clinical letter - Pocono Medical Center

ESSA HEART AND VASCULAR INSTITUTE
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JULY/AUGUST/SEPTEMBER 2009
CLINICAL LETTER
Welcome to the third edition of our clinical newsletter. We certainly appreciate all the
wonderful feedback we have received from our readership.
This edition features an article by Dr. Ponnathpur on Sudden Cardiac Arres! and the use and
indications for Implantable Cardioverter"Defibrillators #ICD’s$. The other article is on
Hypertrophic Cardiomyopathy, a potentially lethal problem involving cardiac muscle. Future
editions of the newsletter will bring articles such as Presentation and Management of Aortic
Dissectio", and The Role of Coronary Stents in the Treatment of Ischemic Heart Diseas#. We also
plan to begin to feature articles on non"cardiac thoracic problems.
Recently, our cardiac surgical program was honored with a 3"star rating #the maximum grade$ by
the Society of Thoracic Surgeons #STS$ for outstanding performance and outcomes. STS
employs extremely strict criteria such as mortality, morbidities #stroke, infection$, length of stay,
etc. in evaluating cardiovascular programs in the United States. When it is realized that the
ESSA Heart and Vascular Institute has been in existence for about only two years, this grand
recognition by the STS is worth a celebration. The success of this cardiothoracic program is
truly an attestation to the tireless e%orts of a dedicated, tenacious team of administrators and
clinical sta%" motivated by excellence in patient care.
There is no longer a reason for the people in this community to leave the area in order receive
cardiovascular and thoracic care. We will continue to provide world"class care to you.
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Have a happy summer!
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Nche Zama MD, PhD
THIS MONTH AT ESSA HEART AND VASCULAR INSTITUTE:
Our Physician Referral Receptio! July 16 at 6PM
Come join us that evening as the Cath Lab hosts a brief lecture by Dr. Zama, an open house,
and re$eshments....Questions, please ca% 570&422&8393
POCONO MEDICAL CENTER!
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JULY/AUGUST/SEPTEMBER 2009
SUDDEN CARDIAC ARREST "SCA# AND “SHOCKBOXES” "ICDS#
DR. VIDYA PONNATHPUR MD, FACC
Department of Cardiology at PMC
Sudden Cardiac Arrest #SCA$, also known as Sudden Cardiac Death #SCD$ is defined as the unexpected
natural death from a cardiac cause within a short time period from the onset of symptoms" an “electrical
accident of the heart”. SCA is responsible for 400,000 deaths a year in the U.S. Despite our growing
knowledge about the mechanisms and markers of this disease, SCA remains di&cult to treat because the
first symptom is often death.
Several risk factors have been identified for SCA. Most of them are the usual risk factors for heart disease:
smoking, inactivity, obesity, advanced age, hypertension, elevated serum cholesterol and glucose intolerance.
About half of SCA patients have myocardial scars or active coronary lesions. A low left ventricular ejection
fraction #LVEF$ is a very important risk factor that a%ects people with and without CAD. An LVEF less
than or equal to 35' significantly increases the risk of SCA. SCA typically involves a malignant arrhythmia.
This requires a substrate or alternate conduction pathway in the heart and a triggering event. It must be
noted, however, that SCA can also be the result of a bradyarrhythmia, which has been estimated to occur in
about 10' of patients.
Hereditary disorders such as Long QT Syndrome #LQTS$ and Brugada Syndrome have been subjects of
considerable interest as causes of SCA.
Unfortunately, no drug class has been able to convincingly reduce the risk of SCA. On the contrary, many
drugs, especially antiarrhythmics, increased deaths in clinical trials.
Many trials have established the role of implantable cardioverter"defibrillators #ICDs$ in patients with low
LVEF. Three trials" MADIT, MADIT II, and SCD&HeFT have made ICDs the mainstay of device therapy,
reducing SCA in patients having a reduced LVEF, less than or equal to 35'.
The MADIT trial showed a 50' reduction in mortality in patients with ischemic cardiomyopathy with
ICDs, compared to medical therapy. This study required an electrophysiology #EP$ study for inducibility of
ventricular arrhythmia.
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POCONO MEDICAL CENTER!
