Mulpuru, Siva K.

AbstractBackgroundRecipients of implantable cardioverter defibrillator (ICD) generator replacement with multiple medical comorbidities may be at higher risk of adverse outcomes that attenuate the benefit of ICD replacement. The aim of this investigation was to study the association between the Charlson comorbidity index (CCI) and outcomes after ICD generator replacement.MethodsAll patients undergoing first ICD generator replacement at Mayo Clinic, Rochester and Beth Israel Deaconess Medical Center, Boston between 2001 and 2011 were identified. Outcomes included: (a) all‐cause mortality, (b) appropriate ICD therapy, and (c) death prior to appropriate therapy. Multivariable Cox regression analysis was performed to assess association between CCI and outcomes.ResultsWe identified 1421 patients with mean age of 69.6 ± 12.1 years, 81% male and median (range) CCI of 3 (0‐18). During a mean follow‐up of 3.9 ± 3 years, 52% of patients died, 30.6% experienced an appropriate therapy, and 23.6% died without experiencing an appropriate therapy. In multivariable analysis, higher CCI score was associated with increased all‐cause mortality (Hazard ratio, HR 1.10 [1.06‐1.13] per 1 point increase in CCI, P < .001), death without prior appropriate therapy (HR 1.11 [1.07‐1.15], P < .0001), but not associated with appropriate therapy (HR 1.01 [0.97‐1.05], P = .53). Patients with CCI ≥5 had an annual risk of death of 12.2% compared to 8.7% annual rate of appropriate therapy.ConclusionsCCI is predictive of mortality following ICD generator replacement. The benefit of ICD replacement in patients with CCI score ≥5 should be investigated in prospective studies.

AbstractBackground and objectivesMacroreentrant atrial tachycardias often occur following atrial fibrillation ablation, most commonly due to nontransmural lesions in prior ablation lines. Perimitral atrial flutter is one such arrhythmia which requires ablation of the mitral isthmus. Our objectives were to review the literature regarding ablation of the mitral isthmus and to provide our approach for assessment of mitral isthmus block.MethodsWe review anatomical considerations, ablation strategies, and assessment of conduction block across the mitral isthmus, which is subject to several pitfalls. Activation sequence and spatial differential pacing techniques are discussed for assessment of both endocardial and epicardial bidirectional mitral isthmus block.ResultsTraditional methods for verifying mitral isthmus block include spatial differential pacing, activation mapping, and identification of double potentials. Up to 70% of cases require additional ablation in the coronary sinus (CS) to achieve transmural block. Interpretation of transmural block is subject to six pitfalls involving pacing output, differentiation of endocardial left atrial recordings from epicardial CS recordings, identification of a slowly conducting gap in the line, and catheter positioning during spatial differential pacing. Interpretation of unipolar electrograms can identify nontransmural lesions. We employ a combined epicardial and endocardial assessment of mitral isthmus block, which involves using a CS catheter for epicardial recording and a duodecapolar Halo catheter positioned around the mitral annulus for endocardial recording.ConclusionsThe assessment of transmural mitral isthmus block can be challenging. Placement of an endocardial mapping catheter around the mitral annulus can provide a precise assessment of conduction across the mitral isthmus.

AbstractBackgroundThere are few data regarding the outcome of a combined cryo‐ and radiofrequency (RF)‐catheter ablation of various types of supraventricular tachycardias (SVTs) originating from near the normal conduction system.METHODSWe analyzed all patients undergoing combined cryo‐ and RF‐ catheter ablation at Mayo Clinic, Rochester, MN as part of the ablation of SVTs with potential risks of injury to the normal conduction system. This study aimed to assess the outcome of a combined cryo‐ and RF‐catheter ablation of various types of SVTs.RESULTSThe study population consisted of 54 patients (38 ± 17 years, 32 men). A combined cryo‐ and RF‐catheter ablation was attempted for septal accessary pathways (APs) in 26, atrioventricular nodal reentrant tachycardia (AVNRT) in 14, atrial tachycardia (AT) in 7, and junctional ectopic tachycardia in 7 patients. Forty‐one patients (76%) were successfully ablated with cryoablation, and RF ablation after an unsuccessful cryoablation ablated the SVTs successfully at the same location in 6 patients (11%). Complication occurred in 1 patient (deep vein thrombosis). The cumulative freedom from SVT rate at 30 days after the procedure was 78% and there was no significant difference in the recurrence rate among the SVTs.CONCLUSIONA combined cryo‐ and RF‐catheter ablation is clinically effective in patients undergoing SVT ablation with the potential risk of injury to the normal conduction system.

