D i a g n o s t i c Too l s f o r Arrhythmia Detection in Adults with Congenital Heart Disease a n d H e a r t F a i l u re Blandine Mondésert, MDa, Anne M. Dubin, MDb, Paul Khairy, MD, PhDa,* KEYWORDS Arrhythmias Electrophysiology Heart failure Adult congenital heart disease Diagnostic testing
KEY POINTS Heart failure and arrhythmias are among the leading causes of morbidity and mortality in adults with congenital heart disease (CHD). The standard 12-lead electrocardiogram (ECG) remains the cornerstone for arrhythmia diagnosis and provides valuable information with regard to associated hemodynamic lesions and prognostic markers for sudden cardiac death. External loop recorders are helpful in diagnosing patients with suspected arrhythmias and monitoring those with known arrhythmias, and may be of value in routinely screening certain subpopulations, such as adults with tetralogy of Fallot. The prognostic value of signal-averaged ECG, heart rate variability, and microvolt T-wave alternans remain to be defined in adults with CHD and heart failure. Pacemakers and implantable cardioverter-defibrillators are equipped with a variety of features that may be helpful in diagnosing and quantifying arrhythmias, including data trends, stored intracardiac electrograms, and responses to antitachycardia pacing therapy.
Progressively declining mortalities across the spectrum of cardiac birth defects are resulting in a growing and aging population of adults with congenital heart disease (CHD) of increasing complexity.1 Heart failure and arrhythmias are among the leading causes of morbidity and mortality in this patient population, with a relationship that is bidirectional.2–4 Heart failure can result in structural and electrophysiologic changes that alter the
expression and function of a variety of membrane transport processes, thereby favoring arrhythmias.5 In contrast, factors that predispose adults with CHD to arrhythmias, such as pressure or volume overload, hypoxemia, fibrosis, and surgical scars, may likewise be implicated in the pathophysiology of heart failure. Moreover, the well-recognized phenomenon of tachyarrhythmia-induced cardiomyopathy may be accentuated in patients with CHD and fragile physiologies, such as those with cyanosis, systemic right ventricles, or univentricular hearts.6,7
Financial Support: Dr P. Khairy is supported by a Canada Research Chair in Electrophysiology and Adult Congenital Heart Disease. Conflict of Interest: Dr P. Khairy has received research funding for investigator-initiated grants from St. Jude Medical, Medtronic, and Boehringer-Ingelheim. a Adult Congenital Center, Montreal Heart Institute, Universite´ de Montre´al, 5000 Be´langer Street East, Montreal, Que´bec H1T 1C8, Canada; b Department of Pediatric Cardiology, Lucile Packard Children’s Hospital, Stanford University, 725 Welch Road, Suite 120, Palo Alto, CA 94304, USA * Corresponding author. E-mail address: [email protected] Heart Failure Clin 10 (2014) 57–67 http://dx.doi.org/10.1016/j.hfc.2013.09.009 1551-7136/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
heartfailure.theclinics.com
INTRODUCTION
58
Monde´sert et al Given the high prevalence and potentially distressing consequences of arrhythmias in adults with CHD and heart failure, promptly recognizing rhythm disorders is an essential component of surveillance and follow-up.8,9 This article discusses and appraises the electrophysiologic tools, both invasive and noninvasive, that are of potential diagnostic or prognostic value in adults with CHD and heart failure.
