Clinical Review

4 EKG Abnormalities: What Are the Lifesaving Diagnoses?

Clinician Reviews. 2014 July;24(7):368-375

References

1. Taggart NW, Haglund CM, Tester DJ, et al. Diagnostic miscues in congenital long-QT syndrome. Circulation. 2007;115:2613-2620.

2. Schwartz PJ, Stramba-Badiale M, Crotti L, et al. Prevalance of the congenital long QT syndrome. Circulation. 2009;120:1761-1767.

3. van Noord C, Eijgelsheim M, Stricker BH. Drug- and nondrug-associated QT interval prolongation. Br J Clin Pharmacol. 2010;70:16-23.

4. Credible Meds Web site. Available at: http://crediblemeds.org. Accessed April 8, 2014.

5. Schwartz PJ, Priori SG, Spazzolini C, et al. Genotype-phenotype correlation in the long QT syndrome: gene specific triggers for life threatening arrhythmias. Circulation. 2001;103:89.

6. Chiladakis JK, Kalogeropoulos A, Koutsogiannis N, et al. Optimal QT/JT interval assessment in patients with complete bundle branch block. Ann Noninvasive Electrocardiol. 2012;17:268-276.

7. Ercan S, Altunbas G, Oylumlu M, et al. Congenital long QT syndrome masked by atrial fibrillation and unmasked by hypokalemia. Am J Emerg Med. 2013;31:451.e3-451.e6.

8. Goldenberg I, Moss AJ, Zareba W. QT interval: how to measure it and what is “normal.” J Cardiovasc Electrophysiol. 2006;17:333-336.

9. Podrid PJ. ECG Response: August 20, 2013. Circulation. 2013;128:869.

10. Olde Nordkamp LR, Wilde AA, Tijssen JG, et al. The ICD for primary prevention in patients with inherited cardiac diseases: indications, use, and outcome: a comparison with secondary prevention. Circ Arrhythm Electrophysiol. 2013;6:91-100.

11. Schwartz PJ. Pharmacological and non-pharmacological management of the congenital long QT syndrome: the rationale. Pharmacol Ther. 2011;131:171-177.

12. Berne P, Brugada J. Brugada syndrome 2012. Circ J. 2012;76:1563-1571.

13. Brugada P, Brugada J. Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a distinct clinical and electrocardiographic syndrome. A multicenter report. J Am Coll Cardiol. 1992;20:1391-1396.

14. Antzelevitch C, Brugada P, Borggrefe M, et al. Brugada syndrome: report of the second consensus conference: endorsed by the Heart Rhythm Society and the European Heart Rhythm Association. Circulation. 2005;111:659-670.

15. Brugada J, Brugada R, Antzelevitch C, et al. Long-term followup of individuals with the electrocardiographic pattern of right bundle-branch block and ST-segment elevation in precordial leads V1 to V3. Circulation. 2002;105:73-78.

16. Eckardt L, Probst V, Smits JP, et al. Long-term prognosis of individuals with right precordial ST-segment-elevation Brugada syndrome. Circulation. 2005;111:257-263.

17. Giustetto C, Drago S, Demarchi PG, et al; Italian Association of Arrhythmology and Cardiostimulation (AIAC)-Piedmont Section. Risk stratification of the patients with Brugada type electrocardiogram: a community-based prospective study. Europace. 2009;11:507-513.

18. Probst V, Veltmann C, Eckardt L, et al. Long-term prognosis of patients diagnosed with Brugada syndrome: Results from the FINGER Brugada Syndrome Registry. Circulation. 2010;121:635-643.

19. Nielsen MW, Holst AG, Olesen SP, et al. The genetic component of Brugada syndrome. Front Physiol. 2013;4:179.

20. Bayés de Luna A, Brugada J, Baranchuk A, et al. Current electrocardiographic criteria for diagnosis of Brugada pattern: a consensus report. J Electrocardiol. 2012;45:433-442.

21. Veltmann C, Schimpf R, Echternach C, et al. A prospective study on spontaneous fluctuations between diagnostic and non-diagnostic ECGs in Brugada syndrome: implications for correct phenotyping and risk stratification. Eur Heart J. 2006;27:2544-2552.

22. Sacher F, Probst V, Maury P, et al. Outcome after implantation of a cardioverter-defibrillator in patients with Brugada syndrome: a multicenter study-part 2. Circulation. 2013;128:1739-1747.

23. Rosner MH, Brady WJ Jr, Kefer MP, et al. Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues. Am J Emerg Med. 1999;17:705-714.

24. Keating L, Morris FP, Brady WJ. Electrocardiographic features of Wolff-Parkinson-White syndrome. Emerg Med J. 2003;20:491-493.

25. Blomström-Lundqvist C, Scheinman MM, Aliot EM, et al; European Society of Cardiology Committee, NASPE-Heart Rhythm Society. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias—executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) developed in collaboration with NASPE-Heart Rhythm Society. J Am Coll Cardiol. 2003;42:1493-1531.

26. Ho CY. Hypertrophic cardiomyopathy in 2012. Circulation. 2012;125:1432-1438.

27. Gersh BJ, Maron BJ, Bonow RO, et al; American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines; American Association for Thoracic Surgery; American Society of Echocardiography; American Society of Nuclear Cardiology; Heart Failure Society of America; Heart Rhythm Society; Society for Cardiovascular Angiography and Interventions; Society of Thoracic Surgeons. 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2011;124:e783-e831.

28. Paterick TE, Jan MF, Paterick ZR, et al. Cardiac evaluation of collegiate student athletes: a medical and legal perspective. Am J Med. 2012;125:742-752.

29. Maron BJ. Hypertrophic cardiomyopathy. In: Bonow RO, Mann DL, Zipes DP, et al (eds). Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Saunders; 2011:1582-1594.

