Polymorphic Ventricular Tachycardia: Terminology, Mechanism, Diagnosis, and Emergency Therapy.

Polymorphic ventricular tachyarrhythmias are highly lethal arrhythmias. Several types of polymorphic ventricular tachycardia have similar electrocardiographic characteristics but have different modes of therapy. In fact, medications considered the treatment of choice for one form of polymorphic ventricular tachycardia, are contraindicated for the other. Yet confusion about terminology, and thus diagnosis and therapy, continues. We present an in-depth review of the different forms of polymorphic ventricular tachycardia and propose a practical step-by-step approach for distinguishing these malignant arrhythmias.

Continuous Heart Rate Monitoring for Automatic Detection of Life-Threatening Arrhythmias With Novel Bio-Sensing Technology.

Aims: Assessing the effectiveness of novel bio-sensing technology (CardiacSense), for accuracy and reliability of automatic detection of life-threatening arrhythmias. Methods and Results: This prospective study consisted of Eighteen patients (13 males and 5 females, mean age 59.4 ± 21.3 years) undergoing induction of ventricular tachycardia/fibrillation or provocation of transient ventricular asystole. We tested the detection of provoked ventricular arrhythmias by a wrist-worn watch-like device which uses photoplethysmography (PPG) technology to detect the cardiac rhythm. We used simultaneous electrocardiographic (ECG) recordings as gold standard for arrhythmia definition and confirmation of beat-to-beat detection. A total of 1,527 QRS complexes were recorded simultaneously by ECG and PPG. The overall correlation between the ECG (R-R intervals) and the PPG (G-G intervals) was high, with a correlation coefficient of R = 0.949 (p < 0.001). The device accurately detected all events of mimicked life endangering arrhythmias, including five events of transient (adenosine-induced) ventricular asystole as well as seven episodes of monomorphic ventricular tachycardia and 6 events of ventricular fibrillation. Conclusion: This proof-of-concept study suggests that wearable devices using PPG technology, currently used to detect atrial fibrillation, may also have a role as automatic detectors of life-threatening arrhythmias.

Sustained Elevation of Vascular Endothelial Growth Factor and Angiopoietin-2 Levels After Transcatheter Aortic Valve Replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) exposes the systemic vasculature to increased mechanical forces. Endothelial adaptation to mechanical stimuli is associated with angiogenic activation through various growth factors. We studied the potential angiogenic shift evoked by TAVR. METHODS: From a cohort of 69 consecutive patients undergoing TAVR, we excluded patients with conditions known to affect angiogenic factors, and serum vascular endothelial growth factor (VEGF) and angiopoietin (Ang)-1 and Ang-2 were assessed by ELISA. We assessed in vitro the properties of endothelial cells after exposure to serum collected from patients undergoing TAVR using adhesion, migration, and Matrigel angiogenesis assays. The correlation between changes in angiogenic factors and cardiac functions was evaluated on 30- day echocardiograms. RESULTS: The study population consisted of 46 patients (82 ± 5 years). Two days after TAVR the post/pre TAVR ratio of VEGF, Ang-1, and Ang-2 was 5.38 ± 4 (P < 0.001), 1.05 ± 0.49 (P = 0.27), and 4.65 ± 2.01 (P < 0.001), respectively. The increase in VEGF and Ang-2 showed a significant correlation (r = 0.609; P < 0.001), but no correlation was found with hemolysis or tissue injury markers. Patients with relatively low levels of VEGF or an Ang-2 rise had more severe aortic stenosis and coronary disease at baseline. Exposure of endothelial cells to post-TAVR serum induced adhesion, migration, and tube formation compared with pre-TAVR serum. An increase in VEGF levels correlated with improvement in pulmonary systolic pressure and a right ventricular fractional area change at 30 days, (r = 0.54 and r = 0.48, respectively; P < 0.01). CONCLUSIONS: Sustained elevation of VEGF and Ang-2 levels occur after TAVR, reflecting a systemic angiogenic shift. A rise in VEGF levels is associated with a decrease in pulmonary blood pressure in patients undergoing TAVR.

Forced diuresis with matched hydration in reducing acute kidney injury during transcatheter aortic valve implantation (Reduce-AKI): study protocol for a randomized sham-controlled trial.

