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Sudden Cardiac Death (SCD): Facts, Guidelines and Beyond It is tough to make predictions, especially about the future Mandeep Bhargava Cleveland Clinic Intensive Review of Cardiology SUDDEN CARDIAC DEATH • SCD: – Death from unexpected circulatory arrest within an hour of onset of symptoms • SCA: – Death from unexpected circulatory arrest within an hour of onset of symptoms, where medical intervention reverses the event Intensive Review of Cardiology QUESTION • A 30 year old male presents with palpitations and Class II shortness of breath for a year. He has no syncope or family history of SCD. He has also noticed some occasional swelling in the feet. • Physical examination shows mild pedal edema and minimally elevated JVP. He has an irregularly irregular pulse and a short systolic murmur at the apex. Chest is clear. An EKG is shown below and a 24 hour telemetry shows consistency of this pattern most of the time • Echocardiogram show a dilated LV with global hypokinesia and an LVEF of 27% with moderate MR. Intensive Review of Cardiology EKG Intensive Review of Cardiology Which of the following is the most appropriate next step in his management: 1. 2. 3. 4. 5. DC cardioversion Flecainide 100 mg twice daily Mapping and ablation of the arrhythmia Single chamber ICD implantation Admit for Amiodarone loading Intensive Review of Cardiology Which of the following is the most appropriate next step in his management: 1. 2. 3. 4. 5. DC cardioversion Flecainide 100 mg twice daily Mapping and ablation of the arrhythmia Single chamber ICD implantation Admit for Amiodarone loading Intensive Review of Cardiology SUDDEN CARDIAC DEATH • The single most important prognostic determinant is the underlying heart – Ejection Fraction – Scars – Electrical homogeneity Intensive Review of Cardiology Reduced Left Ventricular Ejection Fraction (LVEF) Remains the Single Most Important Risk Factor for Overall mortality and Sudden Cardiac Arrest 1.00 1.00 0.98 p log-rank 0.002 0.96 Survival Survival 0.96 0.98 0.94 No PVCs 0.92 1-10 PVCs/hr 0.90 0.94 0.92 p log-rank 0.0001 0.90 > 10 PVCs/hr 0.88 0.88 A 0.86 0.86 0 30 60 90 120 150 180 Days Patients without LV Dysfunction (LVEF >35%) 0 30 60 90 120 150 Days Patients with LV Dysfunction (LVEF ≤ 35%) Maggioni AP. Circulation. 1993;87:312-322. Intensive Review of Cardiology CAUSES OF SCD 12% Other Cardiac Cause 88% Arrhythmic Cause Albert CM. Circulation. 2003;107:2096-2101. Intensive Review of Cardiology SCD: UNDERLYING ARRHYTHMIAS Torsades de Pointes 13% VT 62% Bradycardia 17% Primary VF 8% B Adapted from Bayes de Luna A. Am Heart J. 1989;117:151-159. ayés de Luna A. Am Heart J. 1989;117:151-159. Intensive Review of Cardiology Witnessed Arrhythmia during SCD as a function of time % Time to tracing (minutes) Hallstrom et al, Emergency health services Q 1:41-47, 1983 (modified) Survival as a function of FIRST WITNESSED RHYTHM Initial Rhythm of Cardiac Arresst Victims : Unknown time VF Asystole EMD VT Asystole 40% Survival: 25% VF 40% Survival: 1% EMD 19% Survival: 6% VT 1% Weaver et al,.N Engl J Med 319:661-666, 1988 SCA Survival = Early Defibrillation • Only effective treatment for SCA is an electrical shock delivered by: - Automated external defibrillator (AED) - Implantable cardioverter-defibrillator (ICD) • Time is critical: Each minute of delay reduces survival by 10% Intensive Review of Cardiology IMPORTANT PARADOXES • 65% of SCDs occur in patients with LVEF > 35% • In 50% patients with SCD, it may be the first manifestation of heart disease • Up to 50% of SCDs may be non arrhythmic in autopsy studies • Reducing PVCs/NSVT does not improve mortality • The proportions of PEA is noted to be on the rise THE MYERBURG PARADOX How can we effectively identify patients at-risk? SCD-HeFT, MADIT II AVID, CASH MADIT I, MUSTT Myerburg RJ, et al. Circulation. 