NONINVASIVE ELECTROPHYSIOLOGIC TOOLS The 12-lead Electrocardiogram The standard 12-lead electrocardiogram (ECG) is an indispensable tool for assessing adults with CHD and heart failure. It is critical in characterizing a broad spectrum of bradyarrhythmias and tachyarrhythmias, providing diagnostic clues in patients with previously undetected CHD (Fig. 1), and screening for associated hemodynamic complications, such as obstructive lesions. Typical ECG features in adults with common forms of CHD are summarized in Table 1.10 Moreover, the ECG can provide important prognostic information.11–13 A wider QRS complex has been associated with increased risk of heart failure and sudden death in various congenital and noncongenital forms of heart disease. A QRS duration greater than 180 milliseconds is often retained in proposed risk stratification schemes for sudden death in patients with tetralogy of Fallot.11,12,14,15 Correlations have also been described, albeit less consistently, between QRS duration and ventricular arrhythmias/sudden death in patients with complete transposition of the great arteries and
intra-atrial baffles.13 In this patient population, associations have been reported between diastolic and systolic right ventricular volumes, N-terminal pro brain natriuretic peptide levels, and QRS duration.16 In patients with Fontan surgery, QRS duration has been independently associated with peak oxygen capacity in multivariate analyses.17 Associations between QT interval prolongation and increased mortality have also been described in diverse populations.18,19 However, QRS duration and QT intervals are highly correlated, with the QRS complex constituting a sizable segment of the QT interval. As such, QT and JT dispersion, which quantify the difference between the longest and shortest respective intervals on a 12-lead ECG, are considered by some to more accurately reflect dispersion of repolarization. In patients with tetralogy of Fallot, the combination of prolonged QRS duration and increased QT20 or JT dispersion21 seems to more accurately predict ventricular arrhythmias than QRS duration alone.
External Loop Recorders The value of routine serial ambulatory ECG monitoring (eg, 24-hour Holter recordings) remains debated in patients with CHD at large. Nevertheless, external loop recorders are generally considered helpful in evaluating patients with symptoms suggestive of arrhythmia (eg, palpitations, syncope), monitoring those with known arrhythmias (eg, sick sinus syndrome, paroxysmal atrial tachyarrhythmia), and assessing responses to therapy (eg, rate control in patients with permanent atrial tachyarrhythmias). Considering the high
Fig. 1. Twelve-lead ECG. A 12-lead ECG was performed in a 38-year-old man with no known CHD who complained of dyspnea on exertion. Q waves over the right precordial lead (V1), absent septal q waves in V5 and V6, and abnormal Q waves in lead III suggest a diagnosis of congenitally corrected transposition of the great arteries with right-to-left septal depolarization. Complete atrioventricular block is noted.
Diagnostic Tools for Arrhythmia Detection prevalence of supraventricular and ventricular arrhythmias in adults with CHD and heart failure, external loop recorders are among the commonly prescribed diagnostic tools for arrhythmia detection. In a recent retrospective study of adults with CHD, the prevalence of detected arrhythmias was 2-fold higher by Holter monitors than standard ECGs (31% vs 15%).22 Arrhythmias consisted of isolated ectopy in 17%, supraventricular tachycardia in 12%, ventricular tachycardia in 7%, high-grade atrioventricular block in 5%, and pacemaker issues in 3%. A quarter of the patients with arrhythmias detected by Holter had no arrhythmias on ECG and 80% of patients with detected arrhythmias were asymptomatic. In symptomatic patients, 37% experienced similar symptoms during Holter monitoring, allowing a diagnosis to be established. A second series assessed Holter monitor results in 189 patients with tetralogy of Fallot (N 5 100), Fontan surgery (N 5 51), or transposition of the great arteries with atrial baffles (N 5 38).23 The test was considered clinically significant if it prompted a change in therapy. Using this definition, the investigators reported a modest (40%) sensitivity for routine monitoring and a high (96%) negative predictive value for future clinically significant arrhythmias. Relevant to adults with CHD, the diagnostic yield improved with older age.
