Archive

Archive for the ‘Electrophysiology’ Category

Cardiovascular Implantable Electronic Devices: end of life and perioperative management

HeartOne  provides learning modules for CSANZ members. This post is motivated by a module:

The following are excerpts from HRS consensus document.
icdeol01
icdeeol02
The following are excerpts for HRS statement on peri-operative management CIED:
hrssperiop01
hrsperiop02
hrsperiop03
hrsperio04
hrsperiop05
The issue of radiotherapy is worthy of mention. From the consensus document:
hrsradiation
A useful template from a Dutch paper.
radiotherapydutch
Categories: Electrophysiology

Journal Club 23 September 2015

September 25, 2015 Leave a comment

Paper

Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker

Presenter

PM

Summary

BACKGROUND

Cardiac pacemakers are limited by device-related complications, notably infection
and problems related to pacemaker leads. We studied a miniaturized, fully selfcontained
leadless pacemaker that is nonsurgically implanted in the right ventricle
with the use of a catheter.

METHODS

In this multicenter study, we implanted an active-fixation leadless cardiac pacemaker
in patients who required permanent single-chamber ventricular pacing. The primary
efficacy end point was both an acceptable pacing threshold (≤2.0 V at 0.4 msec)
and an acceptable sensing amplitude (R wave ≥5.0 mV, or a value equal to or
greater than the value at implantation) through 6 months. The primary safety end
point was freedom from device-related serious adverse events through 6 months.
In this ongoing study, the prespecified analysis of the primary end points was
performed on data from the first 300 patients who completed 6 months of followup
(primary cohort). The rates of the efficacy end point and safety end point were
compared with performance goals (based on historical data) of 85% and 86%,
respectively. Additional outcomes were assessed in all 526 patients who were enrolled
as of June 2015 (the total cohort).

RESULTS

The leadless pacemaker was successfully implanted in 504 of the 526 patients in
the total cohort (95.8%). The intention-to-treat primary efficacy end point was met
in 270 of the 300 patients in the primary cohort (90.0%; 95% confidence interval
[CI], 86.0 to 93.2, P = 0.007), and the primary safety end point was met in 280 of
the 300 patients (93.3%; 95% CI, 89.9 to 95.9; P<0.001). At 6 months, device-related
serious adverse events were observed in 6.7% of the patients; events included device
dislodgement with percutaneous retrieval (in 1.7%), cardiac perforation (in 1.3%),
and pacing-threshold elevation requiring percutaneous retrieval and device replacement
(in 1.3%).

CONCLUSIONS

The leadless cardiac pacemaker met prespecified pacing and sensing requirements
in the large majority of patients. Device-related serious adverse events occurred in approximately
1 in 15 patients.

Supplementary Material

Supplementary material is available here.

Journal Club 19 August 2015

Paper

Arrhythmic Mitral Valve Prolapse and Sudden Cardiac Death

Presenter

SH

Summary

Background

Mitral valve prolapse (MVP) may present with ventricular arrhythmias and sudden cardiac death (SCD) even in the absence of hemodynamic impairment. The structural basis of ventricular electric instability remains elusive.

Methods and Results

The cardiac pathology registry of 650 young adults (≤40 years of age) with SCD was reviewed, and
cases with MVP as the only cause of SCD were re-examined. Forty-three patients with MVP (26 females; age range,19–40 years; median, 32 years) were identified (7% of all SCD, 13% of women). Among 12 cases with available ECG, 10 (83%) had inverted T waves on inferior leads, and all had right bundle-branch block ventricular arrhythmias. A bileaflet involvement was found in 70%. Left ventricular fibrosis was detected at histology at the level of papillary muscles in
all patients, and inferobasal wall in 88%. Living patients with MVP with (n=30) and without (control subjects; n=14) complex ventricular arrhythmias underwent a study protocol including contrast-enhanced cardiac magnetic resonance. Patients with either right bundle-branch block type or polymorphic complex ventricular arrhythmias (22 females; age range, 28–43 years; median, 41 years), showed a bileaflet involvement in 70% of cases. Left ventricular late enhancement
was identified by contrast-enhanced cardiac magnetic resonance in 93% of patients versus 14% of control subjects (P<0.001), with a regional distribution overlapping the histopathology findings in SCD cases.

