A false decrease in the automatically measured atrial pacing threshold when using the automatic pacing threshold adjustment algorithm.

Automatic pacing threshold adjustment algorithms and remote monitoring are widely used to improve the utility of pacemakers and ensure patient safety. However, healthcare providers involved in the management of permanent pacemakers should know the potential pitfalls of these functions. In this report, we present a case of atrial pacing failure induced by the automatic pacing threshold adjustment algorithm that went unnoticed even under remote monitoring.

The feasibility of leadless pacemaker implantation for superelderly patients.

BACKGROUND: The safety and efficacy of the leadless pacemaker (LP) have been confirmed in previous reports, yet studies on LPs in superelderly patients are limited. METHODS AND RESULTS: A total of 62 patients aged over 85 years old were implanted with single-chamber pacemakers due to symptomatic bradyarrhythmia at Sakakibara Heart Institute from May 2014 through July 2019. We divided them into two groups, a transvenous (TV) single-chamber pacemaker group (35 patients) and an LP group (27 patients), and compared the groups. Mean participant age was 90.3 ± 3.8 y.o., 41.9% were male, and mean participant body mass index (BMI) was 21.3 kg/m2 . The LP group contained a significantly larger proportion of patients with dementia than the TV group did (63% vs. 37.1%, P = .04). The complication-free rate tended to be lower in the LP group in spite of the higher frequency of dementia (88.6% vs. 92.6%, P = .68). At implantation, the pacing threshold was significantly higher in the LP group than in the TV group (1.30 ± 0.91 V vs. 0.71 ± 0.23 V, P < .01), but over the first 3 months after the operation the pacing threshold in the LP group gradually improved (0.82 ± 0.2 V vs. 1.05 ± 1.02 V, P = .16). The procedure time and time from operation to discharge were also shorter in the LP group. CONCLUSIONS: LP implantation appears to be safe and is accordingly becoming the cornerstone for Japanese superelderly patients indicated for single-chamber pacemakers, even for those with small bodies and dementia. However, careful procedures and long follow-ups are needed until a greater volume of data is reported.

A safe and simple approach to avoid fast junctional rhythm during ablation in patients with atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Fast junctional rhythm (JR) during slow pathway modification for atrioventricular nodal reentrant tachycardia (AVNRT) is a predictor of serious atrioventricular block. This study investigated the boundary to avoid fast JR during ablation with three-dimensional (3D) electroanatomical mapping in AVNRT patients. METHODS AND RESULTS: Participants were 129 consecutive patients with common AVNRT who received anatomical ablation to an antegrade slow pathway at our institution between August 2013 and March 2019. Successfully ablated sites with JR were evaluated in terms of distances and angles in the left and right anterior oblique views (LAO and RAO, respectively) to the proximal His bundle (His) site using 3D mapping. We divided JR by heart rate: JR1 ≥150 bpm and JR2 <150 bpm. Average age was 61 ± 16 years; 41.1% of patients were male. The distance from the most proximal His to the JR1 and JR2 site was not significantly different (11.9 ± 4.4 vs 10.7 ± 4.5 mm, P = .24). JR1 predominantly appeared closer to the left ventricle than JR2 in LAO (110.5 ± 19.1° vs 77.5 ± 18.6°, P < .01), and was more posterior from the proximal His in RAO (30.8% vs 6.8%, P < .01). The vertical line drawn down from the proximal His in the LAO view was a good indicator of JR1 appearance (sensitivity and specificity 84.6% and 81.6%, respectively). CONCLUSION: The vertical line drawn down from the proximal His in the LAO view can be employed as a boundary to avoid fast JR during ablation in AVNRT.

Prolapse Volume to Prolapse Height Ratio for Differentiating Barlow's Disease From Fibroelastic Deficiency.

BACKGROUND: As mitral valve (MV) repair for Barlow's disease remains surgically challenging, it is important to distinguish Barlow's disease from fibroelastic deficiency (FED) preoperatively. We hypothesized that the prolapse volume to prolapse height ratio (PV-PH ratio) may be useful to differentiate Barlow's disease and FED.Methods and Results:In 76 patients with MV prolapse who underwent presurgical transesophageal echocardiography, the 3D MV morphology was quantified: 19 patients were diagnosed with Barlow's disease and 57 with FED. The patients with Barlow's disease had greater prolapse volume and height than the patients with FED, as well as greater PV-PH ratio (0.61±0.35 vs. 0.17±0.10, P<0.001). Receiver-operating characteristic analysis revealed that with a cutoff value of 0.27, the PV-PH ratio differentiated Barlow's disease from FED with 84.2% sensitivity and 84.2% specificity. Net reclassification improvement showed that the differentiating ability of the PV-PH ratio was significantly superior to prolapse volume (1.30, P<0.001). After being adjusted by each of prolapse volume and height, annular area and shape, and the number of prolapsed segments, the PV-PH ratio had an independent association with Barlow's disease. CONCLUSIONS: The PV-PH ratio was able to differentiate Barlow's disease from FED with high accuracy. 3D quantification including this value should be performed before MV repair.

