Leadless pacemaker perforations: Clinical consequences and related device and user problems.

BACKGROUND: Cardiac perforation during leadless pacemaker implantation is more likely to require intervention than perforation by a transvenous lead. This study reports the consequences of Micra pacemaker perforations and related device and operator use problems based on information the manufacturer has submitted to the Food and Drug Administration (FDA). METHODS: FDA's Manufacturer and User Facility Device Experience (MAUDE) database was searched for Micra perforations. Data extracted included deaths, major adverse clinical events (MACEs), and device and/or operator use problems. RESULTS: Between 2016 and July 2021, 563 perforations were reported within 30 days of implant and resulted in 150 deaths (27%), 499 cardiac tamponades (89%), 64 pericardial effusions (11%), and 146 patients (26%) required emergency surgery. Half of perforations were associated with 139 (25%) device problems, 78 (14%) operator use problems, and 62 (11%) combined device and operator use problems. Inadequate electrical measurements or difficult positioning were the most frequent device problems (n = 129); non-septal implants and perforation of other structures were the most frequent operator use problems (n = 69); a combined operator use and device problem resulted in 62 delivery system perforations. No device or operator use problem was identified for 282 perforations (50%), but they were associated with 78 deaths, 245 tamponades, and 57 emergency surgeries. CONCLUSION: The Micra perforations reported in MAUDE are often associated with death and major complications requiring emergency intervention. Device and use problems account for at least half of perforations. Studies are needed to identify who is at risk for a perforation and how MACE can be avoided or mitigated.

Ripple Frequency Determined via a Novel Algorithm Is Associated With Atrial Fibrillation Termination and Freedom From Atrial Fibrillation.

Background: Persistent atrial fibrillation (AF) is a complex arrhythmia, and attaining freedom from AF with ablation has been challenging. Objectives: This study evaluated a novel CARTO software algorithm based on the CARTO Ripple map for AF termination and 18-month freedom from AF. Methods: Consecutive patients who underwent first-time ablation for persistent AF were included. A high-density Ripple map was created using a Pentaray catheter. Following PVI, ablation was performed at locations with rapid Ripple activations, a protocol previously described by us. Patients were followed for 18 months to assess rhythm outcomes. A retrospective analysis was performed using the CARTO Ripple frequency software algorithm. The Ripple frequency algorithm quantifies amplitude changes in the bipolar electrogram. Results: A total of 115 AF maps were analyzed from 84 patients (mean age 65.9 years, 63.1% men). The top quartile of Ripple frequency corresponded to a visual reference with 96.7% sensitivity and 91.1% specificity. AF terminated during ablation in 88.1% of patients: pulmonary vein antrum alone (14.9%) or pulmonary vein plus nonantral sites (85.1%). The top quartile of Ripple frequency was present in nonantral areas associated with AF termination with 90.2% sensitivity and 86.5% specificity. After 14.0 ± 6.5 months and 1.2 ± 0.4 ablations, 78 (92.9%) of 84 patients were free of AF, and 79.8% were free of any atrial arrhythmia. Conclusion: A novel algorithm for automated analysis of CARTO Ripple frequency demonstrated good sensitivity and specificity for detecting atrial regions in persistent AF in which ablation is associated with frequent AF termination and freedom from AF during follow-up.

Major adverse clinical events associated with implantation of a leadless intracardiac pacemaker.