1998. 97:1514-1521. Intensive Review of Cardiology PREVENTION OF SCD • The key to SCD prevention is to identify high risk patients – Low left ventricular ejection fraction • Coronary artery disease, previous MI • Dilated cardiomyopathy and heart failure – Inherited cardiac syndromes • Survivor of sudden cardiac death • Family history of sudden cardiac death – Idiopathic VF Intensive Review of Cardiology VT/VF AFTER ACUTE MI Long Term Management • Late Sustained VT/VF – Concerning if sustained VT/VF after 48 hours – ICD for “secondary” prophylaxis if no reversible factor • If reversible factors present – Beta-blockers and ACE inhibitors – Reassess LVEF at 6 weeks/3 months depending on revascularization Intensive Review of Cardiology ICM: Secondary prophylaxis • 3 large trials have shown a benefit with ICD therapy Total mortality • AVID Trial • CASH Study • CIDS Trial 25% less 12% less 20% less Arrhythmic deaths 3% vs 7.4% 1.5% vs 5.1% 3% vs 4.5% Conolly S, EHJ 2000 ICM: Secondary prophylaxis Meta-analysis P<0.05 P<0.05 •Meta-analysis of these 3 trials: 28% reduction Conolly S, EHJ 2000 ICM: Secondary prophylaxis Meta-analysis P<0.05 P<0.05 •Main benefit in patients with an LVEF < 35% Conolly S, EHJ 2000 ICM: Secondary Prevention • Survivors of known sudden cardiac death without any reversible cause are Class I indications for an ICD • Patients with unexplained syncope, scars and inducible VT are also indications for an ICD ICM: Primary Prevention TRIAL DISEASE EPS ICD BENEFIT MADIT 1 CAD; EF <35% + + MUSTT CAD; EF <40% + + MADIT 2 CAD; EF < 30% - + SCD HFT CAD & NICM; EF<35% - + ICM: Primary Prevention Trials Mortality No AA Tx Medical Tx ICD Absolute Reduction Relative Reduction MADIT 1 MUSTT* MADIT 2 32% 10% 22% 54% 48% (28%) 55% (33%) 18% (10%) 31% (23%) 60% 19.8% 14.2% 5.6% 31% 5 YR (2YR) *MUSTT ICM and NICM: Primary Prevention SCD-HeFT (@ 2.5 years) DEFINITE (@ 2 years) MADIT 2 @ 2 years COMPANION @ 1 year Total ICD Medical RX 9.0% 13.0% 8.1% 13.8% 19.8% 14.2% 19.0% 12.0% Absolute Reduction 4.0% (7.2%@5yrs) 5.7% 5.6% 6.0% Relative Reduction (27%@ 5yrs) 34% 31% 36% ICM: Primary Prevention Trials TRIAL DISEASE EPS ICD BENEFIT MADIT 1 CAD; EF <35% + + AllMUSTT the trials showed of+ICD CAD; EF <40% superiority + compared to best medical therapy MADIT 2 CAD; EF < 30% - + SCD HFT CAD & NICM; EF<35% - + ICM: Primary Prophylaxis Early intervention after MI/revascularization* • CABG Patch Trial: ICD with revascularization No benefit with ICD in the immediate • IRIS: Early post MI intervention post MI or post revascularization period • DINAMIT: Early post MI intervention *Optimize medical therapy presumed ICM: CONCLUSION • ICD therapy is useful in patients with ischemic cardiomyopathy with severe LV dysfunction (LVEF<35%) beyond 42 days of MI or 90 days or revascularization • ICD therapy is useful in patients with an EF of 3540% if they have NSVT and inducible VT • ICD therapy has no proven benefit within 6 weeks of an MI or 90 days of revascularization • ICD therapy has no proven benefits in the very sick NYHA