T-wave Alternans Testing in Pacemaker Patients

Comparison of Pacing Modes and Long-Term Prognostic Relevance

Marc Dorenkamp, M.D.; Christoph Breitwieser, M.D.; Andreas J. Morguet, M.D.; Joachim Seegers, M.D.; Steffen Behrens, M.D.; Markus Zabel, M.D.

Disclosures

Pacing Clin Electrophysiol. 2011;34(9):1054-1062.

Conclusion

TWA occurs frequently in pacemaker patients with preserved LV function. It is predictive of outcome but only if physiologic atrial pacing is used.

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There are no conflicts of interest.

Acknowledgments
This work was in part presented at the 31st Annual Scientific Sessions of the Heart Rhythm Society in Denver, Colorado, May 12–15, 2010.

Cite this: T-wave Alternans Testing in Pacemaker Patients - Medscape - Sep 01, 2011.

Table I. Clinical Characteristics of Patient Population
Age, years	68 ± 13
Male sex, n (%)	32 (51)
LV ejection fraction, %	61 ± 13
Pacemaker indication, n (%)
Sinus node dysfunction	33 (52)
2° AV block	27 (43)
Bifascicular block	3 (5)
% Atrial pacing (median [range])	5 (0–78)
% Ventricular pacing (median [range])	0 (0–28)
Heart diseases and risk factors, n (%)
Coronary artery disease	25 (40)
Prior myocardial infarction	11 (18)
Prior PCI/CABG	20 (32)
Dilated cardiomyopathy	8 (13)
Valvular heart disease	5 (8)
Hypertrophic cardiomyopathy	2 (3)
Hypertension	31 (49)
Diabetes mellitus	14 (22)
Medication use, n (%)
beta-blockers	23 (37)
ACE inhibitors/ARBs	38 (63)
Digoxin	13 (21)
Statins	18 (29)

ACE = angiotensin-converting enzyme; ARB = angiotensin-receptor blocker; AV = atrioventricular; CABG = coronary artery bypass grafting; LV = left ventricular; PCI = percutaneous coronary intervention.

Table II. Microvolt TWA Test Results
		Ventricular Pacing			Total
		Pos	Neg	Indet	Total
Atrial pacing	Pos	5	4	4	13
	Neg	4	14	9	27
	Indet	3	7	13	23
Total		12	25	26	63

Pos = positive; Neg = negative; Indet = indeterminate.

Table III. Grouped Microvolt TWA Test Results
		Ventricular Pacing
		Neg	Nonneg	Total
Atrial pacing	Neg	14	13	27
Atrial pacing	Nonneg	11	25	36
Total		25	38	63

Neg = negative; Nonneg = nonnegative.

Table IV. Clinical Characteristics during Atrial Pacing
	Nonnegative TWA Results	Negative TWA Results	P Value
Patients, n	36	27
Age, years	66 ± 14	69 ± 12	0.31
Male sex, n (%)	20 (56)	12 (44)	0.45
LV ejection fraction, %	56 ± 18	63 ± 15	0.10
Pacemaker indication, n (%)
Sinus node dysfunction	17 (47)	16 (59)	0.45
2° AV block	17 (47)	10 (37)	0.45
Bifascicular block	2 (6)	1 (4)	1.00
% Atrial pacing (median [range])	7 (0–78)	4 (0–37)	0.33
% Ventricular pacing (median [range])	0 (0–28)	0 (0–27)	0.25
Heart diseases and risk factors, n (%)
Coronary artery disease	15 (42)	10 (37)	0.80
Prior myocardial infarction	7 (19)	4 (15)	0.74
Prior PCI/CABG	10 (28)	10 (37)	0.59
Dilated cardiomyopathy	5 (14)	3 (11)	1.00
Valvular heart disease	3 (8)	2 (7)	1.00
Hypertrophic cardiomyopathy	1 (3)	1 (4)	1.00
Hypertension	20 (56)	11 (41)	0.31
Diabetes mellitus	9 (25)	5 (19)	0.76
Medication use, n (%)
β-blockers	13 (36)	10 (37)	1.00
ACE inhibitors/ARBs	25 (69)	13 (48)	0.12
Digoxin	10 (28)	3 (11)	0.12
Statins	9 (25)	9 (33)	0.58

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