BACKGROUND: Leadless intracardiac pacemakers were developed to avoid the complications of transvenous pacing systems. The Medtronic Micra™ transcatheter pacemaker is one such system. We found an unexpected number of major adverse clinical events (MACE) in the Food and Drug Administration's Manufacturers and User Facility Device Experience (MAUDE) database associated with Micra implantation. OBJECTIVE: The purpose of this study was to describe these MACE and compare them to implant procedure MACE in MAUDE for Medtronic CapSureFix™ active-fixation transvenous pacing leads. METHODS: During January 2021, we queried the MAUDE database for reports of MACE for Micra pacemakers and CapSureFix leads using the simple search terms "death," "tamponade," and "perforation." Reports from 2016-2020 were included. RESULTS: The search identified 363 MACE for Micra and 960 MACE for CapSureFix leads, including 96 Micra deaths (26.4%) vs 23 CapSureFix deaths (2.4%) (P <.001); 287 Micra tamponades (79.1%) vs 225 tamponades for CapSureFix (23.4%) (P <.001); and 99 rescue thoracotomies for Micra (27.3%) vs 50 rescue thoracotomies for CapSureFix (5.2%) (P <.001). More Micra patients required cardiopulmonary resuscitation (21.8% vs 1.1%) and suffered hypotension or shock (22.0% vs 5.8%) than CapSureFix recipients (P <.001). Micra patients were more likely to survive a myocardial perforation or tear if they had surgical repair (P = .014). CONCLUSION: Micra leadless pacemaker implantation may be complicated by myocardial and vascular perforations and tears that result in cardiac tamponade and death. We estimate the incidence is low (<1%). Rescue surgery to repair perforations may be lifesaving. MACE are significantly less for implantation of CapSureFix transvenous ventricular pacing leads.

Reliability and longevity of implantable defibrillators.

PURPOSE: We hypothesized that data in manufacturers' product performance reports (PPRs) can provide clinically valuable ICD and cardiac resynchronization defibrillator (CRT-D) reliability and longevity information. METHODS: Data were obtained from 2019 PPRs. Kaplan-Meier (K-M) probabilities of freedom from malfunction, normal battery depletion (NBD), and NBD + malfunction were calculated for ICD and CRT-D pulse generators (PGs) with LiMnO2 or LiSVO/CFx batteries marketed in the USA from 2010 to 2019 and compared using the log-rank test. Malfunctions (MAL) included PGs that were found outside specifications. RESULTS: Study population included 1,149,803 ICD and CRT-D PGs: Abbott (ABT; 35.1%), Biotronik (BIO; 4.6%), Boston Scientific (BSC; 23.5%), and Medtronic (MDT; 36.9%). Significant differences in reliability (p < 0.001), defined by freedom from MAL, were found between manufacturers; the majority of 6808 MAL occurred in ABT devices (n = 4045; 59.4%), followed by BSC (n = 2384; 35.0%), MDT (n = 338;5.0%), and BIO (n = 41; 0.6%). Battery failure (n = 890; 57.9%) was the most common cause of MAL compromising therapy; analysis of unique ABT battery MAL-indicated problem appeared a year prior to advisory. Significant differences (p < 0.001) in battery longevity, as defined by freedom from NBD, were found between manufacturers. Overall performance (freedom from NBD + MAL) favored BSC for CRT-D PGs and MDT and BIO for ICDs. BSC subcutaneous ICD reliability was inferior to its transvenous ICD (p < 0.001). CONCLUSION: PPRs contain valuable data that can be aggregated and analyzed to inform physicians. Differences in product reliability exist between manufacturers. Battery longevity has improved, but MAL have significantly impacted performance. PPR data may be useful for assessing product problems and new technology.

High shocking and pacing impedances due to defibrillation lead calcification.