Efficacy and Accuracy of Novel Automated Mitral Valve Quantification: Three-Dimensional Transesophageal Echocardiographic Study.

BACKGROUND: Previous studies indicated that the three-dimensional features of the mitral valve (MV) have a significant impact on MV disease. However, quantification of MV with manual tracing software was too time-consuming for routine clinical practice. This study was performed to investigate the efficacy and accuracy of MV quantification with a novel highly automated commercially available software package developed for this purpose. METHODS: Using the manual tracing and automated package, two expert sonographers and one cardiologist individually analyzed three-dimensional datasets acquired with transesophageal echocardiography from 74 patients (15 with functional mitral regurgitation, 32 with MV prolapse, and 27 normal subjects) retrospectively. Time for analysis and inter-observer agreement were compared between the two methods, and agreement of measurements was analyzed using Cronbach's α. RESULTS: Time for analysis using the automated package was significantly shorter than manual tracing (whole cohort, 260 ± 65 vs. 381 ± 68 seconds, P < 0.001; functional mitral regurgitation, 234 ± 42 vs. 378 ± 64 seconds, P < 0.001; MV prolapse, 293 ± 69 vs. 407 ± 67 seconds, P < 0.001; normal controls, 235 ± 52 vs. 351 ± 60 seconds, P < 0.001). There was good agreement among all three observers using both methods, and measurements with the automated package agreed well with the manual tracing values. CONCLUSIONS: The novel automated software package reduced time for quantification of MV with similar accuracy compared to the manual method. Automated quantification is useful and may be a key to widespread adoption of three-dimensional quantification in clinical practice.

Diagnostic Performance of an Automated Blood Pressure Monitor With an Irregular Heartbeat Algorithm Designed to Detect Atrial Fibrillation.

Background: Early detection of atrial fibrillation (AF) remains an unsolved challenge and because the greatest risk factor for AF is hypertension, blood pressure (BP) monitors with AF detectors have been developed. We evaluated the clinical performance of an irregular heartbeat (IHB) algorithm built into an A&D automated BP monitor for AF diagnosis. Methods and Results: Each of the 239 enrolled patients underwent BP measurement 3 times using the A&D UM-212 with the IHB algorithm. Real-time 3-lead ECG was recorded using automated ECG analysis software. Independent of the ECG analysis software results, 2 cardiologists interpreted the ECG and made the final diagnosis. Of the 239 patients, 135 were in sinus rhythm, 31 had AF, and 73 had non-AF arrhythmias. The respective sensitivity, specificity, and accuracy of the IHB algorithm for AF diagnosis were 98.9%, 91.2%, and 92.2% for the per-measurement evaluation, and 96.8%, 95.7%, and 95.8% for the per-patient evaluation (3/3 positive measurements). The respective sensitivity, specificity, and accuracy of the ECG analysis software for AF diagnosis were 91.4%, 97.9%, and 97.1% for the per-measurement evaluation, and 77.4%, 99.5%, and 96.7% for the per-patient evaluation (3/3 positive measurements). Conclusions: The IHB algorithm built into an A&D automated BP monitor had high diagnostic performance for AF in general cardiology patients, especially when multiple measurements were obtained.

Sheath shape pattern during leadless pacemaker implantation.

PURPOSE: Options for shaping the delivery sheath of leadless pacemakers (LPs) based on the cardiac anatomy of patients are limited. We predicted the shape of the LP sheath during implantation using preoperative computed tomography (CT) and intraoperative fluoroscopy. METHODS: Forty-eight patients with implanted LPs due to symptomatic bradyarrhythmia were divided into two groups, α-loop and non-α-loop, based on the shape of the LP delivery sheath head at implantation. Angles between the inferior vena cava (IVC) and the interventricular septum (IVST), and the IVC and right ventricular apex (RVA) were measured by CT. The relationship between the final sheath shape and position of the IVC and the right or left side of the line drawn vertically from the deflection point of the sheath in the LAO view on fluoroscopy was assessed. RESULTS: Angles between the IVC and IVST (44.4 ± 5.9° vs. 50.2 ± 6.8°) and IVC and RVA (52.5 ± 5.3° vs. 58.8 ± 7.8°) on CT were significantly (p < 0.01) smaller in the α-loop group. To predict the α-loop shape, a combined IVC-IVST angle < 50° and IVC-RVA angle < 55° revealed higher sensitivity (81.8%). The delivery sheath positioned right of the vertical line was more frequent in the α-loop group (90.9% vs. 23.1%, p < 0.01). CONCLUSIONS: When the preoperatively calculated angles of IVC to IVST and RVA on CT were narrow, the right side of the sheath in the IVC from the vertical line drawn from the deflection point in the LAO view indicated the need to shape the delivery sheath head into an α-loop during LP implantation.

