Richard A. Grimm

Echocardiography for cardiac resynchronization therapy: recommendations for performance and reporting--a report from the American Society of Echocardiography Dyssynchrony Writing Group endorsed by the Heart Rhythm Society.

Echocardiography plays an evolving and important role in the care of heart failure patients treated with biventricular pacing, or cardiac resynchronization therapy (CRT). Numerous recent published reports have utilized echocardiographic techniques to potentially aide in patient selection for CRT prior to implantation and to optimized device settings afterwards. However, no ideal approach has yet been found. This consensus report evaluates the contemporary applications of echocardiography for CRT including relative strengths and technical limitations of several techniques and proposes guidelines regarding current and possible future clinical applications. Principal methods advised to qualify abnormalities in regional ventricular activation, known as dyssynchrony, include longitudinal velocities by color-coded tissue Doppler and the difference in left ventricular to right ventricular ejection using routine pulsed Doppler, or interventricular mechanical delay. Supplemental measures of radial dynamics which may be of additive value include septal-to-posterior wall delay using M-mode in patients with non-ischemic disease with technically high quality data, or using speckle tracking radial strain. A simplified post-CRT screening for atrioventricular optimization using Doppler mitral inflow velocities is also proposed. Since this is rapidly changing field with new information being added frequently, future modification and refinements in approach are anticipated to continue.

Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo contrast: Characterization by simultaneous transesophageal echocardiography

OBJECTIVES This study assessed the function of the left atrial appendage in the pericardioversion period to gain insights into mechanisms involved in thromboembolism after cardioversion of atrial fibrillation. BACKGROUND Systemic embolization associated with electrical cardioversion of atrial fibrillation is thought to originate from the left atrium or left atrial appendage, or both. However, the mechanism involved is poorly understood. METHODS We studied left atrial appendage function with transesophageal echocardiography in 20 patients with atrial fibrillation before and after successful electrical cardioversion. We measured left atrial appendage emptying and filling velocities by pulsed wave Doppler echocardiography, characterized Doppler emptying patterns, measured atrial appendage areas and assessed the presence or absence of spontaneous echo contrast or thrombus. RESULTS Organized left atrial appendage function returned in 16 (80%) of 20 patients immediately after cardioversion. Atrial appendage emptying velocities before cardioversion were greater in patients without (0.39 +/- 0.02 m/s) than in those with (0.25 +/- 0.12 m/s) spontaneous echo contrast (p = 0.045). Furthermore, emptying velocities before cardioversion were significantly greater than late diastolic emptying velocities after cardioversion (0.31 +/- 0.15 vs. 0.14 +/- 0.12 m/s, p = 0.0001), as well as in both the group with (0.25 +/- 0.12 vs. 0.13 +/- 0.13 m/s, p = 0.001) and the group without (0.39 +/- 0.02 vs. 0.15 +/- 0.12 m/s, p = 0.01) spontaneous echo contrast. In addition, left atrial and atrial appendage spontaneous echo contrast developed in 4 of 20 patients and increased in intensity in 3 of 20 patients in the immediate postcardioversion period. CONCLUSIONS Organized left atrial appendage function returns in most patients immediately after cardioversion of atrial fibrillation. However, its function is impaired compared with that before cardioversion. Furthermore, spontaneous echo contrast increased in 7 (35%) of 20 patients after cardioversion. These observations suggest that stunned left atrial appendage function after cardioversion may predispose the chamber to thrombus formation, which may play a role in the mechanism involved in the occurrence of embolization after cardioversion.

Insights From a Cardiac Resynchronization Optimization Clinic as Part of a Heart Failure Disease Management Program

OBJECTIVES Our aim was to determine the feasibility and value of a protocol-driven approach to patients with cardiac resynchronization therapy (CRT) who did not exhibit a positive response long after implant. BACKGROUND Up to one-third of patients with advanced heart failure do not exhibit a positive response to CRT. METHODS A total of 75 consecutive ambulatory patients with persistent advanced heart failure symptoms and/or adverse reverse remodeling and CRT implanted >6 months underwent a comprehensive protocol-driven evaluation to determine the potential reasons for a suboptimal response. Recommendations were made to maximize the potential of CRT, and adverse events were documented. RESULTS All patients (mean left ventricular [LV] ejection fraction 23 +/- 9%, LV end-diastolic volume 275 +/- 127 ml) underwent evaluation. Eighty-eight percent of patients had significantly better echocardiographic indexes of LV filling and LV ejection with optimal setting of their CRT compared with a temporary VVI back-up setting. Most patients had identifiable reasons for suboptimal response, including inadequate device settings (47%), suboptimal medical treatment (32%), arrhythmias (32%), inappropriate lead position (21%), or lack of baseline dyssynchrony (9%). Multidisciplinary recommendations led to changes in device settings and/or other therapy modifications in 74% of patients and were associated with fewer adverse events (13% vs. 50%, odds ratio: 0.2 [95% confidence interval: 0.07 to 0.56], p = 0.002) compared with those in which no recommendation could be made. CONCLUSIONS Routine protocol-driven approach to evaluate ambulatory CRT patients who did not exhibit a positive response is feasible, and changes in device settings and/or other therapies after multidisciplinary evaluation may be associated with fewer adverse events.