Conclusions

MVP is an underestimated cause of arrhythmic SCD, mostly in young adult women. Fibrosis of the
papillary muscles and inferobasal left ventricular wall, suggesting a myocardial stretch by the prolapsing leaflet, is the structural hallmark and correlates with ventricular arrhythmias origin. Contrast-enhanced cardiac magnetic resonance may help to identify in vivo this concealed substrate for risk stratification.

Supplementary Material

The editorial is available here.

Journal Club 11 March 2015

Paper

Effect ofperiproceduralamiodaroneonprocedureoutcome
in patientswithlongstandingpersistentatrial fibrillation
undergoing extendedpulmonaryveinantrumisolation:
Results fromarandomizedstudy(SPECULATE)

Presenter

PM

Summary

BACKGROUND

The impactofamiodaroneonablationoutcomeinlong-
standing persistentatrial fibrillation(LSPAF)patientsisnotknownyet.
OBJECTIVE The purposeofthisstudywastoassesstheeffectof
amiodarone onprocedural-outcomesinLSPAFpatientsundergoing
catheter ablation.

METHODS

We enrolled112LSPAFpatientsonamiodaroneand
scheduled toundergoatrial fibrillation (AF)ablation.Patientswere
randomized toamiodaronediscontinuation4monthsbeforeablation
(group1,n ¼ 56) andacontrolgroup(group2,n ¼ 56)inwhich
ablationwasperformedwithoutamiodaronediscontinuation.All
patientsunderwentpulmonaryvein(PV)antrumandposteriorwall
isolation, defragmentationandextraPVtriggersablation.Patientswere
followedupforrecurrencefor32 8 monthspost-ablation.Repeat
proceduresinallrecurrentpatientswereperformedoffamiodarone.

RESULTS

During ablation,AFterminationwasmorefrequentin
group 2comparedtogroup1[44(79%)vs32(57%), P ¼ .015].
After high-dosageisoproterenol,morenon-PVtriggersweredis-
closed ingroup1comparedtogroup2(42[75%]vs24[43%]
respectively, P o.001). Group2hadlowerprocedure,radiofre-
quency and fluoroscopy timescomparedtogroup1(2.7 1 vs
3.11 h,6913 minvs87 11 minand6414 minvs85 18
min respectively, p o .05). At32 8 monthfollow-up,onoroff
antiarrhythmic drugsuccessratewas37(66%)ingroup1and27
(48%) ingroup2(P ¼ .04). Duringredo,newnon-PVtriggersites
were identified ingroup2patients.

CONCLUSION

Periprocedural continuousamiodaronewasassoci-
ated withhigherorganizationrateandlowerradiofrequency
ablation rate.However,maskingnon-PVtriggersincreasedthelate
recurrence rate.

Journal Club 16 July 2014

Paper

Clinical Classifications of Atrial Fibrillation Poorly Reflect Its Temporal Persistence Insights From 1,195 Patients Continuously Monitored With Implantable Devices

Presenter

AL

Summary

Objectives

This study aimed to identify how accurately the current clinical atrial fibrillation (AF) classifications reflect its
temporal persistence.

Background

Clinical classification of AF is employed to communicate its persistence, to select appropriate therapies, and as
inclusion criterion for clinical trials.
Methods Cardiac rhythm histories of 1,195 patients (age 73.0  10.1 years, follow-up: 349  40 days) with implantable
devices were reconstructed and analyzed. Patients were classified as having paroxysmal or persistent AF by
physicians at baseline in accordance with current guidelines. AF burden, measured as the proportion of time spent in
AF, was obtained from the device. Additionally we evaluated the agreement between clinical and device-derived AF
classifications.

Results

Patients within the same clinical class were highly heterogeneous with regards to AF temporal persistence.
Agreement between the clinical AF classification and the objective device-derived assessments of AF temporal
persistence was poor (Cohen’s kappa: 0.12 [95% CI: 0.05 to 0.18]). Patient characteristics influenced the clinical
decision to classify AF as paroxysmal or persistent. Higher ejection fraction (odds ratio: 0.97/per unit [95% CI: 0.95
to 0.98/per unit]; p < 0.0001) and presence of coronary artery disease (odds ratio: 0.53 [95% CI: 0.32 to 0.88];
p ¼ 0.01) were independently associated with a lower probability of being classified as persistent AF for the same
AF burden level.

