Left Ventricular Contraction Pattern Research Articles

The influence of pacing site to left ventricular myocardial contraction patterns and function

Objective To evaluate left ventricular(LV)myocardial contraction patterns and function when pacing in different right ventricular(RV)sites and discuss echocardiogarphic method to evaluate physiologcal pacing mode.Methods This study included 26 patients with paroxysmal supraventricular tachycardia without organic heart disease.Four pacing modes including right atrium pacing(AAI),RV apex pacing(VVI-RVA),RV septal pacing(VVI-IVS)and RV outflow tract pacing(VVI-RVOT)were performed on the patients in a random order after succussful radiofrequency ablation.The parameters measured in each pacing mode included(1)LV systolic function parameters:LV twist angle(Twist),aortic systolic velocity-time integral(VTIAo)and LV global strain(Ge)；(2)LV contracting pattern:segmental peak systolic strain(Se),the time to peak value(TPe),and the distribution of segmental Se,TPe in each layer or wall.The relationship between Se,TPe of each wall was analyzed.[Results]Pacing from RV sites showed lower Twist,VTIAO and Ge than AAI mode.Ge demonstrated significant difference in three RV sites pacing mode(VVI-RVOT＞VVI-IVS＞VVI-RVA,P＜0.05).Compared with the AAI mode,the distribution of segmental Se,TPe in the each layer or wall alerted significantly in three RV sites pacing mode,especially in VV1-RVA.The distribution pattern was similar in VVI-RVOT and VVI-IVS.Furthermore,the wall Se collated negtively with wall TPe(r =-0.51,P＜0.001).[Conclusions]Compared with AAI mode,RV pacing,especially the VVI-RVA induced the alternation of LV contraction patterns and reduction of systolic function.Longitudinal strain parameters can be used to assess the myocardial contraction patterns and function in different pacing mode. Key words: Echocardiography; Cardiac pacing,artificial; Ventricular function,left; Speckle tracking imaging

Right or Left Ventricular Pacing in Young Minipigs With Chronic Atrioventricular Block

Background— Left ventricular (LV) dyssynchrony may occur as a result of right ventricular (RV) pacing and is a known risk factor for the development of heart failure. In children with complete atrioventricular block, pacing-induced dyssynchrony lasting for decades might be especially deleterious for LV function. To determine the hemodynamic and ultrastructural remodeling after either RV free wall or LV apical pacing, we used a chronic minipig model. Methods and Results— Fourteen piglets 8 weeks of age underwent atrioventricular node ablation and were paced from either the RV free wall or the LV apex at 120 bpm for 1 year (7 age-matched minipigs served as controls with spontaneous heart rates of 104±5 bpm). Echocardiographic examinations, pressure-volume loops, patch-clamp investigations, and examinations of connexin43, calcium-handling proteins, and histomorphology were carried out. RV free wall–paced minipigs exhibited significantly more LV dyssynchrony than LV apex–paced animals, which was accompanied by worsening of LV function (maximum LV mechanical delay/LV ejection fraction: RV free wall pacing, 154±36 ms/28±3%, LV apical pacing, 52±19 ms/45±2%, control 47±14 ms/62±1%; P =0.0001). At the cellular level, both pacemaker groups exhibited a significant reduction in L-type calcium and peak sodium current, shortening of action potential duration and amplitude, increased cell capacity, and alterations in the calcium-handling proteins that were similar for RV free wall– and LV apex–paced animals. Conclusions— The observed molecular remodeling seemed to be more dependent on heart rate than on dyssynchrony. LV apical pacing is associated with less dyssynchrony, a more physiological LV contraction pattern, and preserved LV function as opposed to RV free wall pacing.

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<i>Circulation: Cardiovascular Imaging's</i> Editors' Picks

Ictus y síndrome de takotsubo: una relación recíproca

Takotsubo syndrome is a transient stress cardiomyopathy associated with a distinctive left ventricular contraction pattern. It has been described as a cardioembolic source or as a consequence of stroke. Two patients are reported that illustrate the reciprocal relationship between Takotsubo syndrome and stroke and the physiopathological mechanisms implicated are analyzed. Two women aged 70 and 78 years respectively are described. The first one was admitted with electro-cardiogram ST-segment elevation, slight troponin elevation and stroke symptoms. Ecocardiography and cardiac magnetic resonance findings were consistent with Takotsubo syndrome that was the probable source of cardioembolic stroke. The second patient suffered a Takotsubo syndrome 72 hours after a brain infarction involving the insular cortex that was considered the trigger of Takotsubo syndrome. Takotsubo syndrome and stroke may have a reciprocal etiological relationship that is suggested by the temporal profile between the two processes. Cardiac magnetic resonance may aid in the establishment of the diagnosis of Takotsubo syndrome.