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JULY/AUGUST/SEPTEMBER 2009
SUDDEN CARDIAC ARREST "SCA# AND“SHOCKBOXES” "ICDS#$ continued %om p2
The MADIT II trial did not require an EP
study. These patients were simply post"MI
patients with LVEF less than or equal to 30'.
ICDs significantly reduced the risk of all"cause
mortality by 31'.
The SCD"HeFT is the largest device trial. Both
ischemic and nonischemic cardiomyopathy
#LVEF less than or equal to 35'$ patients with
NYHA Class II or III symptoms were
included. This trial showed that ICDs reduced
all"cause mortality by 23' compared to
Amiodarone or a placebo. In fact, Amiodarone
did as well as the placebo.
Michel Mirowski #1924" 1990$ is generally credited as the inventor of the ICD. He was the director of the
Coronary Care Unit at Baltimore Sinai Hospital in 1968. He published the first manuscript on ICDs, and
the medical community’s response was one of denunciation. In 1980, however, the first human ICD
implant occurred. By 1985, 800 devices had been implanted in the U.S. and Europe. The FDA gave the
clearance for the first ICD in 1985. Over the past 20 years the devices have become smaller and have better
diagnostics.
A modern ICD compared to one $om 1987
It is very important to identify patients who are at risk for SCA and evaluate them for the possibility of
prophylactic ICDs #for primary prevention$. It is much easier for secondary prevention to implant ICDs
as these patients would have survived a near fatal event. In fact, no patient who has survived a cardiac
arrest secondary to a malignant arrhythmia should leave the hospital without an evaluation for ICD
implantation #if clinically appropriate$
Case Study 1.
A 67 year old male with a 4 year history of nonischemic cardiomyopathy, LVEF of 15', had been evaluated
for ICD implantation at a di%erent institution but had refused the ICD. Patient was admitted with
congestive heart failure exacerbation on optimal medical therapy. During this admission the patient
agreed to proceed with prophylactic ICD implantation which was done. He was discharged home and was
readmitted 2 weeks later with 4 ICD shocks. ICD interrogation revealed that he had a malignant
ventricular arrhythmia and ICD therapy saved his life.
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POCONO MEDICAL CENTER!
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SUDDEN CARDIAC ARREST "SCA# AND“SHOCKBOXES” "ICDS#$ continued %om p3
#It is important to note that inappropriate ICD therapy can occur in 20' to 25' of patients secondary to
supraventricular arrhythmias$
Case Study 2.
A 60 year old black female was a survivor of out"of"hospital cardiac arrest secondary to ventricular
fibrillation. Evaluation revealed nonischemic cardiomyopathy, LVEF of 25'. She was scheduled for ICD
implantation for secondary prevention of SCA. Unfortunately this had to be postponed due to bleeding
issues and bilateral upper extremity thrombosis as well as acute renal failure. She made a remarkable
recovery over the next 2 to 3 months and was sent home with a LifeVest #external defibrillator$. After rehab
and recovery, she successfully underwent ICD implantation and is doing well.
INDICATIONS FOR IMPLANTABLE CARDIOVERTER/DEFIBRILLATOR 'ICD(
A patient, at risk for sudden cardiac death based on at least one of the criteria marked below, has been
receiving Optimal Medical Therapy and has reasonable expectation of survival with good functioning status
for more than one year can be considered for this procedure.
For Primary Prevention ICD! with history of CABG or PCI the waiting period is 90 days, for post!MI
patients, the waiting period is 40 days.
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Criteria For Secondary Prevention:
Cardiac arrest due to ventricular tachycardia #VT$ or ventricular fibrillation #VF$
Congenital High risk for VT/VF
Spontaneous VT/VF, spontaneous or induced by electrophysiology study #EPS$
Hemodynamically unstable VT
Syncope after extensive cardiac evaluation and deemed clinically at risk for SCA
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Criteria for Primary Prevention:
Ejection fraction #EF$ <30'. Prior MI>40 days. NYHA Class I
LVEF 31"40'. NYHA Class I"III. NSVT, CAD, prior MI, and inducible sustained VT/VF by EPS
LVEF< or = 35'. NYHA Class II"III. History of MI
Non ischemic dilated cardiomyopathy #NIDCM$ #medically managed for > 3 months$ LVEF , or = to
35'.