PURPOSE: We have reported the calcification of Endotak defibrillation leads that required replacement. The aim of this study was to assess calcified Endotak Reliance leads in the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database and compare them to calcified Sprint Fidelis, Sprint Quattro Secure, Riata, and Durata leads in MAUDE. METHODS: We searched the MAUDE database from 2008 to 2019 for defibrillation lead calcification using the terms "calcium," "calcification," and "calcified". Included were explanted leads whose manufacturers found calcium on the shocking and/or pacing electrode. RESULTS: The MAUDE search identified 113 calcified defibrillation leads that qualified for the study, including 109 Endotak Reliance leads, 1 Sprint Quattro Secure lead, 2 Durata leads, 1 Riata ST lead, and no Sprint Fidelis lead. The sign of calcification was a gradual increase in shocking or pacing impedance. Average implant time was 7.4 ± 3.1 (range: 1.3-16.5) years. Only Endotak Reliance leads had shocking coil calcification (n = 72; 66.0%) and five (6.9%) of these failed defibrillation threshold (DFT) testing. Distal pacing electrode calcification affected 55 (50.4%) Endotak Reliance leads. The four other leads had pacing ring electrode calcification only. CONCLUSION: Endotak Reliance defibrillation leads appear prone to shocking coil and/or distal pacing electrode calcification. High impedances may compromise defibrillation and pacing therapy. Patients who have these leads should be monitored; those exhibiting high shocking impedances should be considered for DFT testing. Lead replacement should be considered for pacemaker-dependent patients whose leads exhibit progressively high impedances.

Outcomes Before and After the Recall of a Heart Failure Pacemaker.

Importance: Timely and complete disclosure of medical device defects is necessary to manage patient care safely and effectively. Objectives: To determine if the manufacturer's recommendations following the recall of a medical device were timely and complete, the follow-up information and data provided to patients and physicians were adequate for managing patient care, and the actions taken by the US Food and Drug Administration (FDA) regarding the recall were appropriate. Design, Setting, and Participants: This single-center retrospective case series included 90 of 448 patients who were implanted with a cardiac resynchronization therapy pacemaker at the Minneapolis Heart Institute from May 2003 through January 2011; this pacemaker was recalled in November 2015. In addition, returned product reports submitted by the manufacturer to the FDA via the Manufacturer and User Facility Device Experience (MAUDE) database from January 2008 through December 2018 were analyzed. Main Outcomes and Measures: Clinical outcomes were serious adverse clinical events that occurred before and after the November 2015 recall notifying physicians and patients that the device's battery could fail unexpectedly because of high internal impedance. Technical outcomes were signs and causes of failure. Results: Five of 90 patients observed during 2015 experienced syncope when their pacemakers stopped pacing owing to battery or wire connection defects prior to the recall. Of the 90 patients, 37 (41%) were men, and the median (interquartile range) age at implantation was 71.3 (66.1-78.2) years. Analysis of the MAUDE data revealed that battery failures prior to the recall were associated with serious adverse events that included 1 death, 1 cardiac arrest, 5 syncopal attacks, and 6 heart failure exacerbations; 3 additional prerecall syncopal events were caused by wire connection defects. The manufacturer and the FDA were aware of the battery and wire connection defects for 19 months before issuing the recall, yet the wire connection problem was not included in the advisory and physicians were not informed that interrogating the pacemaker could result in loss of pacing. The FDA classified the recall as class II rather than the more critical class I. Conclusions and Relevance: This case series study of patients implanted with a defective pacemaker found that the pacemaker recall was delayed and that subsequent communications did not include all critical information needed for safe and effective patient care. These findings should prompt reforms in how the medical device industry and the FDA manage future medical device recalls.

Outcomes after pacemaker implantation in patients with new-onset left bundle-branch block after transcatheter aortic valve replacement.

New-onset left bundle branch block (N-LBBB) after transcatheter aortic valve replacement (TAVR) is a challenging clinical dilemma. In our single-center study, 60 out of 172 patients who underwent permanent pacemaker implantation (PPM) after TAVR had N-LBBB (34.9%). At a median follow-up duration of 357 days (IQR, 178; 560 days), two patients (3.5%) were completely pacemaker-dependent, and four others (7%) were partially dependent. Twelve patients (24%) recovered conduction in their left bundle at a median follow-up duration of 5 weeks (IQR, 4; 14 weeks). Due to the lack of clinical predictors of pacemaker dependency, active surveillance is warranted and may be an alternative to permanent pacemaker implantation.