Class IV patients* *Beware of the need of CRT Nonischemic Cardiomyopathy • Two major trials have included substantial number of patients with NICM – DEFINITE – ScD HeFT • Inclusion – Patients with an LVEF of 30-35% – NYHA II-III – Optimal medical therapy for 3-9 months – CHF for at least 3 months DEFINITE TRIAL P>0.05* P<0.05 NEJM 2004; 350:21 SCD HeFT Trial 23% reduction in mortality P<0.05 P<0.05 NNT higher in NICM vs ICM NEJM 2004; 352:225 Syncope and NICM Time to first shock was shorter in the syncope group of patients 50% of patients with syncope had appropriate ICD shocks Recurrent syncope was associated with arrhythmias Should be treated with an ICD Knight B, et al. JACC 1999 ROLE OF EPS IN NICM • Minimal Utility • “AT BEST” only in patients with documented scars or concerns for BBRT • Specificity only for induced VT and not VF EP Study and Sarcoidosis Mehta et al: •Study of 76 patients with biopsy proven sarcoid •11% inducibility •Mean EF 36% in inducible group vs 55% in non inducible group Circ Arrhythm Electrophysiol; 2011;4:43 NICM: CONCLUSION • Patients benefit from an ICD if they have NICM, LVEF <35% beyond 3 months of optimally treated heart failure, NYHA II-III symptoms • Unexplained syncope in the setting of NICM portends poor prognosis and merits an ICD • EP study has no role in risk stratification unless there is significant documented scarring as in cardiac sarcoid • MRI and genetics may be newer tools HYPERTROPHIC CMP • Risk for SCD – Prior VT/VF/cardiac arrest – Syncope of “unclear” cause – Family history of sudden cardiac death – Severe septal thickness (> 3 cm septum) – Other minor criteria: • NSVT • Failure of BP to rise on exercise stress • Extensive scar on the MRI; absence is a good sign Intensive Review of Cardiology 50 year old male has a syncopal episode. On EMS arrival, ventricular fibrillation is shocked to SR. In the ED he is alert and oriented. ECG is shown below. • What is best approach for his long term survival? – A. Administer thrombolytic therapy – B. Emergent percutaneous intervention to the LAD – C. ICD implantation – D. EP study and ablation of accessory pathway Intensive Review of Cardiology 50 year old male has a syncopal episode. On EMS arrival, ventricular fibrillation is shocked to SR. In the ED he is alert and oriented. ECG is shown below. • What is best approach for his long term survival? – A. Administer thrombolytic therapy – B. Emergent percutaneous intervention to the LAD – C. ICD implantation – D. EP study and ablation of accessory pathway Intensive Review of Cardiology BRUGADA SYNDROME •Genetic channelopathy causing loss or dysfunction of sodium channels •About 5 in 10000 have such a pattern •Responsible for about 12-20% of “Idiopathic VF” in “normal” heart BRUGADA SYNDROME • ICD implantation should be considered in – – – – Survivors of sudden cardiac death Unexplained syncope Fever induced Brugada pattern ? Inducibility of “VF” on EP study Males have a higher risk; mainly nocturnal deaths Family history helps in “DIAGNOSIS” and not “PROGNOSIS”/risk stratification Quinidine (Ito blocker) and catheter ablation may be used to treat ICD storms. ARRHYTHMOGENIC RV CMP • Predominant RV cardiomyopathy – Progressive fibrofatty replacement of the RV – Hypokinetic and thinned areas (Echo/MRI) – May involve the LV • Strong familial transmission (>50% of patients) • Presentation with syncope, VT or sudden death – VTs generally with multiple LBBB morphologies, often precipitated