Circumferential myocardial contraction patterns in patients with idiopathic frequent premature ventricular complexes from the right ventricular outflow tract

BackgroundThe pathogenesis of frequent premature ventricular complexes (PVCs) in patients without overt cardiovascular disease is considered idiopathic. Idiopathic PVCs are predominantly from the right ventricular outflow tract (RVOT) and considered a reversible cause of left ventricular (LV) dysfunction. ObjectivesWe investigated whether alternations in LV contraction patterns exist in patients with idiopathic frequent PVCs originating from the RVOT. MethodsSegmental myocardial circumferential strain (CS)–time curves were acquired from 29 patients with idiopathic frequent RVOT-PVCs and 30 healthy subjects. Peak CS and the time to peak CS (TPcs) of each segment were analyzed, with the standard deviation of TPcs for 18 LV segments (SDtpcs) calculated. All values of patients with RVOT-PVCs were recorded during both sinus beats (PVC-S) and ventricular extrasystoles (PVC-V), respectively. ResultsThe distribution of peak CS and TPcs in the PVC-V was opposite that of the healthy subjects. The distribution of TPcs of PVC-S within the different layers differed from that of healthy subjects. These patients had significantly greater dyssynchrony compared with the healthy subjects assessed by SDtpcs (healthy subjects: 6.7%±1.9%, PVC-S: 8.1%±3.1%, PVC-V: 9.7%±3.4%, healthy subjects vs. PVC-S p=0.04; healthy subjects vs. PVC-V p=0.001). Furthermore, a positive correlation was observed between PVC frequency and SDtpcs of PVC-S (r=0.44, p=0.02). ConclusionsIdiopathic frequent RVOT-PVCs can induce alterations in the LV myocardial contractile pattern during both sinus beats and ventricular extrasystoles. Circumferential contraction dyssynchrony of patients during sinus beats relates to PVC frequency. Therefore, attention should be paid to patients with frequent RVOT-PVCs, especially those with a high prevalence of PVCs.

Physiological Relevance of Quantifying Segmental Contraction Synchrony

Most current indices of synchrony quantify left ventricular (LV) contraction pattern in terms of a single, global (integrated) measure. We report the development and physiological relevance of a novel method to quantify LV segmental contraction synchrony. LV pressure-volume and echocardiographic data were collected in seven anesthetized, opened-chest dogs under several pacing modes: right atrial (RA) (control), right ventricular (RV) (dyssynchrony), and additional LV pacing at either apex (CRTa) or free wall (CRTf). Cross-correlation-based integrated (CCSI(int) ) and segmental (CCSI(seg) ) measures of synchrony were calculated from speckle-tracking derived radial strain, along with a commonly used index (maximum time delay). LV contractility was quantified using either E(es) (ESPVR slope) or ESPVR(area) (defined in the manuscript). RV pacing decreased CCSI(int) at LV base (0.95 ± 0.02 [RA] vs 0.64 ± 0.14 [RV]; P < 0.05) and only CRTa improved it (0.93 ± 0.03; P < 0.05 vs RV). The CCSI(seg) analysis identified anteroseptal and septal segments as being responsible for the low CCSI(int) during RV pacing and inferior segment for poor resynchronization with CRTf. Changes in ESPVR(area) , and not in E(es) , indicated depressed LV contractility with RV pacing, an observation consistent with significantly decreased global LV performance (stroke work [SW]: 252 ± 23 [RA] vs 151 ± 24 [RV] mJ; P < 0.05). Only CRTa improved SW and contractility (SW: 240 ± 19 mJ; ESPVR(area) : 545 ± 175 mmHg•mL; both P < 0.01 vs RV). Only changes in CCSI(seg) and global LV contractility were strongly correlated (R(2) = 0.698, P = 0.005). CCSI(seg) provided insights into the changes in LV integrated contraction pattern and a better link to global LV contractility changes.