30. Konno T, Shimizu M, Ino H, et al. Diagnostic value of abnormal Q waves for identification of preclinical carriers of hypertrophic cardiomyopathy based on molecular genetic diagnosis. Eur Heart J. 2004;25:246-251.

Treatment. First rule out or treat any causes of acquired LQTS by taking a careful medication history and evaluating the patient’s electrolytes. Once these have been addressed, a beta-blocker is first-line therapy for symptomatic patients.⁵

Unfortunately, up to 20% of individuals treated with beta-blockers may continue to have syncope.⁵ For these patients, options include a left cardiac sympathetic denervation (LCSD) or placement of an automatic implantable cardioverter-defibrillator (AICD). An LCSD involves removal of the left-sided stellate and/or thoracic ganglia. This procedure can be used instead of, or in addition to, beta-blockers. If the patient’s syncope persists, AICDs are an option. AICDs can be lifesaving, but patients run the risk of adverse effects that include inappropriate shocks and infection.¹⁰ As the result of these therapies, mortality associated with LQTS has dropped to approximately 1%.¹¹

CASE 2 › A 14-year-old boy has a syncopal episode while at rest. A similar event occurred 3 years earlier; at that time, an echocardiogram and EKG were normal. For 2 days, he’s had a cough and low-grade fever. His temperature is 102ºF and he has a productive cough. Based on this EKG (FIGURE 2), what is the likely diagnosis? What is the significance of his fever?

The EKG abnormality and diagnosis. This patient’s EKG showed a type 1 Brugada pattern (FIGURE 2, ARROWS), which strongly supported the diagnosis of Brugada syndrome (BS). BS is an inherited condition caused by a genetic defect in cardiac ion channel function that leads to characteristic EKG changes and a predisposition to ventricular fibrillation.¹² In this case, the fever likely unmasked these EKG findings.

The patient was transferred to a local hospital for treatment of community-acquired pneumonia, and ultimately received an AICD.

Etiology and epidemiology. BS was first described in 1992¹³ and is a major cause of SCD, responsible for up to 4% of all cases of SCD, and 20% of cases of patients without structural heart disease.14 BS is more common in men, and the mean age of diagnosis is 40 to 45.^15-18

Mutations in at least 17 cardiac ion channel genes have been linked to BS.¹⁹ The SCN5A gene—a cardiac sodium channel—is the most commonly implicated, but accounts for only 11% to 24% of all BS cases.¹⁵

Clinical features. Patients with BS may present with syncope, nocturnal agonal respirations, or ventricular arrhythmias.¹² EKG findings include partial or complete right bundle branch block (RBBB) and ST segment elevation in right precordial leads V1 to V3.¹² There are 2 Brugada EKG patterns, a type 1 cloved pattern as seen in our patient’s EKG and a type 2 saddleback pattern.20 EKG findings are dynamic over time and may alternate between normal, type 1, and type 2.²⁰ Factors that modulate EKG appearance include fever, intoxication, vagal tone, electrolyte imbalance, and sodium channel blockade.^12,20

Diagnosis requires a type 1 Brugada pattern on EKG plus a family history of BS, documented ventricular arrhythmia, or arrhythmia-related symptoms such as syncope.¹² Patients with a type 2 Brugada pattern may undergo electrophysiology (EP) testing with Class I antiarrhythmic drugs to induce a diagnostic type 1 Brugada pattern.^12,21 Patients who have Brugada EKG findings but none of the other diagnostic criteria are considered to have a Brugada pattern (rather than Brugada syndrome).¹²

The most concerning outcome of BS is ventricular fibrillation. The estimated annual rate of cardiac events is 7.7% among patients who have experienced an aborted SCD, 1.9% among those who have experienced syncope, and 0.5% in asymptomatic patients.¹⁸

Treatment. The only effective treatment for BS is placement of an AICD; however, complications of AICD placement cause significant morbidity.⁶ Ten years after AICD placement, 37% of patients experienced inappropriate shocks and 29% experienced lead failure.²² Recent modifications in device programming and the addition of remote monitoring have decreased complication rates.^12,22

Management of asymptomatic patients with type 1 Brugada pattern remains controversial because the rate of cardiac events is low, although such events can be fatal.The decision to place an AICD is based on the patient’s prior symptoms, EKG findings, and other factors. Recent guidelines recommend an AICD for all patients with a type 1 Brugada pattern (spontaneous or induced) who also have had an aborted SCD, syncope, or documented ventricular arrhythmia.¹²

Management of asymptomatic patients with type 1 Brugada pattern remains controversial because the rate of cardiac events is low, although such events can be fatal. Asymptomatic patients with type 1 Brugada findings should undergo further EP testing, and should receive AICD only upon demonstration of inducible ventricular arrhythmia.¹²

TABLE 2
Arrhythmias associated with Wolff-Parkinson-White syndrome²³

Arrhythmia	EKG findings	Treatment—unstable patients	Treatment—stable patients (in preferred treatment order)
PSVT, orthodromic	Narrow QRS, loss of delta wave, rate 160-260 beats/min	Synchronized cardioversion	Vagal maneuvers, adenosine, calcium channel blockers, beta-blockers, digoxin, procainamide
PSVT, antidromic	Wide complex tachycardia	Synchronized cardioversion	Procainamide
Atrial fibrillation	Irregularly irregular (RR interval variable with no pattern), ventricular rates that can exceed 300 beats/min	Synchronized cardioversion	Synchronized cardioversion, procainamide
Atrial flutter	Flutter waves, rate normal to tachycardic depending on conduction rate	Synchronized cardioversion	Synchronized cardioversion, procainamide
Ventricular fibrillation	Rapid, erratic electrical impulses	Defibrillation	N/A