by exercise Intensive Review of Cardiology ARVC ECG Characteristics •Anterior precordial T wave abnormalities •Epsilon waves From: McRae et al, CCJM 68:459-67, 2001 Intensive Review of Cardiology ARVC Therapy • ICD: Primary/Secondary prevention – Cardiac arrest or spontaneous VT – Inducible VT with Scars (EP Study) – Depressed LV function/LV involvement – Unexplained syncope – Family history of sudden cardiac death • Drug therapy and catheter ablation – Adjunctive Intensive Review of Cardiology ION CHANNELS AND LONG QT 1 2 0 LQT3 LQT2 3 LQT1 Phase 0 – inward fast Na+ (Gain in LQT3) Phase 1 – outward current – Ito Phase 2 – plateau – inward currents mainly Ca++, Na+ Phase 3 – outward current IKur – ultra rapid delayed rectifier IKr – rapid delayed rectifier (Loss in LQT2) IKs – slow delayed rectifier (Loss in LQT1) Intensive Review of Cardiology 4 LONG QT SYNDROME • How long is Long QT: 440/450 or 470/480 • Risk stratification: – Type of long QT (QT3>QT2>QT1) – Duration of QT interval (>500 ms) – History of syncope • Triggers: – LQT1: Exercise, swimming – LQT2: Alarms, loud noises Intensive Review of Cardiology THERAPY FOR LQTS • Treatment: – Remove triggers and start beta blockers – Consider left cardiac sympathectomy • Indications – Documented cardiac arrest – Symptoms on beta blockers – Very long QT » LQT2 and LQT3 > 500 ms » LQT1 > 550 ms FAMILY HISTORY AND EP STUDY ARE NOT PROGNOSTIC OTHER SUDDEN DEATH SYNDROMES • CPVT: Catecholaminergic Polymorphic Ventricular tachycardia – Defect in calcium handling – Predisposes to exercise induced/bidirectional VT – Beta blockers/Flecainide – ICD for syncope/SCD despite beta blockers For Boards also think Digoxin toxicity. OTHER SUDDEN DEATH SYNDROMES • Short QT syndrome – 340 ms or less – 360 ms or less with syncope – ICD for patients with SCA • Early repolarization syndromes – ICD for survivors of SCA NEWER TOOLS: MRI • MRI • GENETIC TESTING MRI in ICM/HCM Al Jaroudi et al, JACC Cardiovasc Imag 2013 MRI in MYOCARDITIS Al Jaroudi et al, JACC Cardiovasc Imag 2013 Al Jaroudi et al, JACC Cardiovasc Imag 2013 NEWER TOOLS: GENETIC TESTING • • • • • • Long QT Syndrome Brugada Syndrome Hypertrophic cardiomyopathy Short QT syndrome Catecholaminergic Polymorphic VT LV non compaction IDIOPATHIC VF TAKE HOME PEARLS • Ruling out structural heart disease should be the first step for high risk patients for sudden death • Inherited diseases and channelopathies are rare but dangerous and need a close eye • EP studies have a role in only specific patients and has poor negative predictive value • ICD implantation should be considered only on basis of objective data for each specific disease • MRI and genetic tests may become important newer risk stratification tools Intensive Review of Cardiology TAKE HOME PEARLS • Normal Heart VT: treat only if symptomatic, sustained or causing LV dysfunction • Avoid ICD in normal heart VT; ablation often curative • For any sustained VT/VF, first remove reversible factors • If no reversible factors, ICD treatment of choice for primary and secondary prophylaxis Intensive Review of Cardiology PEARLS: AADs and ABLATION • Adjunctive treatment to prevent symptoms or ICD shocks • No survival benefit shown • Class IC drugs only for normal hearts • With structural heart disease, Amiodarone is the most effective • Ablation curative for normal heart VT Intensive Review of Cardiology THANK YOU Intensive Review of Cardiology The syndrome of “borderline” QT How