Sympathetic toggled paroxysmal atrial fibrillation and recurrent premature atrial contractions in ambulatory patients.

BACKGROUND: Autonomic nerve activity is important in the mechanisms of paroxysmal atrial fibrillation (PAF). OBJECTIVE: The purpose of this study was to test the hypothesis that a single burst of skin sympathetic nerve activity (SKNA) can toggle on and off PAF or premature atrial contraction (PAC) clusters. METHODS: Simultaneous recording of SKNA and electrocardiogram (neuECG) recording was performed over 7 days in patients with PAF. RESULTS: In study 1, 8 patients (7 men and 1 woman; age 62 ± 8 years) had 124 episodes of PAF. An SKNA burst toggled both on and off PAF in 8 episodes (6.5%) (type 1), toggled on but not off in 12 episodes (9.7%) (type 2), and toggled on a PAC cluster followed by PAF in 4 episodes (3.2%) (type 3). The duration of these PAF episodes was <10 minutes. The remaining 100 episodes (80.6%) were associated with active SKNA bursts throughout PAF (type 4) and lasted longer than type 1 (P = .0185) and type 2 (P = .0027) PAF. There were 47 PAC clusters. Among them, 24 (51.1%) were toggled on and off, and 23 (48.9%) were toggled on but not off by an SKNA burst. In study 2, 17 patients (9 men and 8 women; age 58 ± 12 years) had <10 minutes of PAF (4, 8, 0, and 31 of types 1, 2, 3, and 4, respectively). There were significant circadian variations of all types of PAF. CONCLUSION: A single SKNA burst can toggle short-duration PAF and PAC cluster episodes on and off. The absence of continued SKNA after the onset might have affected the maintenance of these arrhythmias.

Left Bundle Branch Pacing vs Left Ventricular Septal Pacing vs Biventricular Pacing for Cardiac Resynchronization Therapy.

BACKGROUND: Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are considered to be acceptable as LBBAP strategies. Differences in clinical outcomes between LBBP and LVSP are yet to be determined. OBJECTIVES: The purpose of this study was to compare the outcomes of LBBP vs LVSP vs BIVP for CRT. METHODS: In this prospective multicenter observational study, LBBP was compared with LVSP and BIVP in patients undergoing CRT. The primary composite outcome was freedom from heart failure (HF)-related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, postprocedural NYHA functional class, and electrocardiographic and echocardiographic parameters. RESULTS: A total of 415 patients were included (LBBP: n = 141; LVSP: n = 31; BIVP: n = 243), with a median follow-up of 399 days (Q1-Q3: 249.5-554.8 days). Freedom from the primary composite outcomes was 76.6% in the LBBP group and 48.4% in the LVSP group (HR: 1.37; 95% CI: 1.143-1.649; P = 0.001), driven by a 31.4% absolute increase in freedom from HF-related hospitalizations (83% vs 51.6%; HR: 3.55; 95% CI: 1.856-6.791; P < 0.001) without differences in all-cause mortality. LBBP was also associated with a higher freedom from the primary composite outcome compared with BIVP (HR: 1.43; 95% CI: 1.175-1.730; P < 0.001), with no difference between LVSP and BIVP. CONCLUSIONS: In patients undergoing CRT, LBBP was associated with improved outcomes compared with LVSP and BIVP, while outcomes between BIVP and LVSP are similar.

Chlorhexidine gluconate pocket lavage to prevent cardiac implantable electronic device infection in high-risk procedures.

