-QRS cardiomyopathy causes cardiac reverse remodelling: a single centre non-randomized prospective study

Conflicting data exists on the benefit of cardiac resynchronization treatment (CRT) in patients with narrow QRS (Narrow-QRS) cardiomyopathy (CMP). We determined the effect of CRT in patients with CMP and mechanical asynchrony based on a comprehensive assessment by multiple echocardiographic criteria. Ninety patients, 65 +/- 16 years, 32 with Narrow-QRS <120 ms and 58 with wide QRS >or=120 ms (Wide-QRS) CMP who met criteria for significant mechanical asynchrony by 15 criteria before CRT were studied. Responders were patients in whom end-systolic volume (ESV) reduced by >or=15% post-CRT. There was no difference in the response to CRT in the Narrow-QRS (ESV 132 +/- 60 to 120 +/- 60 mL, P = 0.02) or Wide-QRS (123 +/- 54 to 102 +/- 50 mL, P < 0.01) groups at 1 +/- 2 month follow-up. A difference of >or=40% in time to peak contraction in a cardiac cycle on tissue velocity imaging between the earliest and the most delayed segment had the best area under curve for response to CRT, 0.71 (0.55-0.85), P = 0.02. Using logistic regression model, delay in mid-posterolateral segment of >or=20% in a cardiac cycle compared with remaining 10 segments was the only predictor of response to CRT in the overall study population. Conclusion In patients with CMP and mechanical asynchrony by multiple criteria, response to CRT in Narrow-QRS group is similar to those with Wide-QRS. Greater than or equal to 40% delay in systolic contraction between 12 left ventricular (LV) segments or >or=20% delay of posterolateral segment to other LV segments predicted CRT response.

Pathways of the Heart

Disease heterogeneity presents a formidable challenge for clinical medicine. We are unlikely to develop successful, targeted treatments unless diagnostic schemes begin to reflect the biological complexity underlying superficially similar disease phenotypes. To address heterogeneity, there is an increasing recognition that realistic disease models need to be built on a foundation of quantitative molecular information.1 Such a “systems medicine” approach should ultimately allow classification into biologically more homogeneous groups, with similar prognosis and treatment response. Article see p 371 Oncology has been among the first specialties to embrace molecular profiling to improve clinical decision making. Today, a wealth of expression profiling information exists for tumors, and early efforts are being made to classify patients into likely treatment responders for specific chemotherapeutics.2 The investigation of complex multisystem pathologies, such as cardiovascular disease, has been slower to incorporate molecular profiling, in part, because of the involvement of multiple tissues, many of which are not readily accessible. Moreover, cardiovascular disease, unlike cancer, is not clonal in origin, making experimental analyses more challenging. It is clear, however, that broadly defined diseases such as the cardiomyopathies are the product of diverse genetic and environmental agents3; one can expect that quantitative molecular profiling will shed light on distinct, pathological activities underlying these conditions, thus allowing more meaningful classification schemes beyond those that are solely based on anatomic or hemodynamic considerations. The article by Barth et al4 in this issue of Circulation: Cardiovascular Genetics represents such a broadened search for molecular correlates of cardiovascular disease. The authors focus on the problem of heart failure with mechanical dyssynchrony (DHF) and its treatment by cardiac resynchronization therapy (CRT). Clinically, CRT has been a remarkable success, with significant gains in quality of life and mortality.5 Multiple studies have investigated the physiological consequences of dyssynchrony and …

Reduction in Mitral Regurgitation in Patients Undergoing Cardiac Resynchronization Treatment: Assessment of Predictors by Two‐Dimensional Radial Strain Echocardiography

We utilized the novel approach of 2D radial strain (2-DRS) to evaluate whether left ventricular (LV) mechanical dyssynchrony in mid-LV segments corresponding to papillary muscles insertion sites can predict early mitral regurgitation (MR) reduction post-cardiac resynchronization therapy (CRT). We evaluated 32 patients undergoing CRT (mean age 64 +/- 17 years, 54% males) with MR grade > or =3 determined by the MR jet area/left atrial area ratio (JA/LAA). Fifteen (47%) patients responded to CRT (JA/LAA) < 25%). Sixty-seven percent of responders had mild or no residual MR and 33% had mild-to-moderate MR, while 70% of nonresponders had grade 3 or 4 MR (P = 0.0001) post CRT. The percent reduction in LV end-systolic volume was significantly higher in responders (P = 0.03), as was improvement in LVEF (P = 0.007). Significant delay of time-to-peak 2-DRS in the midposterior and inferior segments prior to CRT was found in responders compared with nonresponders (580 +/- 58 vs. 486 +/- 94, P = 0.002 and 596 +/- 79 vs. 478 +/- 127 ms, P = 0.005, respectively). Responders also had higher peak positive systolic 2-DRS in the posterior and inferior segments compared to nonresponders (22 +/- 13 vs. 12 +/- 7%, P = 0.01 and 17 +/- 9 vs. 9 +/- 7%, P = 0.02, respectively). Logistic regression analysis showed that the differences in pre-CRT inferoanterior time-to-peak 2-DRS of >110 ms and MRJA/LAA <40% as well as 2-DRS >18% in the posterior wall were significant predictors of post-CRT improvement in MR. The presence of a significant time-to-peak delay on 2-DRS between inferior and anterior LV segments, preserved strain of posterior wall, and MRJA/LAA <40% were found to be associated with significant MR reduction in patients post-CRT.