Signal-averaged ECG A signal-averaged ECG (SAECG) uses computerbased processing techniques to produce a highresolution ECG capable of recording microvolt signals noninvasively from surface leads. Random noise that is not synchronized to the QRS complex is canceled out and smaller signals, such as ventricular late potentials, are retained. Such late potentials are thought to arise from areas of slow conduction around scar and are, therefore, considered to indicate an electrophysiologic substrate capable of sustaining potentially malignant reentrant ventricular tachyarrhythmias. Common parameters studied include the duration of the filtered QRS complex, duration of the terminal QRS complex less than 40 mV, and the rootmean-square amplitude of the terminal 40 milliseconds of the QRS complex (Fig. 2). Late potentials were identified in 62% of 242 patients with CHD and ventriculotomy incisions.24 Except for a scalar QRS duration greater than 180 milliseconds, no correlation was found between positive SAECG findings and risk factors for ventricular tachycardia. A series of 66 patients with tetralogy of Fallot consistently reported that a filtered QRS duration greater than 170 milliseconds
was associated with sustained ventricular tachycardia.25 In contrast, a study of 31 patients with right ventriculotomy incisions or postrepair right bundle branch block found that a low-amplitude terminal root-mean-square voltage of 100 mV or less had 91% sensitivity and 70% specificity in predicting inducible sustained or nonsustained ventricular tachycardia.26 Similar sensitivity but lower specificity was seen with QRS duration. The predictive value of a terminal low-amplitude QRS signal duration was weaker still. Moreover, the SAECG could not distinguish between sustained and nonsustained forms of inducible ventricular tachycardia. Given the lingering uncertainties regarding potential indications and their independent prognostic value, the SAECG is not yet considered a mainstream prognostic tool for adults with CHD.
Heart Rate Variability The autonomic nervous system plays an important role in the pathophysiology of heart failure. Several markers of sympathovagal imbalances, as assessed by such tests as heart rate turbulence, baroreflex sensitivity, and heart rate variability (HRV), have been associated with adverse outcomes in patients with heart failure. Heart rate variability refers to beat-to-beat variations in heart rate, or the R-R interval.27 In healthy individuals, R-R intervals vary with the respiratory cycle by shortening during inspiration and prolonging on expiration. Because these fluctuations are predominantly mediated by parasympathetic efferent activity, reduced HRV has primarily been attributed to a reduction in vagal tone. In a series of 258 children with CHD, HRV was reduced in those with New York Heart Association (NYHA) functional class II to IV symptoms but was not associated with hemodynamic parameters.28 Reductions in HRV span the spectrum of cyanotic and acyanotic forms of CHD.29 One study found that HRV was reduced in children with CHD before surgery and declined after surgery, with marked impairment in patients with prolonged postoperative hospitalizations.30 In the largest series to date of 383 postoperative patients with CHD, including 91 with Fontan surgery, impaired HRV predicted a combined end point consisting of hospitalizations and mortality in those with biventricular but not univentricular physiology.31 Given the limited data, the role of HRV in risk stratifying adults with CHD and heart failure remains to be defined. Simpler methods that rely on 3 consecutive 12-lead 10-second ECGs have been proposed,32 which may facilitate more widespread adoption if such information proves valuable in risk stratifying this patient population.
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Table 1 Typical ECG features in common forms of adult CHD Congenital Diagnosis
Rhythm
PR Interval
QRS Axis
Atrial QRS Configuration Enlargement
Ventricular Hypertrophy
Particularities