BACKGROUND: Infection is the most dreaded complication of cardiac implantable electronic devices (CIEDs), particularly in patients undergoing high-risk procedures (eg, generator change, device upgrade, lead/pocket revision). OBJECTIVE: The purpose of this study was to describe the impact of chlorhexidine gluconate (CHG) pocket lavage in high-risk procedures. METHODS: Patients from a prospective multicenter registry undergoing high-risk procedures were included. CHG lavage was performed by irrigating the generator pocket with 20 cc of 2% CHG without alcohol followed by and normal saline (NS) irrigation. Only NS irrigation was performed in the comparison group. The primary efficacy outcome was CIED-related infection at 12 months. The primary safety outcome was any CHG-associated adverse event. The secondary outcome was CIED infection during long-term follow-up. Propensity score matching (PSM) analysis was performed for the primary efficacy outcome. RESULTS: A total of 1504 patients were included. At 12-month follow-up, the primary efficacy outcome occurred in 4 of 904 CHG (0.4%) and 14 of 600 NS (2.3%) subjects (log-rank P = .005). On multivariate analysis, the use of CHG irrigation was associated with a lower risk of infection at 1-year follow-up (Cox proportional hazard ratio [HR] 0.138; 95% confidence interval [CI] 0.04-0.45; P = .001). This effect persisted during long-term follow-up. PSM demonstrated a significant reduction in CIED-related infection for the CHG group (0.2% vs 2.5%; Cox proportional HR 0.08; 95% CI 0.01-0.59; P = .014). No adverse events were associated with the use of CHG. CONCLUSION: CHG lavage during high-risk procedures was associated with a reduction in CIED-related infections without any adverse events reported. The benefits of CHG lavage were observed even during long-term follow up and in PSM analysis.

Left Bundle Branch Area Pacing Versus Biventricular Pacing as Initial Strategy for Cardiac Resynchronization.

BACKGROUND: Left bundle branch area pacing (LBBAP) for cardiac resynchronization therapy (CRT) is an alternative to biventricular pacing (BiVp). OBJECTIVES: The purpose of this study was to compare the outcomes between LBBAP and BiVp as an initial implant strategy for CRT. METHODS: In this prospective multicenter, observational, nonrandomized study, first-time CRT implant recipients with LBBAP or BiVp were included. The primary efficacy outcome was a composite of heart failure (HF)-related hospitalization and all-cause mortality. The primary safety outcomes were acute and long-term complications. Secondary outcomes included postprocedural New York Heart Association functional class and electrocardiographic and echocardiographic parameters. RESULTS: A total of 371 patients (median follow-up of 340 days [IQR: 206-477 days]) were included. The primary efficacy outcome occurred in 24.2% in the LBBAP vs 42.4% in the BiVp (HR: 0.621 [95% CI: 0.415-0.93]; P = 0.021) group, driven by a reduction in HF-related hospitalizations (22.6% vs 39.5%; HR: 0.607 [95% CI: 0.397-0.927]; P = 0.021) without significant difference in all-cause mortality (5.5% vs 11.9%; P = 0.19) or differences in long-term complications (LBBAP: 9.4% vs BiVp: 15.2%; P = 0.146). LBBAP resulted in shorter procedural (95 minutes [IQR: 65-120 minutes] vs 129 minutes [IQR: 103-162 minutes]; P < 0.001) and fluoroscopy times (12 minutes [IQR: 7.4-21.1 minutes] vs 21.7 minutes [IQR: 14.3-30 minutes]; P < 0.001), shorter QRS duration (123.7 ± 18 milliseconds vs 149.3 ± 29.1 milliseconds; P < 0.001), and higher postprocedural left ventricular ejection fraction (34.1% ± 12.5% vs 31.4% ± 10.8%; P = 0.041). CONCLUSIONS: LBBAP as an initial CRT strategy resulted in a lower risk of HF-related hospitalizations compared to BiVp. A reduction in procedural and fluoroscopy times, shorter paced QRS duration, and improvements in left ventricular ejection fraction compared with BiVp were observed.

Safety and Efficacy of a Novel Approach to Pulmonary Vein Isolation Using Prolonged Apneic Oxygenation.