Relationship between myocardial flow reserve by oxygen-15 water positron emission tomography in the subacute phase of myocardial infarction and left ventricular remodeling in the chronic phase.

The purposes of this study were to examine the effects of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) on myocardial flow reserve in patients with acute myocardial infarction (AMI) in the subacute phase using oxygen-15 positron emission tomography (PET) and to elucidate the relationship between the myocardial flow reserve and remodeling in the chronic phase. Sixty patients who had been treated with coronary angioplasty within 12 h after the onset of AMI were enrolled. Patients were divided into an enalapril (ACEI) group and a candesartan (ARB) group. The myocardial flow reserve was measured by oxygen-15 water PET in the subacute phase from the 20th to the 30th day after the onset of AMI. Left ventriculography was performed to measure the left ventricular ejection fraction in the chronic phase about 6 months after the onset. Ten patients (33%) in the enalapril group and 4 patients (13%) in the candesartan group stopped taking their respective medications within a few days of starting, because of side effects such as cough or hypotension. Thus, the prevalence of medication intolerance was higher in the enalapril group. The myocardial flow reserve in the subacute phase and the left ventricular ejection fraction in the chronic phase were lower in the enalapril group (2.08 +/- 0.30 and 42 +/- 6%) than in the candesartan group (2.25 +/- 0.20 and 49 +/- 5%) (p < 0.05). The myocardial flow reserve significantly correlated with the left ventricular ejection fraction in all patients (r = 0.45, p < 0.01). The myocardial flow reserve assessed by PET in the subacute phase after AMI was found to be related to left ventricular remodeling in the chronic phase.

Insufficient Leaflet Remodeling in Patients With Atrial Fibrillation: Association With the Severity of Mitral Regurgitation.

BACKGROUND: The relationship between annular dilatation caused by atrial fibrillation (AF) and mitral regurgitation (MR) remains controversial. We hypothesized that the small ratio of total leaflet area/annulus area (TLA/AA), reflecting insufficient leaflet remodeling to annular dilatation, is a main component of MR in patients with AF. METHODS AND RESULTS: Three-dimensional transesophageal echocardiographic data of the mitral valve were analyzed in 28 AF patients with moderate or severe MR (MR group), age- and sex-matched 56 AF patients with mild or less MR (non-MR group), and 16 control subjects. AA was significantly greater in both the MR (645±126 mm2/m2, P<0.001) and non-MR groups (568±121 mm2/m2, P=0.001) compared with control subjects (444±108 mm2/m2). However, TLA/AA was significantly smaller in the MR (1.29±0.10, P<0.001), but not in the non-MR group (1.65±0.24, P>0.99), compared with control subjects (1.70±0.29). In linear regression analysis, TLA/AA was inversely associated with the effective regurgitant orifice (r=-0.73, P<0.001). The area under the receiver-operating-characteristics curve of TLA/AA was significantly greater than that of AA (0.95 versus 0.72, P<0.001). Multivariable analysis revealed that small TLA/AA (P<0.001) was independently associated with significant MR, while AA was not (P=0.26). CONCLUSIONS: In patients with AF, insufficient leaflet remodeling to annular dilatation, rather than crude annular dilatation, was strongly associated with the severity of MR.

Nicorandil prevents microvascular dysfunction resulting from PCI in patients with stable angina pectoris: a randomised study.