Outcomes following persistent atrial fibrillation ablation using localized sources identified with Ripple map.

BACKGROUND: Ablation of persistent atrial fibrillation (AF) remains challenging. Identification and ablation of localized AF drivers may offer the possibility for improved outcomes. Ripple map is a novel software algorithm that may allow improved localization of possible AF drivers through the whole chamber graphical display of continuously recorded bipolar electrograms. The objective of this study was to determine whether regions of high-frequency Ripple activation (HFRA) observed on Ripple map provide useful ablation targets in patients with persistent AF. METHODS AND RESULTS: Consecutive patients underwent the first-time ablation of persistent AF (n = 162) using a standard stepwise (n = 105) or a Ripple map guided approach (n = 57). Ripple map guided patients underwent pulmonary vein antral isolation followed by ablation of HFRA sites. Acute termination of AF was observed in 91.2% of the Ripple-guided patients vs 52.4% in the stepwise approach, P < .0001. Following a single ablation procedure, after 18 months 98.2% of Ripple map guided patients were free of AF, compared with 81.4% of standard stepwise ablation (P = .005). Freedom from atrial tachycardia (54.4% Ripple map vs 52.4% standard, P = .9) or any atrial arrhythmia (52.6% Ripple map vs 39.0% standard, P = .10) did not differ between the two strategies. In a subset analysis (n = 30 of 56), Ripple map regions corresponded to sites with spatiotemporal dispersion in all atrial locations. No differences were observed in the rate of procedural complications. CONCLUSIONS: Ablation of HFRA sites identified with Ripple map resulted in a higher rate of acute termination and improved freedom from AF compared to a standard stepwise approach.

Internal insulation breaches in an implantable cardioverter-defibrillator lead with redundant conductors.

BACKGROUND: Internal insulation breaches (IBR) may result in implantable cardioverter-defibrillator lead failure and adverse clinical events. Concerns exist that the Durata lead may be prone to IBR. OBJECTIVE: The goals of this study were to assess Durata failures in the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database and compare them to failures in MAUDE for Endotak Reliance and Sprint Quattro Secure (QS) leads. METHODS: We searched the MAUDE database from 2008 to 2018 for IBR and other failure modes. Included were explanted leads whose manufacturers found an insulation or conductor defect not caused by extrinsic factors. RESULTS: The MAUDE search found 1011 qualifying leads. The cause of failure differed among leads (P < .001). The primary cause of Durata failure was IBR (293 of 316 leads [93%]), with IBR accounting for 47% (137 of 293); few QS (9 of 523 [1.7%]) and no Endotak Reliance leads failed because of IBR (P < .001). Durata IBR were responsible for 11 failures to treat ventricular tachycardia/ventricular fibrillation, and all were caused by high-voltage (HV) shorts between the proximal superior vena cava coil and a distal right ventricular coil cable (n = 10) or sensing conductor (n = 1); low values of HV impedance were found in these leads during defibrillation threshold testing (n = 3), after a shock or aborted shock (n = 7), and by an alert (n = 1). Inappropriate therapy was caused by 51 Durata IBR, but no QS IBR. CONCLUSION: Durata implantable cardioverter-defibrillator leads are susceptible to IBR that may result in failure to treat ventricular tachycardia/ventricular fibrillation or inappropriate therapy; such failures may occur without forewarning. HV testing of Durata leads may be indicated during pulse generator replacement or when an insulation defect is suspected.

Autosomal-dominant biventricular arrhythmogenic cardiomyopathy in a large family with a novel in-frame DSP nonsense mutation.