Secundum NSR; [IART/AF atrial septal with age defect Ventricular NSR; PVCs septal defect
0 –180 ; RAD; LAD rSr’ or rsR’ with in Holt-Oran or RBBBi>RBBBc LAHB Normal or mild [; RAD with BVH; LAD Normal or rsr’; 1 AVB 10% 3%–15% possible RBBB
RAE 35%
Uncommon
Crochetage pattern
Possible RAE LAE
Katz-Wachtel phenomenon
AV canal defect
NSR; PVCs 30%
1 AVB >50%
Mod to extreme rSr’ or rsR’ LAD; Normal with atypical
Possible LAE
Patent ductus arteriosus
NSR; [IART/AF with age
[PR 10%–20%
Normal
Pulmonary stenosis
NSR
Normal
Aortic coarctation Ebstein anomaly
NSR
Normal
Normal if mild; RAD Normal; severity with moderate/ severe Normal or LAD Normal
LAE with moderate PDA Possible RAE
BVH 23%–61%; RVH with Eisenmenger Uncommon in partial; BVH in complete; RVH with Eisenmenger Uncommon
NSR; possible EAR, SVT; AF/IART 40% Surgically NSR; PVCs; IART repaired TOF 10%; VT 12%
1 AVB 6%–19%
1 AVB common; short if WPW Normal or mild [
Normal or LAD
Deep S V1, tall R V5 and V6
Low-amplitude multiphasic atypical RBBB Normal or RAD; LAD RBBB 90% 5%–10%
Infero-posteriorly displaced AVN
Often either clinically silent or Eisenmenger RVH; Severity Axis deviation correlates with correlates with R:S in V1 and V6 RVP Possible LAE LVH, especially by Persistent RVH rare voltage criteria beyond infancy RAE with Diminutive RV Accessory pathway Himalayan common; Q II, III, P waves aVF and V1–V4 Peaked P RVH possible if QRS duration waves; RAE RVOT QTd predicts possible obstruction or VT/SCD PHT
L-TGA
NSR
D-TGA/intraatrial baffle
UVH with Fontan
Dextrocardia
LAD
Absence Not if no septal q; Q in III, associated aVF and right defects precordium
Not if no associated defects
Sinus Normal bradycardia 60%; EAR; junctional; IART 25% Sinus Normal in TA; 1 AVB in DILV bradycardia 15%; EAR; junctional; IART >50% NSR; P-wave axis Normal 105 –165 with situs inversus
RAD
Absence of q, Possible RAE small r, deep S in left precordium
RVH; diminutive LV
NSR
Possible LAD
Normal
LAD in single RV, Variable; [[ R and RAE in TA TA, single LV with S amplitudes in noninverted limb and outlet precordial leads RAD
Inverse depolarization and repolarization
Anterior AVN; positive T precordial; WPW with Ebstein Possible AVB if VSD or TV surgery
RVH with single Absent sinus node RV; possible LVH in LAI; AV block with single LV with L-loop or AVCD
Not with situs LVH: tall R V1–V2; inversus RVH: deep Q, small R V1 and tall R right lateral Pathologic Possible LAE Selective ant-lat Q waves; hypertrophy of possible ant-sept posterobasal LV Q waves
Situs solitus: normal P-wave axis and severe CHD Possible ischemia
Abbreviations: AF, atrial fibrillation; ALCAPA, anomalous left coronary artery from the pulmonary artery; ant-lat, anterolateral; ant-sept, anteroseptal; AV, atrioventricular; AVB, atrioventricular block; AVCD, atrioventricular canal defect; AVN, AV node; BVH, biventricular hypertrophy; CHD, congenital heart disease; DILV, double inlet left ventricle; DTGA, complete transposition of the great arteries; EAR, ectopic atrial rhythm; IART, intra-atrial reentrant tachycardia; LAD, left axis deviation; LAE, left atrial enlargement; LAHB, left anterior hemiblock; LAI, left atrial isomerism; L-TGA, congenitally corrected transposition of the great arteries; LV, left ventricle; LVH, left ventricular hypertrophy; NSR, normal sinus rhythm; PDA, patent ductus arteriosus; PHT, pulmonary hypertension; PVC, premature ventricular contraction; QTd, QT dispersion; RAD, right axis deviation; RAE, right atrial enlargement; RBBB, right bundle branch block (i, incomplete; c, complete); RV, right ventricle; RVH, right ventricular hypertrophy; RVOT, right ventricular outflow tract; RVP, right ventricular pressure; SCD, sudden cardiac death; SVT, supraventricular tachycardia; TA, tricuspid atresia; TOF, tetralogy of Fallot; TV, tricuspid valve; UVH, univentricular heart; VSD, ventricular septal defect; VT, ventricular tachycardia; WPW, Wolff-Parkinson-White syndrome. From Khairy P, Marelli AJ. Clinical use of electrocardiography in adults with congenital heart disease. Circulation 2007;116(23):2735; with permission.