Long is LONG QT • Mean QTc in Mayo series is 482 ms • Range is 365 ms to 800 ms • 40% of genetically proven LQT is <460 ms • A lot more normal people have borderline QT (10-20%) • Pretest probability and clinical context mean everything • Understand that genetic test can miss (20-25%) or over-read (2-5%) LQTS How Long is LONG QT TAKE HOME PEARLS FOR BOARDS • For primary prophylaxis, ICD indicated only if – Persistent, severe LV dysfunction (<35%) after adequate therapy – High risk inheritable syndromes • Antiarrhythmics are adjunct and do not improve survival • Catheter ablation – Drug refractory VT – Drug intolerance or patient preference – Primary therapy in normal heart VT Intensive Review of Cardiology TAKE HOME PEARLS FOR BOARDS • Wide QRS tachycardia in structural heart disease is mostly VT • Concordant QRS, Discordant axis, AV dissociation, scarred atypical patterns suggest VT • Acute management for hemodynamic instability or SCA is electric shock • Amiodarone is the most effective drug in acute settings except in Long QT Intensive Review of Cardiology FASCICULAR VT Intensive Review of Cardiology RBBB TACHYCARDIA Vs > As Intensive Review of Cardiology BUNDLE BRANCH REENTRY Intensive Review of Cardiology LBBB TACHYCARDIA Intensive Review of Cardiology Long QT Syndrome LQTS Risk Factors for “Cardiac Events” in LQT1, LQT2, LQT3 Syncope, Cardiac Arrest, Sudden Death • High Risk (50%) – QTc 500 ms: LQT1, LQT2 and Males with LQT3 • Intermediate Risk (30-49%) – QTc 500 ms: Female LQT3 – QTc <500 ms: LQT3, female LQT2 • Low Risk (<30%) – QTc <500 ms: LQT1, Male LQT2 Priori NEJM 348:1866, 2003 Which of the following patients is an appropriate candidate for an ICD • A 28 year old male with hypertrophic cardiomyopathy with syncope and NSVT • A 32 year old male with incessant VT with LBBB pattern and inferior axis, EF 38% • A 78 year old male with prior AWMI, EF 20%, Class IV symptoms on Milrinone • A 65 year old male with dilated CMP, EF 25% with metastatic lung carcinoma Intensive Review of Cardiology KNOW WHEN NOT TO PUT AN ICD • A 28 year old male with hypertrophic cardiomyopathy with syncope and NSVT • A 32 year old male with incessant VT with LBBB pattern and inferior axis, EF 38% • A 78 year old male with prior AWMI, EF 20%, Class IV symptoms on Milrinone • A 65 year old male with dilated CMP, EF 25% with metastatic lung carcinoma Intensive Review of Cardiology VT IN NORMAL HEARTS (IDIOPATHIC) • Outflow Tract VT/PVCs • Fascicular VT • Papillary muscle VT/PVCs Intensive Review of Cardiology VT IN NORMAL HEARTS Outflow Tract VT • Repetitive monomorphic sustained VT or PVCs • Asymptomatic or symptomatic • May have “PVC induced cardiomyopathy” • Treatment – -blockers, CaCB, I or III AADs – Catheter ablation – success rate ~90%+ Intensive Review of Cardiology RV OUTFLOW TRACT VT 30 y/o M with frequent PVCs since age 10, DCM progressive since age 13 -> LVEF 35% Post ablation: LVEF 55% 3 months and 3 yrs afterwards Intensive Review of Cardiology VT IN NORMAL HEARTS Fascicular VT • Reentry involving calcium dependent Purkinje/fascicular fibers • Most common: Right Bundle/Left Superior Axis • Terminated or suppressed by verapamil or diltiazem • Idiopathic VT: High success rates with ablation and do not usually need an ICD Intensive Review of Cardiology ISCHEMIC VT AFTER ACUTE MI • Asymptomatic PVCs, NSVT – May be associated with increased mortality – Usually no need for acute therapy • AIVR – May have relation with