AbstractIntroductionAutonomic modulation has been used as a therapy to control recurrent ventricular arrhythmia (VA). This study was to explore stellate ganglion block (SGB) effect on cardiac electrophysiologic properties and evaluate the long‐term outcome of cardiac sympathetic denervation (CSD) for patients with recurrent VA and structural heart disease (SHD).Materials and MethodsPatients who had recurrent VA due to SHD were enrolled prospectively. Electrophysiologic study and ventricular tachycardia (VT) induction were performed before and after left and right SGB. VA burden and long‐term outcomes were assessed for a separate patient group who underwent left or bilateral CSD for drug‐refractory VA due to SHD.ResultsElectrophysiologic study of nine patients showed that baseline mean (SD) corrected sinus node recovery time (cSNRT) increased from 320.4 (73.3) ms to 402.9 (114.2) ms after left and 482.4 (95.7) ms after bilateral SGB (P = .03). SGB did not significantly change P‐R, QRS, and Q‐T intervals and ventricular effective refractory period, nor did the inducibility of VA. Nineteen patients underwent left (n = 14) or bilateral (n = 5) CSD. CSD reduced VA burden and appropriate ICD therapies from a median (interquartile range) of 2.5 (0.4‐11.6) episodes weekly to 0.1 (0.0‐2.4) episodes weekly at 6‐month follow‐up (P = .002). Three‐year freedom from orthotopic heart transplant (OHT) and death was 52.6%. New York Heart Association functional class III/IV and VT rate less than 160 beats per minute were predictors of recurrent VA, OHT, and death.ConclusionSGB increased cSNRT without changing heart rate. CSD was more beneficial for patients with mild‐to‐moderate heart failure and faster VA.

Background: The treatment of heart failure with reduced ejection fraction has been the subject of numerous randomized controlled trials involving medications and cardiac implantable electronic device therapies. As newer effective pharmacological therapies suggest significant reductions in all-cause mortality, the role of additional device therapy in heart failure with reduced ejection fraction deserves further scrutiny. Methods: A systematic review and network meta-analysis on the effect of medication and device therapies in heart failure with reduced ejection fraction on all-cause mortality was performed. Randomized controlled trials published between January 1980 and July 2017 were identified using Medline, EMBASE, and Cochrane Controlled Register of Trials databases. Pcnetmeta package in R was used to calculate treatment arm–based estimated rates, rate ratios, and probability ranks with 95% credible intervals. Results: Combination therapy of ACE (angiotensin-converting enzyme) inhibitors or ARBs (angiotensin receptor blockers) with β-blockers (BBs) alone or in addition to implantable cardiac defibrillators or cardiac resynchronization therapy with defibrillators demonstrated a significant reduction of all-cause mortality when compared with placebo. By probability rank, implantable cardiac defibrillator+ACE inhibitor or ARB+BB+mineralocorticoid receptor antagonist, implantable cardiac defibrillator+ACE inhibitor or ARB+BB, and angiotensin receptor-neprilysin inhibitor+BB+mineralocorticoid receptor antagonist combination therapies have the highest probability of being ranked the best treatment. There was no significant difference in the rate of mortality when comparing angiotensin receptor-neprilysin inhibitor+BB+mineralocorticoid receptor antagonist to implantable cardiac defibrillator+optimal pharmacological combination therapy. Conclusions: BB and renin-angiotensin system blockers alone or in combination with defibrillator device therapy have robust evidence for a reduction in mortality compared with placebo. The comparative efficacy of pharmacological therapy with angiotensin receptor-neprilysin inhibitors and device therapy deserves further investigation.

AbstractBackgroundAtrial fibrillation (AF) among patients with heart failure with reduced ejection fraction (HFrEF) is associated with adverse clinical outcomes. Our primary aim was to evaluate patient‐centered outcomes and surrogate outcomes following catheter ablation (CA) of AF among patients with HFrEF compared to standard medical therapy with or without device therapy (atrioventricular node ablation and cardiac resynchronization therapy).MethodsA systematic literature review was performed limiting our searches to randomized control trials reporting outcomes of CA compared to standard medical therapy with or without device therapy were included. Patient‐centered outcomes were relative reduction in all‐cause mortality, heart failure readmissions, and recurrence of AF. Surrogate outcomes of interest were change in ejection fraction, change in peak oxygen consumption, reduction in brain natriuretic peptide levels, change in 6‐minute walk distance, and change in Minnesota living with heart failure score.ResultsSeven randomized control trials (Patient n = 721) met our inclusion criteria. All trials used radiofrequency energy for CA of AF. CA for AF was associated with significantly lower all‐cause mortality (Risk ratio [RR] = 0.52, 95% confidence interval [CI] = 0.35‐0.76, P = 0.001, I2 = 0%), lower rate of heart failure readmission (RR = 0.58, 95% CI = 0.46‐0.74, P < 0.001, I2 = 0%) and lower rate of AF recurrence (RR = 0.33, 95% CI = 0.22‐0.50, P < 0.001, I2 = 68%) as compared to standard medical therapy. Surrogate outcomes showed a similar benefit favoring CA.Conclusion and RelevanceCatheter ablation for AF in HFrEF is associated with improvement in patient‐centered outcomes and surrogate outcomes when compared to standard medical therapy with or without device therapy.