Chronic Apical and Nonapical Right Ventricular Pacing in Patients with High-Grade Atrioventricular Block: Results of the Right Pace Study.

OBJECTIVE: The aim of the study was to compare the two approaches to chronic right ventricular pacing currently adopted in clinical practice: right ventricular apical (RVA) and non-RVA pacing. BACKGROUND: Chronic RVA pacing is associated with an increased risk of atrial fibrillation, morbidity, and even mortality. Non-RVA pacing may yield more physiologic ventricular activation and provide potential long-term benefits and has recently been adopted as standard procedure at many implanting centers. METHODS: The Right Pace study was a multicenter, prospective, single-blind, nonrandomized trial involving 437 patients indicated for dual-chamber pacemaker implantation with a high percentage of RV pacing. RESULTS: RV lead-tip target location was the apex or the interventricular septum. RVA (274) and non-RVA patients (163) did not differ in baseline characteristics. During a median follow-up of 19 months (25th-75th percentiles, 13-25), 17 patients died. The rates of the primary outcome of death due to any cause or hospitalization for heart failure were comparable between the groups (log-rank test, p = 0.609), as were the rates of the composite of death due to any cause, hospitalization for heart failure, or an increase in left ventricular end-systolic volume ≥ 15% as compared with the baseline evaluation (secondary outcome, p = 0.703). After central adjudication of X-rays, comparison between adjudicated RVA (239 patients) and non-RVA (170 patients) confirmed the absence of difference in the rates of primary (p = 0.402) and secondary (p = 0.941) outcome. CONCLUSIONS: In patients with indications for dual-chamber pacemaker who require a high percentage of ventricular stimulation, RVA or non-RVA pacing resulted in comparable outcomes. This study is registered with ClinicalTrials.gov (identifier: NCT01647490).

[Teamwork for cardiac imaging: coronary computed tomography angiography and low-dose radiation exposure: a cardiology center experience]. / Teamwork per l'imaging cardiaco: tomografia computerizzata coronarica e bassa dose di esposizione radiologica, esperienza di un centro cardiologico.

BACKGROUND: Multidetector coronary computed tomography angiography (CCTA) is increasingly used for noninvasive imaging of the coronary arteries. Radiation exposure, however, is a potential limitation to a more extensive use of this imaging modality. We aimed to demonstrate that a professional teamwork approach, including a cardiologist and a radiologist in performing CCTA, may allow to obtain best quality exams with very low radiation doses. METHODS: A total of 998 consecutive patients underwent CCTA in accordance with the most recent guidelines. The following procedures were undertaken to reduce the radiation dose: (a) preliminary cardiological evaluation to check for CCTA eligibility; (b) optimized heart rate control with beta-blockers and/or ivabradine; and (c) the use of nonstandardized computed tomography protocols and algorithms for dose reduction. RESULTS: All the patients underwent a preliminary cardiological evaluation; 89% of them were pretreated with oral or intravenous beta-blockers and/or ivabradine; 806 patients (81%) were scanned by means of prospective gating, which allowed a radiation dose exposure of 161 ± 68.64 mGy; 192 patients (19%) underwent a retrospective gating protocol, with a radiation dose exposure of 1135.15 ± 485.87 mGy. In 13 patients (1%) CCTA was uninterpretable because of artifacts. Exam quality was not affected by the use of low-dose computed tomography scanning. Coronary calcium score and/or left ventricular functional analysis were never performed. CONCLUSIONS: The preliminary selection and preparation of patients and optimized scanner utilization allow a substantial reduction in radiation dose for most of the patients submitted to CCTA without affecting image quality. In our experience, a team approach was necessary to allow a "low-dose learning curve" and a progressive reduction in radiation doses administered to patients by means of the prospective gating protocol.

Left ventricular rotation and twist assessed by four-dimensional speckle tracking echocardiography in healthy subjects and pathological remodeling: a single center experience.