A novel autosomal-dominant in-frame deletion resulting in a nonsense mutation in the desmoplakin (DSP) gene was identified in association with biventricular arrhythmogenic cardiomyopathy across three generations of a large Caucasian family. Mutations that disrupt the function and structure of desmosomal proteins, including desmoplakin, have been extensively linked to familial arrhythmogenic right ventricular cardiomyopathy (ARVC). Analysis of data from 51 individuals demonstrated the previously undescribed variant p.Cys81Stop (c.243_251delCTTGATGCG) in DSP segregates with a pathogenic phenotype exhibiting variable penetrance and expressivity. The mutation's pathogenicity was first established due to two sudden cardiac deaths (SCDs), each with a biventricular cardiomyopathy identified on autopsy. Of the individuals who underwent genetic screening, 27 of 51 were heterozygous for the DSP mutation (29 total with two obligate carriers). Six of these were subsequently diagnosed with arrhythmogenic cardiomyopathy. An additional nine family members have a conduction disorder and/or myocardial structural changes characteristic of an evolving condition. Previous reports from both human patients and mouse studies proposed DSP mutations with a premature stop codon impart mild to no clinical symptoms. Loss of expression from the abnormal allele via the nonsense-mediated mRNA decay pathway has been implicated to explain these findings. We identified an autosomal-dominant DSP nonsense mutation in a large family that led to SCD and phenotypic expression of arrhythmogenic cardiomyopathy involving both ventricles. This evidence demonstrates the pathogenic significance of this type of desmosomal mutation and provides insight into potential clinical manifestations.

Design, Challenges, and Implications of Quality Improvement Projects Using the Electronic Medical Record: Case Study: A Protocol to Reduce the Burden of Postoperative Atrial Fibrillation.

Postoperative atrial fibrillation (POAF) is a frequent complication of cardiac surgery, which results in increased morbidity, mortality, length of stay, and hospital costs. We developed and followed a process map to implement a protocol to decrease POAF: (1) identify stakeholders and form a working committee, (2) formal literature and guideline review, (3) retrospective analysis of current institutional data, (4) data modeling to determine expected effects of change, (4) protocol development and implementation into the electronic medical record, and (5) ongoing review of data and protocol adjustment. Retrospective analysis demonstrated that POAF occurred in 29.8% of all cardiovascular surgery cases. Median length of stay was 2 days longer (P<0.001), and median total variable costs $2495 higher (P<0.001) in POAF patients. Modeling predicted that up to 60 cases of POAF and >$200 000 annually could be saved. A clinically based electronic medical record tool was implemented into the electronic medical record to aid preoperative clinic providers in identifying patients eligible for prophylactic amiodarone. Initial results during the 9-month period after implementation demonstrated a reduction in POAF in patients using the protocol, compared with those who qualified but did not receive amiodarone and those not evaluated (11.1% versus 38.7% and 38.8%; P=0.022); however, only 17.3% of patients used the protocol. A standardized methodological approach to quality improvement and electronic medical record integration has potential to significantly decrease the incidence of POAF, length of stay, and total variable cost in patients undergoing elective coronary artery bypass graft and valve surgeries. This framework for quality improvement interventions may be adapted to similar clinical problems beyond POAF.

Approach to reduction of ventricular arrhythmias and implantable cardioverter-defibrillator therapies in patients with heart failure.

PURPOSE OF REVIEW: Prevention of ventricular arrhythmias and implantable cardioverter-defibrillator (ICD) therapies in patients with heart failure will be reviewed. RECENT FINDINGS: ICD utilization in patients with heart failure has resulted in significantly improved long-term survival. However, there is growing evidence that ICD shocks are associated with increased morbidity and mortality. As a result, there is increasing emphasis on the treatment strategies to avoid ICD therapies. Optimal heart failure management with medical as well as cardiac resynchronization therapy when indicated is an essential part of treatment; however, adjunctive measures may be necessary to suppress ventricular arrhythmias, prevent unnecessary shocks, and improve quality of life. SUMMARY: Device programming can help avoid ICD therapies by delaying time to detection, increasing detection rate cutoffs, and discriminating between supraventricular and ventricular arrhythmias. Still, as patients live longer with advanced stages of heart failure, there will be a need to suppress sustained ventricular arrhythmias that would otherwise require ICD therapy. Antiarrhythmic drugs offer a noninvasive option to help suppress ventricular arrhythmias. With more experience and better catheter mapping and ablation techniques, there is a movement toward an early invasive strategy for ventricular tachycardia management in patients with heart failure.