Letter by Naqvi and Motallebi Regarding Article, “Left Ventricular Resynchronization Is Mandatory for Response to Cardiac Resynchronization Therapy”

To the Editor: Bleeker et al1 propose that in patients selected on the basis of both electrical and a single mechanical dyssynchrony measure derived from maximum delay during left ventricular (LV) ejection between peak systolic velocities among 4 basal LV segments, immediate resynchronization (of at least 20%) after cardiac resynchronization treatment (CRT) predicts reduction in LV end-systolic volume by at least 10% at 6-month follow-up. The editorial accompanying the article by Bleeker and colleagues2 appropriately “cautions” against relying on a single “dyssynchrony” measure and on “early resynchronization” …

Timed Artificial Insemination of Two Consecutive Services in Dairy Cows Using Prostaglandin F2α and Gonadotropin-Releasing Hormone

Timed artificial insemination (TAI) protocols use PGF2α and GnRH injections to synchronize ovulation. The objective was to evaluate the PGPG protocol (d 0, PGF2α; d 3, GnRH; d 11, PGF2α; d 13, GnRH and TAI) for first TAI and also examine methods for second TAI in nonpregnant cows. A factorial test of the first PGF2α and first GnRH injections within the PGPG protocol was performed (the last PGF2α and GnRH injections were deemed essential to the TAI). Lactating dairy cows (n = 804) in a commercial herd were assigned to 1 of 5 first-TAI treatments, which were PGPG, GPG (d 0, no treatment; d 3, GnRH; d 11, PGF2α; d 13, GnRH and TAI), PPG (d 0, PGF2α; d 3, no treatment; d 11, PGF2α; d 13, GnRH and TAI), and PG (d 0, no treatment; d 3, no treatment; d 11, PGF2α; d 13, GnRH and TAI); the Ovsynch protocol (GnRH, 7 d, PGF2α, 2 d, GnRH and TAI) was the positive control. For resynchronization, cows received either GnRH or the control (no injection) on d 22 after TAI. Nonpregnant cows on d 28 were then treated with PGF2α on d 29, GnRH on d 31, and TAI [i.e., resynchronization treatments of ReGPG (received GnRH on d 22) and RePG (did not receive GnRH on d 22)]. Pregnancy rates for PGPG, GPG, PPG, PG, and Ovsynch were similar at d 28 after first TAI. Analyses of multiple explanatory factors by logistic regression detected an effect of uterine or ovarian abnormality on the d-28 pregnancy rate (normal more likely to be pregnant). Day-42 pregnancy rates were affected by uterine or ovarian abnormality (normal more likely to be pregnant), postpartum disease occurrence (healthy cows more likely to be pregnant), milk production, and days in milk. Treatment was not significant for the d-42 pregnancy rate. Effects of postpartum disease, milk production, and days in milk on the d-42 pregnancy rate were apparently manifested through their effects on embryonic loss between d 28 and 42 of pregnancy. High-producing cows that received TAI early postpartum were most likely to experience embryonic loss. Day-42 pregnancy rates after the resynchronization treatment were affected by an interaction of the first synchronization treatment with the resynchronization treatment. We concluded that although PGPG can be used for TAI, a simpler TAI protocol that includes the last 2 injections (PGF2α, 2 d; GnRH and TAI) would be equally effective.

Left ventricular electromechanical delay in patients with heart failure and normal QRS duration and in patients with right and left bundle branch block

We sought to define the reference values of intra-left ventricular (LV) electromechanical delay (EMD), and to assess the prevalence (and pattern) of intra-LV dyssynchrony in patients with heart failure (HF) and normal QRS and in patients with right and left bundle branch block. We used tissue Doppler imaging echocardiography and a six-LV wall model to study LV EMD in 103 patients [41 with HF and normal QRS, 22 with right bundle branch block (RBBB), and 40 with left bundle branch block (LBBB)], and in 59 controls. In controls, the median intra-LV EMD was 17 ms, (inter-quartile range 13-30); 95% of controls had a value < or =41 ms. Patients showed a longer intra-LV EMD than controls: 33 ms (20-57) in patients with normal QRS, 32 ms (23-50) in RBBB patients, and 50 ms (30-94) in LBBB patients. Intra-LV dyssynchrony (defined as intra-LV EMD >41 ms) was present in 39, 36, and 60% of the patients, respectively. On average, HF patients showed the same pattern of activation as controls, from the septum to the posterior wall, but activation times were significantly prolonged. In RBBB patients the activation sequence was directed from inferior to anterior and in LBBB from anterior to inferior wall. Left ventricular dyssynchrony was present in several patients with HF and normal QRS, and in patients with RBBB; conversely, 40% of LBBB patients showed values of LV EMD within the normal range. Left ventricular activation sequence was different between groups. Assessment of LV synchronicity by means of imaging techniques may be more important than QRS duration or morphology in selecting patients for cardiac resynchronization treatment.