2012 EHRA/HRS expert consensus statement on cardiac resynchronization therapy in heart failure: implant and follow-up recommendations and management

2012 EHRA/HRS expert consensus statement on cardiac resynchronization therapy in heart failure : implant and follow-up recommendations and management

Exclusion of atrial thrombus by transesophageal echocardiography does not preclude embolism after cardioversion of atrial fibrillation. A multicenter study.

BACKGROUND Transesophageal echocardiography (TEE) has been used recently to detect atrial thrombi before cardioversion of atrial arrhythmias. It has been assumed that embolic events after cardioversion result from embolism of preexisting atrial thrombi that are accurately detected by TEE. This study examined the clinical and echocardiographic findings in patients with embolism after cardioversion of atrial fibrillation despite exclusion of atrial thrombi by TEE. METHODS AND RESULTS Clinical and echocardiographic data in 17 patients with embolic events after TEE-guided electrical (n = 16) or pharmacological (n = 1) cardioversion were analyzed. All 17 patients had nonvalvular atrial fibrillation, including four patients with lone atrial fibrillation. TEE before cardioversion showed left atrial spontaneous echo contrast in five patients and did not show atrial thrombus in any patient. Cardioversion resulted in return to sinus rhythm without immediate complication in all patients. Thirteen patients had cerebral embolic events and four patients had peripheral embolism occurring 2 hours to 7 days after cardioversion. None of the patients were therapeutically anticoagulated at the time of embolism. New or increased left atrial spontaneous echo contrast was detected in four of the five patients undergoing repeat TEE after cardioversion including one patient with a new left atrial appendage thrombus. CONCLUSIONS Embolism may occur after cardioversion of atrial fibrillation in inadequately anticoagulated patients despite apparent exclusion of preexisting atrial thrombus by TEE. These findings suggest de novo atrial thrombosis after cardioversion or imperfect sensitivity of TEE for atrial thrombi and suggest that screening by TEE does not obviate the requirement for anticoagulant therapy at the time of and after cardioversion. A randomized clinical trial is needed to compare conventional anticoagulant management with a TEE-guided strategy including anticoagulation after cardioversion.

ACCF/HRS/AHA/ASE/HFSA/SCAI/SCCT/SCMR 2013 appropriate use criteria for implantable cardioverter-defibrillators and cardiac resynchronization therapy

Steven R. Bailey, MD, FACC, FSCAI, FAHA, Moderator Andrea M. Russo, MD, FACC, FHRS, Writing Group Liaison [⁎][1] Suraj Kapa, MD, Writing Group Liaison Michael B. Alexander, MD, FACC[§][2] Steven R. Bailey, MD, FACC, FSCAI, FAHA[∥][3] Ulrika Birgersdotter-Green, MD, FHRS[∥][3] Alan S.

Echocardiographic correlates of left ventricular structure among 844 mildly hypertensive men and women in the Treatment of Mild Hypertension Study (TOMHS).

BackgroundEchocardiography provides a noninvasive means of assessing left ventricular (LV) structure and evidence of LV wall remodeling in hypertensive persons. The relation of demographic, biological, and other factors with LV structure can be assessed. Methods and ResultsLV structure was assessed by M-mode echocardiograms for 511 men and 333 women with mild hypertension (average blood pressure, 140/91 mm Hg). Measurements ofLV wall thicknesses and internal dimensions were made, and estimates of LV mass indexes and other derivations of structure were calculated. LV hypertrophy criteria were based on previously reported echocardiographic population studies of normal subjects. These measures were compared by age, sex, race, body mass index, systolic blood pressure, antihypertensive drug use, physical activity, alcohol intake, cigarette smoking, and urinary sodium excretion. Despite virtual absence of ECG-determined LV hypertrophy, 13% of men and 20%o ofwomen had echocardiographically determined LV hypertrophy indexed by body surface area (g/m2), and 24% of men and 45% of women had LV hypertrophy indexed by height (g/m). Black participants had slightly higher mean levels of wall thickness than nonblack participants but similar LV mass. Systolic blood pressure and urinary sodium excretion were significantly and independently associated with LV mass index and LV hypertrophy using both g/m2 and g/m. Body mass index was significantly related to LV mass index and LV hypertrophy using g/m. Smoking was significantly associated with LV mass index, i.e., using continuous measurement but not using the dichotomy for LV hypertrophy. ConclusionThis study of a large population of men and women with mild primary hypertension, largely without ECG evidence of LV hypertrophy, showed a substantial percentage of participants with echocardiographically determined LV hypertrophy. LV mass indexes correlated positively with systolic blood pressure, body mass index, urinary sodium excretion, and smoking.