BACKGROUND: Improved ablation catheter-tissue contact results in more effective ablation lesions. Respiratory motion causes catheter instability, which impacts durable pulmonary vein isolation (PVI). OBJECTIVES: This study sought to evaluate the safety and efficacy of a novel ablation strategy involving prolonged periods of apneic oxygenation during PVI. METHODS: We conducted a multicenter, prospective controlled study of 128 patients (mean age 63 ± 11 years; 37% women) with paroxysmal atrial fibrillation undergoing PVI. Patients underwent PVI under general anesthesia using serial 4-minute runs of apneic oxygenation (apnea group; n = 64) or using standard ventilation settings (control group; n = 64). Procedural data, arterial blood gas samples, catheter position coordinates, and ablation lesion characteristics were collected. RESULTS: Baseline characteristics between the 2 groups were similar. Catheter stability was significantly improved in the apnea group, as reflected by a decreased mean catheter displacement (1.55 ± 0.97 mm vs 2.25 ± 1.13 mm; P < 0.001) and contact force SD (4.9 ± 1.1 g vs 5.2 ± 1.5 g; P = 0.046). The percentage of lesions with a mean catheter displacement >2 mm was significantly lower in the apnea group (22% vs 44%; P < 0.001). Compared with the control group, the total ablation time to achieve PVI was reduced in the apnea group (18.8 ± 6.9 minutes vs 23.4 ± 7.8 minutes; P = 0.001). There were similar rates of first-pass PVI, acute PV reconnections and dormant PV reconnections between the two groups. CONCLUSIONS: A novel strategy of performing complete PVI during apneic oxygenation results in improved catheter stability and decreased ablation times without adverse events. (Radiofrequency Ablation of Atrial Fibrillation Under Apnea; NCT04170894).

Ablation of atrial fibrillation beyond pulmonary vein isolation: Do additional ablation lesions impact left atrial function?

INTRODUCTION: Electrical isolation of pulmonary veins (PVI) is a cornerstone for atrial fibrillation (AF) ablation. The overall effect of AF ablation, and especially lesions beyond PVI, on left atrial (LA) function is currently poorly understood. Our aim was to determine if LA function is different in patients after extensive LA ablation compared to PVI only. We performed non-inferiority analysis of LA function after PVI with additional nonpulmonary vein ablation lesions in LA (PVI+) and PVI alone. METHODS: We studied 68 patients consecutive patients who underwent AF ablation and who had complete transthoracic echocardiogram (TTE) within 12 months before AF ablation and 1-12 months after the procedure. Patients were stratified into two groups: PVI only and PVI+. Primary outcome was change in LA reservoir strain (LASr). Noninferiority margin was defined at 6%. RESULTS: The PVI only group had a higher proportion of patients with paroxysmal AF (70% vs. 30%). The PVI+ group was observed to have a slightly higher increase in LASr compared to PVI alone (5.0% vs. 4.3%, p < .01 for noninferiority). LASr noninferiority was confirmed when adjusted for age, sex, coronary artery disease, hyperlipidemia, and AF type, rhythm at preprocedure TTE in a multivariable linear regression model, 90% CI (-5.46 to 2.04), p < .01. CONCLUSION: LA functional improvement evaluated by LASr was noninferior after PVI with additional LA ablation lesions compared to PVI alone. These findings were confirmed when adjusted for confounding clinical variables, suggesting that more extensive ablation does not negatively affect LA function.

Tumescent local anesthesia versus general anesthesia for subcutaneous implantable cardioverter-defibrillator implantation: A cost-effectiveness analysis.

BACKGROUND: General anesthesia (GA) is the standard anesthetic approach for subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Nonetheless, GA is expensive and can be associated with adverse events. Tumescent local anesthesia (TLA) has been shown to reduce in-room and procedural times and to decrease post-procedural pain, all of which could result in a reduction in procedure-related costs. OBJECTIVE: The purpose of this study is to compare the cost-effectiveness of GA and TLA in patients undergoing S-ICD implantation. METHODS: The present study is a prospective, nonrandomized, controlled study of patients who underwent S-ICD implantation between 2019 and 2022. Patients were allocated to either the TLA or the GA group. We performed a cost analysis for each intervention. As an effectiveness measure, the 0-10 point Numeric Pain Rating Scale at 1, 12, and 24 hours post-implantation was analyzed and compared between the groups. A score of 0 was considered no pain; 1-5, mild pain; 6-7, moderate pain; and 8-10, severe pain. Cost-effectiveness was calculated using incremental cost-effectiveness ratios. RESULTS: Seventy patients underwent successful S-ICD implantation. The total cost of the electrophysiology laboratory was higher in the GA group than in the TLA group (median ± interquartile range US$55,824 ± US$29,411 vs US$37,222 ± US$24,293; P < .001), with a net saving of $20,821 when compared with GA for each S-ICD implantation. There was a significant decrease in post-procedural pain scores in the TLA group when compared with the GA group (repeated measures analysis of variance, P = .009; median ± interquartile range 0 ± 3 vs 0 ± 5 at 1 hour, P = .058; 3 ± 4 vs 6 ± 8 at 12 hours, P = .030; 0 ± 4 vs 2 ± 6 at 24 hours, P = .040). CONCLUSION: TLA is a more cost-effective alternative to GA for S-ICD implantation, with both direct and indirect cost reductions. Importantly, these reduced costs are associated with reduced postprocedural pain.