Clinical Characteristics and Cardiovascular Magnetic Resonance Findings in Stress (Takotsubo) Cardiomyopathy

Stress cardiomyopathy (SC) is a transient form of acute heart failure triggered by stressful events and associated with a distinctive left ventricular (LV) contraction pattern. Various aspects of its clinical profile have been described in small single-center populations, but larger, multicenter data sets have been lacking so far. Furthermore, it remains difficult to quickly establish diagnosis on admission. To comprehensively define the clinical spectrum and evolution of SC in a large population, including tissue characterization data from cardiovascular magnetic resonance (CMR) imaging; and to establish a set of CMR criteria suitable for diagnostic decision making in patients acutely presenting with suspected SC. Prospective study conducted at 7 tertiary care centers in Europe and North America between January 2005 and October 2010 among 256 patients with SC assessed at the time of presentation as well as 1 to 6 months after the acute event. Complete recovery of LV dysfunction. Eighty-one percent of patients (n = 207) were postmenopausal women, 8% (n = 20) were younger women (aged ≤50 years), and 11% (n = 29) were men. A stressful trigger could be identified in 182 patients (71%). Cardiovascular magnetic resonance imaging data (available for 239 patients [93%]) revealed 4 distinct patterns of regional ventricular ballooning: apical (n = 197 [82%]), biventricular (n = 81 [34%]), midventricular (n = 40 [17%]), and basal (n = 2 [1%]). Left ventricular ejection fraction was reduced (48% [SD, 11%]; 95% confidence interval [CI], 47%-50%) in all patients. Stress cardiomyopathy was accurately identified by CMR using specific criteria: a typical pattern of LV dysfunction, myocardial edema, absence of significant necrosis/fibrosis, and markers for myocardial inflammation. Follow-up CMR imaging showed complete normalization of LV ejection fraction (66% [SD, 7%]; 95% CI, 64%-68%) and inflammatory markers in the absence of significant fibrosis in all patients. The clinical profile of SC is considerably broader than reported previously. Cardiovascular magnetic resonance imaging at the time of initial clinical presentation may provide relevant functional and tissue information that might aid in the establishment of the diagnosis of SC.

Left Ventricular Contraction Patterns in Patients With Suspected Acute Coronary Syndrome and Normal Coronary Angiograms: A New Look at the Takotsubo Syndrome

Original descriptions of the takotsubo syndrome (TS) included a characteristic left ventricular (LV) contraction pattern, "apical ballooning." Recently, several reports have associated contraction patterns not strictly conforming to the original description with TS. The specifics of the contraction pattern seem to set TS apart from the much larger population of patients with acute coronary syndrome (ACS) but no obstructive coronary artery disease (OCAD). This study was undertaken to compare patients with midventricular and apical dysfunction with those with other LV contraction patterns. If TS can present with a variety of patterns of LV dysfunction, then both those with and those without the pattern should have the clinical components previously assigned to the syndrome. We studied LV contraction patterns in consecutive ACS patients referred for consideration of emergent or urgent percutaneous coronary intervention. Of the 893 patients evaluated in 2008, we excluded 862 on the basis of OCAD, preexisting LV dysfunction, or an obvious alternative cause of symptoms. The remaining 31 (3.5%) also had no OCAD but manifested an LV contraction abnormality. We compared the 15 patients (1.7%) whose ventriculograms met criteria for TS with the 16 patients (1.8%) whose did not. The most common alternative pattern was global hypokinesis, followed by a variety of segmental contraction abnormalities. Patients with the TS pattern were older and had evidence of greater myocardial injury. More than 85% were women. The TS pattern identifies a distinct subset of ACS patients with a remarkable predominance of postmenopausal women and is therefore fundamental to the definition of this entity. This distinctive facet of the syndrome is likely to be an important clue to its pathogenesis. We did not encounter patients with other patterns of LV dysfunction that could be thought to represent stress-induced cardiomyopathy. Copyright © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Altered Left Ventricular Contraction Pattern during Right Ventricular Pacing: Assessment Using Real‐Time Three‐Dimensional Echocardiography

Chronic right ventricular apical (RVA) pacing has been associated with increased risk of heart failure and adverse outcome. The acute effects of RVA pacing on three-dimensional (3D) ventricular function and mechanical dyssynchrony are not well known. We performed a real-time 3D echocardiographic (RT3DE) study to assess global and regional left ventricular function during RVA pacing. Twenty-six patients with implanted cardiac devices and normal intrinsic atrioventricular conduction were included in the study. RT3DE was performed during intrinsic sinus rhythm and during RVA pacing. Quantification of global and regional left ventricular function was performed offline by time-volume analysis of 16 myocardial segments. Time to reach minimum regional volume was calculated for each segment as a percentage of the cardiac cycle. The systolic dyssynchrony index (SDI) was defined as the standard deviation of these time periods. Longitudinal function was assessed by time-volume analysis of apical, midventricular, and basal segments. During RVA pacing, a reversed apical-to-basal longitudinal contraction sequence was observed in 58% of all patients. RVA pacing was associated with increased left ventricular (LV) dyssynchrony (SDI increase from 4.4 ± 2.2% to 6.3 ± 2.4%, P = 0.001) and reduced LV ejection fraction (decrease from 53 ± 13% to 47 ± 14%, P = 0.05). RT3DE assessment of LV function provides evidence that pacing from the RVA results in acute alterations in LV contraction sequence and increased LV dyssynchrony. Further studies are warranted to assess the potential of RT3DE to identify patients who might be at increased risk of pacing-induced heart failure or who might benefit from alternate-site or multisite pacing.

