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Longitudinal shortening is traditionally considered the predominant part of global right ventricular (RV) systolic function. Less attention has been paid to transverse contraction. The aim of this study was to evaluate RV transverse motion by cardiovascular magnetic resonance (CMR) in a large cohort of patients and to assess its relationship with RV ejection fraction (RVEF).We retrospectively analyzed the CMR scans of 300 patients referred to our center in 2010. RVEF was determined from short axis sequences using the volumetric method. Transverse parameters called RV fractional diameter changes were calculated after measuring RV diastolic and systolic diameters at basal and mid-level in short axis view (respectively FBDC and FMDC). We also measured the tricuspid annular plane systolic excursion (TAPSE) as a longitudinal reference.Our population was divided into 2 groups according to RVEF. 250 patients had a preserved RVEF (40%) and 50 had a RV dysfunction (RVEF ≤ 40%). Transverse and longitudinal motions were significantly reduced in the group with RV dysfunction (p.0001). After ROC analysis, areas under the curve for FBDC, FMDC and TAPSE, were respectively 0.79, 0.82 and 0.72, with the highest specificity and sensitivity respectively of 88% and 68% for FMDC (threshold at 20%) for predicting RV dysfunction. FMDC had an excellent negative predictive value of 93%.RV fractional diameter changes, especially at the mid-level, appear to be accurate for semi-quantitative assessment of RV function by CMR. A cut-off of 20% for FMDC differentiates patients with a low (EF≤40%) or a preserved RVEF.

A 68-year-old female with a history of paroxysmal atrial fibrillation and complete atrioventricular (AV) block was referred for palpitations and suspicion of pacemaker dysfunction (model Philos II DR-T, Biotronik, Berlin, Germany). Baseline electrocardiogram (ECG) showed a dual-chamber pacemaker with an inappropriate behavior (Fig. 1, Panel A). Pacemaker programmed parameters were as follows: pacing mode DDD-R; basic rate 60 beats per minute (bpm); upper rate 130 bpm; dynamic paced AV delay 180/140 ms; dynamic sensed AV delay 135/95 ms; AV safety window 100 ms; atrial sensitivity 0.5 mV (bipolar); ventricular sensitivity 2.5 mV (bipolar); atrial and ventricular pulse amplitude and width 3.6 V and 0.40 ms, respectively (both unipolar). Pacemaker testing showed the following results: battery impedance 0.3 k ; sensed P wave 3 mV, sensed R wave 25 mV; atrial and ventricular pacing thresholds 0.6 and 0.4 V, respectively; atrial and ventricular lead impedances 442 and 560 , respectively (stable). Testing of the atrial pacing threshold in AAI mode at 70 bpm allowed the diagnosis to be made (Fig. 1, Panel B). What is the mechanism of the pacemaker “dysfunction”? How can it be solved?

Background Cardiovascular magnetic resonance (CMR) is the gold standard to measure right ventricular ejection fraction (RVEF). Longitudinal shortening is historically known to be the predominant part of its global systolic function and less attention has been paid to the transversal contraction. The aim of this study was to evaluate RV transverse motion in a large cohort of patients referred for CMR and assess its relationship with RVEF.

BackgroundCardiovascular magnetic resonance (CMR) with endocardial delineation of the right ventricle is the gold standard to measure right ventricular ejection fraction (RVEF). Longitudinal shortening is historically known to be the predominant part of its global systolic function and less attention has been paid to the transversal contraction. The aim of this study was to evaluate RV transverse motion in a large cohort of patients referred for CMR and assess its relationship with RVEF.MethodWe retrospectively analyzed the CMR scans of 300 consecutive patients referred for CMR between January and December 2010. Reference RV ejection fraction was determined from short axis sequence after delineating endocardial contours. Transverse parameters called RV fractional diameter changes were calculated after measuring RV diastolic and systolic diameters at basal and medial level in short axis view (respectively FBDC and FMDC). We also measured the tricuspid annular plane systolic excursion (TAPSE) in the four chambers view as a longitudinal reference.ResultsPopulation was divided into 2 groups according the RVEF. 250 patients had a preserved RVEF (>40%) and 50 had a RV dysfunction (RVEF≤40%). Both transverse and longitudinal motions were significantly reduced in the group with RV dysfunction (p