Diagnostic Tools for Arrhythmia Detection
ALCAPA
1 AVB >50%; AVB 2%/y
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Fig. 2. (A) Normal SAECG tracing with a filtered QRS duration of 93 milliseconds (normal 20 mV), and a filtered QRS duration less than 40 mV of 28 milliseconds (normal
KEY POINTS Heart failure and arrhythmias are among the leading causes of morbidity and mortality in adults with congenital heart disease (CHD). The standard 12-lead electrocardiogram (ECG) remains the cornerstone for arrhythmia diagnosis and provides valuable information with regard to associated hemodynamic lesions and prognostic markers for sudden cardiac death. External loop recorders are helpful in diagnosing patients with suspected arrhythmias and monitoring those with known arrhythmias, and may be of value in routinely screening certain subpopulations, such as adults with tetralogy of Fallot. The prognostic value of signal-averaged ECG, heart rate variability, and microvolt T-wave alternans remain to be defined in adults with CHD and heart failure. Pacemakers and implantable cardioverter-defibrillators are equipped with a variety of features that may be helpful in diagnosing and quantifying arrhythmias, including data trends, stored intracardiac electrograms, and responses to antitachycardia pacing therapy.
Progressively declining mortalities across the spectrum of cardiac birth defects are resulting in a growing and aging population of adults with congenital heart disease (CHD) of increasing complexity.1 Heart failure and arrhythmias are among the leading causes of morbidity and mortality in this patient population, with a relationship that is bidirectional.2–4 Heart failure can result in structural and electrophysiologic changes that alter the
expression and function of a variety of membrane transport processes, thereby favoring arrhythmias.5 In contrast, factors that predispose adults with CHD to arrhythmias, such as pressure or volume overload, hypoxemia, fibrosis, and surgical scars, may likewise be implicated in the pathophysiology of heart failure. Moreover, the well-recognized phenomenon of tachyarrhythmia-induced cardiomyopathy may be accentuated in patients with CHD and fragile physiologies, such as those with cyanosis, systemic right ventricles, or univentricular hearts.6,7
Financial Support: Dr P. Khairy is supported by a Canada Research Chair in Electrophysiology and Adult Congenital Heart Disease. Conflict of Interest: Dr P. Khairy has received research funding for investigator-initiated grants from St. Jude Medical, Medtronic, and Boehringer-Ingelheim. a Adult Congenital Center, Montreal Heart Institute, Universite´ de Montre´al, 5000 Be´langer Street East, Montreal, Que´bec H1T 1C8, Canada; b Department of Pediatric Cardiology, Lucile Packard Children’s Hospital, Stanford University, 725 Welch Road, Suite 120, Palo Alto, CA 94304, USA * Corresponding author. E-mail address: [email protected] Heart Failure Clin 10 (2014) 57–67 http://dx.doi.org/10.1016/j.hfc.2013.09.009 1551-7136/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
heartfailure.theclinics.com
INTRODUCTION
58
Monde´sert et al Given the high prevalence and potentially distressing consequences of arrhythmias in adults with CHD and heart failure, promptly recognizing rhythm disorders is an essential component of surveillance and follow-up.8,9 This article discusses and appraises the electrophysiologic tools, both invasive and noninvasive, that are of potential diagnostic or prognostic value in adults with CHD and heart failure.