Clinical Summaries

Clinical Summaries

Circumferential myocardial strain in cardiomyopathy with and without left bundle branch block.

BackgroundCardiac resynchronization therapy (CRT) has been shown to decrease mortality in 60-70% of advanced heart failure patients with left bundle branch block (LBBB) and QRS duration > 120 ms. There have been intense efforts to find reproducible non-invasive parameters to predict CRT response. We hypothesized that different left ventricular contraction patterns may exist in LBBB patients with depressed systolic function and applied tagged cardiovascular magnetic resonance (CMR) to assess circumferential strain in this population.MethodsWe determined myocardial circumferential strain at the basal, mid, and apical ventricular level in 35 subjects (10 with ischemic cardiomyopathy, 15 with non-ischemic cardiomyopathy, and 10 healthy controls). Patterns of circumferential strain were analyzed. Time to peak systolic circumferential strain in each of the 6 segments in all three ventricular slices and the standard deviation of time to peak strain in the basal and mid ventricular slices were determined.ResultsDyskinesis of the anterior septum and the inferior septum in at least two ventricular levels was seen in 50% (5 out of 10) of LBBB patients while 30% had isolated dyskinesis of the anteroseptum, and 20% had no dyskinesis in any segments, similar to all of the non-LBBB patients and healthy controls. Peak circumferential strain shortening was significantly reduced in all cardiomyopathy patients at the mid-ventricular level (LBBB 9 ± 6%, non-LBBB 10 ± 4% vs. healthy 19 ± 4%; both p < 0.0001 compared to healthy), but was similar among the LBBB and non-LBBB groups (p = 0.20). The LBBB group had significantly greater dyssynchrony compared to the non-LBBB group and healthy controls assessed by opposing wall delays and 12-segment standard deviation (LBBB 164 ± 30 ms vs. non-LBBB 70 ± 17 ms (p < 0.0001), non-LBBB vs. healthy 65 ± 17 ms (p = 0.47)).ConclusionsSeptal dyskinesis exists in some patients with LBBB. Myocardial circumferential strain analysis enables detailed characterization of contraction patterns, strengths, and timing in cardiomyopathy patients with and without LBBB.

Can Acute Occlusion of the Left Anterior Descending Coronary Artery Produce a Typical “Takotsubo” Left Ventricular Contraction Pattern?

The takotsubo syndrome (TS) takes its name from a distinctive left ventricular (LV) contraction abnormality. Patients with this disorder present with clinical findings of an acute ischemic event. Despite the absence of obstructive coronary artery disease, there is a hallmark LV contraction abnormality, namely hypercontractility of the base but akinesia or dyskinesis of the apex. Many discount a role for the epicardial coronary arteries in this disorder because the LV contraction abnormality appears to overlap >1 vascular territory. To test this assumption we analyzed the contraction pattern associated with left anterior descending coronary artery (LAD) occlusion. From May to September 2006, 43 patients underwent primary percutaneous coronary intervention for acute ST-elevation myocardial infarction due to LAD occlusion. Their left ventriculograms were randomly mixed with those of 47 patients clinically labeled as TS. Two reviewers unaware of the clinical diagnosis characterized the LV contraction pattern of all 90 as typical of TS or not. In 6 of the 43 patients (14%) with primary PCI the 2 reviewers considered the pattern to be typical, and in 5 (12%), 1 of 2 reviewers did. Thus, in 26% >/=1 reviewer believed that the pattern associated with LAD occlusion was typical of TS. In conclusion, the characteristic TS contraction pattern may be seen in some patients with acute occlusion of the LAD. It would be premature to dismiss the possibility of transient LAD occlusion as part of the pathogenesis of that disorder.