Failure of a novel silicone-polyurethane copolymer (Optim™) to prevent implantable cardioverter-defibrillator lead insulation abrasions.

AIM: The purpose of this study was to determine if Optim™, a unique copolymer of silicone and polyurethane, protects Riata ST Optim and Durata implantable cardioverter-defibrillator (ICD) leads (SJM, St Jude Medical Inc., Sylmar, CA, USA) from abrasions that cause lead failure. METHODS AND RESULTS: We searched the US Food and Drug Administration's (FDA's) Manufacturers and User Device Experience (MAUDE) database on 13 April 2012 using the simple search terms 'Riata ST Optim™ abrasion analysis' and 'Durata abrasion analysis'. Lead implant time was estimated by subtracting 3 months from the reported lead age. The MAUDE search returned 15 reports for Riata ST Optim™ and 37 reports for Durata leads, which were submitted by SJM based on its analyses of returned leads for clinical events that occurred between December 2007 and January 2012. Riata ST Optim™ leads had been implanted 29.1 ± 11.7 months. Eight of 15 leads had can abrasions and three abrasions were caused by friction with another device, most likely another lead. Four of these abrasions resulted in high-voltage failures and one death. One failure was caused by an internal insulation defect. Durata leads had been implanted 22.2 ± 10.6 months. Twelve Durata leads had can abrasions, and six leads had abrasions caused by friction with another device. Of these 18 can and other device abrasions, 13 (72%) had electrical abnormalities. Low impedances identified three internal insulation abrasions. CONCLUSIONS: Riata ST Optim™ and Durata ICD leads have failed due to insulation abrasions. Optim™ did not prevent these abrasions, which developed ≤ 4 years after implant. Studies are needed to determine the incidence of these failures and their clinical implications.

Independent multicenter study of Riata and Riata ST implantable cardioverter-defibrillator leads.

BACKGROUND: Riata and Riata ST leads (St Jude Medical, Sylmar, CA) are prone to failure. There are no independent multicenter reports regarding Riata or Riata ST lead performance. OBJECTIVE: To conduct a retrospective multicenter study of Riata and Riata ST leads that were implanted and followed at 7 centers. METHODS: The study included adults who received St Jude Medical Riata or Riata ST leads. Data for Quattro Secure leads were obtained from an earlier study. RESULTS: From 2002 to 2010, 1081 patients received a Riata (n = 774) or Riata ST (n = 307) lead. Follow-up was longer for Riata than Riata ST leads (4.2 ± 2.4 years vs 3.3 ± 1.7 years; P<.0001). During the study, 67 leads failed (6.2%), including 62 of 774 Riata (8.0%) and 5 of 307 Riata ST (1.6%) leads. Forty-seven of 67 lead failures (70.1%) were caused by electrical malfunction, and 20 lead failures (29.9%) were due to externalized conductors (ECs) that were electrically intact. Of 110 leads examined fluoroscopically, ECs were found in 26 of 81 Riata (32%) and 1 of 29 Riata ST (3.4%) leads. Of 26 Riata leads with ECs, 7 (27%) were malfunctioning. Riata leads had lower overall and malfunction free survival compared to Quattro leads (P<.0001), while Riata ST lead survival was not different (P = .422). CONCLUSIONS: The survival of Riata (but not Riata ST) leads was lower than Quattro leads; however, Riata ST leads had significantly shorter follow-up than Riata leads. ECs were common in Riata leads, and more than a quarter of Riata leads that had ECs were malfunctioning. Our observations suggest that systematic fluoroscopic examination of patients with Riata leads is appropriate.

