Totally Leadless Dual-Device Implantation for Combined Spontaneous Ventricular Tachycardia Defibrillation and Pacemaker Function: A First Report.

Subcutaneous implantable cardioverter defibrillators (S-ICDs) provide effective defibrillation, while also reducing the risk of long-term lead problems. However, S-ICDs do not offer bradycardia or antitachycardia pacing and therefore use has been limited. Combined implantation of an S-ICD with a leadless pacemaker (LP) has been proposed to overcome this limitation. Although a handful of combined S-ICD/LP implantations have been reported for Nanostim (St Jude Medical, St Paul, MN) as well as Micra LP (Medtronic, Minneapolis, MN) systems, none have documented delivery of appropriate shock therapies for spontaneous ventricular tachycardia. We report the first case of effective defibrillation for spontaneous ventricular tachycardia in a patient with combined Micra LP and S-ICD.

One-Month Global Longitudinal Strain Identifies Patients Who Will Develop Pacing-Induced Left Ventricular Dysfunction over Time: The Pacing and Ventricular Dysfunction (PAVD) Study.

BACKGROUND: Predicting which individuals will have a decline in left ventricular (LV) function after pacemaker implantation remains an important challenge. We investigated whether LV global longitudinal strain (GLS), measured by 2D speckle tracking strain echocardiography, can identify patients at risk of pacing-induced left ventricular dysfunction (PIVD) or pacing-induced cardiomyopathy (PICMP). METHODS: Fifty-five patients with atrioventricular block and preserved LV function underwent dual-chamber pacemaker implantation and were followed with serial transthoracic echocardiography for 12 months for the development of PIVD (defined as a reduction in LV ejection fraction (LVEF) ≥5 percentage points at 12 months) or PICMP (reduction in LVEF to <45%). RESULTS: At 12 months, 15 (27%) patients developed PIVD; of these, 4 patients developed PICMP. At one month, GLS was significantly lower in the 15 patients who subsequently developed PIVD, compared to those who did not (n = 40) (GLS -12.6 vs. -16.4 respectively; p = 0.022). When patients with PICMP were excluded, one month GLS was significantly reduced compared to baseline whereas LVEF was not. One-month GLS had high predictive accuracy for determining subsequent development of PIVD or PICMP (AUC = 0.80, optimal GLS threshold: <-14.5, sensitivity 82%, specificity 75%); and particularly PICMP (AUC = 0.86, optimal GLS threshold: <-13.5, sensitivity 100%, specificity 71%). CONCLUSIONS: GLS is a novel predictor of decline in LV systolic function following pacemaker implantation, with the potential to identify patients at risk of PIVD before measurable changes in LVEF are apparent. GLS measured one month after implantation has high predictive accuracy for identifying patients who later develop PIVD or PICMP.