NONINVASIVE ELECTROPHYSIOLOGIC TOOLS The 12-lead Electrocardiogram The standard 12-lead electrocardiogram (ECG) is an indispensable tool for assessing adults with CHD and heart failure. It is critical in characterizing a broad spectrum of bradyarrhythmias and tachyarrhythmias, providing diagnostic clues in patients with previously undetected CHD (Fig. 1), and screening for associated hemodynamic complications, such as obstructive lesions. Typical ECG features in adults with common forms of CHD are summarized in Table 1.10 Moreover, the ECG can provide important prognostic information.11–13 A wider QRS complex has been associated with increased risk of heart failure and sudden death in various congenital and noncongenital forms of heart disease. A QRS duration greater than 180 milliseconds is often retained in proposed risk stratification schemes for sudden death in patients with tetralogy of Fallot.11,12,14,15 Correlations have also been described, albeit less consistently, between QRS duration and ventricular arrhythmias/sudden death in patients with complete transposition of the great arteries and
intra-atrial baffles.13 In this patient population, associations have been reported between diastolic and systolic right ventricular volumes, N-terminal pro brain natriuretic peptide levels, and QRS duration.16 In patients with Fontan surgery, QRS duration has been independently associated with peak oxygen capacity in multivariate analyses.17 Associations between QT interval prolongation and increased mortality have also been described in diverse populations.18,19 However, QRS duration and QT intervals are highly correlated, with the QRS complex constituting a sizable segment of the QT interval. As such, QT and JT dispersion, which quantify the difference between the longest and shortest respective intervals on a 12-lead ECG, are considered by some to more accurately reflect dispersion of repolarization. In patients with tetralogy of Fallot, the combination of prolonged QRS duration and increased QT20 or JT dispersion21 seems to more accurately predict ventricular arrhythmias than QRS duration alone.
External Loop Recorders The value of routine serial ambulatory ECG monitoring (eg, 24-hour Holter recordings) remains debated in patients with CHD at large. Nevertheless, external loop recorders are generally considered helpful in evaluating patients with symptoms suggestive of arrhythmia (eg, palpitations, syncope), monitoring those with known arrhythmias (eg, sick sinus syndrome, paroxysmal atrial tachyarrhythmia), and assessing responses to therapy (eg, rate control in patients with permanent atrial tachyarrhythmias). Considering the high
Fig. 1. Twelve-lead ECG. A 12-lead ECG was performed in a 38-year-old man with no known CHD who complained of dyspnea on exertion. Q waves over the right precordial lead (V1), absent septal q waves in V5 and V6, and abnormal Q waves in lead III suggest a diagnosis of congenitally corrected transposition of the great arteries with right-to-left septal depolarization. Complete atrioventricular block is noted.
Diagnostic Tools for Arrhythmia Detection prevalence of supraventricular and ventricular arrhythmias in adults with CHD and heart failure, external loop recorders are among the commonly prescribed diagnostic tools for arrhythmia detection. In a recent retrospective study of adults with CHD, the prevalence of detected arrhythmias was 2-fold higher by Holter monitors than standard ECGs (31% vs 15%).22 Arrhythmias consisted of isolated ectopy in 17%, supraventricular tachycardia in 12%, ventricular tachycardia in 7%, high-grade atrioventricular block in 5%, and pacemaker issues in 3%. A quarter of the patients with arrhythmias detected by Holter had no arrhythmias on ECG and 80% of patients with detected arrhythmias were asymptomatic. In symptomatic patients, 37% experienced similar symptoms during Holter monitoring, allowing a diagnosis to be established. A second series assessed Holter monitor results in 189 patients with tetralogy of Fallot (N 5 100), Fontan surgery (N 5 51), or transposition of the great arteries with atrial baffles (N 5 38).23 The test was considered clinically significant if it prompted a change in therapy. Using this definition, the investigators reported a modest (40%) sensitivity for routine monitoring and a high (96%) negative predictive value for future clinically significant arrhythmias. Relevant to adults with CHD, the diagnostic yield improved with older age.