Initial experience with stylet-driven versus lumenless lead delivery systems for left bundle branch area pacing.

INTRODUCTION: Left bundle branch area pacing (LBBP) has emerged as an alternative method for conduction system pacing. While initial experience with delivery systems for stylet-driven and lumenless lead implantation for LBBP has been described, data comparing outcomes of stylet-driven versus lumenless lead implantation for LBBP are limited. In this study, we compare success rates and outcomes of LBBP with stylet-driven versus lumenless lead delivery systems. METHODS: Eighty-three consecutive patients (mean age 74.1 ± 11.2 years; 56 [68%] male) undergoing attempted LBBP at a single institution were identified. Cases were grouped by lead delivery systems used: stylet-driven (n = 53) or lumenless (n = 30). Baseline characteristics and procedural findings were recorded and compared between the cohorts. Intermediate term follow-up data on ventricular lead parameters were also compared. RESULTS: Baseline characteristics were similar between groups. Successful LBBP was achieved in 77% of patients, with similar success rates between groups (76% in stylet-driven, 80% in lumenless, p = 0.79), and rates of adjudicated LBB capture and other paced QRS parameters were also similar. Compared with the lumenless group, the stylet-driven group had significantly shorter procedure times (90 ± 4 vs. 112 ± 31 min, p = 0.004) and fluoroscopy times (10 ± 5 vs. 15 ± 6 min, p = 0.003). Ventricular lead parameters at follow-up were similar, and rates of procedural complications and need for lead revision were low in both groups. CONCLUSION: Delivery systems for stylet-driven and for lumenless leads for LBBP have comparable acute success rates. Long-term follow-up of lead performance following use of the various delivery systems is warranted.

Anatomical considerations and clinical interpretation of the 12-lead ECG in the prone position: a prospective multicentre study.

AIMS: The aim of this study is to provide guidance for the clinical interpretation of electrocardiograms (ECGs) in prone position and to establish the electroanatomic explanations for the possible differences to supine position ECGs that may be observed. Additionally, to determine if prone back ECG can be used as an alternative to standard ECG in patients who may benefit from prone position. METHODS AND RESULTS: The ECG in supine (standard ECG), prone back (precordial leads placed on the patient's back), and prone anterior position (precordial leads placed in the standard position with the subjects in prone position) were prospectively examined on 85 subjects. Comparisons of ECG parameters between these positions were performed. Computed tomography (CT) scans were performed in both positions to determine possible electroanatomic aetiologies for prone-associated ECG changes. There were significant differences in QRS amplitude in Leads V1-V5 between supine and prone positions. Q waves were more frequently observed in prone back position vs. supine position (V1: 74.1 vs. 10.6%, P < 0.0001; V2: 23.5 vs. 0%, P < 0.0001, respectively). Flat and inverted T waves were more common in prone back leads (V1: 98 vs. 66%, P < 0.0001; V2: 96 vs. 8%, P < 0.0001; V3: 45 vs. 7%, P < 0.0001). The 3D-CT reconstructions measurements corroborated the significant inverse correlation between QRS amplitude and the distance from the centre of the heart to the estimated lead positions. CONCLUSION: In prone back position ECG, low QRS amplitude should not be misinterpreted as low voltage conditions, neither should Q waves and abnormal T waves are considered anteroseptal myocardial infarction. These changes can be explained by an increased impedance (due to interposing lung tissue) and by the increased distance between the electrodes to the centre of the heart.

Arrhythmia patterns during and after hospitalization for COVID-19 infection detected via patch-based mobile cardiac telemetry.