Apical Ballooning Syndrome or Takotsubo Syndrome: A Novel Cardiac Syndrome

Apical Ballooning Syndrome or Takotsubo Syndrome: A Novel Cardiac Syndrome

Unusual abnormal left ventricular contraction pattern associated with subarachnoid hemorrhage

Unusual abnormal left ventricular contraction pattern associated with subarachnoid hemorrhage

Left ventricular free wall rupture in a Caucasian female with takotsubo syndrome: a case report and a brief literature review

The takotsubo syndrome is a clinical entity that can mimic an acute myocardial infarction. It is characterised by anginal chest pain with ST-T elevation in precordial leads, without coronary obstruction at angiography; its distinctive feature is a peculiar pattern of left ventricular contraction, with expansion of the apical segments and basal hyperkinesis, also known as 'apical ballooning'. This syndrome usually has a good prognosis, with normalisation of the left ventricular contraction impairment within several days, although Japanese authors have described two cases of free left ventricular wall rupture in these patients.We describe a case of apical ballooning syndrome complicated by left ventricular rupture in a Caucasian old female. To our knowledge, this is the first-ever case of a fatal outcome in the Caucasian population, due to free wall ventricular rupture, and confirms that the takotsubo syndrome may lead to a fatal cardiac event.

Regional differences in the force-frequency relation of human left ventricular myocardium in mitral regurgitation: implications for ventricular shape

Sphericalization of the left ventricular (LV) chamber shape in patients with mitral regurgitation (MR) contributes to increased LV wall stress and energy consumption. On the basis of previous observations, we hypothesized the existence of regional differences in the force-frequency relation (FFR) within the LV that may contribute to its shape. Accordingly, in the present study, we assessed regional variation in the FFR in patients undergoing surgery for chronic, nonischemic MR with class II-III heart failure symptoms and related our findings to the in vivo LV shape. FFRs (steady-state isometric twitches, 0.2-3.4 Hz, 37 degrees C) were evaluated in MR myocardium from the LV subepicardial free wall (MR-FW) and papillary muscle (MR-PM) and from the subepicardial free wall in coronary artery bypass graft patients with normal LV contraction patterns [nonfailing (NF)]. Ascending slope, optimal stimulation frequency, and maximal twitch tension of the FFR were depressed in MR-FW and MR-PM compared with NF (P < 0.05). FFR depression was greater in MR-PM than in MR-FW. Between 107 and 134 beats/min, twitch tension became weaker in MR-PM, whereas it increased in MR-FW. Elevation of intracellular cAMP with forskolin eliminated FFR depression in MR-FW but not in MR-PM. MR-PM also had a 35% lower myosin heavy chain content and slowed twitch kinetics. In MR patients, the echocardiographic end-diastolic LV shape (end-diastolic eccentricity index = long axis/short axis) correlated with the ratio of ascending FFR slopes such that the end-diastolic eccentricity index increased 10% per 15% increase in slope ratio (r = 0.88, P = 0.01). These regional differences in the frequency dependence of contractility between the free wall and papillary myocardium may contribute to changes in LV shape in MR as well as during exercise.

Color Doppler Tissue Velocity Imaging Can Disclose Systolic Left Ventricular Asynchrony Independent of the QRS Morphology in Patients with Severe Heart Failure

A QRS width greater than 120 ms is assumed to be a marker of inter- and intraventricular asynchrony in severe heart failure (HF) patients. Color Doppler tissue velocity imaging (c-TVI) with a time resolution of 10 ms was used to study regional left ventricular (LV) longitudinal systolic contraction pattern in HF patients with left and right bundle branch block (LBBB and RBBB) and in patients with normal QRS width. We studied 12 women and 23 men with severe HF, with a mean age of 66 +/- 11 years in New York Heart Association functional Class 2.9 +/- 0.6. Twenty patients had LBBB and 10 of those were accepted for cardiac resynchronization therapy by biventricular pacing (CRT). Ten patients had normal QRS width, and five had RBBB. In the echocardiographic apical four chamber view, regional peak LV tissue velocities and regional LV time differences of peak tissue velocities were compared at basal and mid-LV segments. There were no significant differences in regional mean peak tissue velocities among the patient groups. In patients with LBBB accepted for CRT, the LV lateral free-wall movement at basal LV was 29 ms delayed during main systole, almost significantly different from LBBB patients not accepted for CRT (P = 0.075). Even in HF patients with normal QRS width or RBBB, significant asynchronous longitudinal LV contraction was observed. For the detection of regional longitudinal LV contraction asynchrony in patients with severe HF, supplementary methods to the surface ECG, such as c-TVI, are strongly recommended.

P-156 Reverse remodeling of systolic left ventricular contraction pattern by long-term cardiac resynchronization therapy

P-156 Reverse remodeling of systolic left ventricular contraction pattern by long-term cardiac resynchronization therapy

P-156 Reverse remodeling of systolic left ventricular contraction pattern by long-term cardiac resynchronization therapy

P-156 Reverse remodeling of systolic left ventricular contraction pattern by long-term cardiac resynchronization therapy

Etiologies of left bundle branch block and correlations with hemodynamic and angiographic findings

Etiologies of left bundle branch block and correlations with hemodynamic and angiographic findings