BACKGROUND: Acute kidney injury (AKI) is observed in up to 41% of patients undergoing transcatheter aortic valve implantation (TAVI) and is associated with increased risk for mortality. The aim of the present study is to evaluate whether furosemide-induced diuresis with matched isotonic intravenous hydration using the RenalGuard system reduces AKI in patients undergoing TAVI. METHODS/DESIGN: Reduce-AKI is a randomized sham-controlled study designed to examine the effect of an automated matched hydration system in the prevention of AKI in patients undergoing TAVI. Patients will be randomized in a 1:1 fashion to the RenalGuard system (active group) versus non-matched saline infusion (sham-controlled group). Both arms receive standard overnight saline infusion and N-acetyl cysteine before the procedure. DISCUSSION: The Reduce-AKI trial will investigate whether the use of automated forced diuresis with matched saline infusion is an effective therapeutic tool to reduce the occurrence of AKI in patients undergoing TAVI. TRIAL REGISTRATION: Clinicaltrials.gov: NCT01866800, 30 April 30 2013.

Hemodynamic performance and outcome of percutaneous versus surgical stentless bioprostheses for aortic stenosis with anticipated patient-prosthesis mismatch.

OBJECTIVES: We aimed to compare the performance and midterm survival of transcutaneous aortic valve replacement (TAVR) and surgically implanted stentless aortic valve replacement (SAVR) for severe aortic stenosis in patients anticipated to have patient-prosthesis mismatch (PPM). METHODS: A retrospective analysis was performed of 86 and 49 consecutive TAVR and SAVR patients with severe aortic stenosis and calculated minimal effective orifice area larger than the best projected effective orifice area. Cox hazard analyses were used to assess the effect of TAVR versus SAVR on outcome. RESULTS: The peak and mean transprosthetic gradient at discharge were lower (P < .001 for both) in the TAVR group. Mild or greater aortic regurgitation was more frequent in the TAVR group (61% vs 7%; P < .0001). At 3 months of follow-up, the mean gradient in the TAVR group was similar to that of the SAVR group but the prevalence of aortic regurgitation was still higher. The unadjusted 3-year survival rate was superior in the SAVR versus TAVR group (91.6% ± 4% vs 67.0% ± 7%; P = .01). Adjustments for both age and comorbidity resulted in loss of the difference in mortality between the 2 groups. CONCLUSIONS: In patients with anticipated PPM, TAVR offers an immediate lower incidence of PPM than SAVR but a greater prevalence of aortic regurgitation. The differences in transaortic gradients became nonsignificant 3 months postoperatively. The question of whether TAVR is a suitable substitute for SAVR in patients with anticipated PPM, in particular, those who are older and sicker, warrants additional investigation.

Long-term clinical and echocardiographic follow-up of the freestyle stentless aortic bioprosthesis: the Tel Aviv Medical Center experience.

BACKGROUND: Stentless aortic bioprostheses were designed to provide improved hemodynamic performance and potentially better survival. OBJECTIVES: To report the outcomes of patients after aortic valve replacement with the Freestyle stentless bioprosthesis at the Tel Aviv Medical Center followed for < or = 15 years. METHODS AND RESULTS: Between 1997 and 2011, 268 patients underwent primary aortic valve replacement with a Freestyle bioprosthesis, 211 (79%) of them in the sub-coronary position. Mean age, Charlson comorbidity index and Euro-score were 71.0 +/- 9.2 years, 4.2 +/- 1.5 and 10.2 +/- 11 respectively, and 156 (58%) were male. Peak and mean trans-aortic gradient decreased significantly (75.0 +/- 29.1 vs. 22.8 +/- 9.6 mmHg, P < 0.0001; and 43.4 +/- 17.2 vs. 12.1 +/- 5.4 mmHg, P < 0.0001 respectively) during 3 months of follow-up. Mean overall follow-up was 4.9 +/- 3.1 years and was complete in all patients. In-hospital mortality was 4.1% (n=11) but differed significantly between the first 100 patients operated before 2006 and the last 168 patients operated after January 2006 (8 vs. 3 patients, 8.0% vs. 1.8%, P = 0.01). Overall, 5 and 10 year survival rates were 85 +/- 2.5% and 57.2 +/- 5.7%, respectively. Five year survival was markedly improved in patients operated after January 2006 compared to those operated in the early years of the experience (92.3 +/- 2.3% vs. 76.0 +/- 4.4%, P = 0.0009). All the 21 octogenarians operated after January 2006 survived surgery, with excellent 5 year survival (85.1 +/- 7.9%). Six patients required reoperation during follow-up: structural valve deterioration in five and endocarditis in one. CONCLUSIONS: Aortic valve replacement with the Freestyle bioprosthesis provides good long-term hemodynamic and clinical outcomes, even in octogenarians. Valve calcification is the major (and rare) mode of valve deterioration leading to reoperation in these patients.