Cardioversion guided by transesophageal echocardiography: The ACUTE Pilot Study : A Randomized, controlled trial

A trial fibrillation is characterized by a lack of organized electrical and mechanical atrial activity that results in an irregular heartbeat and increased risks for congestive heart failure, thromboembolism, and death [1-3]. Since 1962, direct-current cardioversion has been used to restore sinus rhythm in patients with atrial fibrillation [4]. However, successful cardioversion, with the sudden resumption of sinus rhythm, is itself associated with an increased risk for embolic stroke, which can result when thrombi in the left atrial appendage are dislodged [5-12]. Transesophageal echocardiography (TEE) is an excellent method with which to detect thrombi in the left atrial appendage [13-19]. Its use has therefore been proposed as a way to allow cardioversion to be done earlier and more safely than would be possible with conventional therapy, which consists of a total of 7 weeks of treatment with warfarin [14-23]. Recent studies [15-19] indicate that TEE-guided cardioversion with short-term anticoagulation therapy may have several advantages over the conventional approach. These advantages include a decreased risk for embolism, which results from the avoidance of cardioversion in patients who have thrombi in the left atrial appendage [15]; a decreased risk for bleeding, which occurs because anticoagulation therapy can be briefer [19]; greater initial conversion to and long-term maintenance of sinus rhythm, which result from doing cardioversion earlier [18, 19]; and greater cost-effectiveness, which results from the decreased incidence of embolic stroke [17]. The ACUTE (Assessment of Cardioversion Using Transesophageal Echocardiography) Pilot Study was a multicenter, randomized clinical trial designed to compare TEE-guided cardioversion with conventional management of cardioversion in patients with atrial fibrillation who have cardioversion [19]. The study had two objectives: to assess the general feasibility of a TEE-guided approach to cardioversion and to determine the general safety of the TEE-guided approach by comparing its clinical outcome with those of conventional management. Methods Patient Selection Patients who were candidates for electrical cardioversion were eligible for inclusion if they had atrial fibrillation, or atrial flutter with a history of atrial fibrillation, lasting longer than 2 days. Patients were excluded if they had received anticoagulant therapy for more than 7 days, had required urgent cardioversion as a result of hemodynamic instability, had had a cardioembolic event within the previous month, had contraindications to TEE or warfarin, were women with childbearing potential in whom pregnancy could not be excluded, were unable to give informed consent, or were unable to return for a follow-up visit. Our study protocol was approved by the institutional review boards at all clinical sites, and all patients provided written informed consent in advance. Study Protocol Patients who met the inclusion criteria were randomly assigned to receive either a conventional or a TEE-guided approach to cardioversion. Randomization was done using presealed, opaque envelopes that were computer generated and distributed to each clinical site (Figure 1). Random assignments were stratified by site and were generated in blocks of six. Figure 1. The ACUTE (Assessment of Cardioversion Using Transesophageal Echocardiography) study protocol. The conventional approach to cardioversion was that recommended by the American College of Chest Physicians: 3 weeks of therapeutic warfarin therapy, then cardioversion, then 4 weeks of warfarin therapy, and then a follow-up examination at the end of the 4 weeks [23]. Prothrombin times were monitored regularly, and the target international normalized ratio (INR) was 2 to 3. If assigned to the TEE group, patients began receiving anticoagulation therapy at their initial visit. The goal was to have patients therapeutically anticoagulated (therapeutic anticoagulation was defined as a partial thromboplastin time 1.5 to 2.5 times control values or an INR of 2.0 to 3.0) at the time of and after the planned cardioversion, for a total of 4 weeks of therapy. The initial choice of antithrombotic agent was determined by whether the patient was an inpatient or an outpatient at the time of randomization: Heparin was used for inpatients; warfarin was administered to outpatients. Transesophageal echocardiography, with subsequent cardioversion within 24 hours, was then scheduled as soon as stable therapeutic anticoagulation was assured. For example, if a patient was hospitalized and intravenous heparin therapy was administered, TEE was done as soon as a stable therapeutic partial thromboplastin time could be documented (for 24 to 36 hours); subsequent cardioversion was done if the presence of a thrombus was excluded. A 4- to 5-day overlap of warfarin therapy and intravenous heparin therapy was often necessary to maintain adequate anticoagulation after cardioversion. If the patient was to be