POCONO MEDICAL CENTER!
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HYPERTROPHIC CARDIOMYOPATHY
DR NCHE ZAMA MD, PHD
Department of Cardiothoracic Surgery at PMC
Hypertrophic Cardiomyopathy #HCM$ is a disease characterized by hypertrophy, the thickening of the left
ventricular myocardium #heart muscle$. This thickening can be obstructive and impede the normal flow of
blood from the heart. Characteristically, patients with this disorder have supranormal systolic function as
well as impaired diastolic relaxation and compliance.
This disease accounts for a significant number of sudden cardiac deaths in all ages and is one of the leading
causes of cardiac death in young and active people, especially athletes. Cardiomyopathy in HCM is
associated with hypertrophy of sarcomeres #contractile units$ and a loss of the normal cellular arrangement
in myocardial muscle, which leads to myocardial disarray. The cause of HCM is unknown. Patients can
present with either a familial form which follows an autosomal dominant pattern of inheritance with
variable penetrance, or a sporadic form.
Hypertrophy is usually asymmetric, involving the interventricular septum. This is in contrast to symmetric
concentric hypertrophy that is associated with aortic valve stenosis or hypertension. Oftentimes, dynamic
left ventricular outflow obstruction due to systolic anterior motion #SAM$ of the mitral valve anterior
leaflet is encountered can can lead to serious symptoms.
Occasionally, ventricular wall thickening and systolic compression of coronary arteries may lead to critical
coronary insu&ciency involving intramuscular branches. Consequently, the patient can su%er ischemia and
infarction #heart attack$
Many patients with HCM are predisposed to atrial and ventricular arrhythmias.
Symptomatology
Symptoms associated with HCM include:
Dyspnea #shortness of breath$ with exertion
Fatigue
Angina #chest pain or pressure$
Presyncope, syncope #passing out$
Palpitations
Diagnosis
The diagnosis of HCM can be reached after a complete history and physical examination followed by an
echocardiogram. Cardiac catheterization is indicated if the patient is in need of surgery for HCM.
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HYPERTROPHIC CARDIOMYOPATHY&continued $om p5
Treatment
The treatment of HCM depends on symptoms. Medical management does provide symptomatic relief for
most patients. Mainstay of medical therapy consists of beta"blockers and calcium channel blockers. Dual
chamber cardiac pacing has been used but the results of this modality have not been encouraging.
Percutaneous catheter myocardial ablation has been described to relieve left ventricular outflow tract
obstruction in patients with HCM. In this procedure, ethanol is injected in the coronary artery to cause a
controlled septal myocardial infarction. Because of many important associated complication such as
complete heart block requiring a permanent pacemaker, this treatment option is not very popular.
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Normal heart
Hypertrophic Cardiomyopathy
Many surgical techniques have been proposed to relieve left ventricular outflow tract obstruction
associated with HCM. The most commonly employed techniques include Mitral Valve Replacement and
Transaortic Septal Myectomy. Replacement of the mitral valve with a low profile prosthetic valve relieves
the outflow tract obstruction by eliminating systolic anterior motion due to the anterior mitral valve
leaflet. Myectomy provides long"lasting symptomatic relief to patients who have failed medical therapy
and have documented outflow tract obstruction at rest or on provocation. It can be done safely with
minimal complications.
POCONO MEDICAL CENTER!
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POCONO MEDICAL CENTER
JULY/AUGUST/SEPTEMBER 2009
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ESSA HEART AND VASCULAR INSTITUTE
JULY/AUGUST/SEPTEMBER 2009!
PLEASE JOIN US FOR:
Physician Referral Reception
July 16, 6 PM PMC’s Heart and Vascular Institute Cath Lab
Grand Rounds “Best Practices for Stroke Management in 2009”
July 17, noon PMC’s Stroud/Brodhead Rooms
“Clinical Letter”" a publication of ESSA Heart and Vascular Institute at PMC
Editor " R. Eileen Butz RN, CCRN
Questions/Comments? 570.420.5332