Conclusions

The currently used clinical AF classifications poorly reflect AF temporal persistence. Patient characteristics
significantly influence the physician’s classification of AF. Patients classified in identical clinical categories may
be inherently heterogeneous with regard to AF temporal persistence. Further study is required to determine if
patient selection on the basis of objective criteria derived from rigorous AF monitoring can improve reported
outcomes and better identify responders and non-responders to treatments.

Related Material

Classifying AF

Journal Club 23 April 2014

Paper

A Randomized Trial to Assess Catheter Ablation Versus Rate Control in the Management of Persistent Atrial Fibrillation in Heart Failure

Presenter

PM

Summary

Objectives

This study sought to compare catheter ablation with rate control for persistent atrial fibrillation (AF) in heart fail- ure (HF).
Background The optimal therapy for AF in HF is unclear. Drug-based rhythm control has not proved clinically beneficial. Cath-
eter ablation improves cardiac function in patients with HF, but impact on physiological performance has not been formally evaluated in a randomized trial.

Methods

In a randomized, open-label, blinded-endpoint clinical trial, adults with symptomatic HF, radionuclide left ventric- ular ejection fraction (EF) Յ35%, and persistent AF were assigned to undergo catheter ablation or rate control. Primary outcome was 12-month change in peak oxygen consumption. Secondary endpoints were quality of life, B-type natriuretic peptide, 6-min walk distance, and EF. Results were analyzed by intention-to-treat.

Results

Fifty-two patients (age 63 Ϯ 9 years, EF 24 Ϯ 8%) were randomized, 26 each to ablation and rate control. At 12 months, 88% of ablation patients maintained sinus rhythm (single-procedure success 68%). Under rate control, rate criteria were achieved in 96%. The primary endpoint, peak oxygen consumption, significantly increased in the ablation arm compared with rate control (difference ϩ3.07 ml/kg/min, 95% confidence interval: 0.56 to 5.59, p ϭ 0.018). The change was not evident at 3 months (ϩ0.79 ml/kg/min, 95% confidence interval: Ϫ1.01 to 2.60, p ϭ 0.38). Ablation improved Minnesota score (p ϭ 0.019) and B-type natriuretic peptide (p ϭ 0.045) and showed nonsignificant trends toward improved 6-min walk distance (p ϭ 0.095) and EF (p ϭ 0.055).

Conclusions

This first randomized trial of ablation versus rate control to focus on objective exercise performance in AF and HF
shows significant benefit from ablation, a strategy that also improves symptoms and neurohormonal status. The ef- fects develop over 12 months, consistent with progressive amelioration of the HF syndrome.

Supplementary Material

The editorial is here.

Journal Club 2 April 2014

Paper

Survival with Cardiac-Resynchronization Therapy in Mild Heart Failure

Presenter

MD

Summary

BACKGROUND

The Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchro-nization Therapy (MADIT-CRT) showed that early intervention with cardiac-resyn-chronization therapy with a defibrillator (CRT-D) in patients with an electrocardio-graphic pattern showing left bundle-branch block was associated with a significant reduction in heart-failure events over a median follow-up of 2.4 years, as compared with defibrillator therapy alone.

METHODS

We evaluated the effect of CRT-D on long-term survival in the MADIT-CRT popula-tion. Post-trial follow-up over a median period of 5.6 years was assessed among all 1691 surviving patients (phase 1) and subsequently among 854 patients who were enrolled in post-trial registries (phase 2). All reported analyses were performed on an intention-to-treat basis.

RESULTS

At 7 years of follow-up after initial enrollment, the cumulative rate of death from any cause among patients with left bundle-branch block was 18% among patients ran-domly assigned to CRT-D, as compared with 29% among those randomly assigned to defibrillator therapy alone (adjusted hazard ratio in the CRT-D group, 0.59; 95% confidence interval [CI], 0.43 to 0.80; P<0.001). The long-term survival benefit of CRT-D in patients with left bundle-branch block did not differ significantly according to sex, cause of cardiomyopathy, or QRS duration. In contrast, CRT-D was not associ-ated with any clinical benefit and possibly with harm in patients without left bundle-branch block (adjusted hazard ratio for death from any cause, 1.57; 95% CI, 1.03 to 2.39; P = 0.04; P<0.001 for interaction of treatment with QRS morphologic findings).

CONCLUSIONS

Our findings indicate that in patients with mild heart-failure symptoms, left ventricular dysfunction, and left bundle-branch block, early intervention with CRT-D was associated with a significant long-term survival benefit.

Supplementary Material

Paper supplementary material
Editorial