Echo-driven V-V optimization determines clinical improvement in non responders to cardiac resynchronization treatment

Echocardiography plays an integral role in the detection of mechanical dyssynchrony in patients with congestive heart failure and in predicting beneficial response to cardiac resynchronization treatment. In patients who derive sup-optimal benefit from biventricular pacing, optimization of atrioventricular delay post cardiac resynchronization treatment has been shown to improve cardiac output. Some recent reports suggest that sequential ventricular pacing may further improve cardiac output. The mechanism whereby sequential ventricular pacing improves cardiac output is likely improved inter and possibly intraventricular synchrony, however these speculations have not been confirmed. In this report we describe the beneficial effect of sequential V-V pacing on inter and intraventricular synchrony, cardiac output and mitral regurgitation severity as the mechanisms whereby sequential biventricular pacing improves cardiac output and functional class in 8 patients who had derived no benefit or had deteriorated after CRT. Online tissue Doppler imaging including tissue velocity imaging, tissue synchronization imaging and strain and strain rate imaging were used in addition to conventional pulsed wave and color Doppler during sequential biventricular pacemaker programming.

Novel insights on effect of atrioventricular programming of biventricular pacemaker in heart failure – a case series

BackgroundEchocardiography plays an integral role in the diagnosis of congestive heart failure including measurement of left heart pressure as well as mechanical dyssynchrony.MethodsIn this report we describe novel therapeutic uses of echo pulsed wave Doppler in atrioventricular pacemaker optimization in patients who had either not derived significant symptomatic benefit post biventricular pacemaker implantation or deteriorated after deriving initial benefit. In these patients atrioventricular optimization showed novel findings and improved cardiac output and symptoms.ResultsIn 3 patients with Cheyne Stokes pattern of respiration echo Doppler showed worsening of mitral regurgitation during hyperpneac phase in one patient, marked E and A fusion in another patient and exaggerated ventricular interdependence in a third patient thus highlighting mechanisms of adverse effects of Cheyne Stokes respiration in patients with heart failure. All 3 patients required a very short atrioventricular delay programming for best cardiac output. In one patient with recurrent congestive heart failure post cardiac resynchronization, mitral inflow pulse wave Doppler showed no A wave until a sensed atrioventricular delay of 190 ms was reached and showed progressive improvement in mitral inflow pattern until an atrioventricular delay of 290 ms. In 2 patients atrioventricular delay as short as 50 ms was required to allow E and A separation and prevent diastolic mitral regurgitation. All patients developed marked improvement in congestive heart failure symptoms post echo-guided biv pacemaker optimization.ConclusionThese findings highlight the value of echo-guided pacemaker optimization in symptomatic patients post cardiac resynchronization treatment.

Ventricular dyssynchrony and mechanisms of resynchronization therapy

Patients with dilated cardiomyopathy (DCM) that is further complicated by intra-ventricular conduction delay with discoordinate wall motion have increased mortality risk as compared with the general DCM population. Dyssynchrony reduces cardiac systolic function while increasing oxygen consumption, and may be a source of arrhythmia. The recent development of endocardial lead systems to activate the left ventricle prematurely has yielded the novel therapeutic option of resynchronization therapy to correct cardiac dyssynchrony. Using either biventricular or left ventricular pre-excitation, systolic function and energetic efficiency can be substantially enhanced in heart failure patients who have underlying discoordinate contraction. The present review addresses the pathophysiology of cardiac dyssynchrony and the mechanisms that underlie resynchronization treatment.

Ventricular dyssynchrony and mechanisms of resynchronization therapy

Patients with dilated cardiomyopathy (DCM) that is further complicated by intra-ventricular conduction delay with discoordinate wall motion have increased mortality risk as compared with the general DCM population. Dyssynchrony reduces cardiac systolic function while increasing oxygen consumption, and may be a source of arrhythmia. The recent development of endocardial lead systems to activate the left ventricle prematurely has yielded the novel therapeutic option of resynchronization therapy to correct cardiac dyssynchrony. Using either biventricular or left ventricular pre-excitation, systolic function and energetic efficiency can be substantially enhanced in heart failure patients who have underlying discoordinate contraction. The present review addresses the pathophysiology of cardiac dyssynchrony and the mechanisms that underlie resynchronization treatment.