managed as an outpatient, warfarin therapy was initiated on the day of study enrollment, and TEE and subsequent possible cardioversion were scheduled for at least 5 to 7 days later. Again, cardioversion was done when the patient was therapeutically anticoagulated, and all patients received maintenance therapy with warfarin for 4 weeks after cardioversion [15]. In the TEE group, cardioversion was done immediately after or within 24 hours of TEE because of the potential for thrombus formation in the period between TEE and cardioversion. If thrombi were detected in the left or right atrial appendages or atrial cavities, cardioversion was postponed and the patient received warfarin therapy for 4 weeks. After 4 weeks, TEE was repeated and, if no thrombus was detected, cardioversion was done. If a thrombus was still present, another 4-week course of warfarin therapy was administered and cardioversion was not done [15]. Clinical Outcomes Our feasibility outcomes were frequency of cardioversion, frequency of cardioversion occurring as scheduled, time to cardioversion, and time to sinus rhythm. Our clinical safety outcomes were clinically apparent ischemic stroke, transient ischemic attack, systemic embolization, deaths related to cardioversion or episodes of bleeding, and detected episodes of clinical hemodynamic instability (worsening congestive heart failure or hypotension) that rendered the patient unable to complete the protocol. Other outcome variables were the prevalence of thrombi, the number of patients without thrombi who had early cardioversion, and the immediate and follow-up rhythms after cardioversion. These outcomes were assessed for as long as 4 weeks after cardioversion but for no longer than 8 weeks after randomization. In the patients who did not have cardioversion and who spontaneously reverted to sinus rhythm, the variables were assessed at 4 weeks after spontaneous reversion. Study Organization and Procedures The administrative organization of the pilot study is described in the Appendix. Echocardiographic Examination Conventional transthoracic echocardiography was done in both study groups using commercially available equipment. In the TEE group, TEE was done according to standard techniques using phased-array biplane or multiplane transducers [24-26]. Complete transesophageal echocardiographic examination was done, and special attention was paid to imaging the left and right atria and left and right atrial appendages to assess the presence or absence of thrombi and spontaneous echo contrast. Echocardiographic Data Analysis Two-dimensional directed M-mode transthoracic echocardiography was used to derive the left ventricular septal and posterior wall thicknesses and the end-diastolic, end-systolic, and left atrial dimensions. Ejection fraction was calculated using standard techniques [27, 28]. The maximal left atrial and right atrial areas were planimetered on-line, and the severity of mitral regurgitation was qualitatively graded from 0 to 4+ by using color-flow mapping [29]. A thrombus was considered to be present if a mass detected in the appendage or body of the atrium appeared to be distinct from the underlying endocardium, was not caused by pectinate muscles, and was detected in more than one imaging plane. The presence or absence of spontaneous echo contrast was analyzed and defined as dynamic intracavitary echoes with a characteristic swirling pattern distinct from artifact. The degree of spontaneous echo contrast was categorized independently as absent, mild, or severe [30, 31]. Quality Control Measures Standard definitions of echocardiographic measurements were available to all of the clinical centers as part of a pilot operations manual. Echocardiograms at each clinical center were interpreted locally by a single physician who was highly experienced in echocardiography. Videotapes that showed the results of the first five echocardiographic examinations and all videotapes that showed thrombi were forwarded from the clinical centers to a central laboratory and overread by three experienced reviewers for consensus [19]. Electrical Cardioversion Cardioversion was done by using the standard method of Lown and associates [4] with an initial energy of at least 40 J for atrial flutter and 200 J for atrial fibrillation. Statistical Analysis Summaries of clinical, echocardiographic, and outcome data are expressed as means or frequencies with 95% CIs. Data that were not normally distributed were log-transformed and presented as geometric means. Outcomes were compared for the TEE and conventional therapy groups, for patients with and without thrombus (in the TEE group only), and for patients in the TEE and conventional therapy groups who had cardioversion. These analyses were done using the t-test for independent groups for continuous variables and the Fisher exact test for categorical variables. StatXact (Cytel Software, Cambridge, Massachusetts) was used to compute binary CIs; SAS softwar

Longitudinal Strain Delay Index by Speckle Tracking Imaging A New Marker of Response to Cardiac Resynchronization Therapy