BACKGROUND: Coronavirus infection is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20-30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited. OBJECTIVE: We aimed to analyze arrhythmia type and frequency in patients with COVID infection, identifying arrhythmia patterns over time during hospitalization and post discharge utilizing a patch based mobile cardiac telemetry system. METHODS: A prospective cohort study during the COVID-19 pandemic was performed. We included in our study patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring. RESULTS: Quantitative reports for 59 patients were available for analysis. Arrhythmias were detected in 72.9% of patients and at a consistent frequency throughout the monitoring period in 52.9%-89.5% of patients daily. The majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). New onset AF was noted in 15.0% of all patients and was significantly associated with older age (OR 1.4 for 5 yrs. difference; 95% CI 1.03-2.13). Of 9 patients who were discharged with continued patch monitoring, 7 (78%) had arrhythmic events during their outpatient monitoring period. CONCLUSION: In COVID-19 patients arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type and frequency similar to that seen during hospitalization. These findings suggest that the risk of arrhythmia associated with COVID infection remains elevated throughout the hospital course as well as following hospital discharge.

T-wave inversion as a manifestation of COVID-19 infection: a case series.

PURPOSE: Cardiac involvement with COVID-19 infection has become evident by elevated troponin, cardiac arrhythmias, ST segment elevation, myocarditis, fulminant heart failure, and sudden cardiac death. We aimed to describe the association of COVID-19 and T-wave inversion (TWI) in a large case series. METHODS: We conducted an observational, retrospective study of confirmed COVID-19 cases with at least one electrocardiogram (ECG) in a large hospital in New York City (March 23, 2020-April 23, 2020). Patients with new TWI or pseudonormalization were further analyzed. Mortality and the need for invasive mechanical ventilation were the main outcomes. RESULTS: A total of 3225 patients were screened; 195 (6%) were selected for further analysis: 181 with TWI and 14 with T-wave pseudonormalization. Mean age was 66 ± 7 years; 51% were male. TWI were more commonly noted in the lateral (71%), followed by anterior (64%), inferior (57%), and septal (26%) leads. A total of 44 patients (23%) had elevated troponin. A total of 50 patients died (26%). Mortality rates of 35%, and 52% were observed in patients with diffuse TWI, and elevated troponin, respectively. Mortality rate of 80% was observed in patients with both elevated troponin and diffuse TWI. Additionally, 30% of the entire cohort and 58% of patients with elevated troponin required invasive mechanical ventilation. CONCLUSION: Our study demonstrates that new TWI is a relatively common finding in COVID-19 patients. Importantly, our findings suggest that new TWI or T-wave pseudonormalization, particularly with elevated troponin, was associated with higher rates of mechanical ventilation and in-hospital mortality.

Inpatient cardiac monitoring using a patch-based mobile cardiac telemetry system during the COVID-19 pandemic.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is a worldwide pandemic, and cardiovascular complications and arrhythmias in these patients are common. Cardiac monitoring is recommended for at risk patients; however, the availability of telemetry capable hospital beds is limited. We sought to evaluate a patch-based mobile telemetry system for inpatient cardiac monitoring during the pandemic. METHODS: A prospective cohort study was performed of inpatients hospitalized during the pandemic who had mobile telemetry devices placed; patients were studied up until the time of discharge or death. The primary outcome was a composite of management changes based on data obtained from the system and detection of new arrhythmias. Other clinical outcomes and performance characteristics of the mobile telemetry system were studied. RESULTS: Eighty-two patients underwent mobile telemetry device placement, of which 31 (37.8%) met the primary outcome, which consisted of 24 (29.3%) with new arrhythmias detected and 18 (22.2%) with management changes. Twenty-one patients (25.6%) died during the study, but none from primary arrhythmias. In analyses, age and heart failure were associated with the primary outcome. Monitoring occurred for an average of 5.3 ± 3.4 days, with 432 total patient-days of monitoring performed; of these, QT-interval measurements were feasible in 400 (92.6%). CONCLUSION: A mobile telemetry system was successfully implemented for inpatient use during the COVID-19 pandemic and was shown to be useful to inform patient management, detect occult arrhythmias, and monitor the QT-interval. Patients with advanced age and structural heart disease may be more likely to benefit from this system.

Utility of the Modified Frailty Index to Predict Cardiac Resynchronization Therapy Outcomes and Response.