AIMS: Nicorandil, an ATP sensitive potassium channel opener, may reduce the incidence of microvascular dysfunction after percutaneous coronary intervention (PCI) by dilating coronary resistance vessels. The aim of the study was evaluation of the impact of the administration of intravenous nicorandil on measuring the index of microcirculatory resistance (IMR) in PCI to patients with stable angina pectoris (SAP). METHODS AND RESULTS: Intravascular ultrasound (IVUS), fractional flow reserve (FFR), IMR and blood examination (CK-MB), cardiac troponin I (cTnI) immediately post-PCI (and 24 hours later) were performed in 62 consecutive patients with SAP undergoing PCI. FFR and IMR were measured simultaneously with a single coronary pressure wire. IMR was defined as Pd/coronary flow (or Pd* mean transit time) at peak hyperaemia. Patients were randomised to the control (n=29), or nicorandil group (n=33). In the nicorandil group, nicorandil was intravenously administered as a 6 mg bolus injection just before PCI and as a constant infusion at 6 mg/hour for 24 hours thereafter. All volumetric IVUS parameters and FFR were similar between the two groups both pre- and post-PCI. However, IMR immediately post-PCI and cTnI 24 hours post-PCI were significantly higher in the control group compared to the nicorandil group (IMR: 25.4±12.1 vs. 17.9±9.1 units, and cTnI: 0.21±0.13 vs. 0.12±0.08 ng/mL, for control vs. nicorandil). The incidence for cTnI elevation more than fivefold the normal range (>0.20 ng/mL) was significantly larger in the control group than in the nicorandil group (41% vs. 12%, p<0.01). Additionally, the control group showed a closer correlation between plaque volume reduction during stenting as assessed by volumetric IVUS, and cTnI elevation than the nicorandil group (r=0.55 vs. 0.42, p<0.001 for control vs. nicorandil). CONCLUSIONS: In patients undergoing successful coronary stenting for stable angina, administration of nicorandil is associated with reduced microvascular dysfunction induced by PCI.

Four-year clinical outcomes of the OLIVUS-Ex (impact of Olmesartan on progression of coronary atherosclerosis: evaluation by intravascular ultrasound) extension trial.

BACKGROUND: The previous OLIVUS trial reported a positive role in achieving a lower rate of coronary atheroma progression through the administration of olmesartan, an angiotension-II receptor blocking agent (ARB), for stable angina pectoris (SAP) patients requiring percutaneous coronary intervention (PCI). However, the benefits between ARB administration on long-term clinical outcomes and serial atheroma changes by IVUS remain unclear. Thus, we examined the 4-year clinical outcomes from OLIVUS according to treatment strategy with olmesartan. METHODS: Serial volumetric IVUS examinations (baseline and 14 months) were performed in 247 patients with hypertension and SAP. When these patients underwent PCI for culprit lesions, IVUS was performed in their non-culprit vessels. Patients were randomly assigned to receive 20-40mg of olmesartan or control, and treated with a combination of ß-blockers, calcium channel blockers, glycemic control agents and/or statins per physician's guidance. Four-year clinical outcomes and annual progression rate of atherosclerosis, assessed by serial IVUS, were compared with major adverse cardio- and cerebrovascular events (MACCE). RESULTS: Cumulative event-free survival was significantly higher in the olmesartan group than in the control group (p=0.04; log-rank test). By adjusting for validated prognosticators, olmesartan administration was identified as a good predictor of MACCE (p=0.041). On the other hand, patients with adverse events (n=31) had larger annual atheroma progression than the rest of the population (23.8% vs. 2.1%, p<0.001). CONCLUSIONS: Olmesartan therapy appears to confer improved long-term clinical outcomes. Atheroma volume changes, assessed by IVUS, seem to be a reliable surrogate for future major adverse cardio- and cerebrovascular events in this study cohort.

Positron emission tomographic demonstration of myocardial oxidative metabolism in a case of left ventricular restoration after cardiac resynchronization therapy.

A 65-year-old man with a history of coronary artery bypass grafting was admitted because of severe heart failure. Echocardiography showed diffuse severe hypokinesis of the left ventricle (ejection fraction 25%) and severe mitral regurgitation caused by tethering of the leaflet secondary to left ventricular (LV) dilation. He underwent mitral valve annuloplasty and LV papillary muscle imbrication, but postoperative sustained ventricular tachycardia developed and echocardiography showed ventricular dyssynchrony with a long septal-to-posterior wall motion delay (>130 ms). Cardiac resynchronization therapy (CRT) was performed using a biventricular pacing system with an implantable cardioverter defibrillator, but biventricular pacing prolonged the QRS duration from 130 to 160 ms, so (11)C-acetate positron emission tomography was performed to evaluate the CRT. During biventricular pacing, myocardial oxidative consumption decreased by 15% and cardiac efficiency increased by 33%. The plasma brain natriuretic peptide level, which was 9,500 pg/ml preoperatively, decreased to 173 pg/ml just before discharge from hospital.