Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias

Background Unlike T‐wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM. Methods and Results Prospe...

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Main Authors: Praloy Chakraborty, Adrian M. Suszko, Karthik Viswanathan, Kimia Sheikholeslami, Danna Spears, Arnon Adler, Anna Woo, Harry Rakowski, Vijay S. Chauhan
Format: Article
Language:English
Published: Wiley 2021-12-01
Series:Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease
Subjects:
Online Access:https://www.ahajournals.org/doi/10.1161/JAHA.121.022036
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author Praloy Chakraborty
Adrian M. Suszko
Karthik Viswanathan
Kimia Sheikholeslami
Danna Spears
Arnon Adler
Anna Woo
Harry Rakowski
Vijay S. Chauhan
author_facet Praloy Chakraborty
Adrian M. Suszko
Karthik Viswanathan
Kimia Sheikholeslami
Danna Spears
Arnon Adler
Anna Woo
Harry Rakowski
Vijay S. Chauhan
author_sort Praloy Chakraborty
collection DOAJ
description Background Unlike T‐wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM. Methods and Results Prospectively enrolled patients with HCM (n=130) with prophylactic implantable cardioverter‐defibrillators underwent digital 12‐lead ECG recordings during ventricular pacing (100–120 beats/min). QRSA/TWA was quantified using the spectral method. Patients were categorized as QRSA+ and/or TWA+ if sustained alternans was present in ≥2 precordial leads. The VA end point was appropriate implantable cardioverter‐defibrillator therapy over 5 years of follow‐up. QRSA+ and TWA+ occurred together in 28% of patients and alone in 7% and 7% of patients, respectively. QRSA magnitude increased with pacing rate (1.9±0.6 versus 6.2±2.0 µV; P=0.006). Left ventricular thickness was greater in QRSA+ than in QRSA− patients (22±7 versus 20±6 mm; P=0.035). Over 5 years follow‐up, 17% of patients had VA. The annual VA rate was greater in QRSA+ versus QRSA− patients (5.8% versus 2.0%; P=0.006), with the QRSA+/TWA− subgroup having the greatest rate (13.3% versus 2.6%; P<0.001). In those with <2 risk factors, QRSA− patients had a low annual VA rate compared QRSA+ patients (0.58% versus 7.1%; P=0.001). Separate Cox models revealed QRSA+ (hazard ratio [HR], 2.9 [95% CI, 1.2–7.0]; P=0.019) and QRSA+/TWA− (HR, 7.9 [95% CI, 2.9–21.7]; P<0.001) as the most significant VA predictors. TWA and HCM risk factors did not predict VA. Conclusions In HCM, microvolt QRSA is a novel, rate‐dependent phenomenon that can exist without TWA and is associated with greater left ventricular thickness. QRSA increases VA risk 3‐fold in all patients, whereas the absence of QRSA confers low VA risk in patients with <2 risk factors. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.
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spelling doaj.art-367c94e1476549b583486bd4b42a5c582023-01-26T10:36:40ZengWileyJournal of the American Heart Association: Cardiovascular and Cerebrovascular Disease2047-99802021-12-01102310.1161/JAHA.121.022036Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular ArrhythmiasPraloy Chakraborty0Adrian M. Suszko1Karthik Viswanathan2Kimia Sheikholeslami3Danna Spears4Arnon Adler5Anna Woo6Harry Rakowski7Vijay S. Chauhan8Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaDivision of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario CanadaBackground Unlike T‐wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM. Methods and Results Prospectively enrolled patients with HCM (n=130) with prophylactic implantable cardioverter‐defibrillators underwent digital 12‐lead ECG recordings during ventricular pacing (100–120 beats/min). QRSA/TWA was quantified using the spectral method. Patients were categorized as QRSA+ and/or TWA+ if sustained alternans was present in ≥2 precordial leads. The VA end point was appropriate implantable cardioverter‐defibrillator therapy over 5 years of follow‐up. QRSA+ and TWA+ occurred together in 28% of patients and alone in 7% and 7% of patients, respectively. QRSA magnitude increased with pacing rate (1.9±0.6 versus 6.2±2.0 µV; P=0.006). Left ventricular thickness was greater in QRSA+ than in QRSA− patients (22±7 versus 20±6 mm; P=0.035). Over 5 years follow‐up, 17% of patients had VA. The annual VA rate was greater in QRSA+ versus QRSA− patients (5.8% versus 2.0%; P=0.006), with the QRSA+/TWA− subgroup having the greatest rate (13.3% versus 2.6%; P<0.001). In those with <2 risk factors, QRSA− patients had a low annual VA rate compared QRSA+ patients (0.58% versus 7.1%; P=0.001). Separate Cox models revealed QRSA+ (hazard ratio [HR], 2.9 [95% CI, 1.2–7.0]; P=0.019) and QRSA+/TWA− (HR, 7.9 [95% CI, 2.9–21.7]; P<0.001) as the most significant VA predictors. TWA and HCM risk factors did not predict VA. Conclusions In HCM, microvolt QRSA is a novel, rate‐dependent phenomenon that can exist without TWA and is associated with greater left ventricular thickness. QRSA increases VA risk 3‐fold in all patients, whereas the absence of QRSA confers low VA risk in patients with <2 risk factors. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.https://www.ahajournals.org/doi/10.1161/JAHA.121.022036alternansECGhypertrophic cardiomyopathyrisk assessmentventricular arrhythmia
spellingShingle Praloy Chakraborty
Adrian M. Suszko
Karthik Viswanathan
Kimia Sheikholeslami
Danna Spears
Arnon Adler
Anna Woo
Harry Rakowski
Vijay S. Chauhan
Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias
Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease
alternans
ECG
hypertrophic cardiomyopathy
risk assessment
ventricular arrhythmia
title Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias
title_full Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias
title_fullStr Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias
title_full_unstemmed Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias
title_short Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias
title_sort microvolt qrs alternans in hypertrophic cardiomyopathy a novel risk marker of late ventricular arrhythmias
topic alternans
ECG
hypertrophic cardiomyopathy
risk assessment
ventricular arrhythmia
url https://www.ahajournals.org/doi/10.1161/JAHA.121.022036
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