Atrial septal interventions during and after hybrid stage I palliation of hypoplastic left heart syndrome.

BACKGROUND: Hybrid stage I palliation (HS1P) is an alternative approach for initial palliation in hypoplastic left heart syndrome (HLHS) patients. Unlike surgical stage I palliation where atrial septectomy is routinely performed, atrial septal intervention (ASI) during HS1P is variable. In this study, we described our experience with ASI in single ventricle (SV) patients who underwent HS1P and identified factors associated with need for ASI after HS1P. METHODS: Data were retrospectively collected for all HLHS patients who underwent HS1P at our center over the past 12 years. We evaluated ASIs performed during the HS1P (intra-HS1P ASI) and ASIs performed during the period from HS1P to the subsequent surgical stage, either interval Norwood stage I or comprehensive stage II (post-HS1P ASI). Patient factors and procedural data were compared to identify factors associated with undergoing post-HS1P ASI and the impact of ASI on patient outcomes was evaluated. RESULTS: Of 50 SV patients included, 23 (46%) underwent intra-HS1P ASI and 26 (52%) underwent post-HS1P ASI. Need for post-HS1P ASI was lower among patients who had an intra-HS1P ASI as compared to those who did not (30% vs. 70%; p = 0.005). There were no significant differences in short or Midterm outcomes between patients who underwent intra-HS1P ASI or post-HS1P ASI and their counterparts. CONCLUSIONS: ASI is common both during and after HS1P but is generally well tolerated and type of ASI does not significantly impact overall patient outcomes. Our findings suggest that the current approach of individualizing management of ASI in the HS1P population is effective and safe.

The application of root mean square electrocardiography (RMS ECG) for the detection of acquired and congenital long QT syndrome.

BACKGROUND: Precise measurement of the QT interval is often hampered by difficulty determining the end of the low amplitude T wave. Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. Experimental data have shown that the interval between the RMS ECG QRS and T wave peaks (RTPK) closely reflects the mean ventricular action potential duration while the RMS T wave width (TW) tracks the dispersion of repolarization timing. Here, we tested the precision of RMS ECG to assess ventricular repolarization in humans in the setting of drug-induced and congenital Long QT Syndrome (LQTS). METHODS: RMS ECG signals were derived from high-resolution 24 hour Holter monitor recordings from 68 subjects after receiving placebo and moxifloxacin and from standard 12 lead ECGs obtained in 97 subjects with LQTS and 97 age- and sex-matched controls. RTPK, QTRMS and RMS TW intervals were automatically measured using custom software and compared to traditional QT measures using lead II. RESULTS: All measures of repolarization were prolonged during moxifloxacin administration and in LQTS subjects, but the variance of RMS intervals was significantly smaller than traditional lead II measurements. TW was prolonged during moxifloxacin and in subjects with LQT-2, but not LQT-1 or LQT-3. CONCLUSION: These data validate the application of RMS ECG for the detection of drug-induced and congenital LQTS. RMS ECG measurements are more precise than the current standard of care lead II measurements.

Stentless porcine valves in the right ventricular outflow tract: improved durability?

OBJECTIVE: Stentless porcine valves are commonly used for aortic valve replacement in adults, yet their long-term performance in the right ventricular (RV) outflow tract is unknown. We evaluated intermediate-term performance of stentless porcine valves in the RV outflow tract in 150 children and adults over a 10-year period. METHODS: We retrospectively reviewed data on all patients undergoing placement of a pulmonary valve or RV-PA conduit with a stentless porcine prosthesis (>/=19 mm) from 1998 to 2008. Valvar function was assessed with echocardiography. Freedom from reintervention (explantation or catheter-based intervention) was determined by actuarial methods. RESULTS: A stentless porcine prosthesis was placed in the pulmonary position in 150 patients with a median weight and age of 50.1 kg (range 9.8-127) and 15.8 years (range 1.4-55), respectively. There were three early deaths (2%) and no late deaths. Actuarial freedom from reintervention was 100% at 1 year and 95.5% at 5 years. Peak transvalvar gradient at 1 and 5 years was 13+/-12 mmHg and 25+/-11 mmHg, respectively. At last follow-up no patient had severe insufficiency (PI), five patients had moderate PI and the remainder mild or no PI. CONCLUSIONS: Stentless porcine valves function well in the pulmonary position over the intermediate-term and are associated with low rates of reintervention in patients requiring a >19 mm valve or valved conduit. Longer-term follow-up and comparison with other alternatives will be necessary to determine if these valves are superior to commonly used allograft or bovine jugular venous valved conduits.