Signal-averaged ECG A signal-averaged ECG (SAECG) uses computerbased processing techniques to produce a highresolution ECG capable of recording microvolt signals noninvasively from surface leads. Random noise that is not synchronized to the QRS complex is canceled out and smaller signals, such as ventricular late potentials, are retained. Such late potentials are thought to arise from areas of slow conduction around scar and are, therefore, considered to indicate an electrophysiologic substrate capable of sustaining potentially malignant reentrant ventricular tachyarrhythmias. Common parameters studied include the duration of the filtered QRS complex, duration of the terminal QRS complex less than 40 mV, and the rootmean-square amplitude of the terminal 40 milliseconds of the QRS complex (Fig. 2). Late potentials were identified in 62% of 242 patients with CHD and ventriculotomy incisions.24 Except for a scalar QRS duration greater than 180 milliseconds, no correlation was found between positive SAECG findings and risk factors for ventricular tachycardia. A series of 66 patients with tetralogy of Fallot consistently reported that a filtered QRS duration greater than 170 milliseconds
was associated with sustained ventricular tachycardia.25 In contrast, a study of 31 patients with right ventriculotomy incisions or postrepair right bundle branch block found that a low-amplitude terminal root-mean-square voltage of 100 mV or less had 91% sensitivity and 70% specificity in predicting inducible sustained or nonsustained ventricular tachycardia.26 Similar sensitivity but lower specificity was seen with QRS duration. The predictive value of a terminal low-amplitude QRS signal duration was weaker still. Moreover, the SAECG could not distinguish between sustained and nonsustained forms of inducible ventricular tachycardia. Given the lingering uncertainties regarding potential indications and their independent prognostic value, the SAECG is not yet considered a mainstream prognostic tool for adults with CHD.
Heart Rate Variability The autonomic nervous system plays an important role in the pathophysiology of heart failure. Several markers of sympathovagal imbalances, as assessed by such tests as heart rate turbulence, baroreflex sensitivity, and heart rate variability (HRV), have been associated with adverse outcomes in patients with heart failure. Heart rate variability refers to beat-to-beat variations in heart rate, or the R-R interval.27 In healthy individuals, R-R intervals vary with the respiratory cycle by shortening during inspiration and prolonging on expiration. Because these fluctuations are predominantly mediated by parasympathetic efferent activity, reduced HRV has primarily been attributed to a reduction in vagal tone. In a series of 258 children with CHD, HRV was reduced in those with New York Heart Association (NYHA) functional class II to IV symptoms but was not associated with hemodynamic parameters.28 Reductions in HRV span the spectrum of cyanotic and acyanotic forms of CHD.29 One study found that HRV was reduced in children with CHD before surgery and declined after surgery, with marked impairment in patients with prolonged postoperative hospitalizations.30 In the largest series to date of 383 postoperative patients with CHD, including 91 with Fontan surgery, impaired HRV predicted a combined end point consisting of hospitalizations and mortality in those with biventricular but not univentricular physiology.31 Given the limited data, the role of HRV in risk stratifying adults with CHD and heart failure remains to be defined. Simpler methods that rely on 3 consecutive 12-lead 10-second ECGs have been proposed,32 which may facilitate more widespread adoption if such information proves valuable in risk stratifying this patient population.
59
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Table 1 Typical ECG features in common forms of adult CHD Congenital Diagnosis
Rhythm
PR Interval
QRS Axis
Atrial QRS Configuration Enlargement
Ventricular Hypertrophy
Particularities
Secundum NSR; [IART/AF atrial septal with age defect Ventricular NSR; PVCs septal defect
0 –180 ; RAD; LAD rSr’ or rsR’ with in Holt-Oran or RBBBi>RBBBc LAHB Normal or mild [; RAD with BVH; LAD Normal or rsr’; 1 AVB 10% 3%–15% possible RBBB