BACKGROUND: Left ventricular (LV) twist represents a main aspect of ejection. It is defined as the difference between the apical and basal rotation and can be assessed by speckle tracking echocardiography (STE). Twist may be underestimated when assessed by two-dimensional-echocardiography due to the difficulty of identifying the real apex. Aim of this study was to evaluate the LV twist by means of three-dimensional (3D)-STE and verify if the inclusion of the apex can modify the assessment of the global twist. METHODS: LV volume acquisition with a fully sampled matrix array transducer was performed in 30 healthy subjects and 79 patients with cardiomyopathy secondary to different etiologies. Thirty-nine patients had a LV ejection fraction (EF) ≥50% (Group A), 16 showed an EF between 40 and 50% (Group B), and 24 patients had an EF ≤40%(Group C). LV rotation was assessed by 3D-STE at basal, medium, apical, and apical-cap levels. Twist was computed considering the apex either at the apical level (Twist(Api) ) or at the apical-cap level (Twist(AC) ). RESULTS: LV rotation resulted to be progressively higher from base to apical-cap (P < 0.0001) with a significant difference between the apex and the apical-cap level (6.20 ± 3.90° vs. 10.23 ± 7.52°; P < 0.001). Such a difference was constantly found in all Groups (P < 0.01 for Group A, P < 0.05 for Group B and C). Twist(Api) was also significantly lower than Twist(AC) both in the overall population (6.2 ± 3.89° vs. 10.23 ± 7.51°; P < 0.001) and in the different subgroups ( CONTROLS: 9.61 ± 3.39° vs. 13.75 ± 6.51°; Group A: 10.49 ± 4.77° vs. 16.37 ± 8.49°; Group B: 6.67 ± 3.44° vs. 9.14 ± 5.55°; Group C: 33 ± 2.62° vs. 5.26 ± 3.74°; P < 0.05 for all the comparisons). CONCLUSIONS: Identification and inclusion of apical-cap is relevant for twist assessment and can be carried out efficiently by 3D-STE. The inclusion of the true apex in the calculation significantly affects the analysis of twist both in normal individuals and patients with different myocardial diseases.

Three-dimensional simultaneous strain-volume analysis describes left ventricular remodelling and its progression: a pilot study.

AIMS: Three-dimensional (3D)-echocardiography speckle imaging allows the evaluation of frame-by-frame strain and volume changes simultaneously. The aim of the present investigation was to describe the strain-volume combined assessment in different patterns of cardiac remodelling. METHODS AND RESULTS: Fifty patients received a 3D acquisition. Patients were classified as follows: healthy subjects (CNT), previous AMI, and normal ejection fraction (EF; group A); ischaemic cardiomyopathy with reduced EF (group B); hypertrophic/infiltrative cardiomyopathy (group C). Values of 3D strain were plotted vs. volume for each frame to build a strain-volume curve for each case. Peak of radial, longitudinal, and circumferential systolic strain (Rεp, Lεp, and Cεp, respectively), slopes of the curves (RεSl, LεSl, CεSl), and strain to end-diastolic volume (EDV) ratio (Rε/V, Lε/V, Cε/V) were computed for the analysis. Strain-volume curves of the CNT group were steep and clustered, whereas, due to progressive dilatation and reduction of strains, progressive flattening could be demonstrated in groups A and B. Quantitative data supported visual assessment with progressive lower slopes (P< 0.05 for RεSl, CεSl, P= 0.06 for LεSl) and significantly lower ratios (P< 0.01 for Rε/V, Lε/V, and Cε/V). Group C showed an opposite behaviour with slopes and ratios close to those of normal subjects. Correlation coefficients between EDV and slopes of the curves were significant for all the directions of strain (CεSl: r = 0.891; RєSl: r = 0.704; LєSl: r = 0.833; P< 0.0001 for all). CONCLUSION: We measured left ventricular volumes and strain by 3D-echo and obtained strain-volume curve to evaluate their behaviour in remodelling. A distinctive and progressive pattern consistent with pathophysiology was observed. The analysis here shown could represent a new non-invasive method to assess myocardial mechanics and its relationship with volumes.