Ventricular fibrillation episodes related to managed ventricular pacing algorithm in a patient with mitral valve prolapse - "Arrhythmic MVP due to MVP"

We report a case of an implant cardiac defibrillator (ICD) patient who an ICD implanted for ventricular fibrillation (VF) related to mitral valve prolapse. He has 2 episodes of VF in his device lives. First episode of VF in year 2016 was initiated after a pause related to the MVP™ algorithm with a critically timed PVC. MVP™ was turned off which prevented further VF episodes. However, MVP™ was turned back on at the device replacement in 2018. A second VF episode developed with similar mechanism in 2021 and MVP™ was subsequently turned off with no further VF recorded. This case highlights the importance of recognizing the mechanism of initiation of tachy-arrhythmia episodes and serves as an important reminder regarding optimization of device settings at the time of replacement.

Biventricular Function is Impaired in Right Ventricular Septal Pacing-A Prospective Study Using Myocardial Strain Imaging

BACKGROUND

Left ventricular (LV) dysfunction is known to occur after right ventricular (RV) pacing; the effect on RV function is less well studied. The aim of this study was to assess the impact of RV mid-septal pacing upon RV function using the novel parameters of speckle-tracking derived RV global longitudinal strain (RV GLS) and RV free wall strain (RV FWS), as well as the conventional parameters RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and tricuspid annular systolic velocity (RV S').

METHODS

Thirty-two (32) consecutive patients with normal baseline LV and RV function requiring permanent pacemaker insertion (for high-grade AV block or sinus node dysfunction) were prospectively recruited. Echocardiography was performed prior to implantation, at 1 day, 1 month and 1 year after implantation, with 29 patients completing follow-up.

RESULTS

After 1 year, three patients (10%) with otherwise normal RV parameters developed abnormal RV strain patterns. Compared to 1 day after implantation, at 1 year significant reductions were observed in mean RV GLS (-24.8 to -21.8%) RV S' (15.1 to 12.2 cm/s), TAPSE (24.2 to 21.9 mm), RV GLS (-24.8 to -21.8%), left ventricular ejection fraction (LVEF) (66.0 to 57.9%), LV GLS (-19.9 to 17.0), all p<0.01. There was a non-significant reduction for RV FWS (-29.0 to -26.7%, p=0.06) and there was no change in RV FAC (49.1 to 46.9%, p=0.24).

CONCLUSION

We report abnormalities of RV strain developing 1 year after pacemaker insertion. Measurement of myocardial strain is emerging as an additional method to detect patients at risk of RV dysfunction in those who have undergone pacemaker implantation.

Right ventricular global longitudinal strain is an independent predictor of right ventricular function: a multimodality study of cardiac magnetic resonance imaging, real time three-dimensional echocardiography and speckle tracking echocardiography

OBJECTIVES

Accurate assessment of right ventricular (RV) systolic function is important, as it is an established predictor of mortality in cardiac and respiratory diseases. We aimed to compare speckle tracking-derived longitudinal deformation measurements with traditional two-dimensional (2D) echocardiographic parameters, as well as real time three-dimensional echocardiography (RT3DE) and cardiac magnetic resonance imaging (CMR)-derived RV volumes and ejection fraction (EF).

METHOD

Subjects referred for CMR also underwent echocardiography. On both RT3DE and CMR, we measured RV volumes and EF. On 2D echocardiography, we analyzed RV fractional area change, RV internal diastolic diameter, tricuspid annular plane systolic excursion, tricuspid annular tissue Doppler-derived velocity, myocardial performance index, and RV global longitudinal strain (RV GLS).

RESULTS

Sixty subjects were recruited (mean age = 45 ± 10 years; 60% male). RV GLS (R = -0.69, P < 0.001) and RT3DE RVEF (R = 0.56, P < 0.001) correlated well with CMR RVEF. RT3DE RV end-diastolic (RVEDV) and end-systolic (RVESV) volumes also correlated with CMR RV volumes: RVEDV, R = 0.74, P < 0.001 and RVESV, R = 0.84, P < 0.001. In addition, RV GLS best predicted the presence of RV dysfunction, defined as RVEF <48% on CMR (hazard ratio = 7.0 [1.5-31.7], P < 0.01). On receiver operator characteristic analysis, a RV GLS of -20% was the most sensitive and specific predictor of RV dysfunction (AUC 0.8 [0.57-1.0], P < 0.02).

CONCLUSION

RVEF and volumes estimated on RT3DE were closely correlated with CMR measurements. When compared to more traditional markers of RV systolic function and RT3DE, RVGLS produced the highest correlation with CMR RVEF and was a good predictor of RV dysfunction. RV GLS should be considered a complementary modality to RT3DE and CMR in the assessment of RV systolic function.