RAE 35%
Uncommon
Crochetage pattern
Possible RAE LAE
Katz-Wachtel phenomenon
AV canal defect
NSR; PVCs 30%
1 AVB >50%
Mod to extreme rSr’ or rsR’ LAD; Normal with atypical
Possible LAE
Patent ductus arteriosus
NSR; [IART/AF with age
[PR 10%–20%
Normal
Pulmonary stenosis
NSR
Normal
Aortic coarctation Ebstein anomaly
NSR
Normal
Normal if mild; RAD Normal; severity with moderate/ severe Normal or LAD Normal
LAE with moderate PDA Possible RAE
BVH 23%–61%; RVH with Eisenmenger Uncommon in partial; BVH in complete; RVH with Eisenmenger Uncommon
NSR; possible EAR, SVT; AF/IART 40% Surgically NSR; PVCs; IART repaired TOF 10%; VT 12%
1 AVB 6%–19%
1 AVB common; short if WPW Normal or mild [
Normal or LAD
Deep S V1, tall R V5 and V6
Low-amplitude multiphasic atypical RBBB Normal or RAD; LAD RBBB 90% 5%–10%
Infero-posteriorly displaced AVN
Often either clinically silent or Eisenmenger RVH; Severity Axis deviation correlates with correlates with R:S in V1 and V6 RVP Possible LAE LVH, especially by Persistent RVH rare voltage criteria beyond infancy RAE with Diminutive RV Accessory pathway Himalayan common; Q II, III, P waves aVF and V1–V4 Peaked P RVH possible if QRS duration waves; RAE RVOT QTd predicts possible obstruction or VT/SCD PHT
L-TGA
NSR
D-TGA/intraatrial baffle
UVH with Fontan
Dextrocardia
LAD
Absence Not if no septal q; Q in III, associated aVF and right defects precordium
Not if no associated defects
Sinus Normal bradycardia 60%; EAR; junctional; IART 25% Sinus Normal in TA; 1 AVB in DILV bradycardia 15%; EAR; junctional; IART >50% NSR; P-wave axis Normal 105 –165 with situs inversus
RAD
Absence of q, Possible RAE small r, deep S in left precordium
RVH; diminutive LV
NSR
Possible LAD
Normal
LAD in single RV, Variable; [[ R and RAE in TA TA, single LV with S amplitudes in noninverted limb and outlet precordial leads RAD
Inverse depolarization and repolarization
Anterior AVN; positive T precordial; WPW with Ebstein Possible AVB if VSD or TV surgery
RVH with single Absent sinus node RV; possible LVH in LAI; AV block with single LV with L-loop or AVCD
Not with situs LVH: tall R V1–V2; inversus RVH: deep Q, small R V1 and tall R right lateral Pathologic Possible LAE Selective ant-lat Q waves; hypertrophy of possible ant-sept posterobasal LV Q waves
Situs solitus: normal P-wave axis and severe CHD Possible ischemia
Abbreviations: AF, atrial fibrillation; ALCAPA, anomalous left coronary artery from the pulmonary artery; ant-lat, anterolateral; ant-sept, anteroseptal; AV, atrioventricular; AVB, atrioventricular block; AVCD, atrioventricular canal defect; AVN, AV node; BVH, biventricular hypertrophy; CHD, congenital heart disease; DILV, double inlet left ventricle; DTGA, complete transposition of the great arteries; EAR, ectopic atrial rhythm; IART, intra-atrial reentrant tachycardia; LAD, left axis deviation; LAE, left atrial enlargement; LAHB, left anterior hemiblock; LAI, left atrial isomerism; L-TGA, congenitally corrected transposition of the great arteries; LV, left ventricle; LVH, left ventricular hypertrophy; NSR, normal sinus rhythm; PDA, patent ductus arteriosus; PHT, pulmonary hypertension; PVC, premature ventricular contraction; QTd, QT dispersion; RAD, right axis deviation; RAE, right atrial enlargement; RBBB, right bundle branch block (i, incomplete; c, complete); RV, right ventricle; RVH, right ventricular hypertrophy; RVOT, right ventricular outflow tract; RVP, right ventricular pressure; SCD, sudden cardiac death; SVT, supraventricular tachycardia; TA, tricuspid atresia; TOF, tetralogy of Fallot; TV, tricuspid valve; UVH, univentricular heart; VSD, ventricular septal defect; VT, ventricular tachycardia; WPW, Wolff-Parkinson-White syndrome. From Khairy P, Marelli AJ. Clinical use of electrocardiography in adults with congenital heart disease. Circulation 2007;116(23):2735; with permission.
Diagnostic Tools for Arrhythmia Detection
ALCAPA
1 AVB >50%; AVB 2%/y
61
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Fig. 2. (A) Normal SAECG tracing with a filtered QRS duration of 93 milliseconds (normal 20 mV), and a filtered QRS duration less than 40 mV of 28 milliseconds (normal