Deaths caused by the failure of Riata and Riata ST implantable cardioverter-defibrillator leads.

BACKGROUND: Riata and Riata ST leads (St Jude Medical, Sylmar, CA) were recalled in 2011. These leads are prone to externalized conductors. However, it is electrical malfunctions that may result in serious adverse events, including death. OBJECTIVE: To assess the deaths of patients with Riata and Riata ST leads that have been reported to the Food and Drug Administration to determine whether they were due to lead malfunction. A similar analysis was performed for Quattro Secure leads (Medtronic, Inc, Minneapolis, MN). METHODS: In February 2012, we searched the Food and Drug Administration's Manufacturers and User Facility Device Experience database for deaths associated with Riata, Riata ST, and Quattro Secure leads. A lead-related death was a sudden or unexpected death accompanied by evidence of lead malfunction; an indeterminate death was a death that was nonsudden or evidence of lead malfunction was not provided; a not lead-related death was a death that was nonsudden and/or there was no evidence that the lead contributed to the patient's demise. RESULTS: The Manufacturers and User Facility Device Experience database search found 133 deaths; of these, 22 were caused by Riata or Riata ST lead failure and 5 were caused by Quattro Secure lead failure. Riata and Riata ST lead failure deaths were typically caused by short circuits between high-voltage components. No death was due to externalized conductors. CONCLUSIONS: Riata and Riata ST implantable cardioverter-defibrillator leads are prone to high-voltage failures that have resulted in death. These failures appeared to have been caused by insulation defects that resulted in short circuiting between high-voltage components. Externalized conductors were not a factor in these deaths.

Measures of left ventricular dyssynchrony and the correlation to clinical and echocardiographic response after cardiac resynchronization therapy.

There is still no standardized measure of left ventricular (LV) dyssynchrony or definition of response in candidates of cardiac resynchronization therapy (CRT). Recipients of CRT underwent echocardiographic assessment of LV dyssynchrony before and immediately after implantation of a CRT device. Patients were followed for 6 months postimplantation. A total of 44 patients (64 +/- 12 years, 30 men, and 26 with ischemic cardiomyopathy) were included in this analysis. There was a significant decrease in both radial (304 +/- 137 vs 121 +/- 85 ms, p <0.001) and longitudinal (143 +/- 104 vs 95 +/- 43 ms, p = 0.02) measures of LV dyssynchrony immediately after CRT. The immediate post-CRT change in radial (r = -0.43, p = 0.015) but not longitudinal (r = -0.09, p = 0.61) LV dyssynchrony correlated with a significant improvement in the physical component of the quality-of-life score 6 months after CRT. Although a higher baseline longitudinal (p = 0.05) or radial (p = 0.025) LV dyssynchrony predicted a >or=1 improvement in New York Heart Association classification of heart failure 6 months after CRT, acute changes in neither radial (p = 0.71) nor longitudinal (p = 0.89) LV dyssynchrony were predictive of any improved echocardiographic outcomes in follow-up. Concordance between clinical and echocardiographic response to CRT was documented in 72% of patients. In conclusion, both longitudinal and radial measures of LV dyssynchrony improve after CRT. The change in longitudinal but not radial measures of LV dyssynchrony correlates with improved physical quality-of-life score in intermediate term follow-up.

Constrictive pericarditis: an unusual clinical entity suggested during dobutamine stress echocardiography.

A 44-year-old female presents with disabling dyspnea and is unable to perform a regular treadmill stress test; instead a dobutamine stress echocardiogram is performed and although negative for ischemia reveals a vigorous paradoxical motion of the interventricular septum with dilatation of the inferior vena cava without respiratory variation and an increased diastolic flow signal in the hepatic veins after expiration with the infusion of dobutamine. The diagnosis of constrictive physiology is confirmed with cardiac magnetic resonance imaging (MRI) and right heart hemodynamics and the patient underwent pericardiectomy without complications with resolution of symptoms.