The aim of the present study was to investigate the utility of the modified frailty index (mFI) to predict outcomes in patients who underwent cardiac resynchronization therapy (CRT) device implantation. A retrospective cohort study of patients undergoing CRT implantation or upgrade over a 5-year period was performed. The relation between the preprocedural 11-component mFI and clinical outcomes including 1-year mortality, periprocedural and 30-day adverse events, 30-day readmission, length of hospitalization after procedure, and response to CRT defined by changes in left ventricular ejection fraction and end-diastolic volume were studied. Of 283 patients studied, 134 (47.3%) were classified as frail (mFI ≥3). Frailty was associated with an increased risk of 1-year mortality (hazard ratio 5.87, p = 0.033 in multivariate analysis), and increased frequency of adverse events (p = 0.013), 30-day readmission (p = 0.0077), and postprocedural length of stay ≥3 days (p = 0.0005). Frail patients had significantly less echocardiographic response to CRT compared with nonfrail patients with change in left ventricular ejection fraction 6% versus 12% (p = 0.004) and change in left ventricular end-diastolic volume -19.9 versus -43.3 ml (p = 0.006). In conclusion, frailty as assessed by the mFI is associated with an increase in 1-year mortality, adverse events, 30-day readmission, length of stay, and poorer response to CRT after implantation.

Improved scoring system for the electrocardiographic diagnosis of left ventricular hypertrophy.

BACKGROUND: Left ventricular hypertrophy (LVH) is a common manifestation of cardiovascular disease and a risk factor for cardiovascular morbidity and mortality, but available methods for its electrocardiographic (ECG) diagnosis have limited accuracy. AIM: To investigate findings associated with LVH on ECG and developed an improved system for the diagnosis of LVH. METHODS: A cohort study comparing ECG data acquired within 30 days of transthoracic echocardiography (TTE) was performed. Multivariate regression analysis identified ECG findings associated with increased LV mass and mass index. A scoring system was derived and performance compared to established criteria for LVH. RESULTS: Data from 5486 outpatients with TTEs and corresponding ECGs were included in the derivation cohort, 333 (6.1%) of whom had LVH by TTE. In the primary regression analysis, findings associated with LVH were amplitudes of Q in V3, R in V6, S in V3, T in V6, P' in V1, P in V6, as well as R and T-axis discordance, R peak time in V6, QRS duration, weight, height, sex, and age. From this we derived a score consisting of 5 criteria, and validated it in an independent cohort of 910 patients. With a threshold of 1.5 points, sensitivity and specificity were 67.9% and 81.4%, and 62.5% and 83.2% in the derivation and validation cohorts, respectively. With a threshold of 2 points, sensitivity and specificity were 42.3% and 93.0%, and 37.5% and 93.4% in these cohorts. CONCLUSIONS: This score had superior sensitivity for detection of LVH by ECG while making a modest sacrifice in specificity compared to conventional criteria.

Sprue-like histology in patients with abdominal pain taking olmesartan compared with other angiotensin receptor blockers.

AIMS: A severe syndrome characterised by life-threatening diarrhoea and severe sprue-like histology has been described in patients taking the angiotensin receptor blocker (ARB) olmesartan. It is unknown whether there are any histopathological changes in patients without severe diarrhoea exposed to this medication. It is also unknown whether other ARBs cause sprue-like histology. METHODS: Retrospective cohort study of patients with abdominal pain undergoing upper gastrointestinal endoscopy with duodenal biopsy who were taking ARBs. Patients taking olmesartan (n=20) and a non-olmesartan ARB (n=20) were compared with age and sex-matched controls. Histological features (classic sprue-like and other inflammatory changes) were analysed. RESULTS: No single histopathological finding was significantly more common in olmesartan-using patients than controls. However, 10 of 20 olmesartan patients had one or more sprue-like histological features compared with 4 of 20 age-matched and sex-matched controls not taking ARBs (p=0.10). Patients taking ARBs other than olmesartan were not more likely than controls to have one or more of these sprue-like histological features (9/20 vs. 12/20, p=0.34). CONCLUSIONS: There were no statistically significant differences between olmesartan users with abdominal pain and controls for any single histopathological abnormality. However, there were trends towards significance for individual abnormalities as well as for a composite outcome of sprue-like changes. This raises the possibility that there is a spectrum of histological changes associated with olmesartan use.