Journal Club

Deephak Swaminath

Journal

• Incidence and predictors of right ventricularpacing- induced cardiomyopathy

• Shaan Khurshid,MD,* Andrew E.Epstein,MD,FHRS,* Ralph J.Verdino,MD,* David Lin,MD,FHRS,* Lee R.Goldberg,MD,*† ?Francis E.Marchlinski,MD,FHRS,* David S.Frankel,MD,FHRS* .

Heart Rhythm, Vol 11, No 9, September 2014

• Circulation. 1998 .Heart failure and echocardiographic changes during long-term follow-up of patients with sick sinus syndrome randomized to single-chamber atrial or ventricular pacing

• Nielsen JC1, Andersen HR, Thomsen PE, Thuesen L, Mortensen PT, Vesterlund T, Pedersen AK.• Abstract• A total of 225 consecutive patients with sick sinus syndrome and intact atrioventricular

conduction were randomized to either single-chamber atrial pacing (n = 110) or single-chamber ventricular pacing (n = 115). Clinical assessment included New York Heart Association classification, medication, and M-mode echocardiography before pacemaker implantation, after 3 months, and subsequently once every year. At long-term follow-up (mean, 5.5+/-2.4 years), NYHA class was higher in the ventricular group than in the atrial group (NYHA class I/II/III/IV: 65/44/4/0 versus 84/22/2/1 patients, P=.010). Increase in NYHA class during follow-up was observed in 35 of 113 patients in the ventricular group versus 10 of 109 in the atrial group (P<.0005). Increase in dose of diuretics from randomization to last follow-up was significantly higher in the ventricular group than in the atrial group (21+/-49 versus 8+/-42 mg furosemide/d, P=.033). The left ventricular fractional shortening decreased significantly in the ventricular group (from 0.36+/-0.12 to 0.31+/-0.08, P<.0005) but not in the atrial group (from 0.35+/-0.13 to 0.33+/-0.09, P=.087). The left atrial diameter increased significantly in both treatment groups (ventricular group: from 34+/-7 to 41+/-7 mm, P<.0005; atrial group: from 34+/-6 to 37+/-7 mm, P=.002), but the increase was significantly higher in the ventricular group than in the atrial group (P<.0005).

Literature Search

• Lancet. 1994 Prospective randomised trial of atrial versus ventricular pacing in sick-sinus syndrome.

• Andersen HR1, Thuesen L, Bagger JP, Vesterlund T, Thomsen PE.Abstract

• Prospective randomised trial in 225 consecutive patients with the sick-sinus syndrome, randomised to atrial (n = 110) or ventricular (n = 115) pacing and followed for up to 5 years (mean 40 [SD 18] months).

• During follow-up, the frequency of atrial fibrillation was higher in the ventricular group, except at the first follow-up at 3 months. Thromboembolic events (stroke or peripheral arterial embolus) occurred in 20 patients in the ventricular group and in 6 patients in the atrial group (p = 0.0083). 25 patients died in the ventricular group compared with 21 in the atrial group (p = 0.74).

Literature Search• N Engl J Med. 2009 Biventricular pacing in patients with

bradycardia and normal ejection fractionYu CM1, Chan JY, Zhang Q, Omar R, Yip GW, Hussin A, Fang F, Lam KH, Chan HC, Fung JW.

• METHODS:In this prospective, double-blind, multicenter study, we randomly assigned 177 patients in whom a biventricular pacemaker had been successfully implanted to receive biventricular pacing (89 patients) or right ventricular apical pacing (88 patients). The primary end points were the left ventricular ejection fraction and left ventricular end-systolic volume at 12 months.

• RESULTS: At 12 months, the mean left ventricular ejection fraction was significantly lower in the right-ventricular-pacing group than in the biventricular-pacing group (54.8+/-9.1% vs. 62.2+/-7.0%, P<0.001), with an absolute difference of 7.4 percentage points, whereas the left ventricular end-systolic volume was significantly higher in the right-ventricular-pacing group than in the biventricular-pacing group (35.7+/-16.3 ml vs. 27.6+/-10.4 ml, P<0.001), with a relative difference between the groups in the change from baseline of 25% (P<0.001).

Literature search summary

• Patients exposed to frequent RV pacing develop PICM

• Does all the patient develop with RV pacing develop PICM ?

• If a select group is identified then those patients will receive Bivi pacing.

• Why not every one get Bivi pacing? Cost.• Total cost per patient $52,804 vs $40,267(Block-

HF trial).

Methods

• Retrospective study• Inclusion CriteriaPatients with baseline echocardiogram (LVEF) >50%(6 month).A single-chamber ventricular or dual-chamber pace- maker was implanted; frequent(>20%) RV pacing was present;and a repeat echocardiogram was available atleast 1 year after implantation.• Exclusion Criteria: Patients undergoing pulsegenerator change were excluded,as were patients undergoing implantation of implantable cardioverter-defibrillators and single- chamber atrial or biventricular pacemakers.

Data

Data -Definition

• PICM was defined as a >10% decrease in LVEF, with resultant LVEF of 50%.

• Medical records were thoroughly searched for alternative causes of cardiomyopathy, including myocardial infarction,myocardial ischemia on stress testing,severe valvular heart disease,atrial arrhythmias with rapidventricular response,frequent(>20%) ventricular prematuredepolarizations(VPDs),and uncontrolled hypertension.

• When an alternative potential explanation for decrease in LVEF was identified, patients were excluded from further analysis.

Limitation

• Inclusion Bias• To eliminate inclusion bias, all patients would

need to undergo surveillance echocardio- grams regardless of clinical need.

Take Home Points

• PICM maybe more common than previously reported.• Men with wider native QRS duration ,particularly >115

ms , are at increased risk for the development of PICM pacing upfront, given their high risk for the development of PICM, though the effectiveness and cost of this strategy require prospective study.

• At the very least, men with wider native QRS duration warrant closer clinical and echocardiographic follow-up.

• Finally, risk for PICM likely begins below the traditionally accepted cutoff of 40% pacing burden.