Background— In heart failure patients with left ventricular dyssynchrony, contractility in delayed segments does not fully contribute to end-systolic function. We quantified this reserve of contraction related to mechanical dyssynchrony to predict response to cardiac resynchronization therapy by the strain delay index, which was defined as the sum of the difference between peak and end-systolic strain across 16 segments. Methods and Results— In 100 heart failure patients (ejection fraction=26±9%, QRS=154±29 ms, 94% in New York Heart Association class III), we studied left ventricular dyssynchrony before cardiac resynchronization therapy by the strain delay index using longitudinal strain by 2D speckle tracking and by the SD of time to peak myocardial velocity in 12 segments. The optimal cutoff value of the strain delay index to predict response to cardiac resynchronization therapy was determined in a retrospective group (n=65) and then confirmed in a validation group (n=35). Left ventricular end-systolic volume reduction at 3 months >15% (responder) occurred in 64 of 100 patients. In the retrospective group, the strain delay index but not the SD of time to peak myocardial velocity was greater in responders (n=42/65) than nonresponders (35±8% versus 19±7%, P<0.0001), and the optimal cutoff value to identify response to cardiac resynchronization therapy was 25%. In the validation group, strain delay index ≥25% identified 82% (18/22) of responders and 92% (12/13) of nonresponders. Among the entire population (n=100), strain delay index correlated with reverse remodeling in both the ischemic (r=−0.68, P<0.0001) and nonischemic (r=−0.68, P<0.0001) population. Conclusions— Use of the strain delay index with longitudinal strain by speckle tracking has a strong predictive value for predicting response to cardiac resynchronization therapy in both ischemic and nonischemic patients.

Left atrial appendage 'stunning' after electrical cardioversion of atrial flutter: An attenuated response compared with atrial fibrillation as the mechanism for lower susceptibility to thromboembolic events

OBJECTIVES This study sought to determine whether left atrial appendage stunning occurs in patients with atrial flutter and to compare left atrial appendage function in the pericardioversion period with that in patients with atrial fibrillation. BACKGROUND Left atrial appendage stunning has recently been proposed as a key mechanistic phenomenon in the etiology of postcardioversion thromboembolic events in atrial fibrillation. Atrial flutter is thought to be associated with a negligible risk of thromboembolic events; therefore, anticoagulation is commonly withheld before and after cardioversion in these patients. METHODS Sixty-three patients with atrial flutter (n = 19) or atrial fibrillation (n = 44) underwent transesophageal echocardiography immediately before and after electrical cardioversion. In addition to assessing the presence of thrombus and spontaneous echo contrast, we measured left atrial appendage emptying velocity and calculated shear rates by pulsed wave Doppler and two-dimensional echocardiography. RESULTS Patients with atrial flutter exhibited greater left atrial appendage flow velocities before cardioversion than those with atrial fibrillation (42 +/- 19 vs. 28 +/- 15 cm/s [mean +/- SD], p < 0.001). Left atrial appendage shear rates were also higher in patients with atrial flutter (103 +/- 82 vs. 59 +/- 37 s-1, p < 0.001). After cardioversion, left atrial appendage flow velocities decreased compared with precardioversion values in patients with atrial fibrillation (28 +/- 15 before to 15 +/- 14 cm/s after cardioversion, p < 0.001) and atrial flutter (42 +/- 19 to 27 +/- 18 cm/s, respectively, p < 0.001). Shear rates decreased from 59 +/- 37 before cardioversion to 30 +/- 31 s-1 after cardioversion in atrial fibrillation (p < 0.001), and from 103 +/- 82 s to 65 +/- 52 s-1, respectively (p < 0.001), in atrial flutter. This decrease in flow velocity from before to after cardioversion occurred in 36 (82%) of 44 patients with atrial fibrillation and 14 (74%) of 19 with atrial flutter. The impaired left atrial appendage function after cardioversion was less pronounced in the group with atrial flutter (27 +/- 18 cm/s for atrial flutter vs. 15 +/- 14 cm/s for atrial fibrillation, p < 0.001). New or increased spontaneous echo contrast occurred in 22 (50%) of 44 patients with atrial fibrillation versus 4 (21%) of 19 with atrial flutter (p < 0.05). CONCLUSIONS Left atrial appendage stunning also occurs in patients with atrial flutter, although to a lesser degree than in those with atrial fibrillation. These data suggest that patients with atrial flutter are at risk for thromboembolic events after cardioversion, although this risk is most likely lower than that in patients with atrial fibrillation because of better preserved left atrial appendage function.