coronary reperfusion – Generally no need for acute therapy Intensive Review of Cardiology VT/VF EARLY AFTER ACUTE MI – Sustained VT/VF: First 48 hours • Increased in-hospital mortality • May not signify worse long-term prognosis among survivors • Acute therapy – Defibrillation – Antiarrhythmic drugs Intensive Review of Cardiology ISCHEMIC CARDIOMYOPATHY • ICD for secondary prophylaxis – Sustained VT/VF • ICD for primary prophylaxis – LVEF < 35% 6 weeks post MI or 90 days post revascularization – LVEF 35-40% with NSVT: ICD if inducible VT by EP study • Adjunctive treatment – Antiarrhythmic drugs for symptoms/shocks – Catheter ablation Intensive Review of Cardiology NON-ISCHEMIC CARDIOMYOPATHY • VT/VF estimated to be cause of death in 8-50% • Risk Assessment: Echo/?MRI • Secondary prevention: Known survivor of SCD Syncope of unknown origin • Primary prevention: ICD for persistent severe LVEF < 35% after 3 months of CHF symptoms • AADs/Ablation Lower threshold for Bundle Branch Reentry Intensive Review of Cardiology POLYMORPHIC VT • Torsades de Pointes – Associated with Long QT • Polymorphic VT not associated with long QT – May be associated with ischemia or electrolyte abnormalities or drugs • Treatment – Magnesium and reversal of the cause – Defibrillation if degeneration to VF Intensive Review of Cardiology TORSADES: TWISTING OF QRS AROUND THE BASELINE Intensive Review of Cardiology BRUGADA SYNDROME • Presents with syncope or sudden death (VF) often at night – Cause of SCD in young healthy males • RV conduction delay and mid precordial ST elevation – “RBBB-like pattern” with J point elevation V1-V3 – Worsened, unmasked by Na+ channel blockers (e.g. ajmaline, flecainide, procainamide) • Loss of function of Na channel due to SCN5A mutation Intensive Review of Cardiology BRUGADA SYNDROME • Risk stratification – High risk: • Aborted SCD • Syncope • Fever induced Brugada/Males – Low risk: • Asymptomatic patients with diagnostic ECG only after provocative challenge (Type 2 and 3) Intensive Review of Cardiology ANTIARRHYTHMIC DRUGS Class I: Sodium channel blockers IA: Quinidine, Procainamide (Quinidine-Brugada storms) IB: Lidocaine, Mexiletine; Do not prolong QT IC: Flecainide, Propafenone - Normal heart only Class II: Beta Blockers Reduce cardiac mortality and SCD Class III: Potassium Channel Blockers Sotalol, Amiodarone Class IV: Calcium Channel Blockers Fascicular VT Intensive Review of Cardiology MUSTT: Relation of LVEF and EPS to Arrhythmic Death or Cardiac Arrest (Buxton, et al, Circulation 2002;106:2466-2472) HYPERTROPHIC CARDIOMYOPATHY • • • • • Family history of sudden cardiac death Septal thickness > 3 cm Syncope of unclear cause <45 years of age NSVT at a rate of >130 bpm Abnormal BP response of failure to augment >25 mmHg or fall with exercise* Importance of one risk factor ?Role of MRI Role of genetic testing NO role of EP study *Not studied as single risk factor What is the role of Syncope and EP Study in Non ischemic Cardiomyopathy ARVC • Higher risk features – Documented VT/VF/cardiac arrest – Large areas of involvement/LV involvement – Unexplained syncope – Inducible VT on programmed stimulation – Family member with ARVC or sudden death MRI in ICM Al Jaroudi et al, JACC Cardiovasc Imag 2013 MRI in HCM Al Jaroudi et al, JACC Cardiovasc Imag 2013 MRI in NICM Al Jaroudi et al, JACC Cardiovasc Imag 2013 ARVC EKGs: Incomplete RBBB pattern, Epsilon waves, T inversion Presentation with syncope, PVCs, SMVT or PMVT